Jeep Senior

Hi. I'm thinking of upgrading my tires, but the ones I'm thinking of (because of the limited sizes) will make me go from P255/75-17, load rating 108 (or thereabouts), to an LT tire with a 118 load rating.
I'm thinking that it can't hurt to go to a "tougher" tire in terms of more plies, but my main reason is that I like the newer tread design.
And I know that I'll have to adjust my tire pressures for the newer tires' different pressure vs load correlation. And that the new tires are about 5 lbs heavier.

But are there any downsides? I don't mind a somewhat stiffer ride, but I once heard something about it would make the car "bouncier" -- does that mean what I think it does (hopping up and down)? Any truth to that?
Any other downsides?

Thanks.
Ken

tarpon4me

You've already noted a stiffer ride. An LT will likely be heavier, so you may see a slight decrease in MPG. Depending on the brand/model, the LT versions of tires don't carry a warranty either. Just check so you're making an informed decision.

101gargoyles

P is at the beginning of the tire numbers. LT is at the end of them. Apples and oranges here. P means nothing except to the folks making the tires for a metric system market. LT stands for Light truck. the numbers in between remain the same.
Sounds like you are confused because you want to buy on-line. Just go to a real tire place and they can tell you. Just don't ask the questions and tell them they aren't going to get your business. They may not invite your to the street BBQ.

the_jeep_now

P are passenger car tires where LT are light truck tires. LT tires can handle more load.

Lt Vs P at Tire Rack

jk_sea

Heavier tires mean more unsprung mass, which will reduce braking and handling performance. Heavier tires will also cause gas mileage to suffer. You're staying with the same size, so probably not a whole lot of weight gain, but it's there. 5lbs per tire doesn't seem like a lot, but when that becomes rotational mass, it's a lot harder to get moving, and stop, x4.

LT tires usually come in different load ratings. The higher the load, the stiffer they are.

Regarding ride quality, LT tires have much stiffer sidewalls which allow more road force to be transferred directly into the structure of the vehicle. So the ride will be harsher.

If it's just about tread design, I'd say it's not worth it. The reason people go with LT tires is generally for more extreme use cases. But, that's my philosophy of a tire being a functional piece of a car versus something aesthetic.

Phantasm

To reiterate what Tarpon4Me stated. LT tires often carry NO mileage warranty whereas P tires almost invariably do. So you assume the risk of the tire failing or wearing out with little recourse.
For instance: Goodyear Duratrac LT tires are NOT warranted but their Armortrac line is (and for 5k less miles than the Armortrac P version).

https://www.goodyear.com/en-US/tire-warranty/tread-life