Tire Question

[01z71]

After much delay I will be replacing the stock Firestone P265/75/R16 with Goodyear Wrangler AT/S LT265/75/16's.  My question is will the upsize in tires mess up my speedometer a lot or just a few mph's?  

 

Thanks and lookin' forward to my new tires.

[Shotgun]

Looks like your going with the same size dude.I that case you won't have any change in your speedo ???

[fennsz]

same size tire. no change in speedo. you just moved from a passenger tire to a light truck. No difference as far as the speedo is concerned. ???

[01z71]

Thanks guys.  I just go tthe local Goodyear to order them for me.

[Shaners]

Technically not all tires of the same size are the same diameter.  They seem to differ by manufacturer.  But as long as you are staying with 265/75/16's they should be within 1/2" and shouldn't throw your speedo off by very much.

[SilveradoWV]

I went from 245's to 265's (cuz I dont think I could fit 285''s)! So am I going faster than what the speedo says or slower???? How accurate are the signs on the Interstates? When I had the 245's every one of those speed signs would say about 2-3 mph lower than what the speedo was?

[Shaners]

I went from 245's to 265's (cuz I dont think I could fit 285''s)! So am I going faster than what the speedo says or slower???? How accurate are the signs on the Interstates? When I had the 245's every one of those speed signs would say about 2-3 mph lower than what the speedo was?

You are actually going faster than what the speedo reads.  If your speedo reads 65 you are probably going about 68 mph.

 

Therefore your odometer would be off too.  For every 100 miles your odometer records your probably traveled closer to 105 miles.  So when you calculate your true MPG's you have to take that into account.

 

If your speedo was reading faster than the radar signs, then you may be closer to true speed with the new tires.

[SilveradoWV]

Thanks, I have been looking for one of those things lately but unable to find any! Just hope I dont have to have a cop tell me how fast I was goin!!

[Redapple]

The difference is 3.9%.

You are travelling 3.9% faster than the spedo reads.

 

If Spedo says 60, you are actualy going 62.3.

 

Over the span of 100 miles, you will have actually travelled 103.9 miles.

Shaners was very close.

Here is a good link if you want to see differences in tire size:

http://www.miata.net/garage/tirecalc.html

 

Bill

[Shotgun]

Darn I was wrong too,I was gonna say 62.8768943..Go figure

[Redapple]

Toche'. You got me. lol. I just like to be as acurate as possible.

 

Bill