Going From 245 70r17 To 265 70r17 Winter Tires

clintg · December 3, 2009

Hello, I have a 2009 Sierra 2x4 Crew cab. It currently has the stock 245 70R17 wheel on it.

I am looking to put a set of used cooper winter tires on, but they are 265 70R17.According to online calculators, the coopers are 3.6% larger, and effectively make my 3.23 gears work like 3:12's. I have the 4.8L with 4L60 transmission.

I know some of the other trim levels came with this size of tire, are the transmissions geared different, or are they just programmed with a different shift points.

Will putting these tires on void my warranty?

Will these tires damage my transmission in any way?

Not like this truck has much for power, but will a small difference in tire like this make much difference in fuel economy or engine power?

Thank you.

pwall · December 3, 2009

It's not going to hurt anything.

You speedometer will be off slightly. You can get that reprogrammed for the tire size, but since it's winter tires and you'll be putting your 'summer' tires back on, not really worth it.

kawtoy_77 · December 3, 2009

Clint, I am putting the 265/70/17's on my 4X2, and have heard of no probs from other guys running the same setup.

-Clint

rodram · December 3, 2009

... you are only looking at one tire size difference

... you will not have any problems with warranty, or function of your transmission

... you will not likely see any mpg difference... small benefit in difference in gear ratio and yet a small negative effect in having slightly heavier tires

.. depending on your existing tires and which line of Coopers you are planning to use, you might find that the truck rides more stable with the size increase

clintg · December 4, 2009

Great, thank you for the responses, I feel better about going with the 265's now.

I am trying to find the best tire for the dollar, my selection so far is (set of four delivered):

Hankook I Pike RW11 - 245-70R17 for $509.62

Firestone Winterforce - 245-70R17 for $509.71

Bridgestone Blizacks - 245-70R17 for $517.28

Mastercraft Courser MSR - 245-70R17 for $518.94

or i can go for the 265's:

Firestone Winterforce - 265-70R17 for $442.40

What order would you rank theses tires. Are there any that are no good at all?

also, were is the best place on the internet to purchase tires? Best prices i have found so far is discounttiredirect.com, tirerack.com and tire-easy.com.

kawtoy_77 · December 4, 2009

Where do you live Clint? I have a guy local that gets much better pricing. I Got the Hankook DynaPRo ATM RF10's in a 265/70/17 for $538 mounted and balanced OTD.

If you are only using this tire for winter, then I say go with the WinterForce's My g/f's uncle just got them and they look like a good tire. They are ranked well by usuers and I guess in Canada they use them on emergency vehicles....police, ambulance, etc.

clintg · December 4, 2009

Im in Vancouver, BC. But i usually buy everything in Washington State.

kawtoy_77 · December 4, 2009

Im in Vancouver, BC. But i usually buy everything in Washington State.

LOL! well then my local shop prolly isn't gonna help!

Good luck!

-Clint

clintg · December 4, 2009

Buying tires in vancouver is really bad. A full set for $800 is considered a good deal. In Washington, i can get them for $650. I think i will go with the Firestone Winterforce for $430.

kawtoy_77 · December 4, 2009

Buying tires in vancouver is really bad. A full set for $800 is considered a good deal. In Washington, i can get them for $650. I think i will go with the Firestone Winterforce for $430.

Good Luck with those Winterforces and let me know what you think of them. Like I said my g/f uncle just bought them for his Z71, and all the reviews I have read are good!

Silver Wraith · December 4, 2009

Don't count on being able to get anything reprogrammed if you change size; I've been going through this issue. I just made the same swap (actually called the dealership from the tire place and asked if it was an issue to reprogram first...and was told it's not a problem...oops, mistake). I've had the truck in twice, and even with emailing the service manager directions on how to do it by calling for a code to allow them to do this using the Tech 2 (programmer), the service manager insists it cannot be done because this was not an option on my truck.

My truck is equipped like yours...2 wd with 4.8 L, 3.23s and 4L60E. To get the larger size I would have had to have purchased a 4WD or ZR1 package.

The way I read it, if the tire size was an option on any Silverado, it should be doable, but maybe I need to talk to another dealership.

He did tell me it won't hurt anything, won't affect warranty, and my speedometer would be out a bit. But, besides affecting speedo and odometer, it also affects other things in my DIC, like mileage display, kms to empty, etc. On the upside, I'm putting fewer miles on my truck :-)

If none of this bothers you then fire away!