Alternate tire Size?? 265/70/17 to ??

[Mr_Joe]

I have a 2014 GMC Sierra 1500 'double-cab' with stock 265/70/17 tires. I was wanting to go with a narrower and slightly taller tire, using the same factory wheels. The stock tires are 31.1" tall and 10" wide.

I was looking at 235/80/17 which is 31.8" tall and 9.3" wide. This is my preferred choice so far.

Then there is the in between choice, 245/75/17 which shows 31.5" tall and 9.6" wide.

Just started research, assuming they fit on the factory 17" wheels. Then there is the issue of about all but the Winter tires only come in load range 'E'. I actually would like to go with the E tires, with a midrange PSI on the pressure. I only tow midlin to lighter weights and don't care if my ride is a bit more stiff. I also don't care if my speedometer is off some.

I thought I'd swing through here before the local tire shop tells me all the reasons my plan isn't valid. My farm buddy sees no problem with the idea.

 

[Colt45ws]

Seems fine to me. You are going to a heavier duty tire.

A 265/70R17 has 2535lbs capacity at 35psi, 2425lbs at 32psi. These ratings are de-rated 10% when applied to a truck.

So 2281, 2182. So about 2200lbs capacity.
Both, 245/75R17 and 235/80R17 E load rating would need 50psi. This would give you 2270lbs capacity.

Depending on shop, you might need to take wheels in and have them change the tires without the truck. This will usually occur at any of the chain stores.

 

[KD0AXS]

I don't see an issue. I'd think either of those sizes would fit on the factory wheels just fine. The narrower tires should be a little better in the snow, but might not handle quite as well. Some tire shops will only mount the size listed on the door placard, so that could be an issue.

 

[Barkleymut]

Why do you want to change?

 

[userfriendly]

A couple of options are BFG 34/10.50/17 and Cooper ST Maxx 255/80/17.
I just put the 2nd set of 265/60/20 Goodyear SRAs on my son's 2013 GMC 1500 today.
The 1st set came off my 2500 when I moved up to 275/65/20.

 

[UltrafanUK]

If you look in your owners handbook it should give a list of approved tyre size options. If you have lost that important booklet, then see your local dealer to get a copy of the approved tyres. There might be a difference between the winter and summer tyre sizes.

If you fit something non standard the speedo might be in error and in a real bad case ther ABS warning light will illuminate.

 

[userfriendly]

My GE AC44 locomotives have ground speed radar that compares it to wheel speed for traction control purposes.
Too much of a discrepancy, and it backs the power off the axle that is in over speed.
How would a pick up truck know that the tires are larger than stock?

 

[Mr_Joe]

I will look in the owner's manual to see if they list alternate sizes. I may ask a mainstream shop then a smaller one what they think about the idea. I could take wheels in removed from the truck, may be a hassle though. I know most won't like to deviate from the OEM listed size.

I don't care about the speedometer off a few miles.

As to why do it? I think it may improve mileage slightly. I get a taller truck, more ground clearance. I like Load range E tires. The current tires seem wider than needed. If one can put those goofy 'low profile' tires on a 4x4 I don't see how my idea is all that crazy.

 

[buck91]

Bought my f150 used with LT E 235/80/17. Replaced with p265/70/17 and the driving experience was Much improved.

 

[Mr_Joe]

I stopped by the Firestone shop today to chat. Yeah, no need to buck the system. The two very experienced guys I spoke to weren't real keen on my idea. They said they had seen it before, the main issue is going to the Load range E tires. It's almost required since those sizes don't exist in the lower load ranges, except dedicated Winter tires.

I'll see if the minimal upgrade is possible. I may end up going the easy route with the same size.