tire size question

[bishopTS]

has anyone ever measured a 31in tire? or a 33?
I have noticed that most all brands of 31in tires are 29 and a half.
and 33in tires are 31 and 3/4.
except super swamper brand.

has anyone else noticed that?

 

[Quatre Coureur]

Yes. BFGs are notoriously known for being shorter than advertised. Ever mount up taller tires with your stock gearing and think, "it's not as bad(performance)as I thought it would be"... That's because of what's called 'Static Loaded Radius'. SLR is measured from the centerline of your axle to the ground. BFGs 33" tires typically measure at 32.5" tall. When mounted on your vehicle, depending on its weight, the SLR will be around 15-15.5". Times 2 = 30"-31" this is the leverage your gearing is actually working against. That's why, especially if u have a V-8, u may hardly notice the difference. Us guys running 22REs, well its a different story altogether and a gear change is mandatory. Not just to compensate for the added height, but the added weight also.

Sorry I went off on a tangent there! :wow: I guess I was bored...

 

[bishopTS]

Yes. BFGs are notoriously known for being shorter than advertised. Ever mount up taller tires with your stock gearing and think, "it's not as bad(performance)as I thought it would be"... That's because of what's called 'Static Loaded Radius'. SLR is measured from the centerline of your axle to the ground. BFGs 33" tires typically measure at 32.5" tall. When mounted on your vehicle, depending on its weight, the SLR will be around 15-15.5". Times 2 = 30"-31" this is the leverage your gearing is actually working against. That's why, especially if u have a V-8, u may hardly notice the difference. Us guys running 22REs, well its a different story altogether and a gear change is mandatory. Not just to compensate for the added height, but the added weight also.

Sorry I went off on a tangent there! :wow: I guess I was bored...

lol tangents have to come out eventually
my boss put 33s on his xj and I broke his heart when I put a tape measure to it and it was 31 and 3/4. I think mainly because my 285/70/17s were taller :nod: