First let me say I am an idiot when it comes to tires and what sizes I can or can't put on my truck, but I need to buy new tires. I have a 2003 GMC 1500HD 4x4 quadrasteer. The one issue I have with the truck is the tires are too small. Can anyone tell what is the largest size I can go to WITHOUT having to do any major modifications? I understand I'll have to have my transmission recalibrated, but I'm not sure how large I can go and really dont trust the tire dealers to tell me, any help is greatly appreciated

I went to my local dealership with that exact question. They gave me an entire list of tires based on size of what would fit correctly. A lot depends on what size wheel/rim you are running now. If you like I can post the list later today or tomorrow that my dealer gave me base on a 2005 4x4.

Have a good day.

Bill

O5Quadrasteer-Thanks for the help. If you could post the list your dealer provided it would be great. The tires and rims are stock from the dealer, rims are 16...

Just wrote myself a note to make sure I answer you tonight. Sorry about the delay went straight to the fire station last night after work and never got home until early this morning and now back to my regular job.

The only issue I see you might have is my stock tires were 17's. But then I am thinking you can most still go as big as the tires on the list I show you since the wheel wells are most likely the same size.

Here is a site for figuring out tires sizes and the differences you will have in your speedometer; http://www.miata.net/garage/tirecalc.html

When I post the tires tonight I will also let you know the sizes they work out to. Give me a shout if you have any other questions.

Have a great day.

Bill

05Quadrasteer-thanks I look forward to the info. I've done a little legwork on my existing LT245/75R16 and found that I can go to 265/75R16 without having to recalibrate my transmission. Amazingly, I went to 4 Wheel Parts to get a quote, they started with 285/75/R16, but when I reminded him that I had QS he went to the back office to "check" when he came back he said he could only replace with the same size tires as those already on my truck (245/75/R16)! When I asked why he told me it was "Corp. policy". What a load, anyway based off of what I've read on this forum I think I am going to try to find someone to put on 285/75R16, any thoughts on this?

Here are the maximum tire sizes my dealership gave me. I shall also put the tire size after the figures.

285/65/17 is 31.6
305/55/18 is 31.2
305/50/20 is 32
285/45/22 is 32.1

So my thought on this is actually any tire up to 32 inches in size should work on the truck. Would suggest using the web site I put on the previous response to see what the size of the tires are that you are considering as compared to what the dealer gave me.

One other thing to consider is I have heard some people talk about wether the brakes can handle the larger tires. I know on my previous truck which was 2003 it had standard 16 wheels, my current 2005 came standard with 17 wheels the brakes are much bigger on my 2005.

Another couple of forums I am on that can also be helpeful are gm-trucks.com and fullsizechevy.com

Have a great day.

Bill

Thanks 05Quadrasteer for posting that info I am soon going to need new tires and have been toying with going up to a bigger wheel size. One thing i was concerned with other than clearance is the effect a larger wheel/tire would have on braking. I was looking at going up to an 18" wheel with some BFG g force T/A KDW tires http://www.bfgoodrichtires.com/bfgapp/catalog/tires/gforcetakdw.jsp

I've got the 305-50 20" tires on my truck and the only rubbing issues I had were the fender liners in the front of the front fenders. You'll need to cut these back or your tires will grab those when you back up and make grinding noises - Otherwise all is good.

Remember - Go big on your tires, there's lots of space to fill up in those back fenders. I don't know why GM puts such small wheels and tires on their trucks.

Good luck with your wheel and tire choice.

I agree there is a lot of space there that needs to be covered. I had thought about going to 20's but I cant decide on any wheels a lot of them i have looked at were just too gawdy. Its hard to find something thats cool yet tasteful. It took gm how many years to go from 15 to 16" I was shocked when they started offering the larger wheel options.

Weather is terrible here today, it's freezing, perfect day to go buy tires! I had the dealer mount up a set of 285/75/16 and they looked great, unfortunately the driver side front rubbed and to be honest I dont trust myself to "trim" the fender, so I had them put on 265/75/16 and then crank the torsion to raise the front about an inch. The 285's really looked great but I am happy with the final results of the 265's.

One question, again I have an '03 1500HD 4x4 QS, does anyone if I need to have the transmission recalibrated? I went from 245/75/16 to 265/75/16 just want to make sure I dont mess up my transmission??

quote:

Originally posted by carbonquad:
I agree there is a lot of space there that needs to be covered. I had thought about going to 20's but I cant decide on any wheels a lot of them i have looked at were just too gawdy. Its hard to find something thats cool yet tasteful. It took gm how many years to go from 15 to 16" I was shocked when they started offering the larger wheel options.

The factory 20" wheels look pretty cool. See if you can find a set of take offs or even a set of chrome SS wheels. I've got pics of my truck in the Pics and Vids section to see what Weld Velociti 8's look like on a crew cab.

Good luck on your wheel hunt.
SS

Well I never could decide on any wheels that i liked so I decided to just get tires since my inspection was due. I ended up getting the bridgestone dueler AT REVO's . So far I love em

Carbon,

Did you keep the same size tires as stock?

yes I stayed at the same size as the factory tires at 255-70-16's, these tires seem just slightly bigger than the factory tires and look cool. So far traction seems excellent and the road noise is less than the factory tires (generals)