My 400EX has a set of huge tires on it. The back are 22x11x10. I have seen ppl talk about tire size in relation to gearing. Can someone enlighten me? Do I need to change something and if so does anyone have recommendations?

 

And by gearing I mean sprocket size's.

 

Taller tires will RAISE your effective gearing. You will lose low end torque, but gain some high end speed. (Plus the tires are heavier.)

To compensate for this (and get back to stock gearing) you need to LOWER your gearing. So, you can either change to a SMALLER sprocket in FRONT, and/or a LARGER sprocket in the REAR. A change of 1 tooth in FRONT = about a 3 tooth change in BACK.

Here is my experience. I ran 22" ITP Holeshot XCT's for a while. I went 1 tooth smaller on the front, and it was to much, even with the bigger tires. Any time I bliped the throtle, the front end would stand up and salute! It was to hard to keep the front on the ground, and just wasn't at all safe. I ended up going back to the stock gearing in front, and going 1 tooth larger in back....worked out pretty well....

 

This is great, I just made an Excel Spreadsheet to calculate top speeds in each gear.

With 15 tooth front sprocket and 38 tooth rear (stock) with 22" tires, you will be going the following speeds:

1st 45.9 Km/H
2nd 69.1 Km/H
3rd 90.9 Km/H
4th 113.4 Km/H
5th 133.9 Km/H

In Miles per hour:
28
43
56
70
83


Actually getting to 83 MPH can be quite a task unless you have engine work done and are going downhill. My friend can hit the rev limiter in 5th gear with stock gearing, but he has a UNI Air Filter and a full FMF exhaust system which probably gives him about 3-5 more horsepower.

Just as Reconranger said, bigger tires = heavier. It is harder to rotate bigger tires. If speed is what you're after, get smaller rear tires and change your sprocket gearing. The best idea would be to put on smaller back tires and smaller rear sprocket, you save weight both ways. But not much at all but it would probably make a difference in accelerating from 70-75 MPH.

 

The EX is a great trail quad, and all about low end torque. I finally settled on 20" ITP Holeshot XC tires and one tooth larger in the rear. This lets me put it in 1st gear and just idle through semi-technical trail sections. I lose a little top end, but I have the 450R for going fast in the open desert anyway.

 

Once these Holeshot XCT's wear out I'll prob go with the 20" series. With these tires i do have some crazy top end. I have the 440 big bore so I still have plenty of punch. Plus these things are much bigger than everyone else's and makes my EX look mean. Only thing I don't like is that 1st is just a little high for some trails.

 

One thing about the XCT's is more ground clearance! They are THE tire to run for desert racing.