I have been looking at upgrading the 265/75R16 Bridgestone tires that the truck came with. I have been looking at the Vision Type 81 PETE 19.5 wheels. They are machined aluminum, 7.5" wide and fit the eight lug pattern on the GMC. Before I do this, I thought I would ask about any potential problems with Duramax/Allison programming, Tow/Haul mode, ABS or any other issues I should consider before commiting to the $2K investment?

If you will do a search on Alcoa's and 19.5's you will find the much needed info you are looking for. I think this has been covered a few times on here, just use the search icon at the top of the screen.. Good luck and welcome...

Did it - warned not too - didn't listen - cost me $1,000 to learn. In my opinion, unless you are driving a 2wd street queen with a very heavy 11' camper on super smooth roads with no holes nor ruts nor lines, 19.5 tires do not track well (alignment was perfect) due to construction, beat the hell out of me darting side to side on normal roads and really tore me up on rough roads, and ride somewhat rough on most roads. They do carry weight very well, wear well, and my Rickson polished Elimator rims were first class and the best looking and constructed rims I have ever owned in 40 years of buying lots of custom wheels. Rims a 10+ - tires a 0 in handling and tracking.


P.S. Did not affect ABS, tow haul, etc on my truck. I had already used the following sizes. 245 (stock), 265, 285, 295, 305, 255 - all 16". After selling 19.5, went back to 285 even though I want a load range E tire which I cannot get in a 285.Edited by: gardnerteam

GMC2500HD


I have done a search for everything in the archives on 19.5. I have not seen an in-depth discussion of the effect on the truck's computerized components of going to a 33+" diameter tire from a 32" diameter stock tire. While I'm not so concerned with the possible innaccuracies of the speedometer or odometer, I am wondering about the Allison. It has just started working well in Tow/Haul mode after 1300 miles of driving in the mountains with the camper loaded. I am wondering if the adaptive feature of the shift controller will be affected.


I have seen much discussion in the past about re-programing for larger tires, but most of that has had to do with the ABS braking.





Gardener team,


I know from some of your earlier posts that you put stuff through it's paces. It seems to me that there are lots of 19.5" tires to choose from. That has been one of the more confusing parts of this. There seem to be a wide range of tread patterns, sidewall stiffness and load ranges. I'm surprised that you had that bad an experience with the tires you had. I have been told to stay away from a tire that is heavily siped on the edges since they will likely have a lot of squirm.


I have load range E tires on the truck now. They are Bridgestone 265/75R16's that came from the factory and they have 3415#'s per tire load rating. With my rear axle weight when loaded, I only have 200#'s per tire of safety margin and that's why I was thinking about the 19.5's.


I have seen 19.5" tire with load ratings from 3600#'s to about 4600#'s, and just about any tread pattern you could want. I am just trying to get it straight about the effect on the trucks computers of the larger diameter tire without reprograming anything.

there are tons of guys running 285's on 16" and the 245 on 19.5 is the same height.... ride rough as can be from wha ti am told unless you load it up alot..... i stuck with the 16"

They do ride rough, but I figure if you are in a 1 ton then it doesn't matter, because the truck is already rough. Got Diesel, there are no computer side effects at all, in any way shape or form. If there were I would of found them by now. I have been running 19.5's for almost 25,000 miles no problems other than rough ride and a little tracking problem every now and then. Most tracking problems can be solved with a different tire, of course no one is going to keep buying tires to solve it. I have found that the on-off road tires track better than the road tires, you also can't run full tire pressure because the truck will just bounce down the road. John

It is going to ride a little rough. There are really no adverse reactions to the truck to running them other than taking it in for service. As far as adverse affects on the odometer, that would be in your favor as far as adding up miles, I would not worry about that.

They do ride rough, but I figure if you are in a 1 ton then it doesn't matter, because the truck is already rough. Got Diesel, there are no computer side effects at all, in any way shape or form. If there were I would of found them by now. I have been running 19.5's for almost 25,000 miles no problems other than rough ride and a little tracking problem every now and then. Most tracking problems can be solved with a different tire, of course no one is going to keep buying tires to solve it. I have found that the on-off road tires track better than the road tires, you also can't run full tire pressure because the truck will just bounce down the road. John What tire psi are you running?

I run 60 in the rears and 70 in the fronts. This is not a low pressure on a regular tire. It is however only half of what the 19.5,s are suppose to run at.

Rough ride doesn't bother me. And all 19.5's, no matter what size or load rating, have the same basic construction. That construction intentionally causes the t read to stay flat. Sidewalls are stiff because of ply - lightest ply I know of is 12, with most being 14 or greater. The treat will not roll over things like passenger car tire, or LT truck tire, but more like a heavy truck tire. Tread and sidewall stay basically rigid. My problem with it is the fact that the tire on anything but a perfectly smooth road would dart and dodge with cracks, lines, holes, cement cracks, ruts, or whatever. The damn things beat the hell out of me for 7500 miles, even when the truck was heavily loaded with stone coming back from Guadelajara Mexico (PS - I load the back seat with stone slabs as well to keep weight forward.) They may or may not work for you. All I am saying is borrow a set from someone and drive them under varying conditions. Strong tires. Rickson is a fabulous wheel.

Who's wheels can I borrow!!!http://www.dieselplace.com/forum/smileys/Rock On.gif

I have some experience with these tires, as I have the his tires mounted on my truck.


Yes, they do wander a bit when the road has cracks. I have no problem with ruts. Dirt road traction is pretty good. Windy roads are a blast with the very stiff sidewalls. The ride is not smooth, but so what? When I put the camper on the truck weighs more than 6 tons.


A heavy camper was scary with the stock tires. Just yesterday I got all my $ worth. On the US 5 outside Gorham CA, coming up on Magic Mountain we went over that "seismic drift" in the road at 75 mph at 6 tons. I think all 4 wheels of the truck came off the ground! Yahoo! That would have been at least two blowouts and near death with the stock tires/wheels.





Rough ride doesn't bother me. And all 19.5's, no matter what size or load rating, have the same basic construction. That construction intentionally causes the t read to stay flat. Sidewalls are stiff because of ply - lightest ply I know of is 12, with most being 14 or greater. The treat will not roll over things like passenger car tire, or LT truck tire, but more like a heavy truck tire. Tread and sidewall stay basically rigid. My problem with it is the fact that the tire on anything but a perfectly smooth road would dart and dodge with cracks, lines, holes, cement cracks, ruts, or whatever. The damn things beat the hell out of me for 7500 miles, even when the truck was heavily loaded with stone coming back from Guadelajara Mexico (PS - I load the back seat with stone slabs as well to keep weight forward.) They may or may not work for you. All I am saying is borrow a set from someone and drive them under varying conditions. Strong tires. Rickson is a fabulous wheel.

Well it's good to hear that there are no conflicts with the engine or transmission programming. I was thinking that the shift patterns that have been establishing in response to the way I am driving would be thrown off. The transmission is finally starting to shift in an acceptable way, especially the Tow/Haul mode which is coming around nicely Regarding the issue of getting service on the truck, I had been thinking that I would keep the stock wheels and tires swap them back if I have to take it to the dealer, but I was worried that the back and forth swapping of tire sizes would confuse the TCM in the Allison.


I sure would like to know what tires are causing the tracking problems so I can avoid them. It sounds like the tread pattern that has problems is the highway rib more than the M/S pattern, but I'm just reading between the lines on what has been said here.

I'm running 225/19.5 general/ricksons on my 2500, the ride is stiffer due to the very short sidewall on the 225, but the tire size is as close stock as you can get, at 60 mph I am actually going 65mph, loaded down when I am towing at 60mph(65actual) the rpm's are right at 1900 ,pulls awesome!, with the bilsteins, rear air bags(5-10psi) and lower tire pressure(70f,60r) the unloaded ride is ok, I commute 30 miles each way to work and it is tolerable.


As soon as the camping season(NOV. 1st.) is over, I will put the put the stockers back on and wait till spring.


The safety margin is so much greater when towing that the tradeoff is worth it!Edited by: bigdaddy650r

My guess is the tracking problems are CAUSED by the stiff sidewalls. In a softer tire the sidewalls would take up some of the lateral irregularities. With a stiff sidewall the lateral shifts in the pavement are transmitted right to the driver.


If you have ever driven a truck with tall sidewall baloon-ish radial tires you know that soft, vague feeling. These tires have the opposet problem.





Well it's good to hear that there are no conflicts with the engine or transmission programming. I was thinking that the shift patterns that have been establishing in response to the way I am driving would be thrown off. The transmission is finally starting to shift in an acceptable way, especially the Tow/Haul mode which is coming around nicely Regarding the issue of getting service on the truck, I had been thinking that I would keep the stock wheels and tires swap them back if I have to take it to the dealer, but I was worried that the back and forth swapping of tire sizes would confuse the TCM in the Allison.


I sure would like to know what tires are causing the tracking problems so I can avoid them. It sounds like the tread pattern that has problems is the highway rib more than the M/S pattern, but I'm just reading between the lines on what has been said here.