# friction roller dai/speed

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

1. ### zukjayNew 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. ### MountainmanActive 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

4. ### MotorBicycleRacingWell-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

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. ### MountainmanActive 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. ### MotorBicycleRacingWell-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. ### MountainmanActive 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. ### zukjayNew 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. ### zukjayNew 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. ### MountainmanActive 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

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

as I ride that THING

11. ### zukjayNew Member

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

12. ### MountainmanActive 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

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

13. ### dchristNew 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. ### srdavoActive Member

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

15. ### pumpbuilderMember

DChrist,

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. ### dchristNew Member

Pumpbuilder
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. ### pumpbuilderMember

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. ### pumpbuilderMember

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. ### dchristNew 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...

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20. ### pumpbuilderMember

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