question for Jettester

[James S]

Hey Joe,

I have a few questions for you about your tires you have on your truck. I am getting a black, 2003 GMC Sierra 2500HD crew cab, SLT long box, and I was going to put on the 285/75 R16 Rangler MTR's, because I hear the factory tires are crap. Can you tell me everything about them. Is the truck more stable, when driving, empty, loaded, and when towing? Is your turning diameter increased? If so, roughly by how much? Are the tires quiet?????? This is vary important! Has your fuel milage increased, or decreased and by how much? What kind of milage are you getting in town, and on the highway at about sixty or sixty-five miles an hour? Can you use the factory rims with those tires? Do I have to tie anything back, the wheel well, or anything else? Does the truck ride any higher with these tires, compared with the factory tires? Were you able to get the speedometer recalibrated, ACCURATELY??? Finally, what is your traction like, in wet and snow? Thanks for this, Joe. I appreciate your input.

James

[DURA-MAX3]

I'm not joe but the dealer can enter the tire size you put on by hooking up the hand held computer to the main system. It tells him the different tire sizes that are already in the computer and all he does is reselect the size you put on it. It has to be a size that already exists in the truck computer, 285/75r16 is in it. I put 265/75r16's on mine and my speed-o is right on the money. The larger tires drop the rpm's a little and did not seem to affect the milage. I put all-terrain cooper's tires on mine and i love them.... Later....

[Allison Jettester]

Hi James,
I've had these tires on my 95 2500 GMC for about 6000 miles before I put them on the 2002. I have 8200 on it so I have 14200 miles on them.

I don't know exactly what caused it but I got some cupping on the center tread lugs on the front and they got really loud. I took it to the Goodyear dealer for re-balancing and rotating as well as alignment. My right castor was out. As you can see in my sig, I put Gabriel air shocks on the front, but have only got 500 miles with them on so that didn't cause the cupping.

I had to crank up the torsion bars to get the tires to clear the front wheel well rubber shield as well as the bumper. Even then I had to cut some off the bottom of the left front rubber shield. Adding air in the shocks also raised the front 3/4 in. I put the air shocks on to stop the front end bounce, especially with the camper on.

The tires are fairly noisy-not as bad as mudders but enough to get a little annoying with the window down.

Dry traction is awesome. In four wheel drive it's hard to get them to spin, even in packed dirt and Juice on 4. I went up a very steep rocky gravely dirt path, probably a grade of 15% and didn't spin at all. Snow is good, but wet is not. The tread is hard for wheeling in the rocks so they don't hold well in the water--have to be careful. It makes them wear well though. I still have almost a half inch of tread left from about 9/16 new.

Haven't noticed any change in turn radius or fuel mileage. I get anywhere from 18.5 to 20.5 highway and 17 to 18 around town. I just towed my Elkhorn 11X, ~3600 lbs in level 2 and only got 11.9 mpg-all highway, but was going 75 most of the time.

You cannot use the factory rims. Goodyear recommends 7.5 to 9.0 inches width. The factory rims are only 6.5. I have 8.5's as my experience has been that the narrower the rim, the more you wear the center of the tire at max pressure.

You cannot get the ECM or TCM programmed for 285's as Duramax3 said-GM won't give that option to the dealers. I have done many measured miles as well as GPS and determined that the speedo and odometer are exactly 10% off (reads low), so you have to add that mentally while your driving-add 5 at 50, 6 at 60 etc.

The truck does ride higher with the tires and mods, but mine was a little higher from the factory than others I've seen.

But most of all, they are awesome looking and I get a lot of comments. I should have some pictures up soon.

Hope this answers your questions,
Joe

[DURA-MAX3]

285/75R16 SIZE TIRE IS IN THE COMPUTER, THE TECH THAT DID MY TRUCK SHOWED ME ON THE HAND HELD ALL THE TIRE SIZES THAT WERE IN THE COMPUTER. SAW IT WITH MY OWN EYES.....

[SoCalDMAX]

DURA-MAX3,

Of course you did. No one is doubting that you saw it. The fact remains that what the tech did with the Tech II did not alter your speedometer or tranny shift points in any way. It merely adjusts ABS settings. This has been discussed at length in previous posts and confirmed by John Kennedy, who owns a Tech II and (I think) knows how to use it. Your change from 245 to 265 tires only made your speedo accurate, before it probably was not.

The only device I'm aware of which actually changes speedometer readings is made by Superlift (Tru-speed?) and according to posts I read here, actually works well.

Regards, Steve