Friction Drive that works in wet weather?

Discussion in 'Friction Drive' started by msamigo, Jul 26, 2015.

  1. msamigo

    msamigo Member

    If you have had success - what type drive wheel are you using?

  2. butre

    butre Well-Known Member

    chain and sprocket. you'll never find anything that works well in wet weather and doesn't eat through your tires in an instant
  3. troyg

    troyg Member

    I don't get the "slips in wet weather" thing, I'm using an old BMP with the knurled steel roller, yeah I have to feather it, but it seems to work in water and snow just fine.I'm betting the staton sliced steel rollers woirk even better.There is a dude on youtube that shows him using the honda gxh50 (I think) in the snow, the guy is a big boy, and he doesn't even feather it, works great.I think it's all proper tire pressure, then pressure against the wheel.The only time I had a tire worn quickly was when I was learning it, on a dry desert pavement, since then no problems.
    libranskeptic likes this.
  4. libranskeptic

    libranskeptic Member

    It worked for me:

    find a; short, tight fitting (maybe i got lucky with my exactly 1" smooth spindle), reinforced industrial hose length for your spindle, like compressed air or hydraulic hose.

    cut 2 suitable rings from the hose and jam them on the spindle with a gap for the center of the tire. the hose rings are to grip the , normally ungripped and unused, "corners" of the tire. Adjust and tweak hose ring placement to suit.

    The hose has steel mesh in it. Harsh but grippy, & meh, the corners go unused on discarded tires anyhoo. My tire were $6 each back then anyhoo. More a clutch plate than a priority safety item. Its the front tire that counts for that. The mesh fragments, if any?, never caused me puncture problems btw.

    I also found striking a balance between tire pressure (gripping surface) and downward force (too much bends axles the unavoidable weaker rear axle) to be a black art for grip in the wet. Its a problem, but it can be solved.

    lets not forget, even if you do have to pedal a bit more than usual, the motor is probably still doing most of the work.

    The simplicity of friction drive has much to commend it for many.
  5. HeadSmess

    HeadSmess Well-Known Member

    once worked, by using a smallish scooter tyre running with a redux chain rather than any metal or "coated" roller.

    more contact area, higher friction material, plus slower surface speed=success!

    very hard to get rubber to slip on rubber...

    it is slightly easier to line the chains up on a separate frame and bolt that to a bike, rather than the fiddle it can be to get a double chain redux lined up with the rear wheel on an actual bike frame.

    ignore the wheel diameter, whats important is the size of the roller that drives the wheel. imagine that its the roller running along the ground.

    and my other method was to use 1/2" star washers clamped to a spindle...mounted on bearings at BOTH ends. OD of the washers was about 13/16... the best i ever had doing it the "simple" direct drive way. easily replaced, cheap. and hardened...
    libranskeptic likes this.
  6. libranskeptic

    libranskeptic Member

    To spell out the guys question, there is a silent "given I like the; DIY, elegant and utter simplicity of friction, ..." preface to it, or he wouldn't be attracted by friction drive.

    Perhaps a typical context to empathise with - "I am a kid with no money, shop skills, car or licence from the flat rural (range anxiety with ebikes) part of USA or Oz (need to be 17 for a license) and i would like to spare mom the chore of driving me and the freedom of wheels. What I do have is a motor and a MTB. What should I do?"

    Its a no brainer even if mom has to collect him in the pickup at times.

    Chain is one solution to slippage, but it introduces many problems/complexities/hazards of its own. Clutch especially. Most need a means of disengaging the running motor from the drive mechanism. Chain guards?.

    My rig was so simple yet practical once i didn't have to fret about rain. I had the best of both worlds.

    The alleged downside of tire wear is a furfy on balance. Its a five minute job replacing a very "meaty" knobby $5 rear 26" MTB tire maybe twice a year on a qiklock wheel. The tire serves triple duty as also, a clutch plate, starter and a torque converter (at times where some slippage is in fact, desirable).

    Soo simple. A brush cutter 2 stroke motor (a boon is they dont have float carbies and can be upended with impunity) and fuel tank on a swing arm from say, the seat post. The spindle is simply raised or lowered on the tire..

    To engage/lower the swing arm, I had quality rope connected to a rearmost point, then down and around the lower rear fork arm, up to a quality cleated single wheel pulley (as used on kids trainer sailboats ) thru the pulley attached to the steering stem, and thence tied off on the seat post.

    So you now have rope running parallel with the crossbar from steering stem pulley to the seatpost. Engaging the spindle with force is easy as you ride, simply use your body weight to push down on the crossbar rope length, and the pulley cleats lock it there.

    To disengage the spindle, i used the very adjustable and versatile advantages of links of a length of chain and a small (3-4") mini trampoline spring (throwouts) from the rear of the swing arm to e.g. the seat, so when the downpull rope was released, the chain/spring raised the swing arm sufficient that it doesn't slam down on wheel on major bumps while raised. A little bumping is tolerable, the tire cushions the force.

    So simply free the downpull rope from the grip of the cleats with an upward tug on the now slack crossbar rope, and the swing arm rises and disengages the motors spindle.

    The swingarm was simply a piece of steel plate (could be improved on weightwise), cut with oxy to shape and drilled for securing it to only one side of the engine housing. No complicated second bearing on other side of the spindle, nor was it needed (it lasted forever til stolen). The spindle simply stuck out at right angles from the motor.
  7. libranskeptic

    libranskeptic Member

    A killer bonus for friction drive which deserves separate mention, is that it's a natural and elegant reduction box. ~No such ungeared petrol motor could effectively propel a rider.

    a 26" rim plus say 3" of tire and a 1" spindle is a 29 to 1 reduction right there. Alter spindle size to suit.
  8. HeadSmess

    HeadSmess Well-Known Member

    the tyre size is irrelevant with FD setups.

    the tyre just acts like an idler gear. reverses direction with no change of gear ratio, be it a 12.5, 16, 20 or other size rim... one roller suits all tyre sizes. unlike chain or similar drives.

    plus its a bit impractical to run the roller itself on the ground, seeing as its smaller than the crankshaft... i am sure something would interfere!
  9. HeadSmess

    HeadSmess Well-Known Member

    a torque converter INCREASES torque. it doesnt just slip...

    i thought this was a kid with no access to shop tools?

    sticking the spindele straight off the shaft may be great for a temporary setup that doesnt see much use, but then you flog out the crank bearing, snap the crankshaft, and if the spindle is just a tapped piece of bar driven by the thread on the strips. or undoes itself. then the flywheel comes off.

    to do a decent friction drive does require a bit more effort than just strapping an engine to a pushie.

    my first one held up for about 3 years, the maiden ride was approx 250 km, with no issues. except the alloy roller i used whilst waiting for the star washers to arrive completely wore out.

    then "someone" started using kero, plain engine oil, sometimes model plane fuel...whatever he could find at the time. it didnt last long after that! :D

    i found using slicks/road tyres was far better than knobbies. the knobs just tended to rip straight off, exposing the nylon cords underneath. then POP!

    them big fat diamond pattern cruiser tyres were the best of all!virtually flat on top with almost no curve to them.
  10. libranskeptic

    libranskeptic Member

    Gosh, you are so right about the gearing thing. How dumb of me. I really thank you, but its a shock that i was so wrong for so long.

    Surely the size of the spindle matters tho?

    I still like friction, as discussed.

    Any hoo, sharing the benefit of my experience, a bog standard 2 stroke weedeater motor, a cheap steel MTB and a 1" smooth steel turned spindle seemed a very nice and practical balance in a mildly hilly part of sydney OZ.

    I just kept the pedal gearing always in the right (very low) gear to have maximum effect when the motor began to stall, and i became very clever about never actually stopping - to avoid the hassle of restarting or disengaging.

    BTW, Ebikes win hands down at riding at "almost stall" speed, which i do a lot of, being patient and courteous among pedestrians while walking my old dog.
  11. libranskeptic

    libranskeptic Member

    good input

    correct, as described, that needs doing in a shop from a template of the engine housing. A drill and oxy isnt a big ask. Many trades use them. I think i could avoid that, but it would take some trial and error to be sure.

    perhaps torque converter isnt the right term. Slippage is the same as slipping a clutch, which can compensate for lack of engine torque - keeps the motors revs up.

    re "
    to do a decent friction drive does require a bit more effort than just strapping an engine to a pushie", well, as discussed, my experience is that you pretty much can. Just saying, it sure worked well as my reliable, sole transport when i was dead broke - which explains the tire thing, chinese $5 rear tires worked ok for me. Maybe 2 tires pa, gripped ok, 100km pw.

    I can only say the spindle as described got a thrashing from me and a previous owner, and the motors bearing held up fine.
  12. HeadSmess

    HeadSmess Well-Known Member

    ha ha, chinese tyres are different kettles of fish. el kmarts always did fine... whereas the set of racing knobs someone gave me...real expensive suckers... shredded.

    i live in the hills district. my first ride was to newcastle and back. mooney mooney bridge was the most scary thing i have ever done! averaged about 55-60km/h

    yes, you can strap em on... but i used to jump mine, having it stuck on the back of a bmx as a 16 yr old. i found out quickly how easily "strong looking" setups tended to bend and fall off. to the point that i had a pivot behind the seat brazed to the frame, a piece of machined square tube running two flange bearings to take the spindle, the engine basically just bolted on, the spindle being driven by a cush drive, using the two clutch bolts to engage with two holes in the end of the spindle. very easy to work on. just undo engine bolts and it came off. spindle just poked through the bearings, nut on the end clamped the star washers in place, took about ten minutes to swap them over.

    it took a few tries to perfect the design!
    maybe when i was twenty or so... i used to be in tears coming up galston gorge with even the slightest trace of moisture on the road.

    turnbuckles on either side to the rear axle, with a pivot, linkages etc so i could lock it off, lock it on, and slip the wheel as necessary, which wasnt too often, but try as hard as i could... i could never get it to stick in the wet. the slightest trace of moisture up a 5 km hill, like galston gorge, had me cursing, swearing and crying all at the same time.

    or you had the pressure wound on so hard the tyre deformed and the engine was virtually stalling.

    with a 13/16 OD roller!

    still, other than that... definitely the best FD ever had. no other engine after i blew that one ever seemed to go as hard. shame really :( husqvarna brushcutters are the best engines for sure!

    the last one i ever made did what i first mentioned... a hacked up scooter using some minor redux gears, that was definitely water proof! but i chose to use a 10 speed racer with inevitable results...i think my mother ended up throwing it out one day... at least, i havent seen it in ten years or so...

    electric being (almost) the only option allowed here now, i have to agree...its ideal for just puttering along. though i walk (run) the dog by using the pitbike!
  13. Daniel FC

    Daniel FC New Member

    YOOO!! I live in the south of Chile and there is a lot of rain here, I want to buy a Friction Drive kit for my trek but because of the rain I was doubting but I had a great idea, havent tested yet but I think is perfect. Solution: Hidrophobic sprays coating for the tires, NEVERWET or other products they cost 20 dolars!!!! the tires will repell the water and mud so the fricion woulilnt be affected and you can aplly the same product to the friction wheel. tell me if you try it!! greetings!