Converting Front Wheel Drive To Chain Drive

Discussion in 'General Questions' started by 5-7HEAVEN, Apr 22, 2010.

Tags: Add Tags
  1. 5-7HEAVEN

    5-7HEAVEN Guest

    :idea:I'm trying to convert my Staton front friction drive to chain drive.

    My first concern is which front axle to use. I intend to mount a 65-tooth sprocket with 18-tooth at the jackshaft. A 10-tooth sprocket will chain up to another 10-tooth on the engine's 5:1 gearbox.

    My first concern is which front axle to use. Does anyone know which wheel and axle will fit? I have a Giant Rincon bike with original suspension fork.

  2. 5-7HEAVEN

    5-7HEAVEN Guest

    Okayyy, making progress!

    Okay, I'll be using my BMP friction drive housing, modified rear struts and mounting brackets instead of Staton. Bearings are slipfit, so easy access, installation and parts replacement. Staton housing is harder to replace moving parts.

    Using a HD front mountain bike wheel with disc brake hub I have on another bike. It has 12g SS spokes, so it should endure.

    Tension for the #25 chain will be handled by loosening/tightening/locking the BMP rear mounting struts.

    This 54-tooth sprocket using #25 chain bolts right onto the disc hub:

    A 15-tooth sprocket slips onto the BMP 1/2" axle shaft, which is now a jackshaft. Clutch drum of course is not installed, and neither is the friction roller.

    A 14-tooth sprocket slips on the outboard side, outside of the BMP housing:

    The above sprockets are all from the same website.

    A 14-tooth sprocket slips onto the 5:1 gearbox shaft, which then bolts onto my Mitsubishi engine. I got this sprocket from Jerry, aka thescooterguy,com

    Final drive will be 18:1, similar to Staton's 18.75:1 gear chain drive.

    Now to find/fab an engine mounting plate, which will then bolt onto the BMP's channel. Engine will be positioned so that the 14-tooth sprocket on the gearbox llines up with the 14-tooth sprocket on the outboard end of the BMP housing.

    The engine will sit 2.25" higher than friction drive location. It will also move about 2" inward.
    Last edited by a moderator: Apr 22, 2010
  3. 5-7HEAVEN

    5-7HEAVEN Guest

    Well, the #25 sprockets arrived, but they don't match the gearbox sprocket and chain that scooterguy sent me for another project. The gearbox sprocket is 8mm, uses 8mm chain, NOT 25mm chain.:ack2:

    My mistake, hopefully no big deal. I found a 15-tooth sprocket at an online site that will fit onto the 5:1 gearbox AND use a #25 chain. Need to order that $10 part.:detective:

    The 54-tooth sprocket arrived, and bolts directly onto the front disc brake hub! This Trek Rincon bike uses vee-brakes, so I'm not sacrificing the front brakes in order to convert to chain drive.This sprocket is only about 4.25", so chain and sprocket shouldn't take much space.

    Waiting on 1/2" axles I ordered from

    So far, this project hasn't cost much:

    54t sprocket...$29.95
    14t sprocket...$9.95
    15t sprocket...$9.95
    1/2" Titan jackshaft...$4.99
    15t gearbox sprocket to be ordered...$10

    I have bearings and collars on hand, as well as a spare disc brake wheel.

    Instead of using my Staton front friction housing, I'll use my BMP housing. This is mainly because it takes less than 2 minutes to change bearings, axles, collars, etc. Also, there's a 1.5" roller in the Staton unit. To remove the roller and bearings require a day's wait at the machine shop...and an $80 charge. :whistling:

    The hardest part of this project will be fabbing an engine plate, which will bolt onto the top of the BMP housing.

    Sorry, no pictures. I'll post them later.
    Last edited by a moderator: Apr 29, 2010
  4. 5-7HEAVEN

    5-7HEAVEN Guest

    I'm sorry if I did not fully explain what I'm doing on this project and why.

    I have had many friction drive installs in the past years, even a front friction drive that looked goofy but worked well. Performance-wise, friction drive is great. There are less moving parts, so less chance of breakdowns. I can live with the major friction drag, but excessive tire wear and flat tires compels me to change to chain drive. Instead of buying heavy chaindrive boxes or axle-mounted kits and deal with high cost and difficult tire changes, I'm gonna modify my existing friction drive units and convert the friction housings to chain drive. The clutch drum and friction rollers get tossed out. In its place, an 1/2" axle slips in with sprockets as a makeshift jackshaft. The engine is then relocated onto the top of the drive housing, sporting a new 5:1 gearbox and corresponding sprocket. A short chain then links engine and jackshaft. Jackshaft is chained to the big sprocket bolted onto the disc brake hub wheel.The friction drive's rear supports become the chain tensioner. Adding shims or adjusting bolts ala Titan engine rear carrier adjusts the chain from engine to jackshaft. By juggling the sprocket sizes at the outboard jackshaft sprocket., gear ratio can be changed to suit one's needs from hillclimbing to flat out runs.

    This conversion is possible with rear friction drive also.

    Hope this clears any confusion.
    Last edited by a moderator: Apr 29, 2010
  5. 5-7HEAVEN

    5-7HEAVEN Guest

    My axles from Dax arrived. They're slightly larger than 1/2", so my sprockets won't slip on. I just spoke with Duane. That's the only axle size he's ever used for the Titan carrier. I'll try to make it fit, because they fit my purpose well and the price was GREAT!

    My BMP axle also arrived.The sprockets DO slip onto it. I can use this as a second choice, but I'd like to use Dax axles. For one, they were used specifically for Titan's jackshaft. For two, they're much longer, so can also bolt another pulley or sprocket on the other side, for a small generator, if the need arises.:idea:

    My #25 sprocket with 15 teeth to fit the gearbox 6-pinion spline is in the mail, should arrive next week.
  6. loquin

    loquin Active Member

    Sounds like the axle may be a metric, 13mm in size. If that's the case, you could locate a 13mm drill bit, and bore out the sprocket to fit on a drill press.
  7. SimpleSimon

    SimpleSimon Active Member

    Well, it ain't an elegant solution, but I know it works - I've done it.

    Take a portable drill with a chuck big enough to accept the axle and lock it into a vice, with the bare end of the axle sticking out (or put it in a drill press if you have one), then use emery cloth looped around that portion of the axle you need reduced, fire the drill up. Stop frequently to mic the shaft, and when you are as close as you can reasonably get change to a glass cloth with a very high grit number for final polish/sizing.

    It is tedious, but it works.
  8. 5-7HEAVEN

    5-7HEAVEN Guest

    Loquin, I might go with Simple Simon's way.

    The 15-tooth gearbox #25 sprocket arrived. It fits perfectly.

    Now I just need to mount the front friction drive housing, measure for chain length and fabricate the engine mount,:detective:

    TREEWK Member

    5-7, Could You Just Buy A Piece Or 1/2" Dia Keyed Shaft.. Are You Mounting The Jackshaft Sprocket That Drives The Front Wheel Inside The Friction Drive Channel? I Guess You Said You Were Movint The Channel Over 2 Inches. Oh, Are You Aware That The 5:1 Gear Box Reverse`s Rotation. That Will Not Be A Problem, But The Gearbox Has To Be On The Right Hand Side Of Bike Then The Jack Shaft Can Drive Either Side Of Wheel. Split collars are much nicer to work with than set screw type and hold much better. Just Trying To Help. Ron
    Last edited: May 4, 2010
  10. 5-7HEAVEN

    5-7HEAVEN Guest

    Ron, yes, I could buy a 1/2" shaft online. I am mounting a 14t or 15t sprocket inside the friction drive channel. Another 15t sprocket mounts on the same shaft, but outside the right side of the channel, when you look from the rider''s position. That way, the muffler or pipe is closer to the rider.

    Yes, gearbox will force the engine and all sprockets to rotate clockwise. The 54t sprocket mounts on the right side of the wheel. It bolts directly onto the disc brake hub.

    So far, everything simply bolts onto the bike. The only custom piece will be the motor mount.:detective:
  11. 5-7HEAVEN

    5-7HEAVEN Guest

    I purchased 10 feet of quality Hitachi #25 chain on ebay:

    Seller wanted $20 plus $4.95 shipping. I offered $14.05; he accepted, so chain will cost $19.

    Be sure to shop around. A popular vendor wanted $50 for 10 feet, then a whopping $51.61 for UPS shipping, for total of $101.61. (I paid $19).

    Ron, I did end up buying 18" of 1/2" keyed shaft, broached collars and keys from this robotic supply house:

    Seems like quality stuff, and I paid $36. They had annealed shafts, but I needed to be able to cut to length for THREE of my projects.

    Same other vendor wanted $135 for all this stuff. I paid $55.:jester:
    Last edited by a moderator: May 7, 2010
  12. 5-7HEAVEN

    5-7HEAVEN Guest

    Hey, Wait a Minute!!

    A wild idea came to me that I could keep the engine in its friction-drive mounted position. Then, I would use BMP's clutch drum, spacers and friction roller shaft to mount the #25 sprockets (#25-size are the smallest sprockets; a 90-tooth sprocket is about 7.5" in diameter). then occured to me that my engine would need 18:1 gear ratio. Even if I were to find a 10-tooth sprocket, that would only give me 9:1 ratio.

    I would need a 180-tooth sprocket, which I don't think exists. If I find one, then no need for 5:1 gearbox, fabbing motor mounts and locating the engine 2.5" higher from its present position. :idea:

    A 180-tooth #25 sprocket would be about 14.3" in diameter. Not TOO big. That'd work for front AND rear friction drive conversion. And it would bolt onto Staton rear hub with left-hand thread for freewheeling.

    Man, that'd make for a CLEAN installation.

    Maybe I'll look for it online....:detective:
    Last edited by a moderator: May 7, 2010
  13. 5-7HEAVEN

    5-7HEAVEN Guest

    It Won't Work.

    I just remembered something. Engine rotation is counterclockwise; friction roller contacts the tire, which then spins clockwise.

    Engine in the friction drive position with sprockets will spin the chain in reverse...

    unless you drill new mounting holes on the other side of the housing and relocate the engine to the other side...:idea:

    ORRR reverse the housing 180 degrees and drill new 1/2" holes for the front mounting bracket.:idea:

    A 10-tooth sprocket with 1/2" bore using #25 chain might not exist, but a 14t sprocket does. Using 14t requires a 252-tooth driven gear on the hub. Of course, this sprocket would have to be custom made, with a diameter of 20".

    Unsure how much stress a 20" metal sprocket would be when mounted by four small bolts in a 2" circle at the wheel hub, though.:detective:
  14. 5-7HEAVEN

    5-7HEAVEN Guest


    In recalculating this, using a common 14-tooth #25 drive sprocket would necessitate a 252-tooth, 20"-diameter #25 chain sprocket. Too much custom work on a sprocket which MIGHT not work. The 2" bolt circle has me worried.

    HOWEVER, a GEBE drive pulley, belt and ring MIGHT work. This is in a new thread I created elsewhere in this forum.:jester:

    BTW, the Hitachi 10-foot chain arrived. What a deal! $19 for 10' of chain. For those who've never seen a #25 chain, they are MUCH smaller than bike chain. I hope the chain works; Staton uses #25 on their axle-mount engine kits, but chain length is much shorter:

    Waiting on the 1/2" keyed axle shaft; vendor emailed and said it'll be in the mail tomorrow.