# Tire replacement **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** gmc, 1500\ **Created:** [February 11, 2010, 12:28am UTC](https://community.cartalk.com/t/tire-replacement/44254 "2010-02-11T00:28:21Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![chimma](https://avatars.discourse-cdn.com/v4/letter/c/13edae/32.png) [@chimma](https://community.cartalk.com/u/chimma)\ **Post date:** [February 11, 2010, 12:28am UTC](https://community.cartalk.com/t/tire-replacement/44254/1 "2010-02-11T00:28:21Z")
i have 245/70-16 tires on a 2004 gmc c1500 sierra and would like to install 235/75-16 tires. will this cause great harm in the overall performance of the truck? ---
**Author:** ![Caddyman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/caddyman/32/23_2.png) [@Caddyman](https://community.cartalk.com/u/Caddyman)\ **Post date:** [February 11, 2010, 12:49am UTC](https://community.cartalk.com/t/tire-replacement/44254/2 "2010-02-11T00:49:44Z")
You will not even notice the difference…The diameter is probably almost identical… ---
**Author:** ![CapriRacer](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/capriracer/32/22_2.png) [@CapriRacer](https://community.cartalk.com/u/CapriRacer)\ **Post date:** [February 11, 2010, 11:33am UTC](https://community.cartalk.com/t/tire-replacement/44254/3 "2010-02-11T11:33:40Z")
Your first step ought to be to look for the vehicle tire placard - which on GMC trucks is located on the driver’s door or doorpost. That will tell you the original tire size and the proper pressure for that size. ---
**Author:** ![UncleTurbo](https://avatars.discourse-cdn.com/v4/letter/u/e9a140/32.png) [@UncleTurbo](https://community.cartalk.com/u/UncleTurbo)\ **Post date:** [February 11, 2010, 1:27pm UTC](https://community.cartalk.com/t/tire-replacement/44254/4 "2010-02-11T13:27:18Z")
You are looking at a narrower and taller tire as the replacement. If they fit on the wheels OK, and I think they will, then you should be fine. You can expect your speedometer to have some error in the reading vs actual speed. This is easy to check with a GPS unit. Otherwise the narrower tire might have a bit less grip, but I’d bet hardly noticeable. In snow the new tires might do better, but tread design is a big part of snow traction so you’ll just have to see how they do when the snow flies. ---
**Author:** ![dagosa](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/dagosa/32/9837_2.png) [@dagosa](https://community.cartalk.com/u/dagosa)\ **Post date:** [February 11, 2010, 2:58pm UTC](https://community.cartalk.com/t/tire-replacement/44254/5 "2010-02-11T14:58:51Z")
I agree…there is [Powerdog.com](http://Powerdog.com) to check the overall diameter of the two. I go from 265/65-17 to 265/70-16 in the winter. Though not a direct comparison to yours, like Caddyman said, the differences are insignificant if the ratios and treadwidth result in the same outside diameter; which yours look like they do. ---
**Author:** ![dagosa](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/dagosa/32/9837_2.png) [@dagosa](https://community.cartalk.com/u/dagosa)\ **Post date:** [February 11, 2010, 3:04pm UTC](https://community.cartalk.com/t/tire-replacement/44254/6 "2010-02-11T15:04:56Z")
245/70-16 6.8" 14.8" 29.5" 92.7" 684/mi 60MPH 10000mi N/A 235/75-16 6.9" 14.9" 29.9" 93.9" 675/mi 59MPH 9875mi 1.3% As you can see…the difference is .1 inches radius, and less than 1.3 % circumferance rolling distance …don’t worry as long as all are matched.