Does a gear hub can hold a 212 predator?
LandSpeedRecord
Dealer
There isn't an internal hub that can hold up to a China girl even when it's in the wheel. People have had success using the Sturmey SX3 as a jackshaft even a few others by over driving them by 10 to 1 or better if I remember right. Get your reduction right on the jackshaft and you will go twice as fast on virtually any bicycle as you should with just one gear and a decent centrifugal clutch or torque converter. I love 212's but they will twist all but the strongest bicycle parts in half in short order and bicycle internal shift hubs are exceptionally fragile even under a strong pair of human legs.
Last edited:
cannonball2
Well-Known Member
Actually an IGH will work with smaller 4strokes when handled properly(easy shifting). However I agree a 212 is a torque monster and would make short work of most IGHs.
Maybe the SX3 would work. It easily handles the sudden loading of pedal starting a CG, and I have miss shifted a time or two under full engine load with no issues. Having it apart before using it in the build showed it to be pretty beefy.
Gearing is much nicer over a single speed. Even if the bike has a super top end it much nicer to ride there with reduced rpms/vibes that gearing offers. I would guess a higher end derailleur set up could be used. Would be pretty easy to set up say a five speed. A 212 surely wouldn't need any more. There are 3speed derail hubs also. Have to jackshaft it of course.
Maybe the SX3 would work. It easily handles the sudden loading of pedal starting a CG, and I have miss shifted a time or two under full engine load with no issues. Having it apart before using it in the build showed it to be pretty beefy.
Gearing is much nicer over a single speed. Even if the bike has a super top end it much nicer to ride there with reduced rpms/vibes that gearing offers. I would guess a higher end derailleur set up could be used. Would be pretty easy to set up say a five speed. A 212 surely wouldn't need any more. There are 3speed derail hubs also. Have to jackshaft it of course.
LandSpeedRecord
Dealer
Cannonball2, one of your SX3 jackshafts was exactly what I was referring too. On one hand it's an interesting concept to see how well it would do with a 212 but on the other if you bolt a known torque converter or even a centrifugal clutch with the right reduction the 212 will pull hard off the line and when geared right be at a very comfortable rpm at even 50mph plus. Even the 79cc is capable of that once you really set it up right. I am admittedly too biased to the single speeds because of what I have achieved with them and how much I worked on geared systems that never measured up to what I had hoped. I would definitely like to see a geared 212 or 79 Predator that performs at least as well as a converter or clutch with jackshaft. A 79 with the SX3 as the jackshaft like you build might be one of the sweetest combo's possible. Hmmm my next personal bike...
cannonball2
Well-Known Member
You are right. Nothing beats a torque converter for an easy durable trans. With basically infinite ratios it has a speed for any situation.
Might be interesting to jackshaft a 79cc to an SX3 that's in the wheel.
Might be interesting to jackshaft a 79cc to an SX3 that's in the wheel.
LandSpeedRecord
Dealer
Cannonball2, your work has been an inspiration for me from the beginning. I'm just reading your Schwinn Del Mar-Briggs build with the pillow blocks thru the BB to a nexus hub in the wheel. I am curious if you think any internal geared hubs could hold up too higher power from a heavily modded China girl. You know how long I've been at the Bonneville goal and I am finnally knocking at the door with a pure single speed direct drive 66cc. But for a street aplication I would still love to find a way to shift a powerful motor and be able to push it hard.
Oh and I mean an IGH in the wheel like this post originnaly mentioned.
Oh and I mean an IGH in the wheel like this post originnaly mentioned.
Last edited:
cannonball2
Well-Known Member
I would think if any IGH is going to do it the SX3 would be the one.
Seems the Nexus which I initially thought some what fragile is holding up under 3/3.5hp Briggs 4stroke use. These engines make a good bit of torque at lower rpms where the build is ridden most and they survive. I doubt a tightly wound 2stroke would make much more torque. The trick is in the shifting. For your hiperf engine feathering the clutch for a smooth blend in would be important. Its a sudden loading that is rough on the hub.
Heck if you can recoil start the CG run a Nexus, they are cheap enough. I have bought complete wheels in the $75 range.
Heres an interesting idea. Years back my daughter left me with an engineless VW beetle. I just happened to have a 25hp Briggs V-twin. I installed a large torque converter on the Briggs, made a mount to marry it to the VW trans axle then hooked everything up. It was cool. Had no formal clutch. You just put it in gear, and took off. When it was time let off and shift. The neat thing was each gear had a huge range that was automatically adjusted by the TC. I could get 60mph on the flats which is very similar to the domestic(german) 28hp VW. Neat thing it would automatically "downshift" while in fourth to easily climb hills. Really very little shifting was necessary and it would take off quite well in second. The local Briggs rep wanted to feature it in the quarterly magazine and I wrote an article only to have it squelched by upper management because of possible liability issues. Oh well.
Moral of this long story is imagine a 79 or a 212 thru a TC to the bottom bracket driving and IGH. You could run a very tall ratio that the engine usually couldn't handle and the TC would make it possible on take off and on through the range. Also each gear would have a large range of speed. I could see some high terminal speed with this set up.
Seems the Nexus which I initially thought some what fragile is holding up under 3/3.5hp Briggs 4stroke use. These engines make a good bit of torque at lower rpms where the build is ridden most and they survive. I doubt a tightly wound 2stroke would make much more torque. The trick is in the shifting. For your hiperf engine feathering the clutch for a smooth blend in would be important. Its a sudden loading that is rough on the hub.
Heck if you can recoil start the CG run a Nexus, they are cheap enough. I have bought complete wheels in the $75 range.
Heres an interesting idea. Years back my daughter left me with an engineless VW beetle. I just happened to have a 25hp Briggs V-twin. I installed a large torque converter on the Briggs, made a mount to marry it to the VW trans axle then hooked everything up. It was cool. Had no formal clutch. You just put it in gear, and took off. When it was time let off and shift. The neat thing was each gear had a huge range that was automatically adjusted by the TC. I could get 60mph on the flats which is very similar to the domestic(german) 28hp VW. Neat thing it would automatically "downshift" while in fourth to easily climb hills. Really very little shifting was necessary and it would take off quite well in second. The local Briggs rep wanted to feature it in the quarterly magazine and I wrote an article only to have it squelched by upper management because of possible liability issues. Oh well.
Moral of this long story is imagine a 79 or a 212 thru a TC to the bottom bracket driving and IGH. You could run a very tall ratio that the engine usually couldn't handle and the TC would make it possible on take off and on through the range. Also each gear would have a large range of speed. I could see some high terminal speed with this set up.
LandSpeedRecord
Dealer
I like the design of that build and love the BB jackshaft but we have to have pedals here in AZ. That's why I figure I am stuck with left side drive and can't use an SX3 in the wheel. That's impresive on the Nexus. I wouldn't be suprised if your Briggs doesn't make more torque than even my most strung out 66cc. I figure I am pushing close to 6hp from the speed we are getting but probably less torque than Lance Armstrong on a heavily medicated day lol. I am liking the idea of trying a Nexus in the wheel. I have some extra SBP parts and odds and ends from my last HuaSheng shifter bike that got cannibalized to build a Predator 79 for a friend.
Last edited:
outlawmotorizedbikebuild
New Member
I am planing to build a fat tire with a 212 but i want to incorporate to the build 212 predator and a belt drive, but i wander what kind of gear hub is capable to support an 212 modified for performance, any suggestions? brands or models?
Thanks in advance!!!
Hi my name is Dre I have perfected the 212 motor on three types of bikes the OCC Chopper the swim Blackwell beach cruiser and the Mongoose 4 inch Fat Tire Bike. I always use the comet torque converter you get them off of eBay the price is down very low for them now. The rear sprocket I use a 48 tooth 415 sprocket and the front sprocket off of the jackshaft I use a 9 tooth 415.. please don't ask me to send pictures I am new to this forum and trying to navigate how to put pictures on it is being quite a task for me.
scotto-
Custom 4-Stroke Bike Builder
I have a 212+cc Predator (first generation) that I have been racing for over 5yrs. now and it's gone from single speed TC at 10hp to 2 disc cent. clutch at 26hp.
Either way gears have not been needed for this application but a jack shaft is required of course. Currently running a gear ratio of 11.11:1
The primary gearing is 12t on the Vortex clutch to a 25t sprocket using #35 chain and the secondary is 9t sprocket to a 48t sprocket on the hub with a #41 chain.
Tried and true... I've won many races using this setup.
t
http://i1250.photobucket.com/albums...3490807_5048952332456084999_n_zpsntyd5dtm.jpg
Either way gears have not been needed for this application but a jack shaft is required of course. Currently running a gear ratio of 11.11:1
The primary gearing is 12t on the Vortex clutch to a 25t sprocket using #35 chain and the secondary is 9t sprocket to a 48t sprocket on the hub with a #41 chain.
Tried and true... I've won many races using this setup.
thttp://i1250.photobucket.com/albums...3490807_5048952332456084999_n_zpsntyd5dtm.jpg
Last edited:
Tony01
Well-Known Member
Yeah that's what I meant. Cool.