friction roller dai/speed

Discussion in 'Friction Drive' started by zukjay, Jan 13, 2009.

  1. zukjay

    zukjay New Member

    here are some numbers i crunched to come up with some general top speeds for different sized roller. of course this asumes you engine has the umph to turn at 6000rpm while loaded and also factor in some loss of energy to friction and wind. this should help some folks out. tire size doesnt matter much with friction drive, except a taller tire traverses variances(pot holes, curbs, debris) in the road much easier than a small say 12"-16" wheel. but thats not to say small wheels wont work just that there not ideal.

    mph at 6000rpm

    roller dia. Speed

    1" 17mph
    1 1/4" 22mph
    1 1/2" 26mph
    1 5/8" 29mph
    1 3/4" 31mph

  2. Mountainman

    Mountainman Active Member

    seems to be off just a little

    1" roller with a 1.6 hp hits around 22.5 mph with a 200 lb rider

    note -- a 1 3/4" roller is a pretty large THING
    think that your miles per hour would be higher (38 mph ?) -- if it could be done
    may not have the top end -- so as to get there

    always fun as we ride those friction driven THINGS
    Last edited: Jan 13, 2009
  3. srdavo

    srdavo Active Member

  4. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    His figures are correct for 6000 rpm

    HP has nothing to do with the calculation except if you
    don't have enough HP to pull your ratio

    Same goes for your weight

    Your Robin Subaru 35 cc motor pulls higher than 6000 rpm
    Probably redlines at 7600 rpm like the Honda gx 35

    I just bought a Staton Robin Subaru friction drive with a 1 1/8" roller,
    just got it yesterday so I haven't installed it yet

    At 6000 rpm it will pull 20.1 mph
    7600 rpm = 25.4 mph

    Is your clutch drum still ringing and dinging MM?

  5. Mountainman

    Mountainman Active Member

    that would be a nice top speed Forbisher 25.4
    after being broken in -- would like to know if you reach that
    mine seems pretty peaked out at 22.5 mph with the 1" roller

    my clutch drum
    think that it's making typical centrifugal clutch sounds
    guess that I am getting used to it also
    don't notice it that often
    sometimes it seems to do it more than others
    runs well though

    as I ride that motor bike Thing
    Last edited: Jan 13, 2009
  6. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    What oil are you using in your Robin? 30 weight?

    1" roller at 7600 rpm = 22.6 mph so I guess you are
    maxing it out
    1 1/8" roller at 7600 = 25.4 mph

    Should be able to max it out as its pretty flat around here and
    I weigh 175 lbs

    1 1/4" roller at 7600 = 28.3 mph

    I bought my Staton friction drive used so it is already broken in....

    I got a spare 7/8" roller and a clutch drum too which I have been
    playing with.....
    I think I have the clutch ringing problem fixed, just have to test my
    modification out on the bike

    PS: If DetonatorTuning is reading this....

    1 1/2" roller at 10,000 rpm = 44.6 mph
    1 1/2" roller at 12,000 rpm = 53.5 mph

    Last edited: Jan 13, 2009
  7. Mountainman

    Mountainman Active Member

    yes -- using good old 30 weight -- I think that's what was recommended
    get's a little hot down here (so calif) in the summers as you know

    some have claimed much higher top speed than what I am getting
    with the same basic set up

    Robin 1.6 hp
    1" roller
    fair quality mountain bike
    overall weight bike and rider 150 aprox
    achieving a 22.5 mph on the true level ground

    that's almost 1/5 th the speed that my stock Harley's used to do
    more than happy with that

    all that I can truly say for sure is
    anytime on two wheels
    it is fun to ride that MB THING
  8. zukjay

    zukjay New Member

    yea i went with 6000rpm so im not taxing the engine so much and i dont want to max out at the speed i want to go. here in indiana top speed by law must be 25mph or less(unless no one is look'n) and thats not quite the speed of sound but these things are made for fun anyway right(ive never seen anyone on one without a huge smile) and of course transportation.

    are we aloud to ride these on bike trails, by law in Indiana they are not motor vehicles so all the signs that say no motor vehicles shouldn't apply right. but even if the laws doesnt forbid it im sure its would be frowned upon and maybe some harassment by bored policemen. we have so many trails here i could almost go any where in town and barley touch a road its been a few years sense i rode a motorized bike but from what i remember folks on the road just dont care enough to watch out.
  9. zukjay

    zukjay New Member

    it seems to me that load(weight) is less of a speed robber than wind well unless on hilly terrain, lower=not slower i bet recumbents are a little faster with any given engine compered to a standard bike
  10. Mountainman

    Mountainman Active Member

    hilly terrain

    yes -- the old hilly terrain
    will knock off a few mph

    regarding riding on bicycle, walking and hiking trails

    here in Calif the trails are a no no for sure ticket
    but in your state -- never know until you ask

    for other questions regarding state MB laws in Calif
    I have found law enforcement agencies within the state
    e-mailed them my question
    I liked their reply
    carry a copy with me everywhere I ride my MB

    as I ride that THING
  11. zukjay

    zukjay New Member

    good advice mountain man, i will call my local coppers and find out what they say.
  12. Mountainman

    Mountainman Active Member

    you will probably find them to be pretty cool
    monies are getting much tighter these days
    but I did find pooolice and sheriff sites
    where there were officers who's main jobs seemed to be
    answering questions through e-mail

    for once I can say -- that's a darn good THING
  13. dchrist

    dchrist New Member

    Just recently purchased the DE HondaGX50 kit. I'm still tweeking it, but one day last week the temp reached 47 degrees here in the northeast so decided to give the bike a try. I have the 1.75 roller installed and reached a speed of 29 mph, but didn't want to over stress the engine the first time out. I've read the different speeds suggested but don't think I will know for certain until the engine is broken in. I have the Maxis 2.5 hookworm filled to 65 psi, as I read that was a pretty good pressure for the friction drive systems. I've already replaced the throttle with an old scram twist shifter with the indexing spring removed and works like a charm, cost was 4 bucks. I know some you have crunched numbers but does anyone have the actural riding experience for the numbers?
  14. srdavo

    srdavo Active Member

    Yes to Both....and the Numbers don't lie!! :grin5:
  15. pumpbuilder

    pumpbuilder Member


    With the 1.75" I think you will hit pretty close to 40 when its broken in with the DE kit. I use the same tires as you, they really make a difference and the "manual" not the centrifical clutch DE Encore Model on the bike in the photo.

    With the hills you have in PA if your not looking for speed I bet with the 1.25 or 1.5" ones you won't have to pedal at all and get 20-25 mph when its broken in. Thats assuming the Honda 50 has a simular RPM rating as the 43 cc mitsu I have.
  16. dchrist

    dchrist New Member

    I'm not sure what the rpm rating is on the Honda but I'm hoping for a top end close to 40 but would be satisfied with 35. I've cut out rollers from oak from 1.5 to 2.0 and plan on trying different ones to see which one is best for my purposes. The terrain is not to bad where I live, not many hills so I looking for speed over climbing ability. Am I correct that you're riding a bent....if so that might be getting you a couple more MPH than my mountain bike. DE suggests like you that the 35 to 40 is doable...What size roller do you run on yours? I'm curious as to what is a reasonable break in period? Thanks for your thougths.
  17. pumpbuilder

    pumpbuilder Member

    Well I am ashamed to admit I do not know if your engine is two stroke or not. Two strokes break in on the first tank of fuel. A four stroke I figure about five hours.

    When its engine only, no pedaling like the first poster said its all about RPM and grip of the roller on the tire, my bent is less effected by winds so I will go faster then a MB into the wind but I have been passed by MB's with tailwinds.... it all balances out.

    With the Mitsu 2 stroke I expect I have a higher RPM then a 4 stroke but TBH I don't know how they will compare. I have always found Rob and Kristen at DE to be very straight forward as to what performance I would get.

    Did you get the automatic or the manual?
  18. pumpbuilder

    pumpbuilder Member

    I use a 1.5" mostly, that way I can roam around at lower RPM at 20-25 but goose it up into the 30's on busy roads to run with the auto's.
  19. dchrist

    dchrist New Member

    The Honda engine I have is the GX50 4 cycle....I went to the Staton Inc. website and checked the stats and its rated at 2.10 hp at 7000 rpms. All the reading I've done about engines in gerneral terms of course, say that the 2 cycles are gernerally a better choice for long distance commuting and can run all day wide open which isn't recommended for 4 cycles. I went with the Honda because the gas mileage was supposed to be substantially better (over 200 mpg with a 200lb rider) than the 2 cycles (maybe 140 mpg). What little riding I have done (15 degrees takes the fun out of riding) felt like I could cruise all day at 25mph with the 1.75. I can't engage the system under 11 mph due to bogging down. If you're useing a 1.5 roller I should be able to get well into the 30's with the 1.75...
    I have the DE manual system....figued I didn't need the clutch since I had the disengagement feature. When the weather warms and I get out do some riding I'll post my experiences.
    I put in a picture or two...made a couple of changes to the mounting of the DE system...

    Attached Files:

  20. pumpbuilder

    pumpbuilder Member

    That's a nice looking bike, I would get a more cusshy seat myself.....