TV tire size

Given the choice would you put a P275/55R20 tire or a P255/65R17 tire on a vehicle used for towing?

I've read here that many would prefer an LT (Light Truck) tire as their sidewalls are stiffer; so the additional trailer tongue weight and all your gear don't cause a lot of squirm when the truck is fully loaded. But they also give a harsher ride, especially when the truck is unloaded.

Will the narrow sidewalls of the R20 tire cause less squirm when towing? Apparently they will cause a harsher ride.

[Harry Womack]

I use LT265/70R/17E. I had P265/70R/17 and the back of the Suburban would sway. With the new tires I don't even know the trailer is back there. I run the new tires at 42 PSI.
The 20" tires are not to be used off road on most vehicles

I know off-roaders like lots of side-wall to stop pinching the tire against the wheel. But I'll never be doing any rock climbing with this rig.

But from what you and others have said, LT tires would definitely be better ...

Hmmmm, well, maybe I can trade the fancy 20" wheels and tires for some smaller wheels with LT tires. I'll look into that. Thanks for the advice.

Another thought. Find out the maximum load for the tire. Each tire will be carrying, if the load is evenly distributed, half of the axle load.

Weigh the vehicle while loaded.

The weight on my rear axle is approximately 3,400 pounds when the is no cargo and no trailer. I would need P tires rated for 1,700 pounds. I don't think P tires will carry that load.

P tires are fine for an SUV used exclusively as a passenger car. My wife's Lexus SUV has P tires on it, but I would never use to tow anything.

[Harry Womack]

I had the P rated tires on my Suburban with a max pressure rating of 44 PSI. I replaced them with the now obsolete Michelin LTX M & S tires with the exact load carrying capacity as the original tires except at 36 PSI. The tires with the 44 PSI towed better that the 36 PSI tires because of less side wall flex. If I was buying P rated tires I would look for the 44 PSI rated tire. I noticed that the new LTX M & S-2 tires have a 44 PSI rating. The tires that I used on all of my other Suburbans were load range C tires. They were perfect for towing and had a good ride also. Because Chevrolet is using 17" standard I can not get these tires. The automobile companies are using so many tire sizes the manufactures can not offer as many load ranges as they used to.

With a lot of people converting their TM's from load range C to load range D, it is interesting to hear about load range C on the TV and load range D on the TM.

I laugh at the thought, because my truck weighs 6315 when completely empty. I run load range E.

I will agree that a sufficiently light TV you can use tires with a lower load rating.

A friend of my daughter's was going to replace the wheels on her Tahoe with 20 or 21 inch wheels, because thy look cool. The results in a tire that does not have much distance between the bead and the tread. makes for some interesting conversations about side wall flex.

She changed her mind when I asked her if she would be towing anything.

Discussing low profile tires is a completely different subject.

Originally Posted by PopBeavers

Another thought. Find out the maximum load for the tire. ... I would need P tires rated for 1,700 pounds. I don't think P tires will carry that load.

The P tires I mention above have a load index of 111 which I guess translates into 1090kg each (2403# each) at 42psi. And the truck I'm looking at has axle ratings (depending on configuration) of up to 2177kg (4799#). So two of those tires at 42psi matches the max rear axle rating.

It's a new truck with the original tires, so one would expect the tires to match or exceed the axle ratings.

My question about side wall depth had more to do with the tire's rigidity, especially under load. I would expect the low profile tire to be more stiff, less squirmy (if both were inflated to the same tire pressure). I understand that's why race cars have such extreme low profile tires. But the tradeoff is a harsher ride, and for an off-roader (and any place with pot-holes), the possibility of banging the tire on the rim.

But the difference between 166mm (.65x255mm) and 151mm (.55x275mm) is only ~10%, so it's probably not a big issue anyway.

[Harry Womack]

All 3/4 Ton or 1 ton vehicles come with Load range E tires standard. It is required for the manufacture not to put any lower rated tire on them. Load range C works well with 1/2 ton vehicles.

Originally Posted by Harry Womack

All 3/4 Ton or 1 ton vehicles come with Load range E tires standard. It is required for the manufacture not to put any lower rated tire on them. Load range C works well with 1/2 ton vehicles.

Seems reasonable to me.

However, is my Chevy 1500HD a 1/2 ton truck or a 3/4 ton truck>

I claim that Chevy named it wrong. It is really a 2500LD.

Because I have over 3,000 pounds on the rear axle, I like the load range E tires.

1/2 ton is not always a clearly defined description of a truck or SUV.