sprocket sizes

[js3350z]

I have a 04 400ex with stock gearing and tires, well my back tires are almost slicks now so... I am going to be getting some new rear tires and if I upsize to 21" rears would you reconmend 23" in the front (will it feel wierd without extra in the front also) and what size sprockets would I get to come as close as possible to "stock" ratio

thanks

[gotwarrior]

The 23's will not feel funny at all.. All it will do is give you more ground clearance...

In my opinion I wouldn't change your gearing at all..

[Scro]

23's are mostly used for desert racing, where you are not turning alot and ground clearance is important. The tallest I would go is 22's on the front. Even then, you can feel the difference in the amount of roll the tire has in a high speed corner because of the extra sidewall.

[js3350z]

so, if I do put on 21's in the back, what sprockets should I use to get as close to stock gearing as possible (if not exact to stock, a little lower would be preferred)

2004 stock gearing

thanks

[jdboy]

One tooth smaller on the front would be a little lower than stock with 21's. Hope this helps! The lower gear really makes the 400's nice in the woods for the really technical stuff.

[js3350z]

cool, thanks for the input

[northwest Texas]

If your stock gearing is 15/38 like the earlier models (I don't remember when they changed it) then you have a ratio of 2.53 (rear sprocket / front sprocket = ratio) with stock 20" tires

If you go to a 21" tire then look at the following:


14/37 = 2.52
15/40 = 2.54

Those get you close to stock, almost identical.

Here's some that make you a little lower since you said you might go lower

14/39 = 2.65
14/38 = 2.59
15/42 = 2.67
15/41 = 2.60

All those figures assume a 20" tire equals 20" and same for 21"

You'll be fine with the 22" up front. I wouldn't go to a 23" unless maybe you went to a 22" rear. For no more increase in height I don't think you'd notice the increase in seat height with the taller tires.