Should I go back to OEM size tires?

I just went from 245/75s to 265/65s and I can definitely tell a difference. It changed the way the trans shifts on hills, and it doesn't hold top gear as easily.

Every little bit helps. Won't notice much difference in power nor the nonsense about 265s not fitting right on 6.5" wide rims.

If you like the bigger tire look or want the additional load capacity, keep the 265s.
If you want every last bit of performance for the truck, stock, get the 245s. They'll be cheaper as well.

IMHO, GM has the 6.5" bead to bead rim width both because it is cheaper and for the higher ride quality

Ride quality, as the tire's sidewalls has more of a 'bend back', or whatever technical term is use to describe it

But, narrower rim, even withing the rim width range, will have the tire's bend back allow the rim/wheel to "roll over" more than with a wider rim

The tires slip angle also increases as the rim gets narrower on the recommended rim width. More if going narrower than recommended width range...and...the slip angle is less with wider rim width...but that is more for precision driving than towing

My Suburban came with LT245/75R16E's on 6.5" wide rims. They are okay for me, but consider myself not a normal driver

For normal drivers, the stock LT245/75R16E's will be fine on stock wheels

twodownzero wrote:

CapriRacer wrote:
2007 Suburban 2500's came with 6.5" width wheels. An LT265/75R16 requires a 7" wide wheel minimum. Using a narrow wheel tends to make the vehicle follow the ruts in the road and makes it sensitive to cross winds.

If true, that's certainly strange. Trucks came with 8" wide wheels even 30+ years ago when they came with 235mm tires. I agree that proper wheel width is a consideration I'd take into account.

I had two SW 3500s, ran 265s on stock rims, did not like it vs a 7.5" rim. If one looks at tire load charts, you lose about 200 lb of capacity with narrower rims.

Marty

CapriRacer wrote:
2007 Suburban 2500's came with 6.5" width wheels. An LT265/75R16 requires a 7" wide wheel minimum. Using a narrow wheel tends to make the vehicle follow the ruts in the road and makes it sensitive to cross winds.

If true, that's certainly strange. Trucks came with 8" wide wheels even 30+ years ago when they came with 235mm tires. I agree that proper wheel width is a consideration I'd take into account.

2007 Suburban 2500's came with 6.5" width wheels. An LT265/75R16 requires a 7" wide wheel minimum. Using a narrow wheel tends to make the vehicle follow the ruts in the road and makes it sensitive to cross winds.

Personally, I would keep the 265s. If you think you're really hurting for the slight amount of extra grunt, go with the 245s. I run a 285 on my pickup and while the big mountain passes require downshifting, compared to 20 years ago, trucks have so much horsepower that I don't think it even matters that much. I am passing semis on every mountain pass anyway, what's another few percent of output? If you don't venture off the pavement much, the 245s are better, and skinnier tires are better in snow and ice. On wet or dry surfaces though, you'll notice more traction with the wider tires.

Howdy Langley neighbor!

We've towed our TT around 7 western states and I thought we've been on some pretty challenging mountain roads. Then last month we towed our TT from Langley BC to Banff & Jasper in Alberta and back. Now that was a very mountainous road trip!!

I would go back to the OEM sizes but I would say it depends on the tire design. Up until last month, we had an F250 for 7 years. Then we bought a 2012 GMC Sierra 2500HD which came with 265 wide 17" tires and needed replacing. After talking to a local retired tire dealer owner with 30 years exp. in the biz, we bought 245 wide Goodyear Wrangler tires which have a stiff kevlar sidewall and are LRE OEM size. He showed me what the sidewall is like in Michelins we used to have on the F250 - very flexible in comparison.

The Sierra now tows our 29' TT like it was on rails. Waaay better than the F250 with Michelin LTX 245 wide (18") tires. Don't know how much the kevlar sidewalls help but I sure like the new setup. I don't know much about stiffness of tire sidewalls but it might be something to look into. I run our rear tires at 80 psi and front at 75 which helps with handling. I don't think the slightly smaller dia. will make much of a difference but will help, not hinder.

The guy we bought the tires from in Langley races cars at Mission and sells and installs tires out of his home shop in Murrayville. If you want to check out what he might have for your Suburban, send me a PM.

You will gain about 4% in RPM with the smaller size and the engine will produce a very small increase in horsepower by running faster. My guess is that you will have about 5% better performance and the drivetrain will benefit slightly. The cooling system will perform slightly better as well. If you might be operating at large throttle openings, I would use the smaller tires. If handling is the priority, then go with the larger tires.

My 02 on the subject is, I want a tall aspect ratio tire for the terrible Michigan roads. Tires with lower aspect ratio's are more prone to pothole failure because there isn't enough sidewall to absorb the potholer shock and your rims could take a hit too.