who doesn't want a bike that can go on/off road, with a creeper/pullin gear. and a (reliable) way of changing thru gears. i mean a utilitarian bike here. varidrives/cvts/separate gear-driven shiftable transmissions. and since those setups are always custom-made, i thought this should go in DIY. rear hub and sprocket setups that aren't bolted to the spokes would inspire innovation to. as for shift kits, i dont own one so i can't talk, but i dont think you can rack hundreds of miles on pawl/freewheel mechanisms...not very easy to service either.anyway, speak up.
utility bikes/shift systems
- Thread starter Build-a-beast workshop
- Start date
Not to dissuade any thoughts of "varidrives/cvts/separate gear-driven shiftable transmissions" as everything has advantages & disadvantages, but the pawl/freewheel systems are actually really easy to maintain & service... provided ya don't drop any parts under the workbench lol - additionally most of our powertrains rely on some sort of one way freewheel somewhere. I've logged almost five thousand miles in a single summer with my Rollfast & the freewheel in the shiftkit didn't give me the slightest problem. I've heard yer not "supposed" to use grease in them as the pawls may stick, but even before I installed it I repacked it with a quality marine grade bearing grease... and I've not had to do anything to it since. Another advantage of the jackshaft setup is ya don't hafta sweat the "sprocket bolted to the spokes" problem ofc.
I'm not sayin' shiftkits don't have their issues, just that the freewheel isn't one of 'em heh. My biggest problems were chain maintenance, side plate flex & a bit of a "pulsing" symptom. The chain issues annoyed me greatly at first as there's no easy tensioning method, then it occurred to me the miles I was racking up - that it wasn't so much undue chain wear as just the maintenance chains require. I jus' switched to the highest quality chain I could find *shrug* The side plate flex is a problem with the older designs (three piece) and the cloned copies of the same. The copies are of the first edition SBP shiftkit, the 2nd edition was better in that there's a reinforcement plate on the engine drive side, but there's still some flex evident. SBP has developed the 3rd edition which is unitized & the sides are not as long, while I've not run one - a buddy has one and I think they've resolved that issue w/it.
The "pulsing" problem gave me fits however - there was "something" somewhere that was out-of-round causing a sort of lurching under maximum load. After going through the entire shiftkit setup and engine looking for bent shafts & misstamped sprockets - it turns out that it's simply the square tapered shaft on the bottom bracket, where the pedal crank presses on. After replacing both the bearing cartridge and the pedal crank yet still having the problem, I took off the pedal arms and rotated them ninety digress to the next flat and that reduced the symptom a lot.
Interestingly, many don't seem to have this problem... but as I've replaced parts and it's still present just lessened, I've decided it's "tolerable" and perhaps just part of my bikes "personality" heh. It's nearly impossible to get the pedal crank perfectly true on a square shaft and that's the root cause, I could tear it down and experiment with shims etc. - but I've decided not to bother as it's now hardly noticeable, most likely is that my first pedal arm was a lil miscast.
Again tho - nothin' wrong with experimenting with other options, I jus' wanted to give a lil feedback regarding the shiftkits as I think them elegant in their simplicity
I'm not sayin' shiftkits don't have their issues, just that the freewheel isn't one of 'em heh. My biggest problems were chain maintenance, side plate flex & a bit of a "pulsing" symptom. The chain issues annoyed me greatly at first as there's no easy tensioning method, then it occurred to me the miles I was racking up - that it wasn't so much undue chain wear as just the maintenance chains require. I jus' switched to the highest quality chain I could find *shrug* The side plate flex is a problem with the older designs (three piece) and the cloned copies of the same. The copies are of the first edition SBP shiftkit, the 2nd edition was better in that there's a reinforcement plate on the engine drive side, but there's still some flex evident. SBP has developed the 3rd edition which is unitized & the sides are not as long, while I've not run one - a buddy has one and I think they've resolved that issue w/it.
The "pulsing" problem gave me fits however - there was "something" somewhere that was out-of-round causing a sort of lurching under maximum load. After going through the entire shiftkit setup and engine looking for bent shafts & misstamped sprockets - it turns out that it's simply the square tapered shaft on the bottom bracket, where the pedal crank presses on. After replacing both the bearing cartridge and the pedal crank yet still having the problem, I took off the pedal arms and rotated them ninety digress to the next flat and that reduced the symptom a lot.
Interestingly, many don't seem to have this problem... but as I've replaced parts and it's still present just lessened, I've decided it's "tolerable" and perhaps just part of my bikes "personality" heh. It's nearly impossible to get the pedal crank perfectly true on a square shaft and that's the root cause, I could tear it down and experiment with shims etc. - but I've decided not to bother as it's now hardly noticeable, most likely is that my first pedal arm was a lil miscast.
Again tho - nothin' wrong with experimenting with other options, I jus' wanted to give a lil feedback regarding the shiftkits as I think them elegant in their simplicity
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the front freewheel, that one only feels your legs. the poor rear cassette takes the whole beating...their expensive,and most people dont have the tool to even take them off. (elaborate on your rollfast, i wanna hear about its drive system) you HAVE to pack a little grease to get all the bearings back in after dissassembly,after that its heavy gear oil, and if it's sealed like most new bikes, you just let it die with time(idk how to get apart the one-piece freewheeling hubs, the cassette slides off the freewheel piece, know what im talking about?if so spill your guts). (the rear cassette can attribute to the surging, some crappy ones are naturally misaligned, you know what they look like when the wheels moving) i sold and fixed bikes since i was a littln', i can say that derailleurs are some rube goldberg machinations, not that they wont last, just a little over-complicated.(yeah i know their simple to the naked eye, its all the crap and mechanisms that shifts/adjusts/moves/pivots/tensions that i don't like)
Well, the front freewheel w/a shiftkit does transfer the engine's power too, which is why there's a freewheel bearing on it - else ya'd hafta pedal as fast as the engine's output... sorry, I thought that was the freewheel you were referring to - I dunno much about the rear cassette's pawls as I've used the Sturmey Archer X-RD3 3-Speed drum brake hub w/that build - but I've not heard of problems with the multispeed rear cassette's freewheel or derailleur... I've heard of problems with bending the teeth in a "turbine" looking way, but even that doesn't seem common *shrug*
Ifn yer curious, all of my builds have links to their threads & photobucket albums here: http://motorbicycling.com/members/barelyawake-albums-builds-so-far.html
Ifn yer curious, all of my builds have links to their threads & photobucket albums here: http://motorbicycling.com/members/barelyawake-albums-builds-so-far.html
I have done some 60,000 plus miles peddling on rear derailleurs and free wheel sprockets . They are very bullet proof. I used one with a shift kit and could not break it!!
yes....sturmey's are tough...havta break it open yet?! its fun. keep it oiled or anything?(if it had a plug hole on the hub)the pawls on the front freewheel only feel your leg's power, not the engine's,so it would never break,only get sloppier,by that time it'll be throwing chains. legs and electric motors transfer constant/even power, but engines are like little jackhammers...correct me if wrong, but in that split second of the exhaust stroke, where there is no power, wouldn't things in the drivetrain go slack? and on the next fire, the pawls get slammed into the face of the ratcheting drum.makes sense? i've had a gear-reducted scootermotor (w/ built in centrifugal clutch) driving a 3-speed sturmey coaster, and it was probably the direct chain drive, but it ate pawls. because of the hammer effect. you'll notice it, when it starts to snap under load, thats the pawls rounded faces slipping and catching, then finally you wont move anywhere and just chew metal. i know how bulletproof they are,and again, leg peddlin wont kill em, but thats not 60,000 miles on the same freewheel mechanism, or is it? that would be the cats a$$, about 8 round trips around the united states
My leg power is pretty darn good. I got wheels pedaling with over 6000 miles on them and the free wheels are flawless. I ran a 5.8 hp Morini into one was lovy dovy put about 1700 miles on it so far and never ever have been nice to it. http://motorbicycling.com/f47/morini-time-full-sus-project-9048.html
The rear hub free wheels on these hubs especially shimano are outstanding .
A little ol 2 hp china motor will never ever break these free wheels in my experience and opinion. So far on this forum in the last years of the nifty JShaft kit no body has ever messed up a rear wheels free wheel that I ever heard of....
The rear hub free wheels on these hubs especially shimano are outstanding .
A little ol 2 hp china motor will never ever break these free wheels in my experience and opinion. So far on this forum in the last years of the nifty JShaft kit no body has ever messed up a rear wheels free wheel that I ever heard of....
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I cannot ever remember stripping out a free wheel except for the old huffy days. That don't count it was a terrible cold winter the springs behind the paws lost their ump to engage. Out of all my free wheel hubs never stripped one ever. Not saying it cannot be done. I ran a j shaft kit on a china that worked great too.
never stripped the threads off an aluminum hub? i think the gear reduction, plus the chinas/morini's clutch system, plus the jackshaft....it would all go to dampen that jackhammer effect. especially the clutch...(i dont own a kit, so seeing that they had little engageable clutches was awesome) ya'll are eloquent typists, are my excuses for sentences easy-reading?. i dont doubt the beastocity of your legs, but you can't flatten a pawl's contact surface with them...it takes the bee's-wing /jack hammer beats of an un-dampened two-stroke(my POS with the chain drive directly from the output shaft to the three speed hub. the centrifugal clutch and built-in gear reduction didnt help.i think the centrifugal clutch made it worse. compared to the china's morini's engage-able clutch that is...reason being that when an engine fires off with a centrifugal clutch, it wants to grab hard, and on the exhaust stroke, not so much. the china/morini clutch is engaged manually,(constant even pressure) there HAS to be a little slippage/dampening effect when the engine fires off) again feel free to correct me, havn't ever touched a morini/china/huasheng/shift kit/grubbee/etc...
went and looked at the morini full sus.....whats that the nuvinci? i don't know anything about them but the basic cvt concept....they don't use pawls though do they?
Meant to say the Morini started out on a different set up I tried a 9 speed chain set up no dice no body here will use that on a J shaft. Then on to the N.V. wheel . You can't mess up a rear free wheel with a china in my opinion If you tried. I would have a look around the forum and see just how many folks are using J Shafts these days . The free wheels have been definitely stronger than the chains.
j shaft - Google Search
j shaft - Google Search
too expensive with the 9 speed huh? pointless having that many chainrings on a cassette....27 gears of over-lapping ratios. hows the nuvinci holding up? does it take oil or anything?
I could not break the N.V. It had a bit of a duty cycle too it tho. I could get the hub hot. This is a long and brutal thread lol. Youl get the just of it tho from my perspective and cam's.
http://motorbicycling.com/f47/tame-morini-clutch-20970.html
http://motorbicycling.com/f48/inside-nuvinci-hub-21827.html
http://motorbicycling.com/f47/tame-morini-clutch-20970.html
http://motorbicycling.com/f48/inside-nuvinci-hub-21827.html
"WRT to the spikes, most people don't understand that the torque rating of any IC engine is an average number. The actual torque coming from the engine looks something like the EKG trace of a human heart, with a big, short, sharp spike in torque just after TDC. That is what kills transmissions unless you have an isolator of some sort. All automotive drivetrains have them, and most scooter/motorcycle drivetrains have them as well."quoted from Vinci...he states it a little better then "its like a jackhammer". smart dude. the nuvinci would scare me, cost included (idk how much it even is)
i have an idea for a gear-driven trans.belt-input,chain output. or if you have a china/morini...you could shift using it's existing clutch, and run chain drive input AND chain output....almost NO power loss....the trans itself in stock form,can take 18 horses safely...not that a bike can take it....but the trans has proven itself in every way. from decades of service, with only bentonite grease for lubrication, to the immense strains that mower racers put on these things...and these aren't a bunch of drunks on lawnmowers in the backyard.....these things are twin cylinder 40-50 mph machines...probably faster.....the output could come out both sides.....so you could have left or right side drive, or both, depending on the application the trans was used for. its worth looking into, and if you have access to a machine shop, its a pretty easy setup to make. i've just gained access to a machine shop again.....yup...didn't really go into any specifics on the shift mechanisms/brand/number of speeds/parts interchangeability/what exactly it even is/how easy it is to find them. gonna have to poke at me for it though..
i wouldn't start a thread....without something good to talk about (insane, maniacal laugh).........
i did like the nuvinci though.....have to do way more reading. as long as the traction fluid is fresh, theres no metal contact....nothing to wear out but fluid(and it takes alot to do that) the design is pretty flawless. thinking back i remember someone (you know....the type of person thats ignorant to ANYTHING mechanical....which, in this world....is basically everything.) he was given one of those BMW or cadilac bikes with a nuvinci...and to him it was just a bike, that you peddle and shift, like all other bikes.the fluid must've leaked out, he tossed it because "it doesn't peddle anymore".friggin cavemen....the bike was ridden daily by multiple people for about 2 years....mainly they just beat on it...you know...curb hoppin, water submersion (basement). really a shame now that i learned about the nuvinci, that one definitely could have been brought back to life. (don't curse me yet, i never saw the bike, it was tossed before i even knew the guy....or else it would've been mine. give em' the old "yup, thats def. broken, better throw it out,son" yoinkk....
hey i know that engine.the shroud and other plastics are red and black on mine though.great little units, very reliable, i've had a couple, some electric start, havn't seen a chromed one though. i have many tales about seeing these engines abused and neglected,only to keep running and starting dutifully under various conditions and stages of deterioration and have seen them under mile-racking applications(fat kid too young for his license).like rock they are. but do i know who makes them? no....that scooter would throw me on my a$$$$$$$$.nice machine. how many speeds on the nexus? did you pull it off a free bike?!
