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youknouno
06-23-2012, 10:45 AM
Getting ready to throw down some dollars for a Felt. Common sense says that the steel frame is by far the more durable, however I see alot of you guys using aluminum frames. Why is that? Being a super noobie, I want to buy the most durable frame, engine, etc. Seeing as how I'm aiming for max power (considering a 9HP Morini), low maintenance. So, aluminum or steel?

youknouno
06-23-2012, 10:48 AM
Disregard gentlemen, more than enough info is available by way of "search". No need to waste you guys' time. Couldn't figure out how to delete this thread...

wheelbender6
06-23-2012, 01:13 PM
A name brand aluminum frame is OK. I would still prefer a name brand steel bike for a 9hp engine.

youknouno
06-23-2012, 01:23 PM
Thanks Bender. Totally going with the Felt MP, probably order it up next week. Simply because it comes with a few of the bells and whistles I'd like.

bigbutterbean
06-24-2012, 01:20 AM
here is the deal with a morini. they dont just bolt on like a kit engine. they require fabrication, welding, and very good mechanical skills to install on a bicycle. If you dont have all of those, I dont recommend a morini for your first motorbike. a mountain bike with an ht engine (2 stroke) or a 4 stroke with a shift kit should give you a fair amount of performance. however, if you do have the skills and equipment necessary for a morini build, go for it. I just wouldnt recommend aluminum for a morini build. people have cracked steel frames with morini engines.

youknouno
06-24-2012, 04:05 PM
here is the deal with a morini. they dont just bolt on like a kit engine. they require fabrication, welding, and very good mechanical skills to install on a bicycle. If you dont have all of those, I dont recommend a morini for your first motorbike. a mountain bike with an ht engine (2 stroke) or a 4 stroke with a shift kit should give you a fair amount of performance. however, if you do have the skills and equipment necessary for a morini build, go for it. I just wouldnt recommend aluminum for a morini build. people have cracked steel frames with morini engines.


Good points. While I want to get to know an engine all together, I do plan on outsourcing the welds and so forth to a reputable place. Alas, I have decided to buy my frame (Felt MP), order a cheap china girl, learn it and later upgrade. I'll transfer the china to my g/f's huffy. (She won't know the difference:D.) daxtitg

Also, a steel frame is in order. Unfortunately, my fellow Felt-zers have noted that those provide less space for an in tank frame. Totally bummed about that but hey.. anything for a Felt.

youknouno
06-24-2012, 04:07 PM
A name brand aluminum frame is OK. I would still prefer a name brand steel bike for a 9hp engine.

Thanks bender. I'm a little dismayed w/ the fact that an intank frame is a difficult to-do with the steel body but I've seen a pretty awesome behind the seat tank application. I think I'm going to run with that.

bigbutterbean
06-24-2012, 06:47 PM
I got a two gallon plastic yamaha tank from a parts guy for $15 a couple years ago. looks a little big on the bicycle, but holds 2 gallons if I want to fill it up. usually only put a gallon in at a time. plastic is good because it wont rust and develop leaks like a metal tank. some Felt frames have a hollow top tube that I believe a few forum members have adapted for an in frame tank, so you could look into that. the behind the seat tanks are quite expensive unless you want to build your own. If you want to find a used plastic tank, check ebay and craigslist for those.

youknouno
06-25-2012, 10:27 PM
Thanks I think I'll check into that.

bigbutterbean
06-26-2012, 01:15 AM
I would also like to give you a little more advice, but please dont get offended. I see a few people come to the forum that are new to the hobby, and they say I want to do this with my bike, and I want to do that. My advice is this: start simple. looking for a bigger or more stylish gas tank is fine, just dont get caught up in trying to take your kit right out of the box and doing a million different things. Get the kit, put it together, see how it runs and how the parts in the kit hold up, and go from there. Break the engine in, make adjustments as needed, and learn the ins and outs and quirks of your bike. the quality of some of the parts in the china kits is not always the best, and sometimes the parts seem fine at first and break in a month or two. some of it also depends on how well it is put together and how well it is maintained. I say this as one who started out in this hobby with very little mechanical knowledge and no experience, and one who went through a lot of trial and error with my first bike. again as a reminder, this is just some friendly advice. in the end, its up to you to decide how you want to approach building your first motorized bike. However you decide to approach it, I say good luck.

POPS
06-26-2012, 02:00 AM
BBB

Not to contradict you, as your advice is solid but
I remember somewhere in the way back machine,
there was sort of a preflight check list to make a HT
more solid per say.

Skid all the screws in the kit for good ones, The plug and
wire, The acorn nuts on the head and torque the nuts,
The carb seal etc. etc.

Anyone remember.

POP'S

bigbutterbean
06-26-2012, 02:18 AM
Sometimes, the hardware does need upgraded, I have never needed to upgrade mine, except for the bolt that holds my carb onto my intake. I just cut the acorn part off the headbolts. I havent replaced any other hardware in 3 years. I buy ngk plugs, but dont upgrade my wiring. I do check the headbolts every so often, but only with a socket wrench. I just keep going in an x pattern, tightening a little more each time.

POPS
06-26-2012, 02:35 AM
I would guess that the kits today are different than
they were in 08.
All the screws (Bolts) were like butter.
Take them out once and don't reuse them
or they will be stuck in there big time.

POP'S

bigbutterbean
06-26-2012, 02:43 AM
quality control is no better today than it was in '08, or probably any time before that. Personally, I prefer to only replace what I have to. If I find a part to be weak, faulty, or otherwise inadequate, I replace it. Other than that, I run 'em pretty much the way they come. reason being, some of the kits/engines actually do come with decent hardware. My current engine is a year old, and I havent upgraded any of the hardware. Some engines/kits do come with weak/faulty/inadequate hardware, and in that case, it will need to be replaced. in my case, it wasnt necessary.

POPS
06-26-2012, 02:48 AM
quality control is no better today than it was in '08, or probably any time before that. Personally, I prefer to only replace what I have to. If I find a part to be weak, faulty, or otherwise inadequate, I replace it. Other than that, I run 'em pretty much the way they come. reason being, some of the kits/engines actually do come with decent hardware. My current engine is a year old, and I havent upgraded any of the hardware. Some engines/kits do come with weak/faulty/inadequate hardware, and in that case, it will need to be replaced. in my case, it wasnt necessary.

Thanks

Good to know!

POP'S

BE-tech
06-26-2012, 05:59 PM
Getting ready to throw down some dollars for a Felt. Common sense says that the steel frame is by far the more durable, however I see alot of you guys using aluminum frames. Why is that? Being a super noobie, I want to buy the most durable frame, engine, etc. Seeing as how I'm aiming for max power (considering a 9HP Morini), low maintenance. So, aluminum or steel?

You'll be glad you went with the MP. Steel is obviously a lot easier to fab with, you can fix/strengthen it, it rides better, and is cooler IMO :D. It also withstands vibrations better:

I did a quick google search and here is some interesting thought on the two materials (not sure how accurate it is): http://lists.contesting.com/_towertalk/2001-03/msg00652.html

"...With aluminum, the yield strength gradually declines as the
material cycles, with no limit to the degradation. If
a piece of aluminum is vibrating, that represents hundreds of cycles per
second. It doesn't take very long to accumulate millions
of cycles... and eventually the material will fail with a load that it would
have withstood when new.

Steel, on the other hand, cycles differently. Its yield strength does
degrade, but asymptotically to a limited value."

To me this means that in the long run, steel is going to fatigue less than aluminum due to vibration... but I'm definitely no metal expert. Almost all motocross bikes sold today come with an aluminum frame, but they are designed for motorized use from the factory (duh!). Since bicycles are not designed for motorized use and any extra degree of safety is welcomed, I like steel. That being said, design/quality is more important than material used.

youknouno
06-28-2012, 09:53 PM
Bean-
Thanks alot man! I take that advice to heart. I intend to do exactly that. At first I was wide eyed and wanted the coolest this and the best that and I have decided that I can still get all those things-- AFTER I figure out what the h-ll I'm doing. Thanks again.

xenodius
06-30-2012, 12:56 PM
I came here to say just that, BE-tech. That's exactly why I will never own an aluminum bike. Had one for 3 years, and after riding a few times a week, it developed cracks at several points along the frame. Had to abandon it after that. My next roadie was steel... a ~40 year old steel Schwinn. =) Just get steel and don't worry about your frame =)

Also, referring to BBB's post as a newcomer to motorized bikes, it was really good to go through the first assembly really simply. Helped me understand a lot about these motors, and I have lots of ideas about the "perfect" build now, but it's all money and what I have is great for what I need right now. =) I have HD hubs, street tires, front disc brakes... but that's all I changed. Cheers!

BarelyAWake
07-01-2012, 01:13 AM
In this age old debate, I'd like to suggest that for our application that the following;

...That being said, design/quality is more important than material used.

...has a lot more bearing on the subject than out of context "vibration cycle" studies (which also overlooks steel's higher flex rate) - and what suffices for quality & design, what's suitable for the long term effects varies from material to material and ofc application.

Just because it's aluminum doesn't mean it's "bad" just as just because it's steel doesn't mean it's "good" - this is a far too oversimplified view of a somewhat complex subject, one that's often compounded by builder inexperience.

Even "quality" is comparative when both design and application are included - for example even a premium road bike is not necessarily the best choice for the rigors of motorization as it's primary design goal is to be as ultra light weight as possible, many choppers and some cruisers compromise structural integrity for aesthetics and not even all "vintage" bikes can be relied on simply because they're vintage.

All too often folks judge a bicycle to motorize based only on two factors - price and style, thinking the catchphrase "steel is real" will suffice, which overlooks the fact that even steel comes in various grades and types. For example chromoly tends to be brittle and is very challenging to weld properly (more so than even aluminum tubing) so while it's "quality" it may not be the best choice for additional modification & fabrication. It should go without saying a budget mild steel bicycle with sloppy, undercut welds is far more a deathtrap than even a inexpensive but quality aluminum bicycle designed for abuse, one with the heavier beads and additional gusseting such as a mountain bike... and TBH welding/modifying aluminum isn't really all that difficult - it takes slightly more experience than mild steel to weld it well, but not much w/today's MIGs.

It's all about choosing the right tool for the job - and that choice needs to include more than simply budget, style & material bias.

I've both steel and aluminum motorized bicycles and TBH I've not really any greater preference for either material as they both have their advantages & disadvantages.... but after well over 15,000 miles riding both I can say aluminum is more subject to chafe damage (panniers/cables etc) while steel is corrosion prone and flexy, but as long as you've chosen a stout frame design with quality welds and you've built it properly I can assure you vibration rate is not a serious consideration in our application... but if you cut corners w/a sloppy, cheap build - even steel isn't going to be enough to save you ;)

Ibedayank
07-01-2012, 03:21 AM
I prefer steel as it does not take a AC capable Tig welder to repair or modify
anyone with a set of A&O torches .... arcwelder migwelder be it gas or fluxcore only can weld it

BarelyAWake
07-01-2012, 04:04 AM
These are the two machines I use for all of my fabrication projects, be they made of steel, stainless or aluminum - it's a simple matter of swapping out the wire & gas for the project at hand;

110 MIG: http://i305.photobucket.com/albums/nn210/Serenity151/tech/th_IMG_4381.jpg (http://s305.photobucket.com/albums/nn210/Serenity151/tech/?action=view&current=IMG_4381.jpg)
220 MIG: http://i305.photobucket.com/albums/nn210/Serenity151/tech/th_IMG_4383.jpg (http://s305.photobucket.com/albums/nn210/Serenity151/tech/?action=view&current=IMG_4383.jpg)

The 220 does have a spool gun whereas the 110 does not but it's still a pretty good, affordable lil machine for the DIYer - the 220 is obv better, but costly.

While I've access to a TIG, it's too tedious & persnickity for my taste (read skill) & generally, I reserve it for the thin sheet metals (like 16ga fuel tanks). Both ARC & gasless MIG machines are perfectly valid methods of welding and seem to be good choices for the DIYer on a budget... but given their limitations they may not be the best long term investment and TBH I'm just as happy not having to clean slag lol

Gas MIG is almost as versatile as a TIG yet still far less expensive *shrug* Point being, MIG welding aluminum is far easier than many think - a little practice, prep & heat awareness is really all it takes. Honestly? If you've the skill to ARC weld thin wall steel tubing, MIG welding aluminum will be child's play :D

youknouno
07-06-2012, 10:50 PM
I came here to say just that, BE-tech. That's exactly why I will never own an aluminum bike. Had one for 3 years, and after riding a few times a week, it developed cracks at several points along the frame. Had to abandon it after that. My next roadie was steel... a ~40 year old steel Schwinn. =) Just get steel and don't worry about your frame =)

Also, referring to BBB's post as a newcomer to motorized bikes, it was really good to go through the first assembly really simply. Helped me understand a lot about these motors, and I have lots of ideas about the "perfect" build now, but it's all money and what I have is great for what I need right now. =) I have HD hubs, street tires, front disc brakes... but that's all I changed. Cheers!

Hey Xen,
Question - Does your 40 y/o schwinn happen to have those tiny tubes? I'm looking at a classic that has tiny tubes and it worries me although it's a steel frame. Any input?

Here's it
49616

xenodius
07-06-2012, 10:54 PM
Hey Xen,
Question - Does your 40 y/o schwinn happen to have those tiny tubes? I'm looking at a classic that has tiny tubes and it worries me although it's a steel frame. Any input?

Here's it
49616

Well, it's not a cruiser-style. It's a road bike. So yes, it has tiny tubes-- on wheels and frame-- and like I said, it's still great. The frame tubes seem even smaller than the tubes on that cruiser... of course, thickness is important too. =)

youknouno
07-06-2012, 11:02 PM
Thanks man. What sort of engine do you have strapped to that thing?

xenodius
07-06-2012, 11:33 PM
Thanks man. What sort of engine do you have strapped to that thing?

None :-) I don't think I'll ever motorize a road bike. It seems like a sin against the bicycle gods :-)

youknouno
07-06-2012, 11:35 PM
ok cool. i guess that was my concern. i'll have to keep at the research.

youknouno
07-06-2012, 11:36 PM
just noticed - i used to live in spokane. cool little place.

killercanuck
07-07-2012, 09:28 AM
I remember somewhere in the way back machine,
there was sort of a preflight check list to make a HT
more solid per say.

Skid all the screws in the kit for good ones, The plug and
wire, The acorn nuts on the head and torque the nuts,
The carb seal etc. etc.

Anyone remember.

POP'S

This one? Al.Fisherman's Pre-Flight Checklist (https://docs.google.com/document/d/1GcesQihc7-mm3hJGf7UPiqOaRXZ8ekUT99QUZq2qXXE/edit)

gl youknouno, that's a nice looking bike. An HT will hold up fine, as long as the welds aren't rusted through, heh heh.

youknouno
07-09-2012, 07:02 PM
welds look good. there was hardly rust on it. its in the paint shop now ie my patio.

bigbutterbean
07-10-2012, 12:47 AM
the diameter of the tube is not as important as the thickness of the walls and the strength of the welds.

youknouno
07-10-2012, 01:00 PM
BBB-
Whats a good wall thickness? My only way of gauging such a thing is checking the seat tube.

Ibedayank
07-10-2012, 08:06 PM
BBB-
Whats a good wall thickness? My only way of gauging such a thing is checking the seat tube.

would that be for a plain steel frame cromolly or aluminum, titanium or carbon fiber?? as each will be different as the strength of materials is different

bigbutterbean
07-11-2012, 12:35 AM
i honestly wouldnt know. i bought my bike at walmart cause it was cheap, had it two years with no issues so far. an older steel frame would probably have thicker walls than the department store bikes.

youknouno
07-12-2012, 09:48 AM
I picked up a Felt Surf City, which I'm pretty certain is a steel frame. Also got an old Colombia, steel too.

bigbutterbean
07-12-2012, 11:55 PM
A lot of people here like the felts. if i had a choice between a felt and a columbia, i would take the columbia. easy way to tell if your frame is aluminum: get a magnet. aluminum wont attract a magnet. my frame attracts a magnet. my engine doesnt.

youknouno
07-14-2012, 12:27 PM
how to delete a post?

youknouno
07-14-2012, 12:34 PM
Thanks BBB -
The Felt's aluminum.(^) I ended up with the both. Pretty sure the ol' school is a steel frame. Why'd you choose Colombia? I like em both for different reasons.

moonerdizzle
07-14-2012, 12:59 PM
None :-) I don't think I'll ever motorize a road bike. It seems like a sin against the bicycle gods :-)

Forgive me father, for i have sinned, i have strapped a motor onto a old road bike and road it every day all winter long.... lol

multipaul
07-14-2012, 10:00 PM
It is clear, what I'm prefering.
The most expensive frame need not to be the best. High strength materials are often brittle. Chromium and manganese or vanadin are expensive elements and not used very often. High strength is often bought with carbon. Then the steel is not weldable.
The producers think of the cyclists, not to us, people who build engines in their frames.

My bicycle frames are designed for use with engines from factory. 1.05% chrome, 0.7% manganese, 0,25% molybdenum. SAE No. 4130, in Europe known as 25CrMo4. No WalMart quality. And probably durable beyond one's own death.

This material is weldable. But they didn't. The frames are brazed with silver solder.
Cheap is often the enemy of good.

IMHO - Multipaul

bigbutterbean
07-15-2012, 01:44 PM
Thanks BBB -
The Felt's aluminum.(^) I ended up with the both. Pretty sure the ol' school is a steel frame. Why'd you choose Colombia? I like em both for different reasons.

For one, I would never motorize an aluminum frame. There are members here who have done it and have not had any problems, but I'm 6 ft 2 and weigh 280 lbs, and I'm not taking the risk. Also, the Columbia is old steel, probably american, and far more likely to hold up to the stresses of motorization than an aluminum frame.

Saddletramp1200
07-15-2012, 07:24 PM
I will have to tell My Point Beach to start cracking. I have ridden it daily with a DAX 66 for over four years. :)

bigbutterbean
07-15-2012, 11:33 PM
Is the point beach made of aluminum? I have had a cranbrook for two years now, and its held up just fine. No cracks or visible signs of stress at all, and that's with a bgf 68.5cc high comp engine and my 6 ft 2, 280 lb butt on it lol.

Ibedayank
07-16-2012, 12:16 PM
one major point that has been forgotten about welding aluminum

after welding it has to be heattreated to get its strength back or it will only be 1/2 as strong as one that has been heattreated

locell
07-16-2012, 03:45 PM
Pro Tips:

aluminum = light, brittle
steel = soft, heavy

scotto-
07-17-2012, 02:26 AM
Getting ready to throw down some dollars for a Felt. Common sense says that the steel frame is by far the more durable, however I see alot of you guys using aluminum frames. Why is that? Being a super noobie, I want to buy the most durable frame, engine, etc. Seeing as how I'm aiming for max power (considering a 9HP Morini), low maintenance. So, aluminum or steel?

Why not aluminum and steel? Like this: http://motorbicycling.com/showthread.php?t=40923

dnut

BarelyAWake
07-17-2012, 03:01 AM
That - while somewhat true, is an exaggerated simplification yank...

Just about any metal that's used in bicycle frames should be heat treated/annealed/tempered/case hardened/through hardened after welding to optimize the alloy's properties... as an example 4130 chrome moly is particularly susceptible to embrittlement as a result of welding, requiring both pre-heating and post-weld stress relief and the heat control only TIG is capable of, yet I don't see anyone saying "chrome moly is bad" - and I suspect none of the box store bikes are treated in any way whatsoever save paint, regardless of the material used.

Generally speaking these post weld treatments are side stepped in both mass-production and shop fabrication by simply using additional gussets, more weld filler and thicker material than could be utilized in the ideal treated state, the hydroformed/extruded 6000 series aluminum commonly used for the lower cost bicycles no exception.

The applications these heat treatment welding protocols are adhered to stringently are primarily in the most extreme cases of minimalistic construction, aerospace engineering for example - or for our application, the very best of the "high-end" bicycles, where every ounce of excess material is considered a liability... but those bicycles should not be modified in any case, not just for welding/treatment concerns but also the focus on minimalist weight conservation engineering.

It all boils down to common sense, if you start with an overbuilt platform (such as a mountain bike) of even average acceptable quality (wall thickness & factory welds) and are familiar with basic construction & engineering concepts - welding/modifying any material is simply a matter of considering "acceptable risk" and compensating as necessary...

...yet if you are not familiar with such basic construction & engineering concepts and/or utilize only the lowest quality/most inexpensive platforms to modify in any way (including simply motorizing something not designed for such) - no material is "safe" and it all entails some amount of risk. If you have even some fabrication & modification experience, using aluminum has no greater risk then steel - yet if you have little to no experience in fabrication and welding, the material alone won't make any difference.

Again, it's not so much about the material used - it's the design that material is used in that needs be considered, the care & quality in which it's constructed... and that's so variable with our hobby, there's no clear cut rules, no easy answers - for every post warning against aluminum there's an equal or greater number of reported steel frame failures. Every motorized bicycle on this forum has been modified well beyond it's initial operating parameters, every one a risk to some degree - simply focusing on the material used without considering it's design is the fundamental mistake here, most focusing on price and/or aesthetics alone.

Ibedayank
07-17-2012, 03:06 AM
brazed and silver soldered frames need no post or preheat when used on chromolly
so TIG is not the only answer


I would LOVE to see you tig a lugged frame

scotto-
07-17-2012, 03:48 AM
brazed and silver soldered frames need no post or preheat when used on chromolly
so TIG is not the only answer


I would LOVE to see you tig a lugged frame

TIG a lugged frame......you're killing me John, I almost choked on my own saliva laughing.......seriously!

laff laff rotfl

BarelyAWake
07-17-2012, 03:59 AM
Lugged? Brazing & silver soldering? Perfect examples of "Again, it's not so much about the material used - it's the design that material is used in that needs be considered, the care & quality in which it's constructed... and that's so variable with our hobby, there's no clear cut rules, no easy answers..."

happyvalley
07-17-2012, 09:10 AM
Pro Tips:

aluminum = light, brittle
steel = soft, heavy

Short and to the point.

Aluminum is subject to fatigue with repeated stress and why many of the box store aluminum bikes are made of frame members so thick they end up being heavier that a bike made from quality, drawn steel tubing.

culvercityclassic
07-17-2012, 10:06 AM
I built this frame out of steel and all the joints were tig welded with Silicon Bronze filler rod. I will add a couple gussets in certain areas and that's it. I have built a few frames and did some good research with the supplier of the filler rod. Thatís why I chose it.

http://motorbicycling.com/showthread.php?t=39900

Another venture I am on is an aluminum frame with some steel areas mixed in; the main part of the frame will be aluminum. We shall see how that turns out.

The bottom line is I favor steel, but like working with aluminum due to the ease of fabrication.

Now ask me what frame I would chose for a Motorbike build if I had to chose one to purchase...I think Scotto has the answer...

bigbutterbean
07-17-2012, 11:00 AM
I chose my Cranbrook due to the limited budget I was working with. Sometimes,, people have no choice but to buy something inexpensive. I didn't have $300 to spend on an expensive bike, nor did I have the equipment or knowledge to build my own frame. Sometimes, the walmart bikes do break. I still worry sometimes if my frame will break. I do know that I have had it for two years, and it shows no signs of stress. Perhaps I got lucky. All I know is that I paid $75 for this bike, and it may last a few more years. All in all, I say $75 wasn't a bad deal. If I had a choice, would I have chosen a better frame mde of quality american steel? You bet. But I didn't at the time.

happyvalley
07-17-2012, 04:09 PM
There are too many variables to make blanket statements or say 'one size fits all' when much depends on a case by case basis of what a bike is used for plus rider weight, drive train weight and applied power, tour of duty and miles covered.......Some folks are happy with a bike where the wheels stay more or less round and use it joyriding the neighborhood or running errands to the store. Others might want something that can handle more regular commuting. Some might want a bike that can cross a continent. Race bikes, another category, etc etc.

youknouno
07-18-2012, 02:25 PM
'Preciate that fellas. The insight is helpful. I know it get a little technical. The ol' school is steel and the new boy Felt's aluminum. My first china will go onto the Colombia (nicknamed the UFO) and one day all of my motorbike dreams will come true when I get ahold of that italiano monster... she'll go onto the Felt.

Ibedayank
07-18-2012, 03:15 PM
I built this frame out of steel and all the joints were tig welded with Silicon Bronze filler rod. I will add a couple gussets in certain areas and that's it. I have built a few frames and did some good research with the supplier of the filler rod. Thatís why I chose it.

http://motorbicycling.com/showthread.php?t=39900

Another venture I am on is an aluminum frame with some steel areas mixed in; the main part of the frame will be aluminum. We shall see how that turns out.

The bottom line is I favor steel, but like working with aluminum due to the ease of fabrication.

Now ask me what frame I would chose for a Motorbike build if I had to chose one to purchase...I think Scotto has the answer...

being you can't weld steel and aluminum togather I would like you to explain how you plan on doing this besides using bolts or rivets and control the Galvanic corrosion that is caused by using 2 dissimilar metals togather
Galvanic corrosion also happens when using carbon fiber without adding another layer between it and aluminum parts

youknouno
07-18-2012, 07:07 PM
This is getting good.. way more than I expected to learn.

youknouno
07-22-2012, 09:58 PM
Why not aluminum and steel? Like this: http://motorbicycling.com/showthread.php?t=40923

dnut

I guess what I haven't the capacity to understand yet is: What advantage or for what purpose would someone mx n match metals?

locell
07-25-2012, 10:42 AM
I guess what I haven't the capacity to understand yet is: What advantage or for what purpose would someone mx n match metals?

check out this mix-n-match

http://imgur.com/a/SbtRy

bigbutterbean
07-25-2012, 05:44 PM
I guess what I haven't the capacity to understand yet is: What advantage or for what purpose would someone mx n match metals?

I would imagine the reason behind it would be to try to find a good balance between strength and flexibility.

Ibedayank
08-03-2012, 11:24 PM
That - while somewhat true, is an exaggerated simplification yank...

Just about any metal that's used in bicycle frames should be heat treated/annealed/tempered/case hardened/through hardened after welding to optimize the alloy's properties... as an example 4130 chrome moly is particularly susceptible to embrittlement as a result of welding, requiring both pre-heating and post-weld stress relief and the heat control only TIG is capable of, yet I don't see anyone saying "chrome moly is bad" - and I suspect none of the box store bikes are treated in any way whatsoever save paint, regardless of the material used.

Generally speaking these post weld treatments are side stepped in both mass-production and shop fabrication by simply using additional gussets, more weld filler and thicker material than could be utilized in the ideal treated state, the hydroformed/extruded 6000 series aluminum commonly used for the lower cost bicycles no exception.

The applications these heat treatment welding protocols are adhered to stringently are primarily in the most extreme cases of minimalistic construction, aerospace engineering for example - or for our application, the very best of the "high-end" bicycles, where every ounce of excess material is considered a liability... but those bicycles should not be modified in any case, not just for welding/treatment concerns but also the focus on minimalist weight conservation engineering.

It all boils down to common sense, if you start with an overbuilt platform (such as a mountain bike) of even average acceptable quality (wall thickness & factory welds) and are familiar with basic construction & engineering concepts - welding/modifying any material is simply a matter of considering "acceptable risk" and compensating as necessary...

...yet if you are not familiar with such basic construction & engineering concepts and/or utilize only the lowest quality/most inexpensive platforms to modify in any way (including simply motorizing something not designed for such) - no material is "safe" and it all entails some amount of risk. If you have even some fabrication & modification experience, using aluminum has no greater risk then steel - yet if you have little to no experience in fabrication and welding, the material alone won't make any difference.

Again, it's not so much about the material used - it's the design that material is used in that needs be considered, the care & quality in which it's constructed... and that's so variable with our hobby, there's no clear cut rules, no easy answers - for every post warning against aluminum there's an equal or greater number of reported steel frame failures. Every motorized bicycle on this forum has been modified well beyond it's initial operating parameters, every one a risk to some degree - simply focusing on the material used without considering it's design is the fundamental mistake here, most focusing on price and/or aesthetics alone.


then explain this....
Welding

6061 is highly weldable, for example using tungsten inert gas welding (TIG) or metal inert gas welding (MIG). Typically, after welding, the properties near the weld are those of 6061-O, a loss of strength of around 80%. The material can be re-heat-treated to restore -T4 or -T6 temper for the whole piece. After welding, the material can naturally age and restore some of its strength as well. Nevertheless, the Alcoa Structural Handbook recommends the design strength of the material adjacent to the weld to be taken as 11,000 psi without proper heat treatment after the weld. Typical filler material is 4043 or 5356.

http://en.wikipedia.org/wiki/6061_aluminium_alloy

as I have said welding aluminum weakens the metal around the weld and requires heattreating to get its strength back

BarelyAWake
08-04-2012, 12:38 AM
That "80% strength loss" quote is most likely referring to a thick material multiple pass or TIG w/o filler - ie an absolute worst case scenario & not applicable.

Look into using 7005 instead of 6061 as it does not require heat treating & can be naturally aged. It's often used in bike frames & where heat treatment cannot be done after welding. Almost all aluminum bicycles are are designed utilizing a somewhat heavier gauge than the minimum possible, the joint design usually includes gusseting w/this in mind.

http://www.sapagroup.com/pages/493467/Answer%20Book/11_Welding.pdf
http://forums.mtbr.com/frame-building/aluminium-6061-7005-a-607488.html

If you don't like aluminum, don't use it - but it is commonplace regardless & readily utilized in bicycle manufacturing & fabrication, both heat treated and non-heat treated, artificially or naturally aged, or simply compensating for the material's characteristics.

It all boils down to common sense, if you start with an overbuilt platform (such as a mountain bike) of even average acceptable quality (wall thickness & factory welds) and are familiar with basic construction & engineering concepts - welding/modifying any material is simply a matter of considering "acceptable risk" and compensating as necessary...

...yet if you are not familiar with such basic construction & engineering concepts and/or utilize only the lowest quality/most inexpensive platforms to modify in any way (including simply motorizing something not designed for such) - no material is "safe" and it all entails some amount of risk. If you have even some fabrication & modification experience, using aluminum has no greater risk then steel - yet if you have little to no experience in fabrication and welding, the material alone won't make any difference.

Again, it's not so much about the material used - it's the design that material is used in that needs be considered, the care & quality in which it's constructed... and that's so variable with our hobby, there's no clear cut rules, no easy answers - for every post warning against aluminum there's an equal or greater number of reported steel frame failures. Every motorized bicycle on this forum has been modified well beyond it's initial operating parameters, every one a risk to some degree - simply focusing on the material used without considering it's design is the fundamental mistake here, most focusing on price and/or aesthetics alone.

Ibedayank
08-04-2012, 12:45 AM
For what stresses we put these bikes through is there really such a thing as a factory produced frame that is over built? How many frames on this site have you seen hacked up to make something fit that probably should have not been used in the first place. You really think that some noob with a 110 volt welder that can barely weld mild steel will be able to correctly weld an aluminum frame? Come on back it up with facts not your opinion

a HAZ zone is a HAZ zone it does not matter the thickness
only diff between think and thin is the thicker it is the more HEAT you have to put in it and the slower it will cool down

BarelyAWake
08-04-2012, 01:00 AM
...You really think that some noob with a 110 volt welder that can barely weld mild steel will be able to correctly weld an aluminum frame? Come on back it up with facts not your opinion

I'd not trust that "110 volt welder that can barely weld mild steel" regardless - whereas if you're even somewhat competent & w/a quality machine the transition to aluminum fabrication requires only a basic understanding of the materials involved.

"...yet if you are not familiar with such basic construction & engineering concepts and/or utilize only the lowest quality/most inexpensive platforms to modify in any way (including simply motorizing something not designed for such) - no material is "safe" and it all entails some amount of risk."

The facts both for & against are referenced via the included links and by common experience - the aluminum products & fabrications available everywhere.

Saddletramp1200
08-04-2012, 06:24 AM
How you ride makes a difference also. I rip hard on my MTB but take it easy on my Cruiser. (c)

happyvalley
08-05-2012, 01:39 AM
The manufacture of bicycles with aluminum tubing did not come about because aluminum is a stronger alloy than steel, it was because it is a lighter one. The problem with aluminum is it suffers stress cycle fatigue.

This was a mid-range road bike from 8 years ago, about $2500, made with 7005 aluminum tubing that I helped my son build up for him racing the regional club circuit. The pics were after a couple seasons, perhaps 4000 miles or so.

50646
50649
50648
He's a strong rider, rode it hard and did well with it, but it just became fatigued and developed cracks. He's had a lot better luck with carbon tubes as had the road bike industry in general.

Incidently, most of the tubing makers, Easton and Columbus among them, advise 7xxx series tubing should be heat treated after welding.

To quote Columbus:
The alloy 7000 used by Columbus for the tube sets is defined as self-tempering: it is air-hardened. This means that in the areas overheated by the welding the supersaturated structure is restored, which, owing to the natural aging (which takes place at ambient temperature), allows for a 75% recovery of the initial properties after a lapse of time of about 3 weeks. Nevertheless, Columbus advises to carry out a precipitation hardening treatment in the oven in order to give the structure a bigger homogeneity of the precipitates, with consequent improvement of the fatigue behavior of the frame.

BarelyAWake
08-05-2012, 02:35 AM
...not only lighter, but stiffer as well, which also has advantages/disadvantages.

A cracked head tube & seat post clamp are... odd choices to exemplify "stress cycle fatigue" as I would think those would be more directly related to crash damage (head), potential maladjustment (over tightening/crush damage), even poor design (post clamp) *shrug*

In any case, it's well known "road bikes" embrace minimalist construction methods - w/failure not uncommon in the slightest, regardless of the material used - the primary concern is saving every last ounce, even sacrificing integrity to do so. That frame's tubing could be even 1/2 the wall thickness of an aluminum mountain bike, the "integrated" seat post clamp (just tabs welded on instead of an actual clamp) another example of a sacrifice made to conserve weight.

My LBS often has broken road bike frames of all materials & price ranges, it seems w/road bikes the more you pay the less you get.... even a lot more for even a little less lol

Conversely, here's a typical example of a inexpensive ($200) non-heat treated aluminum mountain bike, one that's seen well over 10,000 miles of "high speed" motorized use (two stroke) & abuse with all-season, all-terrain riding & the occasional crash such entails;

http://i305.photobucket.com/albums/nn210/Serenity151/vroom/th_28KGrHqJ21k4E2D69214JBNsNozi6GQ7E7E.jpg (http://s305.photobucket.com/albums/nn210/Serenity151/vroom/?action=view&current=28KGrHqJ21k4E2D69214JBNsNozi6GQ7E7E.jpg)

http://i305.photobucket.com/albums/nn210/Serenity151/vroom/th_09e62496.jpg (http://s305.photobucket.com/albums/nn210/Serenity151/vroom/?action=view&current=09e62496.jpg) http://i305.photobucket.com/albums/nn210/Serenity151/vroom/th_31c5c409.jpg (http://s305.photobucket.com/albums/nn210/Serenity151/vroom/?action=view&current=31c5c409.jpg) http://i305.photobucket.com/albums/nn210/Serenity151/vroom/th_91b191f9.jpg (http://s305.photobucket.com/albums/nn210/Serenity151/vroom/?action=view&current=91b191f9.jpg)

While every other component is worn, corroded (rusted steel parts) or just plain tired from such constant utilization - the frame itself shows no signs of damage, fatigue or cracking & has never needed any repair whatsoever. If it wasn't cheaper to just buy another - I'd happily replace/repair it's assorted components (wheelset, derailleurs, cables, brakes, shifters, etc.) & ride it for another 10,000 miles.

Here's another pic of mountain bike aluminum frame construction just because I think it a wonderful example of material consideration & stress diffusion (an old Haro of mine, prolly going to be an ebike ...someday);

http://i305.photobucket.com/albums/nn210/Serenity151/vroom/th_IMG_4683.jpg (http://s305.photobucket.com/albums/nn210/Serenity151/vroom/?action=view&current=IMG_4683.jpg)


edit: I'm not advocating a cheap bike over an expensive one BTW, rather pointing out the fact road bikes aren't a good example of material integrity (or lack thereof) due to their design perimeters (weight conservation), nor am I even trying to say aluminum is "better or worse" than another material - again, it's all about the design used w/a material & it's application. I'm sure there's other "examples" of broken/cracked aluminum bikes, then again there's plenty of examples of bent/broken/fractured & just plain busticated steel/chromoly/carbon/whatever bikes at every bike shop I've ever been to heh

I think the most common reported motorized bicycle frame failures just happen to be steel - both the Cranbrook & Micargi (prolly b'cause of their commonality/price), but I'd still not blame or recommend against that material itself, I'd suggest poor quality, design & construction.

thegnu
08-05-2012, 09:26 AM
Yeah keep it a lil simple for the first build , as far as aluminum frames I personally will not use them its a soft metal a brittle metal , those two things in my opinion dont make it ideal for a motorized bike the motor adds significantly different loads an stresses to the frame . just my opinion.
Gary

happyvalley
08-06-2012, 01:19 AM
A cracked head tube & seat post clamp are... odd choices to exemplify "stress cycle fatigue" as I would think those would be more directly related to crash damage (head), potential maladjustment (over tightening/crush damage), even poor design (post clamp) *shrug*

Nope, no crash nor maladjustment or any other errant assumption, simply as stated, the aluminum frame began to weaken and developed cracks, as shown, over time and under fairly strenuous but not uncommon road bicycle racing use. I try to post empirical info of what I've seen in actual experience and not the too common internet blather that sometimes poses as expertise. Apples and apples, in this case for example aluminum road bike vs steel road. We have and have had dozens of steel road bikes and never, once, had a steel frame crack.

As to the the use of weld-gusset-weld to beef up aluminum tube joinery, I think the inherent weaknesses in the material speak for themselves by the necessary reinforcement and compensation needed. Frankly I see no wonder in oversize welds and added plate, in fact I find it downright ascetically displeasing, but that's just me, lol. Compare that to the elegant utility of a lugged steel Bridgestone MB1 currently residing in my shop, something no one has yet been able to do with aluminum.

50667

BarelyAWake
08-06-2012, 02:52 AM
...as I have never, once, had any of my aluminum mountain frames crack & I maintain that ultra-light road bikes are a poor choice to exemplify or illustrate the potential in motorized frame use as again, sacrifices have been made for weight considerations - I'd hesitate recommending or using any material "racing road bike" as a motorization candidate for that reason.

It's interesting you've chosen to deride the "weld-gusset-weld to beef up aluminum tube joinery" for the "necessary reinforcement and compensation" needed as when aesthetic considerations are set aside - do not lugs & gusseted plates serve the same purpose, to strengthen the joinery? This need is seen as a liability w/aluminum but not with steel?

I agree lugged steel is often pleasing to the eye, but the purpose is exactly the same as the oversize welds and added plate found on reinforced aluminum... and I find that equally as pleasing when it's well designed & executed, but that's just me, lol.


Again, point being - I maintain that making generalizations for or against a material without consideration of the design used with that material is erroneous. Every material ever used in bicycle frame construction has examples of failure, every material has it's own unique benefits & liabilities - to present examples while disregarding design to substantiate a bias is a misrepresentation of the potential of that material.

"nor am I even trying to say aluminum is "better or worse" than another material - again, it's all about the design used w/a material & it's application"

For another example, it's well known that stretch choppers can suffer flex & integrity issues - yet would one blame the material for these shortcomings or the design?

happyvalley
08-06-2012, 03:26 AM
.I'd hesitate recommending or using any material "racing road bike" as a motorization candidate for that reason.


Nor would or do I and thought that was apparent above but if not, let me disabuse of the notion. As stated, I was comparing road frames, aluminum to steel, for their intended purpose.

It's interesting you've chosen to deride the "weld-gusset-weld to beef up aluminum tube joinery" for the "necessary reinforcement and compensation" needed as when aesthetic considerations are set aside - do not lugs & gusseted plates serve the same purpose, to strengthen the joinery? This need is seen as a liability w/aluminum but not with steel?


Deride? heh, your word and too harsh a term, I don't care that much to de ride but I could also say I don't care to ride them either, lol.

BTW, I was talking about lugs, as in lugged frame bikes so where the mention of "lugs and gusseted plates" in the same sentence comes from I'm not sure. Lugs are fitment, most often hand assembled and brazed, they are the joinery, not slapped on after the tubes are joined to strengthen their union.

Ibedayank
08-06-2012, 06:18 PM
Nor would or do I and thought that was apparent above but if not, let me disabuse of the notion. As stated, I was comparing road frames, aluminum to steel, for their intended purpose.



Deride? heh, your word and too harsh a term, I don't care that much to de ride but I could also say I don't care to ride them either, lol.

BTW, I was talking about lugs, as in lugged frame bikes so where the mention of "lugs and gusseted plates" in the same sentence comes from I'm not sure. Lugs are fitment, most often hand assembled and brazed, they are the joinery, not slapped on after the tubes are joined to strengthen their union.
a lugged frame can not be welded only brazed or silver soldered.
Silver solder have a strength of 70,000 psi wich as it happens to have more strenght then 6000 series arcwelding rods wich have 60,000 psi

now ask your self what is stronger a welded buttjoint frame in steel or aluminum or a lugged silver soldered frame

Goat Herder
08-06-2012, 07:04 PM
http://motorbicycling.com/attachment.php?attachmentid=50646&d=1344146632


http://motorbicycling.com/attachment.php?attachmentid=50648&thumb=1&d=1344147471

http://motorbicycling.com/attachment.php?attachmentid=50649&d=1344147541

To quote Columbus:
I just wanted to note that gussets would not have prevented these cracks where they occurred? Least that's my opinion of where these cracks are presently at.. quoted from above..

I did crack the trailing arms on this bike twice. Never ramped it or down hill-ed it. Never had a motor on all pure peddled. I ran the rear shock stiff enough not to bob when peddling and put triple tree forks on the front with BMX bars. I put about 15,000 miles on this bike replaced the rear triangle once and patched it in the end.

It had a custom tight rear ''road'' cassette with a wider bottom crank bracket. 180 cranks and 52 tooth front cog. this was the quickest street touring, geared full sus bike I ever owned. Sure was bummed when I had too retire it. It has been near impossible to reduplicate this bike. The leverage every where for peddling was perfect. I feel I never did.. Did some sixty mile bikes rides on many occasions. It still sits in my back yard.:( This one is a sample pict.

This bike weighed nothing too.. man it was light.

http://t0.gstatic.com/images?q=tbn:ANd9GcT3-Sc9J3l4yslBbHw9J24WUj4ttbRbj8mWcPaGopleQ-o1TB4sgs-eIsl1hg

If it was made of steel might still be on it today? * pun


I know that when that first Morini motor of Easy Riders was put on a aluminum frame they gave it a good collage try and it was not enough? They did beat the bujeebers out of it tho off roading it. Must be why my Steel bike from them works so well!. lol http://motorbicycling.com/showthread.php?t=243&page=6

David eulen
08-07-2012, 02:23 AM
Getting ready to throw down some dollars for a Felt. Common sense says that the steel frame is by far the more durable, however I see alot of you guys using aluminum frames. Why is that? Being a super noobie, I want to buy the most durable frame, engine, etc. Seeing as how I'm aiming for max power (considering a 9HP Morini), low maintenance. So, aluminum or steel?

I'd go for steel, it will flex, aluminium will crack from the vibration.
Ozy Dave auflg

LaLongueCarabine
09-10-2012, 04:25 PM
the diameter of the tube is not as important as the thickness of the walls and the strength of the welds.

and pre-weld and post-weld heat treatment.

happycheapskate
09-10-2012, 10:47 PM
I'm using an aluminum frame because I got the bike for $50, and I'm using a Dax Friction drive with a Tanaka motor (pretty smooth). If I was going to put 9hp on a bicycle, I would get a frame built of thick steel, something seriously overbuilt and gussetted, because I'd be using the pedals mostly for a semblance of legality or for wheeling it through foot traffic. hahaha.

http://www.650motorcycles.com/images/BSC1.jpg http://www.650motorcycles.com/images/BSC1.jpg

Getting ready to throw down some dollars for a Felt. Common sense says that the steel frame is by far the more durable, however I see alot of you guys using aluminum frames. Why is that? Being a super noobie, I want to buy the most durable frame, engine, etc. Seeing as how I'm aiming for max power (considering a 9HP Morini), low maintenance. So, aluminum or steel?