How Accurate Are Tire Speed Ratings?

AllBlkdOut07 · March 11, 2009

Damn, so I'm just about to order my 35" tires for my lift and I come across the speed ratings on the two tires I was considering.

35x12.5x20 Q speed rating 99mph

35x13.5x20 N speed rating 87mph (a step up from a temp spare )

Not that I plan on driving fast, but just the fact that they're only an N rated tire makes me nervous.

Maybe I should go with the 12.5's afterall. I don't want to worry about cruising at 75-80 on the highway w/o having my tires blow out. But I really preferred the wider tire for my set-up.

tobias · March 11, 2009

Damn, so I'm just about to order my 35" tires for my lift and I come across the speed ratings on the two tires I was considering.

35x12.5x20 Q speed rating 99mph

35x13.5x20 N speed rating 87mph (a step up from a temp spare )

Not that I plan on driving fast, but just the fact that they're only an N rated tire makes me nervous.

Maybe I should go with the 12.5's afterall. I don't want to worry about cruising at 75-80 on the highway w/o having my tires blow out. But I really preferred the wider tire for my set-up.

I'd go with the Q's.

Why you gettin' mudders though if it'll never leave the road?

AllBlkdOut07 · March 11, 2009

But the wider tires would look a lil better.but I hear ya.

I like the aggressive look of the mudders, that's why.

DBVille · March 11, 2009

Speed ratings are basically resistance to heat buildup. Buildup caused by flexing as it runs. Higher speed, more flexing, more heat. All passenger car tires sold in the US for the past 30 years or more have had a rating of 85 mph. You would probably have to run 105 mph for over an hour to cause any problem with the cheapest tire. Oh, and be loaded to rated capacity.

Since you are buying the tire for aesthetics, and not safety, get the one that you want - the wide one.