Originally Posted by dcarver
Needing to buy new tires for my new to me 2500 Yukon xl which currently has 265/75/16 LT Michelins on the stock rims. I like the looks of the 265s but it came with 245/75/16s. Also, there was a good deal on some 235/85/16s. I saw in a post that SmokeyWren was running those. Any thoughts on that size?
I have the 3.73s
LT245/75R16E weight capacity 3042, revs/mile 683
LT235/85R16E weight capacity 3042, revs/mile 657
LT265/75R16E weight capacity 3415, revs/mile 655
The percentage difference in revs/mile will be the percentage difference in effective axle ratio, speedo, odo, and trip meter accuracy. The standard 245s are slightly shorter than the other two, so your speedo should be accurate when running that size. The 235s and 265s are 4.3% taller than the 245, so your 3.73 axle will "feel like" a 3.73 minus 4.3% = 3.57.
The 245s should result in slightly more power/torque for dragging a trailer up a grade. But if you are happy with the towing ability with your 265 tires, then you'll be happy with either the 265s or 235s.
With 265s or 235s, your speedo will be slower by 4.3%. That's 3 MPH at 70 MPH, so an indicated 70 MPH would be 73 MPH on Officer Bob's radar. That's assuming your speedo was accurate with the stock-size tires. But most factory speedos are slightly fast, so the taller tires may correct the speedo instead. Any decent GPS or navigation system will tell you the actual MPH you are making, so it's easy to determine speedo accuracy.
My favorite 16" truck tire is Michelin XPS. Expensive but worth it. But they are limited in sizes available. With traction tread, only the 235s are available in your three sizes. With rib tread, 235s and 245s are available, but not 265s. For my use if I wanted 245s, I would put Ribs on both axles. I put around 100,000 miles on mine with ribs on both axles. But if I wanted tractions on the rear or both axles, then I would run the 235s.
LT265/75R16E is not available in the all-steel XPS design. So if you want to stick with that size, then I would go to Michelin LTX M/S2. Less expensive than the XPS, but still an excellent tire.
I was informed by a tech at a tire shop that while the 245s were on it stock, towing wouldn't be as stable as the 265s. Now I'd like to go back to the 245 series if I could, but I made the decision to get the 2500 Yukon for stability purposes and I don't want to lose anything that I've gained by going back to stock.
That tech didn't know what he was talking about. There is no difference in stability in those three tire sizes provided the tires are inflated to the PSI required by the TRA load/inflation table. The only difference in "feel" when towing will be the slight difference in effective rear axle ratio caused by the difference in revs/mile (i.e., diameter) of the tires. The 235s and 265s will feel identical. The slightly shorter 245 will have slightly more power and torque for climbing hills and mountain passes, but won't be noticeable most of the time.