New Tires

[javamotorsports]

Hello,

I have a 1980 GS850L currently running 130/90/17 rear tire. I have a bike with brand new tires I just picked up to sell for parts has brand new Perrelli sport demon 130/70/17. My concer is how much differance is the 1 inch smaller tire going to change the gear ratio? will it be enough to even notice? I have always run stock size tires. Thank you for any input on this.



Jason.

[Ghostgs1]

Just using a circumference comparison the difference appears to be pretty great. From Hidenau Tires info, the 70 ratio 72.99 inches while the 90 ratio is 82.35. So that means the 90 is traveling 8.79% farther than the 70 on each revolution. Sounds like the engine will be spinning 8.79% faster at a given speed. Ray

[Big T]

It sounds like there will be enough to notice, but that will be offset by the stickier tires

Give it a whirl and see if you like it, you can always change back if you don't