hi all
i wonder if anyone knows if a 47 tooth rear sprocket will fit on a standard length chain
i was running a 14 tooth front to morroco but it got completley donald ducked in 3k miles im not sure but the ten doesnt seem to like the 14 toother
i think i can live with a up two rear off road so any advice would be appriciated



By minkyhead at 2011-05-14

Does this help at all....

The bike has a 520 chain on so each link is 5/8" or 15.875mm.

With 2 extra teeth on the 47T its circumference is 15.875mm x 2 = 31.75mm longer than the 45T.
The chain touches slightly more than half of the rear sprocket, say 55% (or 0.55).
So... 31.75mm x 0.55 = 17.5mm.

So with the stock setup, adjusted correctly, you would need about 17.5mm of free play at the chain adjuster plus a bit for safety/adjustment, say 18.5mm or about 3/4" if you use imperial measurements.

By this I mean, when the stock setup is set and adjusted correctly, you can then loosten the rear wheel spindle and then adjust it so the spindle sits 3/4" further forward you should be able to fit a 47 tooth sprocket with a stock chain. You should be able to just look at it and see if it is likely to work before you move the spindle.

If this cannot be done, the other option is to fit a longer chain as well, 2 links longer at 112 links.

In this case you would loose the 17.5mm (for the 47T) and gain 1 links worth (i.e. one on top and one below) of 15.875mm so this would be a net loss of 17.5mm -15.875 = 1.6mm approx or roughly the same spindle position as stock.

Or you could just ask JMo, She has used 14/48, 14/50 and God only knows what else !

__________________
We are now retired....so....... lots of this and this and no more of this or this

that makes sense ..now ill back off the adjusters and see whats left ill let you know how it goes
thanks for the trouble you took to reply

some you win ....the answer is no
so back to the 13 front for the time being ..ill stick it on when the next chain is needed ...certainly one maby two links extra required