Tire Upgrades

[Pilot12]

Lots of us replace our OEM tires with something completely different. Trucks come with inappropriate tires and the boilerplate in the owner's manual specifically says to stay with same size and (even!) load range. Obviously this is CYA for the most part, but without GM's guidance, how do we know for sure what we can get away with? I mean safety wise as well as damaging the truck. (I know they'll try to tell us the warranty is void even if all we do is remove their logo. But it's a new truck and I'd like them to fix it for free the first couple years.) The door placard and manual only show OEM specs. Am I on my own if I put 50 lbs. in my load range E tires? If something happens everbody can say "he picked the wrong number and shouldn't have even had those tires on." Every other vehicle I've had I just researched tires and put on what I thought was best for my use. Does it seem more complicated than that now, or am I over thinking this?

 

Next, what do I do about the TPMS? Can it be reset for whatever pressure I put in the new tires or is it permanently set to want 35PSI? Can Discount Tire do the reset? I personally like the system and would hate to have to ignore warning lights or jury rig some bypass. The manual isn't entirely clear, probably because it already said don't do it. There MUST be a '"relearn" feature.

 

Sorry if this has been covered; I'm not having any luck with the search funtion. Thanks for any insight you all have.

[Spurshot]

Lots of us replace our OEM tires with something completely different. Trucks come with inappropriate tires and the boilerplate in the owner's manual specifically says to stay with same size and (even!) load range. Obviously this is CYA for the most part, but without GM's guidance, how do we know for sure what we can get away with? I mean safety wise as well as damaging the truck. (I know they'll try to tell us the warranty is void even if all we do is remove their logo. But it's a new truck and I'd like them to fix it for free the first couple years.) The door placard and manual only show OEM specs. Am I on my own if I put 50 lbs. in my load range E tires? If something happens everbody can say "he picked the wrong number and shouldn't have even had those tires on." Every other vehicle I've had I just researched tires and put on what I thought was best for my use. Does it seem more complicated than that now, or am I over thinking this?

 

Next, what do I do about the TPMS? Can it be reset for whatever pressure I put in the new tires or is it permanently set to want 35PSI? Can Discount Tire do the reset? I personally like the system and would hate to have to ignore warning lights or jury rig some bypass. The manual isn't entirely clear, probably because it already said don't do it. There MUST be a '"relearn" feature.

 

Sorry if this has been covered; I'm not having any luck with the search funtion. Thanks for any insight you all have.

 

Yes, you are overthinking this. Buy the tires you determine best for your use. If I were towing a lot, I would not settle for any less than a load range E. In fact, I'm buying E tires for my 1500 08 even though I tow very little now. I'm buying them for their durability off-road and puncture resistance.

 

I think I'll leave my TPMS warning thresholds as is. I don't want a warning at 48 psi or some such number. 35 psi or whatever the factory setting is will still be a safety margin, but not a wear/handling threshold to rely on.

[Pilot12]

quote]I think I'll leave my TPMS warning thresholds as is. I don't want a warning at 48 psi or some such number. 35 psi or whatever the factory setting is will still be a safety margin, but not a wear/handling threshold to rely on.

If I leave the TPMS at 35 (assuming it could be changed), and then I run with 50PSI, I won't get a warning if one tire goes to 35, right? (My car has a "differential" warning.)There is no "over inflation" warning, also correct?

 

I'm like you; tow very light and infrequently, but lean toward the "E" tires for puncture resistance, especially the sidewalls which I have bad luck with. I'm just a little concerned about the stiff ride getting TO the woods. Old truck was suspended softer and "E" was no problem.

[Spurshot]

Kelly,

I don't know about the differential function of the TPMS. Frankly, it's a last resort warning system to me even though I have the full banana individual pressure reading capability from the DIC display.

 

I decided I'm buying the tire I want and will either alter the suspension to match or accept what I get. You've seen my Bilstein threads. I think my 08 Vmax with the NHT pkg (Z85 susp) is very stiffly sprung, but the shock were trash, both front and back. The front shocks were just not enough damping to keep the truck from bouncing around all over the road. The Bilstein fronts fixed that. It wasn't as clear what was going on with the rear suspension. It is so stiffly sprung in the back that it would literally bounce off the pavement on the freeways where the concrete has a washboard like pressure ridge. I'd look in the rearview mirror and see the tailgate bouncing up and down. The dog was uncomfortable on the backseat. I was thinking I would buy some standard pkg (7000 lb GVW) springs for the rear from the junkyard and put airbags on it for heavy loads. Finally, one of you guys said the Bilsteins were 25% off and I bought them. The back just need better damping, just like the front. It rides much better with the Bilsteins. Have you changed the shocks all the way around yet?

[music]

Correct me if I'm wrong here... but you can run E tires at 35 psi, but they don't have the same load rating as a P tire at the same pressure. I've read that 45 psi on the E has the same load as a P at 35. I've also read that an empty, light-weight truck with E tires @ 45 psi can get rough, but you don't need 45 psi when running empty. You get a better "ride" vs "load capacity" with the P tire, but at the expense of safety, lateral flex and "bounce" when hauling/towing.

 

Here's an interesting guide: http://www.goodyear.com/truck/pdf/databook/loadInflation.pdf

[Pilot12]

It rides much better with the Bilsteins. Have you changed the shocks all the way around yet?

Yeah, I did all four at the same time and it rides a lot better over rough roads. I don't think my short wheel base started out as bad as yours though. The towing package is pretty stiff, but I can't say it was bouncing off the ground, just a little squirrely.

[thedave]

I have E rated Michelin LTX's on my 08 and the Tire pressure warning seems to come on between 45-50 psi. I run 40 psi and they ride and tow pretty good. When it comes time to change out these tires though I'm getting rid of the TPMS. The low pressure warning is fine but the high pressure warning is a pain in the rear, especially with tires that are rated up to 80 pounds

[Spurshot]

I didn't realize there was a high pressure warning. Maybe I can convince Justin or someone to fix that for me.

[music]

I didn't realize there was a high pressure warning. Maybe I can convince Justin or someone to fix that for me.

 

Just did a quick search. Looks like a GM Tech-II can adjust the pressures (its in the BCM and EFI only accesses ECM/TCM). I'll be curious to know how this works out on the 1500.

 

http://www.duramaxforum.com/forum/2007-5-g...ms-sensors.html

[Pilot12]

Just did a quick search. Looks like a GM Tech-II can adjust the pressures (its in the BCM and EFI only accesses ECM/TCM). I'll be curious to know how this works out on the 1500.

Wow, now it costs $$ for the fancy valve stems w/ tpms, $$ for computer resets and a trip to the dealer just because we get new tires. Paul Harvey used to say "we've out smarted ourselves."

Well, as long as I'm at the dealer, I'll just get the front end lubed...oh, wait..never mind.

[Spurshot]

I didn't realize there was a high pressure warning. Maybe I can convince Justin or someone to fix that for me.

 

Just did a quick search. Looks like a GM Tech-II can adjust the pressures (its in the BCM and EFI only accesses ECM/TCM). I'll be curious to know how this works out on the 1500.

 

http://www.duramaxforum.com/forum/2007-5-g...ms-sensors.html

 

 

I'm going to meet Justin in a week or so and possibly the place we're at will have a Tech II around. I should have my tires by then.

[BurroWDMS]

Next, what do I do about the TPMS? Can it be reset for whatever pressure I put in the new tires or is it permanently set to want 35PSI? Can Discount Tire do the reset? I personally like the system and would hate to have to ignore warning lights or jury rig some bypass. The manual isn't entirely clear, probably because it already said don't do it. There MUST be a '"relearn" feature.

 

Anyone who is familar with a GM Tech-II can fix that. I had this done to my truck when I had LR-E tires on it. They set the upper/lower from 40-70psi. If you go to a dealer, they'll tell you it can't be done, mainly because they don't want the liability for you putting a 10ply tire on a 1500. Gotta find someone who is willing to do it.

 

In fact, I'm buying E tires for my 1500 08 even though I tow very little now. I'm buying them for their durability off-road and puncture resistance.

 

I had LR-E tires, Nitto Terra Grapplers, I got a big arse screw right in the center of the tread, went through, had to have it patched. No off-roading, just driving around town. I don't buy the puncture resistance

 

My 2 cents on the matter...The 'E' tires ride like $h1t on a 1/2 ton. Personal experience. Been there, did it for about a year, not going back. You're also talking an extra 10-15 lbs of unsprung weight (depending on the size upgrade) on EACH wheel over a factory tire. That is a big deal. So it's harder on your brakes, and harder on your 1/2 ton suspension trying to control it moving around.

[Spurshot]

There's no denying the extra US weight matters. There's also no convincing me that a P tire is worth a damn for off-roading, even light off-road use. Been there, done that. We had 3 new vehicles and only enough tires with air in them for one to get the rest ot the tires back to town for fixting. We were just driving the ranch roads. I was driving one of the vehicles myself for 3 flats. Nicely driving, I might add. I've been there for other people's bad luck with C or P tires while off-road driving.

 

As for weight, they will be well under the weight of the big O/S tires others run, even though I'll be running LR E tires. The diameter will be very close to stock and offset will not be changed like so many other O/S tire setups these guys run on 1500s. Diameter matters for braking more than a relatively small increase in US weight, but it all counts.

 

My "1/2 ton suspension" is a Z85 RPO that has a 1700-1800 lb useful load. Stiff as hell for a "1/2 ton". The manufacturers have blurred, no, well exceeded, the meaning of "1/2 ton pickup". These trucks are closer to or at 3/4 ton ratings. A look back at a 60s or 70s vintage truck in "1/2 ton or 3/4 ton" GVW and empty weight ratings will show that clearly.

 

You're right, I will get a rougher ride from a E tire. As for that big arse screw, yeah, it didn't matter that it was a E tire. But, that trip we had all the flats on was from everything from cactus needles to dried up brush roots. I've made my choice for E tires based on many experiences of others and myself. But if I were cruisin Van Nuys blvd with LEDs in my bed and wheelwells, I'd probably opt for a car tire on my truck.

[VMax2007]

My dealer changed my PSI range for $65.

[Pilot12]

But if I were cruisin Van Nuys blvd with LEDs in my bed and wheelwells,

 

I would LOVE to roll into hunting camp with some of THOSE!! Wish I had more time...

 

I had pretty much decided to try and get a season of hunting out of these stock tires until that little reminder....I've been there done that enough times too. I really hate spending a grand on tires for a new truck, but if I don't do it now, I'll probably doing it the middle of a trip. Maybe the dealer will at least comp the tpms reset....yeah right.