Gearing

Shae Nault · Post by **Shae Nault** » Sun Mar 29, 2009 2:50 pm

i think i have an 11 tooth gear on the clutch but just wanted to know what the best ratio for the track is? any suggestions on what i should be running? thank you!
Shae

Lori Richardson · Post by **Lori Richardson** » Mon Mar 30, 2009 8:34 am

Shae,
I won't claim to be an expert on it, but I can share what I do know about the gearing.
Most of the senior Yamahas are running 10 tooth drivers and the rear gear ranges anywhere from 81 to 86. You should probably aim more around the 83 to 84 range. I am running either an 83 or 84 depending on the race day.

The smoother you are out of the corners, the lower you will be able to go on the gear and have more speed at the end of the straight.
If you are having trouble in the turns, a higher gear (84 or 85) will give you extra pull to come out of the turn and help you recover.

It is all a matter of the ratio between the front and rear gear, so to get the same effect on an 11 tooth driver you would need a rear gear of 91 or so. That is a large gear and you will run a big risk of having it drag the track if you hit a turn, which of course could mean throwing your chain and probably destroying the sprocket.

I hope that helps.

Lori Richardson

Shae Nault · Post by **Shae Nault** » Tue Mar 31, 2009 7:07 pm

thank you Lori!

Bob Preston · Post by **Bob Preston** » Wed Apr 01, 2009 7:32 am

Shae,
I agree with Lori, handling and resulting corner speed is important and directly related to track conditions. I suggest that you have several gears availible and start testing them on a practice day (I have sizes that are two teath apart). I started with the largest, run eight or so laps and check lap times, change gears and repeat until could see a lap time fall off. This will get you in the range for your driving, handling and track on that day, althouigh it will be a good baseline to make changes from.
No matter what gear you are using, I reccomend fixing handling issues first or every time you change handling you will be changing gears. I got this backwards and kept messing with gears when I had more to gain with handling.
Regards,
Bob Preston

Shae Nault · Post by **Shae Nault** » Wed Apr 01, 2009 3:00 pm

thank you Bob great advise!

George Kraus · Post by **George Kraus** » Fri Apr 03, 2009 10:13 pm

Bob,
Can you go back to changing gears. Good pass on me in 7. I think you are getting the handling thing down. Nice driving.
Slow and old.
George Kraus

Bob Preston · Post by **Bob Preston** » Sat Apr 04, 2009 6:10 am

Thanks George...as I recall, you got the spot back on the way out.

George Kraus · Post by **George Kraus** » Sat Apr 04, 2009 3:38 pm

Bob,
Maybe, I was dealing with issues at the time too, way too tight. Still sorting out the MG tires. Still, you did finish in front of me.

George