smaller front sprocket questions

[Davez29]

I was thinking of trying a one tooth less front sprocket for faster acceleration as I dont go flat out at the top but would like to know what drawbacks it creates, any one tried it and does it really help? I understand it will put your speedo readings out, anyone know by how much I would have to re-calibrate my speedo readings by?

[CMSMJ1]

Do it... The speedo will read lower so you'll be less likely to get rumbled by cameras etc..

I run 1t lower on my 30's - for the money, it feels like another 10bhp!

[Davez29]

Thanks, will look into it but I would love to know the exact amount the speedo is out. I suppose my GPS phone might help out there if I can set it up. Do your chains wear out quicker and has anyone tried just taking the rear sprocket up a tooth or two?

[Evilchicken0]

Think about going up on the rear (it's approx -1 front = +3 rear) that will give your chain a little bit of an eaiser life because it doesn't have a tighter radius at the front sprocket. It will shorten your wheelbase a little so check your swingarm / tyre clearance at the pivot end.

[jac_is_smiling]

If you go down one on the front from standard gearing then your speedo will read 7.1% too high.

(((15/39)/(14/39))-1)*100=percentage difference
i.e. if the speedo says 30 youl be doing 28, speedo says 100, your doing 93.

Go up three at the back from standard and your speedo will read 7.7% too high.

n.b. not a total sad b*strd, just had time to burn, and my calculator looked lonely

[Wozza]

Someone made a spreadsheet for this kind of jiggery pokery, can't remember who but it was very useful.

[Davez29]

Thanks for the extra input and info on the speedo readings, will come in very useful when I do decide to change sprockets. If anyone finds the spreadsheet please post here.

thanks again.

Dave

[jac_is_smiling]

http://www.mediafire.com/?wqzzg0yoq2382wz

Spreadsheet for RRL and RRN. Altho obv with some number changing can be setup for any bike gearing combo.

[Davez29]

Thanks jac, will come in handy, appreciated.