Sprockets....

Im replacing the sprockets on the R6 track bike.
(i know i should really be replacing the bike but sprockets are much cheaper )

from what i can find on the net the standard size is 16 front 48 rear

currently this bike has on it a 13 front and 45 rear.

what effect should that have on acceleration and top speed?
most info i have read says to drop 1 in the front and go up 2 in the back. seems strange to me to go down at both ends.

any ideas why the previous owner would do this?
my head hurts when i try to figure it out myself

Currently it has good acceleration and any top speed reduction is not that noticeable by me (other than the speedo being incorrect)

he went down 3 on the front.. thats the same as going up 8 or 9 on the back... hence why he went down 3 on the basck as well....

he probably wanted to go down 1 or 2 on the front, but couldnt get the sprocket or sumthing....

there is a gear program which tells ya ratio's and shit....

im guessing for racing, that would be good for acceleration, but u'd be losing top end... are u racing on tight small tracks?? or longer ones??

Try http://www.jtsprockets.com

Had good life out of them..Hardened carbon steel rather than usual crap though you may want an anodised alloy rear for a trackie.

site also has a very handy gearing chart when you look up the cogs 4 your bike.

Maybe the prev owner went down on both to reduce the wheelbase as much as he could?

Wow, thats a big drop on the front...
I wouldn't go down any more than 1 tooth on the front as the tighter radius will draw HP and wear quicker..

For a 6 I would think 1 down on the front and a couple up on the rear would be fine...

im going to go back to a more standard sizing and then experiment from there.
1 down in the front and a standard rear for now.
we have a heap of spare rear sprockets so we can play around with them later. i wont be surprised if we never do though

the previous owner was racing this bike in victoria and apparantly there is some short course tracks there where you dont get into the higher gears.
so maybe that is something to do with it.

thanks for the advice again.

.............the previous owner was racing this bike in victoria and apparantly there is some short course tracks there where you dont get into the higher gears.
so maybe that is something to do with it.

His last race must have been at Winton.