FWD shaft build

camlifter

camlifter

Active Member
working on a front wheel drive with drive shaft. shaft drive has a 7 speed hub, have the fork and shaft mounted, need to build the reduction gear box and get the motor mounted, this pic is just a mock up, i have to shorten the out put shaft on the motor still and get everything lined up. sorry for the cell phone pic, will post some better ones as the build comes along.
 

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Cam,
You either have waaaaay too much "shop time" available to you, an over active imagination or are tormented by "mechanical dreams" or maybe all three..............LOL. But really looks like a cool project, maybe you will become known as the Audi of the motorized bicycle industry. Keep us posted on the progress of this project. Also just had a thought, they used to make inline/inshaft reduction gears for power drills that plumbers/carpenters used to use when attaching hole saws larger than 6" in diam. to slow the shaft down so it would not flling itself all over the place. Maybe you could adapt one for this use. Just a thought.
 
Now you have me thinking of getting one of those 2 wheel drive, shaft drive bicycles and somehow attaching an engine to it! That would be intresting in the hills!
 
mdlee1958 said:
Cam,
You either have waaaaay too much "shop time" available to you, an over active imagination or are tormented by "mechanical dreams" or maybe all three..............LOL. But really looks like a cool project, maybe you will become known as the Audi of the motorized bicycle industry. Keep us posted on the progress of this project. Also just had a thought, they used to make inline/inshaft reduction gears for power drills that plumbers/carpenters used to use when attaching hole saws larger than 6" in diam. to slow the shaft down so it would not flling itself all over the place. Maybe you could adapt one for this use. Just a thought.
Click to expand...

it all starts out as, what if, lol. i've been looking on line for reduction box's and haven't been able to find any thing thats not way to expensive, also i need to change rotation, motor runs ccw and the drive shaft runs cw, so an inline won't work. i'm using the gears shafts and bearings out of a mazda starter motor and machining a box for them to fit in, should work but it would be nice to find something already made.
 
Is that from a D-drive bike? I've had my hub at the LBS for about 6 months getting a new wheel laced up. I had about the same idea, only rear drive with pedal and engine both driving. Keep us posted.
 
yes it's the d-drive, you could use the free wheel sprocket from a jack shaft kit and do a rear wheel drive bike, but i wanted to do a modern version of the bike bug. i have an HS 50 motor i might try for a rear wheel drive/shaft for my next build.
you can get a d-drive girls bike from amazon.com, free shiping, they have dyno hubs and fork shocks, lights and rear rack. lot of good parts, $249
 
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Kind of what I had in mind. I have a Titan and RS looking for a place to go....just can't find room in the framd unless I mount it high. Sides, I have about leventy twelve other things first. I like the way you think. :>)
 
got a little time to work on the fwd bike. got the gear box done and the motor mounted, just need to short'n up the cables and put on the controls, powder coat everything and she'll be ready for a road test. it's not top heavy like i thought it might be. feels real good, nice balance.
 

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Cam,
What did you wind up using for a reduction gear on the output shaft ? Am just curious as living here in Colo and having to ride in the snow a lot it would be nice having fwd.
 
i used the gears out of a mazda starter. had to make the box to put them in, it comes out to a 2 to 1 ratio at the gear box, then the shaft ring and pinion is 3.5 to 1, plus it has 7 gears. i really need to find a gear box from some other application if i want to build more like this. machining a gear box for each bike is just going to be to time consuming and costly. but as a proof of concept it's working out great.
 
camlifter - what kind of hub are you using , how do you feel it will hold up to the engine . and how is your 3 speed hub on the THX bike holding up ( or does that one really get riden very much ) ?

do you need to baby it when you shift ?
just curious as to how much these internal hubs can take .
 
the hub on this bike is the one that came on the D-drive bike, i'll have to check cause i don't remember. i just used everything from the chainless bike, rear wheel drive shaft and all, and made it fit the schwinn. it's all prety heavy duty and i don't see any problems yet.
the thx bike i've only put a few miles on so far, snowing all winter and more to come here. will be spring before i get a chance to give it a good work out. the way i see it, you give a lot more TQ to the hub through pedalling ( you've got all your weight on an 8 in. crank) than the little engines could ever produce, if there are any problems they should come from high rpm's that the hubs weren't designed for. the sram i hub should be plenty beefy and have no problems. we'll see how it holds up, i'll let everyone know if it fails.
 
thanks for sharing your info , the way i see it then is that the best place for the internal hub , IS IN THE WHEEL , where rpms will be kept to the minimum . even if you are going 40 mph , your hub to wheel ratio will still be the same as if you were going 10 mph .

so as long as you don,t give it excessively hard kicks with the motor it should hold up good .

i think i,m going to work on a design for a cushioning sprocket , that will eliminate , or at least reduce the low rpm hammering from the motor .
 
looks like this build is a bust. something broke in the nexus hub, i now only have 1st and 2nd gears, from 3rd gear on up the wheel locks up and won't spin, i'll tear the hub down to see whats broke. kind of bummed i had high hopes for the shaft drive.
 
After destroying a nexus hub and then hearing this I think I can say that Nexus hubs aren't really hardy enough for motorized bicycles...
 
took it apart last night. the ratchet pawls on the outer gear set were broken and the pecies were getting jammed between the gear set and hub housing. very ez to take apart and will be an ez fix if i can get parts.
prety sure it broke from the touque washer being to weak and letting the axle spin causing it to miss shift. the washer that came with it is really thin. i'm not ready to give up on it yet so i'm off to the lbs to see if i can get the parts to fix it.
 
My local bicycle shop said that they couldn't get parts for them and they are throw-away. Then again they do have a parts list, so you might be able to get parts online.
 
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