CPT150

another way is to go by one of those police deals on the freeway or street that tell you your speed

mustangGT90210

How did I not think of that? Lol that's probably the best way aside from gps

Warlockk

Many shops will check your speedo for you. AAA website has a list.

Golfo

Try to calibrate your speedometer, its not so hard and you can reset it 6 times.
Im about to do mine cause I put new 33s this week.
Here´s how

<iframe width="640" height="360" src=" " frameborder="0" allowfullscreen></iframe>

Golfo

Here is a listing of popular oversize BFG All-Terrain tires with conversion constants:

Tire Size -------------Revs/mile (at 45mph) -------------Conversion Constant

30x9.50R15LT/C ---------- 705 -----------------------------------9.52
31x10.50R15LT/C ---------677------------------------------------9.14
32x11.50R15LT/C--------- 656 -----------------------------------8.86
33x12.50R15LT/C--------- 636 ------------------------------------8.59
35x12.50R15LT/C -------- 599 ------------------------------------8.09

This could help

mattbarron94

That's ****ing hilarious. I did the EXACT same thing on Wednesday. Put on the bfg all terrains 31x10.5x15 replacing my p235/75 r15. I also installed a leveling kit. Couldn't be more happier with the way it changed the look of my truck.

velvet fog

It would be easy to calculate if you had paid attention in math class.

mattbarron94

Coming from the guy with the squidbillies avatar. I'm pretty sure watching that show kills more brain cells than huffing gasoline xD

Matt#93f150

XD

velvet fog

I have a PhD in engineering, so plenty of brain cells to spare, at least for now.