Two Speed Automatic Transmission
- Thread starter msrfan
- Start date
I'm glad to see more people developing automatic transmission for motorized bicycles. My bike shifts 5 gears automatically. Here is another system that could be used.
https://www.youtube.com/watch?v=lPmcULLV4Uc&feature=youtube_gdata_player
https://www.youtube.com/watch?v=85ItYMV4MZM&feature=youtube_gdata_player
The main reason I built my bike was to comply with my state's ( Tennessee ) requirement of automatic transmission system.
https://www.youtube.com/watch?v=lPmcULLV4Uc&feature=youtube_gdata_player
https://www.youtube.com/watch?v=85ItYMV4MZM&feature=youtube_gdata_player
The main reason I built my bike was to comply with my state's ( Tennessee ) requirement of automatic transmission system.
Someone say two-speed auto?
http://www.universalcycles.com/shopping/product_details.php?id=42867&category=2713
Word on the street is that the internal springs are easy to swap out, and if you attach a sprocket to the spinning drum and use it as a jack-shaft, its the shiznit. The core comes out of the drum in one piece.
Btw, I cant wait till you fine tune your setup and get wind of performance.
Ive been using this one for the last 2000 miles.
Check out the sprockets on this mean jack-shaft.
http://www.niagaracycle.com/categories/torker-tri-star-3-speed-coaster-brake-hub
I've got one of these on the shelf, waiting for the secondary sprocket to be attached by my buddy.
http://www.universalcycles.com/shopping/product_details.php?id=48707&category=2713
If you can find a spectro p5, grab it up and weld on a second sprocket. They have even gear-stepping, and all 5 gears are usable by these small engines.
Check out the sprockets on this mean jack-shaft.
http://www.niagaracycle.com/categories/torker-tri-star-3-speed-coaster-brake-hub
I've got one of these on the shelf, waiting for the secondary sprocket to be attached by my buddy.
http://www.universalcycles.com/shopping/product_details.php?id=48707&category=2713
If you can find a spectro p5, grab it up and weld on a second sprocket. They have even gear-stepping, and all 5 gears are usable by these small engines.
Here is my 5 speed setup on a LandRider bicycle.
https://www.youtube.com/watch?v=pGDGIIdn--s&feature=youtube_gdata_player
https://www.youtube.com/watch?v=pGDGIIdn--s&feature=youtube_gdata_player
Thanks LR, I won't be making these for sale, I just felt the need for a heavy duty self contained automatic for my race bike. I have several internally geared hubs but they won't hold up under power.
Consider the max HP of engine and that hp= ( Torque@Hub x RPM@Hub) ÷ 5252
Since Max HP is pretty constant, you will notice that if you raise the RPM, the torque is reduced. The engine at the crankshaft always produces less torque and higher RPM than the back wheel. Somewhere between the back wheel and the crankshaft you will find a sweet spot that can neither break the tranny, nor be too far spread in the gear-ratio.
A 3-speed inside a 26 inch tire has larger difference in the inches-per-revolution-per-gear than a jack shaft. This compounds the possibility of breaking the internal hubs, being at the place receiving the most torque, and having to handle the largest possible jump in drive ratio from the 26" circumference.
When someone says an internal hub cannot handle the power, it is an engineering error. BTW, SA hubs tend to not shift when spinning above 5000 RPM. I recommend the Shimano nexus for reliability at every RPM. It could only be improved over by the Sram iMotion hub, which theoretically would have better shifting speed. Serioulsy, the trike tranny is good for heavy duty abuse. I have a couple thousand miles on them. I live in a very very hilly area. I dont even have peddles to help start...
This torque/rpm is the point most often missed.
Since Max HP is pretty constant, you will notice that if you raise the RPM, the torque is reduced. The engine at the crankshaft always produces less torque and higher RPM than the back wheel. Somewhere between the back wheel and the crankshaft you will find a sweet spot that can neither break the tranny, nor be too far spread in the gear-ratio.
A 3-speed inside a 26 inch tire has larger difference in the inches-per-revolution-per-gear than a jack shaft. This compounds the possibility of breaking the internal hubs, being at the place receiving the most torque, and having to handle the largest possible jump in drive ratio from the 26" circumference.
When someone says an internal hub cannot handle the power, it is an engineering error. BTW, SA hubs tend to not shift when spinning above 5000 RPM. I recommend the Shimano nexus for reliability at every RPM. It could only be improved over by the Sram iMotion hub, which theoretically would have better shifting speed. Serioulsy, the trike tranny is good for heavy duty abuse. I have a couple thousand miles on them. I live in a very very hilly area. I dont even have peddles to help start...
This torque/rpm is the point most often missed.
Okay bowl, did you build one of these hubs? And how did it hold up at the races? I'm just sharing how I hand made a 2 speed transmission and welded it into a race motorbicycle. Thanks for all the info though. Always glad to see how someone else makes things work.
damm dale, i stared at that sucker and commented how it looked like a 4-71 blower but i had no idea their was a two speed in side of it. should have opened my eye's a little better. very nice work indeed. dennis
Thanks Dennis. Nice hanging out with you. I love that photo of you on your new bike. Jeff noticed the two clutches and I think he knew what was going on in there.
Did I build it? naw I paid for it off the shelf for 89 bucks. Did it perform at races? no... weather is to crappy up here for organized races, but as I did mention, its still holding up fine under heavy abuse. Im not knockin' your work. I only pointed out that such a hub exists when someone else said there wasnt an option for ya. I dunno how much that one you have fabbed up actually cost, or the overall amount of work done to get'r there, but hey... the pleasure of the trip is not arriving...
Im sure you'll get way more life out of your unit than a CVT or a SBP kit. lr-jerry's 5 speed auto is also a killer setup. I have a old scooter motor 52cc. I hit 43 mph with this tired old goat using the jack-shaft. I dont even have peddles to assist the motor. So yeah, I think in a race against a motorized bike with a similar sized engine, Id probably kick ass. I can run up steep hills from a dead stop(no peddles
) and I can break 40. Only a very small percent of bikes around here can reach that speed or versatility. Am I bragging? mf'n right I am. I see the tanks being built here occasionally , with giant OHV engines and industrial sized farm conveyor belt parts. Then you hear they make 30 mph tops and weigh in at 100 lbs. Good deal. I think your settup is cool.
Any autoshift system is what I like seeing. It's the way motorized bikes need to go. The reason I say this is most states have an automatic transmission clause. Some states laws even say the operator can't shift gears after the primary drive is engaged. As well as no manual clutching.
With autoshift systems you reap the benefits of multiple gears but still remain legal.
With autoshift systems you reap the benefits of multiple gears but still remain legal.
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Finally fabbed up some guards for my race bike. Flywheel on the left and chains on the right. Now I can lube the chains without getting sprayed while I ride.
Could you post some videos of the tire free spinning and of somebody filming you riding your bike?
Maybe after I add a few goodies and paint. Is there a reason you need to see the rear wheel spinning?