In frame Predator fricton drive build
- Thread starter wayne z
- Start date
I did notice that the stock crank does not hit the motor, just the motor's width keeps 1/2 of the pedals hidden from your feet. I've heard of pedal extensions, but not familiar with them. They may work in this case, instead of bending the crank, since the pedals aren't expected to be used much for pedaling, just for footrests and brake.
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Maybe the ultimate 2 speed F D should have 2 live jackshafts on a swivel. Engage Low speed roller of stone for quick takeoffs and wet traction, and a steel hi speed roller for minimal tire wear and max fuel econemy at cruise speeds. Much simpler than the 2 belt method too.
Heres a few pics of "Shamless". I swapped to a shorter pedal crank and it is as you said Wayne half of the pedals under the engine. Think I have found a way to extend them. This is a remake of the Point Beach I built for my wife. She finally confessed she doent want to ride MBs. Great, another build for me. Being an aluminum frame bike I have kept the frame in mind during the build. The roller drive cantilevers off the motor mounts, not contacting the frame at all. I guess I had a case of "shifter envy" over Waynes bike, so figured a way to incorporate something of one on the build. Its a single speed, so all I am shifting is the roller. I can go from a 1/4" of roller clearance on the tire to way to much down force in less than 10 seconds. Dont think I will try it on the fly, but adjustments are fast and easy. Just happend to have an old VW shifter hanging around to use. The driven pulley is the variable one so I have adjustments from 3.5-4", the spring loaded idler(on the wrong side of the belt in the pic) takes up the difference. Am dropping the bike to 24" wheels, got a pair with a front drum brake on the way. Going to cobble together some kind of springer front I think. Any way its just in the rough stages now. Not trying to jack the thread when its farther along I post a new one.
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The belt is always engaged since its a cent. clutch. It was just slack in the pic. I hadnt moved the idler to the top of the belt when the pic was taken. It keeps constant tension on the belt. Allows for changing the pitch on the adjustable driven pulley and the movement of the entire roller unit. Thats what the shifter moves. In just a few seconds I can completely disengage the drive roller from the tire for free pedaling, or add massive amounts of down load if conditions llke hills, or wet conditions warrant. With high loading it a passible driver in moderate wet conditions.
An idler clutch could have been used, but with the centrifugal clutch the bike will pull away from stop with out pedaling, great in traffic. Not that I have a lot, but is nice on a trip when passing through towns. Just twist and go.
There seems to be so many more avenues to explore with FDs vs. chain drives. Roller diameters, shapes, materials, pressures....ect. I've always wondered if there isn't a way to make a belt tension clutch engage more smoothly as well. My current riding mower has a belt clutch and is sometimes like riding a rodeo bull. I think if your tensioner is closer to the driven pulley than the drive pulley and on the side of the belt leading FROM the drive pulley to the driven pulley it would be less likely to snatch.
I really like the multi-speed ideas as well.
I dismissed them early on when I got interested in building motorized bicycles. My nephew had a factory built FD moped that was a real POS, and the cheesy builds I've seen on youtube had me convinced that FDs are not the best way to go. This thread has made me reconsider.
MHF
P.S. Wayne, what's a good source for pulleys ?
I really like the multi-speed ideas as well.
I dismissed them early on when I got interested in building motorized bicycles. My nephew had a factory built FD moped that was a real POS, and the cheesy builds I've seen on youtube had me convinced that FDs are not the best way to go. This thread has made me reconsider.
MHF
P.S. Wayne, what's a good source for pulleys ?
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I have been buying the die cast pullies from my local hdw store..the Idler pullies from Tractor Supply.
I must have gotten my idler clutch right. It engages very smoothly. I use a wire bale on the end og the handlebar grip to lock the handlever down for"neutral. The locking levers don't lock all the way down against the bar grip.
I must have gotten my idler clutch right. It engages very smoothly. I use a wire bale on the end og the handlebar grip to lock the handlever down for"neutral. The locking levers don't lock all the way down against the bar grip.
On some of the lawn equipment they used an almost square section pulley on the driven to allow the belt some slippage on engagement. These were smooth. It probably worked as well as it did because of the low gearing of the tractor. Might slip under load in a high load situation on an MB.
Nice work on the mount idea, CB2!
it kinda makes a nice, triangulated drive package, independent of the frame.
Where did you get that fancy adjustable sheave? it's a nice one!
...things sneak up on me slowly...
when working with the FD, the wheel/tire diameter are really out of the equation since they are in direct contact with the road surface. Basically it's motor reduction to the FD drive pulley and whatever diameter it is that is effectively the ground speed...
it's a dim lightbulb, but it comes on every now and then! lol
LOL I liked the 'shifter envy' bit...
You fellows are doing very well towards development of a kit package that would be far superior to the HT... it's close!
How much would it complicate things to use a single belt and a cone-shaped FD wheel in contact with the tire for a vari-drive method?
Best
rc
it kinda makes a nice, triangulated drive package, independent of the frame.
Where did you get that fancy adjustable sheave? it's a nice one!
...things sneak up on me slowly...
when working with the FD, the wheel/tire diameter are really out of the equation since they are in direct contact with the road surface. Basically it's motor reduction to the FD drive pulley and whatever diameter it is that is effectively the ground speed...
it's a dim lightbulb, but it comes on every now and then! lol
LOL I liked the 'shifter envy' bit...
You fellows are doing very well towards development of a kit package that would be far superior to the HT... it's close!
How much would it complicate things to use a single belt and a cone-shaped FD wheel in contact with the tire for a vari-drive method?
Best
rc
I think that CB brought up that idea a while back. Another idea might be to use a spring loaded "constant tension" pully from Mcmaster Carr. Sorta pricey at around 80 bux.
Mount it on the jackshaft, and use the idler on a shift, Mash the idler in more to make the spring loaded pullies expand and let the belt run in a smaller circle for higher speeds. Infinate ratios within the adjustment range.http://www.mcmaster.com/#v-belt-pulleys/=f58ivm
Heck, CB's adjustable pully might could be modified to do that. Or use similar parts from a MTD mower drive.
Mount it on the jackshaft, and use the idler on a shift, Mash the idler in more to make the spring loaded pullies expand and let the belt run in a smaller circle for higher speeds. Infinate ratios within the adjustment range.http://www.mcmaster.com/#v-belt-pulleys/=f58ivm
Heck, CB's adjustable pully might could be modified to do that. Or use similar parts from a MTD mower drive.
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Thanks for the kind comments RC! Only reason I posted my build in Waynes thread was to basicly say I think he has come up with the best configuration on an inframe FD. My hats off to him, this is just my spin on it. Will start a thread when the parts start showing up. My pulley is very common, that one came from Grainger and cost around $20+. It allows a pretty good range of adjustment, 1/2" is a lot on an FD. You would not believe the difference a .125" will make in a roller. The spring loaded vari-pulley would be great. A single belt drive and infinate ratios with a simple move of the lever. They tend to be kinda big though and $$$. I have been kicking around the old Snapper drive disc system, a version of it where the driven disc moves across a large driver, heck you couls even have reverse. A cheaper and plentiful vertical mower engine could be used. Parts from the 21" walker mower might be a good place to start, or atleast have a look at. With a horizontal engine, it could be placed with the shaft fore and aft The cone idea would work if you can figure a way to shift it
I am very impressed with this concept, It certainly simplifies building your own motorbike. It is also possible to put it together with hardware store parts.
If your grinding stone still doesn't give you the friction you want, use the roller out of this......
Allstar Performance ALL10550 - Allstar Performance Tire Tools - Overview - SummitRacing.com
If that doesn't bite into your tire, it can't be bitten.
MHF
Allstar Performance ALL10550 - Allstar Performance Tire Tools - Overview - SummitRacing.com
If that doesn't bite into your tire, it can't be bitten.
MHF
