Aluminum framed bikes..

[old motorbike]

...Can they be made to live without cracking?
Rubber mounts?
I have an opportunity to get one reasonable with suspension.
I've been looking to update mine with suspension or get another frame.

 

[NunyaBidness]

I would like to build a frame. I have an aluminum frame that is cracked right above the weld that joins the bottom bracket and the seat post tube. I want to use it to get some angles and build a good steel frame. I am a little worried about a motor on an aluminum frame, especially one of the lighter frames.

 

[TexasDav]

I have a aluminum schwinn and watch it closly ever sence the report about them cracking; so far getting close to 1000 miles and no cracks yet.

 

[tyrslider]

Watch closely Tex, we like ya!

 

[Dan]

I have had 3 or 4 aluminum frames and never had a problem. For just street cruising I think they are fine. I wouldn't go jumping curbs or off road with one though. I have at least 1,000 miles on a wally world point beach cruiser thats on it's second Chinagurl. Still looks great. Except for where I "modded" the down tube with a mallet, snork. One great advantage over steel.



Just my thunking

 

[old motorbike]

Thanks for the responses. I'm happy to hear that some are successful.
I'm tempted to try this one and maybe fab some softer mounts, but I also have a shift kit, which may be a challenge.
Yes I'm also a easier rider, but occasionally hit a hole in the road.

 

[happyvalley]

Aluminum is just fine for rack mounts.

 

[Dan]

Awesome O'MB, never know until you try. May I be so bold as to suggest more ridged mounts? All the rubber and softer mountings I have tried only increased vibration. Any room for the engine to move just made for a paint shaker like action and allowed the movement of the piston to jack hammer the whole bike. I could be totally wrong and there is a way to isolate vibration. I have just found letting it absorb threw out works better. If you get a soft mount to work, I can not wait to see and will buy lunch! Would be cool.

I live in CT and pot holes are just part of the fun. The aluminum has done fine. (even the cheap wheels so far although they need TLC about twice a year)((just grease and truing)

Hope to be of help

 

[toytime]

I don't think the jachshaft kit works too well with rubber mounts and I think Dan has a point. As for aluminum frames, Steel will first crack and show itself while aluminum will just give without warning tending to throw you over the bars.
I'd still try it though, just keep an eye on things.

 

[jasonh]

datz150 came up with some mounts for his aluminum bike for use with the shift kit. No rubber, but they look solid and shouldn't kill the frame. You could probably adjust the size a bit and use a wrap of some kind of rubber....

http://motorbicycling.com/f15/rotten-orange-build-gary-fisher-aquila-2308-4.html#post23028

 

[Creative Engineering]

Rigid mounting an engine that is out of balance is a bad idea from an engineering stand-point...not my theory, just a known fact.

The isolated mounts I did on the last build worked great! Naturally you have to use common sense...Bubble Gum won't work.

And, as Forrest Gump put it...that's all I have to say about that.

Jim

 

[old motorbike]

Great ideas I looked at the bike yesterday. It's an old rental from the beach with 8 speed rear!. It's a big tall bike but not bad with the seat down. Probably enough room for a shift kit.

 

[Dan]

Kool Old Motorbike

 

[old motorbike]

Tomorrow,I want to see what he wants for the old beauty. I can't afford this but I can't stop myself.

 

[old motorbike]

Just went by the bike shop today and he told me to just take the bike and figure what parts I need. I only had about a half hour to look at it and take some of it apart, but my ft. disc brake fits and my suspension seat post fits. I'll get rid of the 8speed cassette. I can feel the soft ride now!

 

[Dan]

sweet. post pics!

 

[old motorbike]

Here it is as of today. I'm taking off parts I don't need and getting parts to work with. New tires and tubes, handle bar, etc. Trading him old parts back. Tonight I installed the tires and just put on the wheels. It's a lot bigger than the old one. I just wanted a little more comfort, better brakes.... and another project that I can't afford!

 

[Dan]

Lookin' good!

Really like the tires, what are they?

 

[old motorbike]

The tires are chen shin (spelling?) that the bike shop had. He thought the flat tread might be good on a MB.
There's less room between the seat post and rear tire, I'll need to move the engine forward some to clear it. The front bar is real fat so it will need a different mount. The mounts will need to be adjustable for the chain on the shift kit and also to balance the stress points on the frame.
I don't know why I'm building this when I have a great finished bike already? Guess this can be as addicting as anything else.
Hope it holds up and don't crack.