What kind of front and rear sprokets?

[elijah354524]

I have stock front and rear sprockets on my 08 wr250x. I was wondering what kind and how big i should go for the front and rear for more power and also how easy is it to install them? Maybye some directions to go along with them?

[SheWolf]

Depends who you ask. I've got a 12t up front, which took a 27 mm socket to get off, no big deal. I can ride single track and hill climb a lot better, plus I can also rip along the pavement and have plenty of shutzpah to pass if I need to. I found I can utilize all the gears efficiently, and it's no longer long legged up top. This is the cheapest route, as you only have to buy just the front sprocket, which is cheaper than buying a rear AND a chain. You could also go up to a 45t in the rear with the stock front, and still use your stock chain. Anything after the 45 and you'll have to get a longer chain.

[elijah354524]

do you know what stock is on the front and rear? Do you know the deal with if i change the sprockets i will loose spped but gain torque or how does that work?

[SheWolf]

If you go to a smaller sprocket up front, you will gain more grunt on the bottom end, but lose some speed off the top end. Going to a bigger back sprocket will effectively do the same, more grunt at the bottom but loss of top end. Check your PM.

[Subaru297]

The stock sprockets are 13 front and 42 rear on the WRX. I ran a 12 front and the stock rear for a while and it is much better than stock.

Today I installed a new chain with a 13 front and a 48 rear and find it a much nicer setup. It feels like a much smoother bike now. All the gears pull nicely, even 6th! I found the stock gear ratios too spread out. The lower gearing helps to lessen the gaps.

I am not sure what my top speed is now but I will try it out with the GPS soon. The speedo is way off now due to the gearing change.

Also, depending on the gearing you won't lose top speed. Unless you are hitting the rev limiter while tapped out in 6th the lower gearing will help the "little" 250 pull a bit longer (higher rpm) in 6th and you may actually add a couple MPH in 6th.

I really like the 13/48 combo I have now. The 12 tooth up front did feel like it added some vibes. The new sprockets and chain feel a lot better.

The job is pretty easy to do. Changing the sprockets out is very easy. 27mm socket for the axle nut and the front sprocket nut. Remove the chain guard up front and the front sprocket nut (apply the rear brake to stop the front sprocket from turning); then remove the rear tire and the 6 bolts holding the rear sprocket on. Replace both sprockets with the new ones. And if you get a chain cut to the right length you are all set. Just reassemble and go riding.

You will have to cut the old chain off unless you want to remove your swing arm (bigger job!). If you want to keep the stock chain then the ratio of 12 front and 45 rear that Shewolf mentioned would be pretty close to 13/48. It may have a little more vibes though, but lots of others report no added vibes with the 12 tooth. YMMV.

[SheWolf]

Nope, no vibes but there is speed loss, JFYI. I lost 8mph going that route. I can still pass and have lots left over tho.

[nvswr250x]

14 front, 42 rear. still got low end torque and handles really smooth on freeway at 70-85mph.

[Subaru297]

Got out for another ride today and had the GPS along. I had a top speed of 144km/h but it was going downhill a little. I got up to 127km/h going the other way. I would think ~135 for a realistic top speed.

That is with 13/48 gearing.

I also installed my speedo healer and adjusted it for an accurate odo. Speedo is out about 5km/h now at highway speeds which I can live with. Before the healer the bike read 100 and the gps read 81km/h! Almost 20% off!

I also just ordered a FMF programmer! Excited!!!

[elijah354524]

good to hear....what is the sppedo healer and where did you buy it? I dont know if that is my next upgrade or what road i should go down first...

[WNYsanch]

On our bikes this is kinda wrong cause we dont make enough power to pull 5th and 6th to the top anyway so the bike actualy picks up on both ends by going smaller/bigger.

I run 13-47 soon to be 13-49 . It vibes a little more on the highway but it is way way well just "better"

[WNYsanch]

Nope, no vibes but there is speed loss, JFYI. I lost 8mph going that route. I can still pass and have lots left over tho.

This is impossible ?

My bike still wont pull 6th I had a top speed of 86 stock now I can break 90 at will. I know this cause my freind has a GSXR600 and he was next to me telling me my speeds.

Someone do the math on 11,000rpm in 6th what does that =, 115 easy it has to

(i am not a math whiz im just throwing out #s to get the point across)

Now do the same math on 11,000rpm in 6th with a 47 it is still way higher than the KNOWN realistic top speed is.

So there you go Impossible

The bike is horsepower/tourq limited not gear, "Thats just the way it is"

[CA250x]

should i?

http://www.rockymountainatvmc.com/cart.do

anyone wanna chime in

[Subaru297]

Your link didn't work. Your cart is usually saved on your computer. Won't work for the rest of us.

But yes you probably should!

[Subaru297]

good to hear....what is the sppedo healer and where did you buy it? I dont know if that is my next upgrade or what road i should go down first...

http://www.12oclocklabs.com/

It is a little electronic device. Remove the seat and it plugs in to the stock wiring. 5 minute job. You can set it for an accurate speedo or odometer but not both unfortunately. There will still be the small difference between the two from the factory.

[CA250x]

Primary Drive Front Sprocket 13 Tooth - 2009 Yamaha WR250X

Part # 1021470103 $8.99

-Primary Drive Rear Steel Sprocket 40 Tooth - 2009 Yamaha WR250X

Part # 1022350052 $19.99

-Primary Drive 520 RDO O-Ring Chain 520x118

Part # 1021270018 $49.30

Shipping & Handling: $7.00

Tax: $.00

Disposal: $.00

total Sub Total: $78.28

Total: $85.28

[Subaru297]

You want to try taller gearing on your bike? Why is that? Lots of highway riding?

I went lower to get a bit more acceleration and love it so far. I also like the apparent closer ratio transmission you get with lower gearing. I don't do much highway if any. Just a commuter and fun bike for me.

?

[CA250x]

hahah yuptaller gearing..its a 250 im not worried about power..i do alot of highway riding so that will be perfect ?

[greer]

I buy their Tusk oil filters by the sackful.

Sarah

[djmamayek]

I am running 14/48 right now, likely to switch to 14/50. I went one tooth bigger on the front so that I could go much bigger on the rear to give the bike a more "moto" look.

[elijah354524]

You guys R messing me up.....I do appreciate the input...I think i am going to look to expand my fifth and seixth gear...i would really like to make them quicker. Any suggestions?