New Truck with old Trailer, Sway issues

[henryj]

Originally Posted by henryj

One aspect of tire stability not mentioned yet is the role of wheel width compared to tire section and tread widths.

My previous '15 Silverado included 18x8.5 wheels and P265 tires as part of NHT max tow package. I immediately replaced the factory tires with Michelin LTX M/S2 also in P265. These Michelins had a 10.7" section and 8.3" tread. I had excellent results with these tires and even bought a second set. IMO the 8.5" wheel and 8.3" tread was a key part of the stability and satisfaction I felt with these tires.

My current '19F150 has 18x7.5" wheels even though it is also the max tow package. I was planning on replacing the factory P275/65 tires with LTX, but missed some parts of my homework. The LTX P275 has a whopping 9" tread width and 11" section width. Far too much tire for a 7.5" rim on a truck meant for towing. I believe this Michelin could well have given me the same kind of instability John is talking about.

While redoing my replacement tire search I found myself fishing in a very small pool. I needed at least 116 Load Index and the same OD as the factory tires to avoid speedometer errors and I didn't want to buy new wider wheels. 255/70 was the ideal tire size, but it was not readily available across brands and didn't have 116 LI. I finally settled on BFG All/Terrain 255/70 LRD. It has a wider tread at 8.4" than I'd like on a 7.5" wheel, but at least the section width of 10.2" is a much better fit for the 7.5" wheels.

I completely missed looking at wheel size on the door stickers of the the inventory trucks before ordering mine. In hindsight, I would have seriously considered the 20x9.5 wheel option. In the end I paid a couple hundred more for LRD tires than I would have paid for the 20" wheels. Am I further ahead? I don't know?

Anyway, when buying trucks, new or used, always look at the wheel width and contemplate what kind of replacement tires are available/better suited for towing.

Henry

20" F150 wheel is actually 20x8.5. Wheel-size.com is a wealth of info for any make. Interesting that LT275/65/18 tire option gets proper size 18x9 wheel where P275/65/18 gets undersized 18x7.5. I should have ordered LT tires.

Henry

[JohnB]

Henry,

Good post. Yes, a tire tread/section width too wide for the rim is another issue when towing. I'm thinking this situation does not crop up so much as with OEM supplied tires/wheels, but can when replacing tires by the owner. This especially can be the case on a "decked out" truck when the owner installs wider tires to, create for them a cooler look. The issue often will not show up until they start to tow with it. Then, pending the towing situation, it can rear its ugly head.

It is good to hear your second generation design LTX MS2 worked well for you. Did you have to run the tire pressures higher than the door sticker stated pressures? Do you by chance know what they changed between the original and the MS2 change?

Thanks

John

[henryj]

Originally Posted by JohnB

It is good to hear your second generation design LTX MS2 worked well for you. Did you have to run the tire pressures higher than the door sticker stated pressures? Do you by chance know what they changed between the original and the MS2 change?

Thanks

John

Door sticker on the '15 Silverado was 35/38. I always ran at least 38/38 and bumped that up 40-42 towing. That truck had a 50/50 weight distribution towing so I wanted the same psi f/r. I tried 44psi--max sidewall psi--on one trip, but that was too harsh and no more stable than 42. On that truck I also changed to Bilstein 4600 shocks after the first towing season.

I've used the original LTX, LTX M/S2 and Defender LTX on 2 different trucks. Couldn't tell any difference.

Henry