Taller tire go faster ? = what size ?  By  gy6fandan (Read 1,731 times)

Speed can be increased, but only if the engine has enough torque to overcome the higher ratio. Better off changing gears than changing wheel diameter if you want to increase top end speed.

Well, since torque has been brought up... I wonder if any of my mods would affect my torque ??

I have recently swapped my final gears to 15/36. Other upgrades include sparkplug, cdi - no rev limit, high ignition coil, dumped air filter box for uni-filter, motorio "dual ramp" 115mm variator (17/13 gram sliders mix), stock clutch with 1500rpm contra spring and... thats about it.

So would a bigger rear tire do anything.... the final gear swap only lowered my rpm's - top speed is 55 on the scooters dash board. 55 mph @ 6k rpm

Take those mixed weights out they really do not work as you would think. Just so you know your rpms are LOW for a 150.
A 150 if it is the GY6 157QMJ motor which is very common makes it's max horsepower right around 7500 rpms.
So get your rpms up by putting in 11 or 12 gram weights that is what usually works great with the 150s. Even all the 13 grams would do better than the 17/13 mix setup.
Alleyoop

Bigger wheel less RPM at same speed,,if you have enough HP to push it like said earlier,,yes it will increase top speed.
Smaller tire,more low end,higher RPM at same speed..I think Buford was thinking sprocket size on a motorcycle..

Usually you would only go one up on the series for potentially a 5% to maybe 10% increase in top end if your bike has enough hp and tourque at the rear wheel to handle it. You would be talking 130/70-13 or if there was enough room maybe a 130/80-13 if they are even available. The tradeoff afterwards on a 150 is that you would be more prone to losing speed to headwinds and going up hills.

A 130/60-16 or 130/60-17 would require larger diameter rims which would add a bit to the cost too. Somtimes keeping the rollers around 12 or 13 grams and going up to the next larger diameter or to sliders will get your belt further out on the drive pully faces and have a greater effect.

Me I traded up to a 250 instead instead of putting a bunch of cash into my 150. Got the speed and better fuel economy in the bargain along with 15 inch rims. Honestly though even when you get what you thought you wanted then you will still end up wanting more.

Some have commented that what I have reported about the Aprilia is more like what you'd expect from a 650cc motorcycle and after riding along side then leap frogging a 600cc Suzuki Bandit for some time I can say that would be a fair assesment as it took him about 15 minutes to catch up after I passed him on a 65/70 mph road. I didn't know him and he just had to find out about the scooter that he was chasing after so we had a nice chat at the stop light when he finally caught up. He thought I had a 750 which I found a bit humerous. Still I do at times finding myself wanting more (acceleration and hill climbing ability) even though the bike has proven capable of speeds approaching 100 mph.

yea i was thinking gear millsc....thanks