New Tires

[Mrslyfox]

Ok, I will attempt to make this short. In short, I have a 1999 4x4 Tahoe. Factory wheels, and Uniroyal Laredo Cross Country tires, size P265/75R-16.
When I originally got the tires, 4 years and 52,000 miles ago it did the same thing its doing now...which I had a slight vibration in a tire a couple weeks ago, took it to my very reliable tire store, Simon Tire in Des Moines Iowa... wont let anyone else handle my tires for my vehicles... anyway, I got 2 new rear tires under warranty.. pro-rated.. but still cheaper than new, being that new ones are $183/each and that doesnt include mounting, balancing etc.. anywho, the problem that I am having is, its tramlining.. for those who dont know, it is wanting to follow the groves in the road, makes it kind of feel like you are on marbles at times. It did this before when all 4 were new. The fronts have 7-8/32 tread left, or 50%, so EXCELLENT wear on these tires, and the tramlining went away over time, forgot all about it until I got these 2 warrantied new tires and now its tramlining again. Does anyone have any idea why the heck it would do this? The original tire size was 235 instead of 265 I believe, but that shouldnt matter I dont think. Alignment was done at the same time I got the new tires, air pressure is 36psi, steering is tight, new pitman arm at same time as alignment, all suspension components seem to be fine, I think I put new shocks on a couple years ago, I dont understand. Any ideas??

 

[clkelley]

I would honestly have to say that 36psi may be a tad too high. Even though it is not at the max pressure for those tires, they do that most often when the tires have a tad too much air pressure whereby causing them to ride with a more concave rounding in the tread. Try lowering the air pressure to 32psi and see if that helps.

 

[Mrslyfox]

Well I can try it, but wouldn't explain why as the tires got a little worn it stopped. Not saying you are wrong but 32 seems a little low isn't it?

 

[clkelley]

No ma'am, not for truck tires on a tahoe, you see, the side walls are pretty stout on those tires, especially with the added pressure and with the added pressure you not only get the concave shape in the tread, you also get less flex in the side wall that actually helps for a smoother ride but also helps the tires themselves sort of "adjust" to road conditions so to speak. I have tested many brands of tires in many situations on many different trucks, I have owned about 12 chevy trucks in the past 10 years and the one common denominator where tire pressures are concerned is that they all wore more evenly and performed better with what almost seems to be too little air pressure. AS a matter of fact, when you have about 32psi in them, on the bottom of the tires, it will they won't look flat, but they will have a bulge in them on the side wall. The thing to remember is that when you are traveling down the road, the tires heat up, this increases the pressure in the tires and puts more pressure on the side walls, etc. So the cold pressure should be closer to 32psi for them perform better when they have "warmed up".

 

[NCFD4303]

I agree with what ckelley is saying on tire pressure. Mine ride better with 33 than 36