Gearing

Hi All,

I have a 83 CR250 which I race MX on, any advice on the best gearing ?

I think the stock gearing is 12/53. I have been advised that 12/56 is the way to go as it minimises the gap between gears.

Any feedback is appreciated.

Cheers Rathers

First my bike is a 82 CR430, but it started life with me as a CR250. Final gearing in both cases was the same.
Honestly, there is no correct answer for all tracks and with 6 speeds my main interest is to have 4 gears to work with on the faster tracks. I use 2nd gear for starts, but generally not otherwise unless there is a square corner. I believe stock gearing is 13/52. I run 13/55 and 13/56. I don't know the number of links I am running off the top of my head, but will confirm to you if desired. I use the 13 tooth (Stock) counter-shaft sprocket because smaller sizes don't transfer energy as efficiently. I'd use a larger size than 13 if it would fit behind my aftermarket case guard and then adjust the rear wheel sprocket to provide an equivalent ratio range or close there to.

Regards,
PC

Thanks PC,

According to my parts manual, the 13 tooth gearbox sprocket is standard on the WR/XC models but the CR has a 12 tooth. Looking at the gearbox parts it appears the CR has some different gears compared to the WR/XC bikes. maybe this explains the difference ?

I agree, I would like to use a 13 tooth but this is quite a drastic change over a 12 tooth, using a 56 rear over a 53 would still increase the gearing by approximately 2.50% (over standard 12/53) with a 13 tooth.

More to mull over.

Cheers Rathers.

I can't tell you what would be best for which course you will encounter. There is an efficiency loss in smaller sprockets, the smaller the sprocket the greater the loss. There is also a tendency for the chain to hit swingarm or swingarm protector which is greater with a smaller sprocket. There is a weight savings in the chain and I suppose also the sprockets if you use smaller. I don't race that venue but I try and not use size 12 and under. Chances are you would want to have second to third and third to fourth setup as best suits the track. Wheel size figures in as well.

Fran