2010 Explorer Tire Size vs Speed

[JimmyT1950]

Since I bought my explorer back in 2010, the speedometer shows 2 mph slower than what I am actually traveling I've checked this with another vehicle following me and a GPS.

Currently I have stock Ford tires P235/65R18 on the vehicle and am considering buying new tires due to wear. Also, these Ford tires have more road noise than I have ever heard in a tire in the 50 years I have been driving.

When I go to the different tire websites shopping for tires, I put in my vehicle information and they all come back saying P235/65R17. I'm not sure what all these numbers mean but could the difference between an R18 and R17 be the problem with the speed offset that I am experiencing.

Also, I have always had very good luck with BF Goodrich Radial TA tires but I'm not sure they still make that style. Any input would be helpful.

 

[BrianDye]

The last number "R18, R16" etc is the size of the wheel. Mine has 16" stock wheels so it's an R16, you have the premium wheels (or aftermarket) which are 18" so it's an R18.

If they are aftermarket larger wheels, it could very well be the problem. An 18" wheel will spin slower than a 16" wheel or 17" wheel when the truck is moving at the same speed.

Also, your noise could very well be front or rear wheel bearings. The noise of these dying bearings is nearly identical to tire noise. I haven't had any issues with any of my Ford's having excessive tire noise.

 

[swshawaii]

True regarding rims, but it's the overall diameter of the TIRES that determines distance traveled, RPM, and actual speed.

Use calculator below or Google "tire calculator" for many variations.

https://tiresize.com/calculator/

 

[mgmgmg]

Ford tires....too funny.... The stock tires are Michelin cross terrain in 18 size which they stopped producing, by far the quietest! Now goodyear makes the loudest! My 2 cents stick with Michelin of BF Goodrich....

 

[USMCBuckWild]

I run Hankook Dynapro AT/M in a 255-60-18 and have had excellent results. These are a more aggresive tire but do well in the rain here. I think my next set will be Michelin, 255-65-18 in either the Defender M/S or the Latitude Touring.