I have a 06 YZ250F that I kitted out to 315 cc's using the RPM/IceCube kit.  It is jetted very well...and has a TON more hit that a std 250F.  It does not even feel like the same bike.

Outdoor Novice MX - I am finding that on uphill sections I am spinning the rear a lot.  I also have a hard time controlling the rear of the bike when I roll on the throttle cornering.  The motor has a very hard hit as soon as I crack the throttle.

Might a wider rear tire be advisable?  I understand that a 110/90-19 is meant for a 2.15" rim (450 set-up)...and may not work well on my stock 1.85 rim...

What about a 110/80-19?  That is wider, but not as tall, and is meant for a 1.85" rim?  Might that work better than the stock 100/90-19?...

...or I will I need to go to a full 450 rear and a 110/90-19 if I want a bigger rear tire...

Edited by Blutarsky, 29 April 2012 - 10:39 PM.

I have two sets of wheels, both are 1.85's and I run 110/90-19's on both sets. Definitely better traction and as a bonus, I've found that the knobbies are larger and less likely to chunk off.

2 ways

1) drop 1-2 teeth on the rear and lower the rpm

2) go to the wider rim and the 110

3) both!

indy rider, on 30 April 2012 - 03:41 AM, said:

Indy....I have heard that putting the 110/90-19 on a 1.85 rim results in the tire getting wobbly because the beads are close together...making the tire bulge a bit....  Have you noticed this at all?

SUnruh, on 30 April 2012 - 08:57 AM, said:

I can also just short shift it....  This thing pulls like a truck...

So...still no one has chimed on in a 110/80-19?  I am curious how that will work.

80% of 110mm = 88mm tire height.  The standard 100/90-19 is 90mm tall...so the tire diameter/circ should be about the same (-12mm roll per tire rev for the 110/80-19).

For traction purposes I run the 110 90 19 on the 250F rim. It definitly helps traction. I also use a Maxxis IT tire as it is a bit heavier than other tires of the same size. This also helps traction a bit and with the big bore kit you have you won't even notice the added weight.

Blutarsky, on 30 April 2012 - 10:57 AM, said:

I've never noticed any sort of wobble with the Michelin Si2-XC's or the MH3's I use...and I run really low tire pressure(6-10 psi) since I'm running the Tubliss tire system.