New chain length... 12-47


Sep 6, 2003
I changed my front sprocket 2 rides ago to a 12 tooth... my chain was already stretched a bit and after 2 rides now I need to get a new one and a new rear sprocket.....

I know, I know... I should have changed them all at once... but anyways... do I need to get a shorter than stock chain ideally? if so, how much?.... I like the added low end I got from droping a tooth in front, should I consider gaining a tooth or two on the rear now also? (I ride tight single track a lot, but still like to get out and open it up sometimes... I rarely stall on the tight stuff now, but often just barely lug it out)

How long should my new chain be?

also, in your most honest opinion, is the O-ring chain worth it?.... I assume they work on the same sprockets?


Dec 30, 2003
I run 12/47 and an o-ring. Anew stock length chain will fit just fine - as the size change from 13 to 12 is very small.

There is no way anything other than an o-ring would hold up with my riding. For many - good chain maint will allow standard chains to last all season. However, a 100 mile enduro will shred any chain no matter the maintenace. They are constantly in the muck, sand and grime and just grinds the thing to pieces.

I am firmly on board with he WD-40 only crew. One o-ring lasts all season under som pretty tough rides. I cant really ask more than that. With chain lube - it just seems to hasten the wearing ans I could only get 1/2 season at most. I ran the stock chain on my KDX when it was new and went to the back clicker in one 70 mile ride.

You can get decent o-ring for $50. Anything lese just inst worth it IMO. I hink you drop 1/4 HP - but on a 30 HP bike, who really cares.


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May 17, 2000
As Moridin said the stock chain length (108) will work with 12/47 or 13/47.

If you are happy with 12/47 and are buying new chain/sprockets then I would suggest 13/50 with a 110 link o-ring chain. The 13/50 is very close to 12/47 but the 13 lasts longer IMO.

The o-ring chain will take alot more abuse without as much stretching or required maintainance. The stock non-oring chain streches like a rubber band.

The o-ring chain is a little fatter so you need to either get a new rear chain guide or modify the existing one with some washers.