Tires: tire size, isuzu rodeo, size tires

Question
My isuzu rodeo currently has 245/70/16 size tires on it A buddy of mine has a set of 245/75/16 bridgetone that are almost brand new he is going to give me. Holding them up to the ones that are on the suv now there doesn't seem to be any difference. Is there? Will these tires work on my truck and rims? Thanks Bill

Answer
Bill,

In theory, the 245/75R16 is slightly taller by about an 1", however, some tire manufacturers will build tires a little of the large side and some will build tires a little on the small side.  So it's possible the tires are very close in dimensions.

However, the 245/75R16's might have letters in front of the numbers and that could change things a great deal.

LT245/75R16's are different animals than P245/75R16's.  LT's need a higher pressure to carry the same load because they are designed for high unit loading and the rubber is strong, but doesn't like flexing very much.  If that is the case, I would recommend against using the LT's.

But even if the tires are P245/75R16, there may be problems.  If built to standard dimensions, the 75 series will cause your speedometer to read lower by about 2 mph (@ 60 mph), which means you would be going 62 mph when the speedo says 60.

But the biggest potential problem is rubbing.  I can't tell you whether or not they will rub because no one publishes the dimensions of the fenderwells.  The only way to be sure to to measure everything - and the folks that do that think it gives them a competitive advantage so they don't share that information.  While I don't think there will be a problem, I can not be certain.