Originally Posted by Watt-man

The 250 can easily pull the 15. And a 16 and a 17, if they would fit. I'm running the equivalent of over 17 teeth on the front, so you might enjoy the following data.

I know I'm going to be the odd man out here, but you know how compromises go. If we use the 13 to "optimize" the low speed gearing, the bike is screaming on the freeway. If we "optimize" the 6th gear for the freeway, the bike is not nearly as useful at low speed on the trail.

So I get that. But right now I'm not able to commute daily to work on my 650, and the 250 has been pressed into service. First, I fit a 15 on the front (kept the stock 42 rear). Nice improvement. Not knowing of any rear sprocket choices that were smaller, the next thing I did was buy a Pirelli MT43 for the rear. That baby is 81.4" in circumference, compared to the stock tire at 76.5". That's the equivalent to keeping the stock rear tire and somehow fitting a 16 tooth front. Loved it more.

I kept poking around. Sure enough, there is a FACTORY STEEL sprocket for this bike with 39 teeth! (P/N 42041-1507)... it's used on the supermoto version of this bike. So I ordered it from my dealer and put it on. Now I'm at the equivalaent of 17.2 teeth on the front with a stock rear tire. And I really like it for commuting. At 6000 rpm, the bike is going 73 mph indicated (66 actual).

So I realize it's a compromise we all have to make, but YES the bike will pull a 15 on the street easily. We did Moab for a week last May, and I ran 15/42 and the stock rear tire for the entire trip and loved it.

Anyway, there's data for what it's worth.

Originally Posted by stephenmarklay

How much do you weigh. I you are 100lbs soaking wet then forgetaboutit

Since mine is going to see a lot of commute duty a 15 is not out of the question.

Originally Posted by ahnh666

15/39 has been the perfect combination for commutes and long distance for me...i fluctuate between 145 lbs. and 150 lbs....add how many more lbs. for armored jacket, pants and boots....

with just k&n, exhaust and jet kit....i can easily cruise along at 85 mph at a comfortable 8,200 rpm....top speed of 95 mph to 100 mph...for mountains...downshift to 5th and it can cruise at 75 mph uphill all day....

Originally Posted by eyyopomps

Hey Gary!
I know this post is a little old by now, but I'm looking for some guidance on the 15t sprocket. I have a 2012 KLX 250s and I just ordered a 15t sprocket for the front, but after pulling off the guard to look at the sprocket it doesnt look like anything bigger than 14 will fit? I just curious to see if it will fit before it shows up.. thanks
-James

Originally Posted by GaryC

A LITTLE old? you mean a little over 2 years old. Ha Ha..
it should fit fine.
If you are lucky, you can go from a 15 to a 13 with a chain adjustment.
Get a 13 for the trails until you get the bigbore kit.
Yes,,, you will get the big bore kit,,, it's inevitable.

Originally Posted by stephenmarklay

How much do you weigh. I you are 100lbs soaking wet then forgetaboutit

Since mine is going to see a lot of commute duty a 15 is not out of the question.