This hardly counts as a modification, but it's certainly an issue of safety. Any time you alter the angle at which the tire bead fits up to the rim beadseat, you are risking a catastrophic failure. That's why most tire shops around here won't even mount an out of spec tire -- too much liability

 

You dont consider adding larger/wider than stock tires a modifcation?

 

You're not really changing anything on the vehicle itself, all you're doing in this case is squeezing something into a place where it doesn't fit.

 

Putting 33 inch tires on a truck with a leveling kit is hardly "squeezing" anything anywhere.

I believe we will just have to agree to disagree on this one.

 

Think about the cross section of the tire. The tire beads are in the proper orientation when seated on a 10" wide rim. If you widen the rim the sidewalls flex outwards pivoting more or less from the shoulder and the beads are rotated by the angle of the sidewall to fit in the wider beadseat. When you get to 11" they have gone as far as they can without the risk of the outer edge of the bead not being located properly on the seat.

The same thing happens when you go narrower. The sidewalls pivot inwards and the beads are forced to rotate by the angle of the sidewall. In this case though since you are now bending the sidewall just above the bead about the lip of the wheel, it is possible that you are adding another strain point. Once you go past 8.5" you have moved the beads inwards as far as possible without compromising their seat on the rim. A narrower rim risks at least the inner edge of the bead not being in proper contact with the rim. It may also put additional loading on the sidewall.

 

well i got 33's on 10 inch wheels so that solves that problem. i just need to get all the mud cleaned off the underside before i install the parts. with 2 inches of lift will i need new shocks?

 

You shouldnt. But you might as well get new ones if they havnt been reaplaced in a while.

 

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