WRX recommended sprocket size?

Hi,

I believe my WRX now has the stock 13/42.

I want to get more power and torque on the lower rpm and sacrifice the top speed but not too much of it.

Which combo should I get ?

Thanks in advance.

It boils down to personal taste. My final drive ratio is just slightly lower than stock. Others opt for a rear sprocket as large as 48T with the stock front sprocket.
I don't take much issue with the gearing. When you drop the final ratio a lot you'll end up shifting a lot more as well.

Two questions?

Are you willing to buy a new chain with your new gearing?

Are you aware you'll also throw off your speedometer A LOT by changing gearing?


Yes - the stock gearing from Yamaha sucks.

I got a 13/48 combo and I love it.

Much more punch down low, and I can still reach about 85 mph (corrected speedo) if all conditions are good.

I bought a 12o'clocklabs speedoDRD to fix speedometer. It was over 20% off after gearing change.

Changing the gearing makes a world of difference.

If you don't want to buy a new chain, but want a quick feel for what a change could mean for you, get a 12t for the front.

Shifting more isn't an issue. We're on 250's - shifting comes with the territory.

My bike came with a 13/45 setup, and I like it a lot. I can hit over 90 mph top speed (corrected with speedohealer), which is more than enough for me.

Thanks for the reply's guys.

Yes I am willing (and it is recommended) to buy a new chain with the new set of sprockets.

I do ride highways so I guess the best for me would be to start with 13-45.

Question, since I currently have the 13-42, going 3 teeth down isn't an issue? For some reason I remember the change for the sprocket should be with 2 teeth at a time for the rear and 1 for the front.

Also I need the 110 chain for the 13-45 right?

Order the chain guard too. Yamaha calls it a 'seal guard' (3D7-22151-00-00 - Yamaha - SEAL, GUARD $34 last one I got )

I've had good luck with a 13x47, but wore out the chain guard in 1800 miles. (Bike was heavily loaded in Baja).
I switched to a 14x50, and the chain guard is now an afterthought, the chain is not touching it at all by the swingarm.

TwilightZone wrote:

Order the chain guard too. Yamaha calls it a 'seal guard' (3D7-22151-00-00 - Yamaha - SEAL, GUARD $34 last one I got )

I've had good luck with a 13x47, but wore out the chain guard in 1800 miles. (Bike was heavily loaded in Baja).
I switched to a 14x50, and the chain guard is now an afterthought, the chain is not touching it at all by the swingarm.

I got almost 10,000 mile on my "chain guard".

Chain is supposed to touch "chain guard". It's actually a chain slider.

If your chain ain't touching the slider I'm betting dollars your chain is too tight.

How can I tell the chain guard needs replacement ?

Spark wrote:

How can I tell the chain guard needs replacement ?

Look at it.



click here <-- clicky


One bolt removal, and some wiggling and twisting can get the thing off the bike and into your hot little hands.

Having grooves from chain is normal. That's why it's there.

<"Chain is supposed to touch "chain guard". It's actually a chain slider.
If your chain ain't touching the slider I'm betting dollars your chain is too tight. "

Sure, it touches the slider, but it doesn't tear the tip of the slider off at the underside of the swingarm pivot. (thats a common failure mode)
Benefit of bigger countershaft sprocket, moves the chain away from the swingarm pivot.

Replacing the slider -------

>"One bolt removal, and some wiggling and twisting can get the thing off the bike "

Put the bike on a centerstand (or whatever it takes to hold it up) and
take out the two bolts holding the kickstand 'plate', just let the kickstand hang, then remove 1 bolt holding the slider.
That makes the process a lot easier.

I'd also get a replacement countershaft sprocket cover and case guard.
It really helps to see what is going on in around the countershat sprocket/chainguard etc...

TwilightZone wrote:

I'd also get a replacement countershaft sprocket cover and case guard.
It really helps to see what is going on in around the countershat sprocket/chainguard etc...

Thanks for all the replys.

What's a countershaft sprocket cover and case guard, if it's what I think it is (front sprocket guard/cover) aren't they the same thing?

Its the two pieces of the same part, so to speak. The OE part is the outer mud cover and a plastic piece that fits between the case and the chain, and its two separate pieces. Many people opt for an aftermarket cover and a steel case saver to let mud and grime out, make it easier to check the front sprocket, and to better protect the case against a broken chain or a rock getting caught between the chain and case.

Spark wrote:

TwilightZone wrote:

I'd also get a replacement countershaft sprocket cover and case guard.
It really helps to see what is going on in around the countershat sprocket/chainguard etc...

Thanks for all the replys.

What's a countershaft sprocket cover and case guard, if it's what I think it is (front sprocket guard/cover) aren't they the same thing?

skierd wrote:

Its the two pieces of the same part, so to speak. The OE part is the outer mud cover and a plastic piece that fits between the case and the chain, and its two separate pieces. Many people opt for an aftermarket cover and a steel case saver to let mud and grime out, make it easier to check the front sprocket, and to better protect the case against a broken chain or a rock getting caught between the chain and case.

click HERE <-- clicky

Sprocket Cover and Case Saver... from Sandman. Yup.
Good investment.

Thanks for all the tips and replys, this forum is very helpful I can't thank you enough :)
Eventually I stayed with the stock size since they didn't have anything else in stock and I really needed to replace them. When I say 'they' I mean every shop in the country. I live in Israel, the supply here is very expensive and usually very small when it comes to parts for most motorcycles.

I'll just order another set for the coming future. Though not having the tools to do it myself , suck :(

A tech at my dealership told me yesterday that dropping a tooth on the front sprocket would "correct" the speedo. In longer words, the lower gear ratio would cause the speedo to read about 8% slower--he said the speedo is off by about this much.

Mad genius or crack dealer--YOU be the judge!

That's the opposite of what would really happen.

A smaller front sprocket has the front sprocket spinning faster at any given road speed when compared to a larger front sprocket.
The speedometer pickup is off the transmission, just to the right side of where the front sprocket mounts.
The stock speedometer reading is already displaying speeds a bit higher than actual.

YZEtc wrote:

That's the opposite of what would really happen.

Dang, that's the second bit of bad advice I've gotten from my dealer's "tech." Thanks.

What was the first?

YZEtc wrote:

What was the first?

He had a set of used WRF rims for sale, claimed they were a direct swap for the WRR's. Fail.

Two teeth, three teeth, doesn't make a difference except for overall gear ratio.

Spark wrote:

How can I tell the chain guard needs replacement ?

Strongly recommend you read this entire thread >> Swingarm eaten by chain