20" rims vs 17" rims

I have a 2007 GMC Yukon Denali with 20" alloy wheels. The chrome is peeling off and the alloy is corroding where the tire bead sits (in fact the wheels are corroding in a number of places). The tire size is P275/55R20 and the radius is approx. 31" The spare is a 17" steel with a tire size of P265/70R17. The radius is also approx. 31". Both tires have a circumference of approx. 97.4".

Is there any reason why I shouldn’t buy new 17" alloy wheels with tire size of P265/70R17? since that is what the stock tire are for this vehicle (The 20" rims were an option offered by GMC)?

The stock tire sizes for this vehicle are 265/65/R18 and 275/55/R20. 265/70/R17’s , while basically the same size as the 265/65/18’s in terms of overall diameter and width were not offered from the factory (other than the spare obviously). If you can find some 17 inch wheels that can clear the brakes without issue, and with the proper offset and bolt pattern you could certainly use them if you wanted.

None at all. Just make sure you get the right size and load rating.

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Tire rack lists 265/70 x 17” as a non-stock size. It’s been a long time since I’ve seen a 70 series tire. While they list a number of different tires, you might have more options with the 18”.

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Yes… I would go back to 17 or maybe 18’s if you like paying for rubber. Not sure how long those heavy 20’s were on there but those lead weight wheel sizes have a way of destroying any and all suspension components. They are unsprung weight and although you may not have noticed, I promise your suspension did.

Pay attention to your suspension just as a bit of insider knowledge, hopefully it is ok but just know those 20’s were a heavy burden for all of those components. So proceed appropriately.


Yes, there is a reason you shouldn’t buy new 17" alloy wheels: New or used 18" or 20" steel wheels would be cheaper, would do the job, and would look good enough on a 12-year old vehicle.


Just go to a local tire and wheel shop , get prices then you can make that decision . They will have all the specs on size for your vehicle.

Neither the 18" or the 20" wheels are cheaper. And neither are the tires.

Honda; I can attest to your unsprung weight theory. the 20" wheels with tire mounted weigh about 100 lbs.

Saw a ok condition set of 3 rims/tires at boneyard. 275/55/20 that had the right bolt pattern for my rig. $20 each is ok. Yep it would be hard to find a 4th

Depends on the wheel. I just put a set of 20x10 wheels on my Mustang this week. The new wheels weigh in at 27.2 pounds each, the old wheels (19x9 in the front, 19x9.5 in the rear) weigh 34 and 37.5 pounds respectively. The tire weight went up by 3 pounds (per tire) in the front, and stayed the same in the rear. So even by going to a larger rim, I actually decreased unsprung weight by about 28 pounds.

Of course it does. You forgot to mention how much a larger lighter wheel cost you. Those who apply huge wheels to Tahoes (on average) dont know or care about unsprung weight. They surely dont invest in forged wheels either. They want them huge and cheap…i.e. large, shiny, thick, heavy. So my mention of heavy wheels more than likely applies. Thats my story and I’m sticking to it. LOL

Recall reading about Honda pax wheels. They wore fast and folks replaced them with stock non pax wheels which were 20+ lbs lighter and it made a difference in ride quality since the shocks/springs were tuned for them. On a minivan? Right

OE wheels on this truck were 18" and 20". Why not go with the smaller OE size?

Check out the price of the corresponding tires that match the wheels you are thinking about before deciding. Some tire sizes are not as popular as others, and the result is they may not be made in the tire manufacturer/model you prefer, or while still available, they are considerably more expensive.

I suspect that the GM engineers are familiar with unsprung weight, the Denali came with 20" wheels. Factory wheels are generally lighter than cheap aftermarket wheels.

If I had to replace these wheels I would choose 17" or 18" wheels, they are more suitable for off road travel.

I must admit I did not know this… For some reason in my head I was picturing an older vehicle with stock 17’s and had 20’s foisted upon it.

Now I need to go find my Footus en Mouthus wash… I may actually be out of it I use it so often.

Since my foot is clearly in my mouth…its no wonder I was talking out my Arse. Sorry, I think I gave some worthless advice here… LOL

Please describe.