Gearing thought

[STAIN]

I was talking an older Yamaha dealer about the Vipers and we got talking about gears. He said some people believe that a gear ratio is a gear ratio is a gear ratio now matter how you achieve it. He says if you can leave your bottom gear a big a possible ( 50t ) and do all your gearing with the top gear you achieve more top speed. Example--a 26-50 will be faster top end than a 21-41--provided you have the power to turn it.
It took a minute to wrap my head around this but I think he is right. The gear ratio is only in relation to each other, not from your bottom gear and drivers, or from your secondary clutch speed and drivers. I don't know if I am smart enough to explain properly but given some thought I can see his point.

 

[ViperBill]

Divide the number of teeth in the top gear into the bottom=ratio 21/42= 2to1 think of the drivers as your wheel larger driver turns slower at a given speed than smaller.

 

[STAIN]

Is this supporting or shooting down this theory? What about the mechanical advantage of the bigger gear? The more I think about it the more my brain hurts.......

 

[cannondale27]

Neither. I believe what you are saying. 2:10 would be faster than 1:5 simply because it's more efficient for the chain to go around a bigger set of sprockets and the bigger gears also would create more of a flywheel effect. Is only so much room in chaincase though.

 

[ViperBill]

I dont think larger gears are more efficient. would be stronger due to more teeth engaged with chain but more friction for the same reason also more weight to turn. acell as well decell. but i dont think there would a noticeable change in performance.

 

[cannondale27]

Probably not but I was thinking the chain loses efficiency on a tighter bend.

 

[titanrcr]

I was talking an older Yamaha dealer about the Vipers and we got talking about gears. He said some people believe that a gear ratio is a gear ratio is a gear ratio now matter how you achieve it. He says if you can leave your bottom gear a big a possible ( 50t ) and do all your gearing with the top gear you achieve more top speed. Example--a 26-50 will be faster top end than a 21-41--provided you have the power to turn it.
It took a minute to wrap my head around this but I think he is right. The gear ratio is only in relation to each other, not from your bottom gear and drivers, or from your secondary clutch speed and drivers. I don't know if I am smart enough to explain properly but given some thought I can see his point.

This was always a very hotly debated topic on the Kart racing forums. Guys would always hash out the pros and cons for large vs small gear sets. In my mind the greater benefit came from running the larger chain and sprockets due to a more gradual turning of the chain plates, less friction. Some guys would argue that with the larger sprockets came more weight and a longer heavier chain. I can't say that I ever saw a benefit one way or the other. For that reason I wouldn't even consider gear set size in a sled. Just look for the best ratio for your setup and forget what size gear set you use. And yes, Ratio is Ratio !