Tow Vehicle Tires

[tvoneicken]

I just read a pretty interesting article on tow vehicle tires in the fall Airstream Life magazine written by Andy Thomson. I won't reproduce the article here, but what was interesting is that he compares the sidewall stiffness of various tire types, which specially helps against sway because stiffer sidewalls reduce the amount of TV rear-end movement as the trailer sways, for example due to a passing semi.
In particular, the LT (light truck) tires have stiffer sidewalls than the P (passenger) tires, but also vehicles with larger diameter wheels and less tall tires. An example he gives are going from a P265/70R17 to a LT245/70R17. The LT is stiffer, but also by going to a 245 the tire width more closely matches the width of the rim and that also reduces side sway. The outer diameter is a tad smaller, so a little speedometer recalibration is on order. Another option he gives is a P235/65R17XL, which rides better than the LT, has more traction, and handles a little more precisely.
All this may be obvious to some of you, but I hadn't stopped to think about it. Well worth a read if you can get a hold of the magazine!

[ROBERTSUNRUS]

Hi, this could be good information depending on what you drive and where you are at. Costco, for one, will only install sizes that are made for your vehicle. We wanted larger tires for my wife's BMW, but they will only install the factory size. While in Montana, on the return route from Alaska, I needed tires for my Lincoln. [they prematurely wore out on the gravel roads of Yukon] Costco not only didn't have any tires for my Lincoln, but said that of the brands that they carry, my size is obsolete. I needed tires now and my other option was to buy them from Les Schwab. The tires that I bought were a bit taller and a bit narrower. I believe that these were the same size as used on the Expeditions. Away from home, and the big city, your choices are very limited.

[tvoneicken]

Yup, you have to go to someone who knows about tires, not someone who sort-of knows how to mount tires...

[slowmover]

which specially helps against sway because stiffer sidewalls reduce the amount of TV rear-end movement as the trailer sways, for example due to a passing semi.

Which is why, IMO, it is important to be painstaking about hitch rigging. If that shows up as close-to-ideal as can be done on multiple re-weighs of "perfected" hitch rigging (weight distribution according to formula), then tire pressure can also be perfected according to loads and not random guess numbers.

If tire pressure changes seem inadequate, then the search for "better" tires (brand, type, size) becomes a more obvious step (unless one has a near mirror image comparable rig).

Just remember that there are trade-offs. I might gain some in switching to a Load Range D tire for my truck with a shorter sidewall, but I would lose some of the trucks utility by being load-restricted as well as in the tires being better able to handle potholes, curbs, etc.

Among Load Range E tires as on the 3/4 and 1-Ton trucks, there are tradeoffs between choices. 2Air went for tires that have superior wet road performance, while I would rather have the wears-like-cast-iron variety (might get 250k miles from but two sets).

I do a lot of research on Tire Rack about tires (beyond other recommendations) and tend to buy from Discount Tire for service as needed in travels. One can also buy from an ordinary authorized dealer and inquire into road warranty provisions. (It would never occur to me to buy tires from the department store chains).

I'd still rather have a sway-eliminating hitch set up on a certified scale. Put the burden where it belongs, IMO. Then things like tires need not deviate as much (in my instance) as to lessen capacity. Had I a minivan, then that hitch plus a wheel/tire change would be among the first things done (including trailer disc brakes) according to what Mr. Thomson and associates have learned over the years.

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