20" Tires for 2005 Yukon XL Denali

dfc · March 29, 2005

Hi all,

I am new to this site since I have just purchased a 2005 Yukon XL Denali for my wife. My question is that I want to put 20" tires on it but had the following questions:

1. The dealer implied that GMC would only warranty problem if I installed the 20" P275 55R20 tires/rims that GMC installed. They told me that they had to make several mod's to the car when 20" wheels are installed and they would only do the required mod's if I bought the tires/rims from them.

They told me that the following systems needed to be modified in the computer, etc...: speedometer, stabilitrak, ABS, tire pressure monitors, etc... They said that the 20" tires drastically changed the trucks performance and these mod's were required.

OK, what the real truth???? If I put on 20" tires and go in for warrranty service, is GMC gonna deny the warranty service since I put after factory 20" tires on my SUV??

After I put on 20" tires/rims, what are the necessary mod's that I have to do.

2. What 20" tires and size does everybody recommend for a Yukon XL Denali?? I am looking for an All Season tires that has good wet and dry traction and pretty good tread life. I will not be lowering the SUV or anything like that. I will just be putting 20" tires/rims on the SUV.

I am thinking about putting on P275 55R20's? Will the vehicle handling drastically change??

3. I read on this forum about GM not recommending 20" tires on there 2004 trucks? Does this apply to the 2005 Yukon XL's?

Thanks for your help.....

SS Crew · May 4, 2005

20" wheels and tires are a factory option, so as long as you use the same size tire as the factory tire, the dealer should be able to download the proper information into your computer.

If the service guy plays dumb, talk to the service manager.

denaliman04 · May 5, 2005

I went through the same thing when I got my 20s. Unless you don't mind a service message everytime you start your truck, you will need to install the pressure sensors on the new wheels. I would suggest buying a new set for the new wheels just in case you want to put the originals on in winter. I paid about $40 each from the dealer. Make sure that the pressure sensors will work with the wheels you purchase. They should sit flat against the inside of the rim. I purchased my tires from the dealer because they were the cheapest price around. I was told that the eagle ls-2 tire is a special program tire that gm and goodyear have so the gm dealers get a price break. I have noticed a very slight vibration at high speeds and also notice the bumps more with the bigger wheels/tires. When you get the tires balanced make sure that they use the stick on weights on the middle of the wheel. My installer first balanced the tires with the clip on weights and my truck shook bad. Went back and they rebalanced with the stick on weights and they were fine. I got the same talk from my dealer about the reprogramming. I don't understand how the trucks performance can be changed if the overall diameter of the tire is the same. I would also like to get some other opinions about this, as I have not reprogrammed my computer yet. Hope this helps you. Hers some pics of my 04 Denali with the 20s.