Author Topic: Tire Size Change Issue  (Read 1979 times)

Punk052

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Tire Size Change Issue
« on: March 01, 2011, 03:04:42 AM »
Ok, so I moved to a larger set of tires this fall. I love them and think they improved everything about the scooter. But I have had an issue with speed and acceleration. I have checked everything and nothing seem wrong. New Bel, new rollers (20g) and carb cleaned and checked, new spark plug and everything tested. My question is, with a larger diameter rear tire, would I need heavier weights to match the extra torque from the rear wheel? It tops out at about 50-55mph and it never gets into "low" or "high" gear. nothing ever seems to shift. Any ideas would help.

TechGuy

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Re: Tire Size Change Issue
« Reply #1 on: March 02, 2011, 12:27:43 AM »
I have some ideas... but first, some questions.

Did you use rollers or sliders in the CVT?

Did you use a Kymco belt?.. or something like a Gates or Polini.

Punk052

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Re: Tire Size Change Issue
« Reply #2 on: March 02, 2011, 01:06:50 AM »
New rollers, and I tried gates and kymco belts.

Punk052

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Re: Tire Size Change Issue
« Reply #3 on: March 04, 2011, 03:31:36 PM »
Does this sound right to everyone? lager diamiter rear tire mean lower rpm across the cvt with 20g weights. this means lower engine rpm across the board. so the fix would be lighter roller weights to raise rpm back to the power band of the engine. So to get my top speed back I should do the counter intuitive act of lighter roller weights?

TechGuy

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Re: Tire Size Change Issue
« Reply #4 on: March 05, 2011, 12:47:39 AM »
The tire size cannot be enough different to change your top speed from 75-80 down to 5-55... assuming you're still using the original wheels.

The weight of the rollers will change the rate of acceleration but not likely to change the speed that much

Are they the correct diameter?

Weight roller Outside Diameter
Standard 22.92~23.08 mm
Service Limit 22.0mm

Punk052

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Re: Tire Size Change Issue
« Reply #5 on: March 05, 2011, 01:16:55 AM »
yes they are the right diameter. any ideas?

TechGuy

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Re: Tire Size Change Issue
« Reply #6 on: March 06, 2011, 03:43:54 PM »
I am using 28x18 21 gram sliders, instead of rollers. I can easily cruise in the 75-80 MPH indicated range, and i am a big guy.

I don't know if your 20 grame rollers have limited your speed, but I guess it's possible they don't have enough mass to over come the springs.

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