A new shift concept for the engineers....

Thanks Ron!

The more I mess with it...the more confident I am: it's going to work!

I got the programs for all of the sprockets done today, and cut a few 52T sprockets. The Stainless is a real pain to deal with compared to Aluminum.

I had to run the cutter around the tooth profile twice at a slooowww speed to get them clean.

Heavy duty 410 chain fits perfectly.

Tomorrow I will make the rest of them, and post pics of the clusters.

I'm going to polish these to a high luster just for grins.

The pics below show a 52T, beveled and ready for service.

Jim
 

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bairdco said:
i was thinking about that, too. with a freewheel you'd need to pull start it.

the main reasons for a freewheel are to set up your pedals for corners, stops, etc, and with multi-geared bikes, deraileurs don't work when pedaling backwards, so they don't work with a coaster brake.

weight is another reason. internally geared hubs and coasters weigh a lot more than what's essentially a front hub with a gear(s) screwed on.

it would be awesome to have a freewheel for coasting down hills, so your chain's not slapping around, but if i had gears, i wouldn't need to coast down hills...
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Exactly Baird:

And what I'm figuring...without a freewheel on the left side...the clutch can be disengaged and the chain will be free floating...shift...engage the clutch, and throttle on...Just like any other conventional, manually shifted vehicle.

Of course the rider could, with finesse, shift without the clutch...just like any other conventional, manually shifted vehicle.

Jim
 
Was tuning my kid's multi-speed bmx yesterday and I'd never noticed before or maybe I just hadn't payed attention to it but the teeth on the cluster aren't straight, they're kind of tilted in and skewed toward the next larger sprocket. Kind of hard to explain, imagine the kerf bends on a circular saw blade but all bent one direction. When I noticed it kind of made sense, seems like it would help the chain bite onto the next sprocket.
 
Kevlarr said:
Was tuning my kid's multi-speed bmx yesterday and I'd never noticed before or maybe I just hadn't payed attention to it but the teeth on the cluster aren't straight, they're kind of tilted in and skewed toward the next larger sprocket. Kind of hard to explain, imagine the kerf bends on a circular saw blade but all bent one direction. When I noticed it kind of made sense, seems like it would help the chain bite onto the next sprocket.
Click to expand...

Yes...post #13

Jim
 
Yes GH...I weighed the 52T today...1.73 lbs. I will definitely put them back in the CNC and lighten them up.

I cut 4 more SS sprockets today...it's really slow going...I had forgotten just how nasty 304SS is to machine.

The milling cutters don't last...I figured I might have had the speed and feed wrong, but when I got home I checked and I had it set almost perfect.

In Aluminum I set the spindle to 4,500 R.P.M. and the feed rate at 15 Inches per minute.

In Stainless, the spindle speed is 1,650 R.P.M. and the feed rate is 2.5 IPM.

The good news is; these are going to be "forever" sprockets. The Baja guys use SS sprockets because they do not wear out!

Jim
 
Any way you can use the kit included spoke mounted sprocket Jim?
Free sprocket. Heck I have 2 I didn't need you can have.
This will be mounting to the hub and not the spokes correct, you may have said in a previous post but this topic is 9 pages long now.
 
KCvale said:
Any way you can use the kit included spoke mounted sprocket Jim?
Free sprocket. Heck I have 2 I didn't need you can have.
This will be mounting to the hub and not the spokes correct, you may have said in a previous post but this topic is 9 pages long now.
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KC,

Yes, I plan on mounting the cluster to one of my sprocket adapters.

I appreciate the offer, but I need specific tooth count sprockets in order to make it work.

The stainless is a real pain, but I'll get through it. Like all things that are difficult, once the sprockets are finished, it will be water under the bridge and I can concentrate on the deraileur set-up.

Jim
 
Jim's lightening holes are a pretty thing ;)
even countersunk on both sides :)
 

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I was messing around today so I sandwiched a 50t and 44t sprocket together and it fit fine on the bike, my chain was not long enough for the 50t, but the concept looked like a solid idea. I think Jim's idea of only making it a 4t jump between sprockets is about right, 6t looked doable but I think 4t would work better. My current spring tensioner should do the job, just have to adjust for more play when I get my longer chain. Even if I can't get the derailer idea to work, I can stop my bike and kick the chain up or down a sprocket, then roll backwards about 3feet to set the chain on the new sprocket.
 
ferball said:
I was messing around today so I sandwiched a 50t and 44t sprocket together and it fit fine on the bike, my chain was not long enough for the 50t, but the concept looked like a solid idea. I think Jim's idea of only making it a 4t jump between sprockets is about right, 6t looked doable but I think 4t would work better. My current spring tensioner should do the job, just have to adjust for more play when I get my longer chain. Even if I can't get the derailer idea to work, I can stop my bike and kick the chain up or down a sprocket, then roll backwards about 3feet to set the chain on the new sprocket.
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Any photos? I'll be interested to hear how it works out. It was a good idea you had! Yes, even if the derailleur doesn't work and you have to manually change the chain over to a different sprocket it would make a big difference in hilly areas. Did you add a spacer between the two? Weld it together or bolt it? Is it a rag joint connection to the rear wheel? What is the spring tensioner? Photos are good. I wonder how Jim is doing with the derailleur. He's a smart guy, so I imagine he'll figure something out. I want to thank you for sharing the idea in the first place.
SB
 
I used the standard rag joint, and I put the sprockets with the convex sides together and it provides enough space for the chain. I will post pics after I get a longer chain and my tensioner modded. I am using the stock tensioner with a storm door spring. I will post some pics in a few days...
 
Good deal, I'll be interested to see what you come up with. It sound like a 48 tooth along with the 44 that comes with a kit would be a good combination for hill climbing capability. For the speed addicts a 44 and a 40 maybe.
I'm interested both in the "poor boy, manual" version and what Jim comes up with which is going to be pretty cool. If his is a "fireball shifter" yours is a "ferball shifter".
SB
 
I'm fairly new here but just found this thread and find it interesting and would like to throw out a few ideas. I have built a few two wheelers of various types that I have engineered myself but all of single speed design. I would love to have a two or three speed bike but there are a few problems mostly what have already been discussed here. One is how to change gears, fairly easy on a low powered bicycle where a small chain can be used and moved around easily. Not possible with a chain large enough to handle say a 3 HP or more. At least no one has seemed to make one work yet. There were at least 200 motorcycle companies early last century that tried just about every design and none had anything like a stacked gear setup. All had a sliding gear tranny of some sort.
Another topic is stopping once you get moving at say 50 MPH. A coaster brake stops just fine at about 20, but 50 is something different. Brakes must be upgraded if you value your skin.
Next, I had a buddy try a motor on a three speed bicycle hub, it lasted only a few miles before it self destructed. Not a feasible option.
My humble opinion is if you want to go faster, your going to need gears, more brakes, and possible clutch. Now your talking about motorcycles!
 
LouieMCman said:
...Next, I had a buddy try a motor on a three speed bicycle hub, it lasted only a few miles before it self destructed. Not a feasible option...
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It can be, not all hubs are created equally. This Sturmey Archer X-RD3 isn't anything particularly fancy (other than built in drum brake) and it's dealt with my shift-kit abuses for about three thousand miles and counting ;)
 

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Use that hub as a jack shaft you would have about three times ( or what ever the reduction is ) the braking power. Same goes for the drive end even a cheeper hub would last longer. Just my thinking...Curt
 
I'm still working on it guys...unfortunately new products have to be worked in with the regular production schedule for parts that are owed to customers...this is why new products are slow to come about.

In the production schedule; we make sprocket adapters, sprockets, intakes, cylinder heads, and motor mounts. We are a small shop and the machines have to be utilized for orders before prototypes can be made!

Jim
 
Well I trashed my bike yesterday, couldn't find the right size master link to resize my chain for the larger sprocket, so I tried to get away with on that was a little to wide....Long story short threw the chain and ganked my engine in good shape so I have to redo the mounts. I knew I had to redo the mount, I was just hoping to wait until winter... So I will be a week or so before I get back to experimenting. I have an idea for a tensioner derailer system, which should be easy for me to fabricate, and if it works I will post so you professionals can make it fancier... But I have to put my bike back together first.
 
Creative Engineering said:
I'm still working on it guys...unfortunately new products have to be worked in with the regular production schedule for parts that are owed to customers...this is why new products are slow to come about.

In the production schedule; we make sprocket adapters, sprockets, intakes, cylinder heads, and motor mounts. We are a small shop and the machines have to be utilized for orders before prototypes can be made!

Jim
Click to expand...

Jim, I think it can be done, but not cheaply. It would end up being a custom-made hub. Tell me what you think of this idea, Jim:
You've noticed how ten-speed wheels are flatter on the side with the cassette. To have a cassette of drive sprockets (maybe only two of them) you'd need to construct a LHD hub with that side being the flat, freewheel side.
Rather than having the deraileur moving about, which others pointed out would put the chain out of alignment with the engine drive, you could instead have the drive cassette slide in and out on a splined shaft of the hub. The guide wheel/tensioner would remain lined up with the engine. In three-speed style, a shifting lever or cable entering that side of the hub would slide the drive cassette in or out, lining up the desired drive sprocket with the engine and the tensioner keeping the chain on-course to complete the process. I haven't sketched it out yet, but I can see the operation of it in my head. (I know that doesn't help you over there.) I don't have a machine shop or I'd just build one and try it out, spend endless months tweaking, and eventually come up with something. If you can figure out what's going on in my head - it's all yours.
 
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