KTM 520 BB Gearing

So I've been reading all these gearing threads and it got me to thinking. My bike is an 08 carbed KTM 450 EXCR. I've had this bike for years and its served me well but it needed some love at the end of last season. I just got the motor back from Thumper Racing where I had Travis convert it to a single sump and add a big bore kit making it a 520. I know the first thing everyone asks is why not just buy a 530, well the answer is the 530 uses a different crank than the 450 which actually makes it a stroker where the 520 is a bore so it still revs like a 450. The big advantage of the 520 is it makes about 30 percent more power down low, peak power is just under 60 but its in the meat of the power band where the real benefits are so I won't need to rev the pi$$ out of it anymore. The Exc being street legal has the wide ratio tranny, I have a 12 tooth front but I ran a 13 last season and on long pulls I had to kick it down from 3rd to 2nd most of the time. It would be nice to be able to pull 3rd and hold it, the BB should help that.

So im going to a LT this year from my ST what gearing will work best with my new setup?


M5

Don't bother with the 12 tooth front at all I take it?

M5

My kit was brand new last season. When I installed it the chain was way too tight to use the 13 so I ran the 12 for one day till the chain stretched. I notice this year there are some marks on the under side of the MH frame where the chain passes by. I'm wondering if it is from the one day I ran the 12. Is the 12 too small a diameter or did I just let it get too far out of adjustment one day.


M5

So here are the KTM gear ratios wide ratio and close ratio.

Wide ratio. Gears/teeth 1st to 6th 14:36, 17:32, 19:28, 22:26, 24:23, 26:21
On wheels 14:48 sprockets. Ratio. 19.18, 14.40, 11.64, 9.33, 7.57, 6.38

Close ratio 16:32, 18:30, 20:28, 22:26, 24:24, 21:18
15.80, 13.16, 11.06, 9.33, 7.90, 6.77

It's interesting to see the ratios for 4th are identical and 5 and 6 are close but who really cares. Clearly the biggest difference is first gear, it's really short on the wide ratio 2nd and 3rd aren't really that different.

M5