GL550 Tire Wear
My 450 has 19s, and there are about as many options for me as the 550s with 21s. The Pirellis that the dealership somehow CPOd my car with have been horrible since day 1.
On the next set, either Contis or Michelins, I'm thinking of rotating them every 3k to see if it helps.
Also, I've run everything from 32 to 38 psi all around. I've always found MB suggested tire pressure to be unnecessarily low, however on the GLs, I'm thinking it's (32) just right
Pay attention to that higher rear number - it's only under full load. I made that mistake when I got mine, and the rear end felt like it was gonna bounce into the sky over bumps. Running 32/32 now.....unless I'm hauling a load.
.....and as to the idea of reverse-mounting non-directional tires to get more out of them....is this technically and feasibly sound as a tire maintenance procedure in this situation?
Last edited by will_w204; Jun 14, 2014 at 05:49 PM.




Belt shifting was blamed for early radial tire failures, (Back in the Firestone 500 days) but I don't know any non-directional tire you can't cross rotate.
http://www.tirerack.com/tires/tirete....jsp?techid=43
Belt shifting was blamed for early radial tire failures, (Back in the Firestone 500 days) but I don't know any non-directional tire you can't cross rotate.
http://www.tirerack.com/tires/tirete....jsp?techid=43
UTQG rates tires to give a semblance of expected wear life on tires given similar driving conditions. If most drivers follow a front to back and back to front pattern, you will find the UTQG numbers matching actual driving numbers. I follow the F to B and B to F, and I always get 35K+ per pair of 30K rated tires. Granted I don't do two-wheel dragstrip launches and I don't do hockey stops. I have never replaced all four tires at the same time, I usually replace pairs when I see the wear bars on the tire tread. I do have some reservations about cross pattern rotation on assymmetric non-directional tires, I find the grooving to be somewhat similar to directional tires.
Cross pattern rotations, although the method is altruistic in nature, it benefits the tire companies more than the consumer. Yes you get optimal performance from the tread as it wears down, but how many of us GL350 drivers actually do rally racing and "performance" driving? If I wanted to do a winding road full of S-turns, i'll take a coupe or a sportster.
Last edited by drgeeforce; Jun 26, 2014 at 01:12 PM.




UTQG rates tires to give a semblance of expected wear life on tires given similar driving conditions. If most drivers follow a front to back and back to front pattern, you will find the UTQG numbers matching actual driving numbers. I follow the F to B and B to F, and I always get 35K+ per pair of 30K rated tires. Granted I don't do two-wheel dragstrip launches and I don't do hockey stops. I have never replaced all four tires at the same time, I usually replace pairs when I see the wear bars on the tire tread. I do have some reservations about cross pattern rotation on assymmetric non-directional tires, I find the grooving to be somewhat similar to directional tires.
Cross pattern rotations, although the method is altruistic in nature, it benefits the tire companies more than the consumer. Yes you get optimal performance from the tread as it wears down, but how many of us GL350 drivers actually do rally racing and "performance" driving? If I wanted to do a winding road full of S-turns, i'll take a coupe or a sportster.
. . . . Because doing cross and back rotations I got 65K miles from the factory fit tires on my Pilot and 100K from the Michelins I replaced them with.
We also got 55K from the tires on my E-350 4-Matic Sport (Still with tread until an alignment issue killed 2 tires so I did the set)
(not including driver, passengers and luggage)! Mine is a GL450 (5300 lbs) and I found that pressure is definitely a big factor. I replaced the fisrt set of Contis after driving barely 30K using 38psi. I got a new set of Contis (because I installed them at MB dealer and they only approve Pirelli or Conti for my GL), set the pressure to 32 psi and adjusting the rear to 38 when I loaded the car. After 12500 miles of serious
driving (sun, rain, and snow: went from FL to NC, the NC and back to FL) tires still are 65%. I use nitrogen and rotate them every car service (13K). For alignment I use MB dealer because they offer the full alignment (four wheels).There are some other options for 19" but MB only approve Pirelli and Continental. I know some dealers have Dunlop SP Sport Maxx, however the tire is only good for summer.
Last edited by DarthVaderpa; Jun 26, 2014 at 08:11 PM.
The Best of Mercedes & AMG
. . . . Because doing cross and back rotations I got 65K miles from the factory fit tires on my Pilot and 100K from the Michelins I replaced them with.
We also got 55K from the tires on my E-350 4-Matic Sport (Still with tread until an alignment issue killed 2 tires so I did the set)
Tires that are UTQG rated 800 and above, getting 100K+ miles, are becoming more common on the roadways. Attributing cross-rotation to this high value is suspect since you didn't try other rotation methods.




The 55K tires on my E were from early 2010 (Certainly rated under 500)
So let me understand, all documentation recommends cross rotation, and I have gotten exceptional life.
Yet, you have received average life from front-rear rotation, and you think I may have just built myself a myth?????
(not including driver, passengers and luggage)! Mine is a GL450 (5300 lbs) and I found that pressure is definitely a big factor. I replaced the fisrt set of Contis after driving barely 30K using 38psi. I got a new set of Contis (because I installed them at MB dealer and they only approve Pirelli or Conti for my GL), set the pressure to 32 psi and adjusting the rear to 38 when I loaded the car. After 12500 miles of serious
driving (sun, rain, and snow: went from FL to NC, the NC and back to FL) tires still are 65%. I use nitrogen and rotate them every car service (13K). For alignment I use MB dealer because they offer the full alignment (four wheels).There are some other options for 19" but MB only approve Pirelli and Continental. I know some dealers have Dunlop SP Sport Maxx, however the tire is only good for summer.
I have a theory that PSI in light of the sheer weight of this vehicle is a critical factor, but your statement of "dead at 30k with 38 psi" and "still at 65% with 12,500 at 32 PSI" looks like the exact same result to me




Usually higher pressure (up to the tires design limits) yields better life.
That calculation would mean the tires would be worn out by 30k, exactly the same as the OEMs at 38 psi, which would seem to indicate 32 vs 38 makes zero difference whatsoever in tire life.
Again, I'm just making a point with his calculation. I would like to verify that a 6psi difference in pressure may make NO difference AT ALL in tire wear, or if that was a mis-statement




That calculation would mean the tires would be worn out by 30k, exactly the same as the OEMs at 38 psi, which would seem to indicate 32 vs 38 makes zero difference whatsoever in tire life.
Again, I'm just making a point with his calculation. I would like to verify that a 6psi difference in pressure may make NO difference AT ALL in tire wear, or if that was a mis-statement
OK, misread your post.
There are so many variable to tire life that it is easy to build myths.
I have consistently found much better than typical life (and I drive fairly hard) by doing the following.
1) Keeping the tires at the highest pressure I feel is safe. (Hard until the ride becomes noticeably bouncy)
(Usually 4 to 8 PSI above recommended, always at least 2 PSI below sidewall rating)
2) Cross Rotating regularly.
It might be a myth, but in 30+ years have never had a set of tires not go at least 40K (That was about all I could tease out of an old Range Rover) unless it was a alignment issues (F-ing Ford Company Car) or road hazard failure) 100K is my record.
There are so many variable to tire life that it is easy to build myths.
I have consistently found much better than typical life (and I drive fairly hard) by doing the following.
1) Keeping the tires at the highest pressure I feel is safe. (Hard until the ride becomes noticeably bouncy)
(Usually 4 to 8 PSI above recommended, always at least 2 PSI below sidewall rating)
2) Cross Rotating regularly.
It might be a myth, but in 30+ years have never had a set of tires not go at least 40K (That was about all I could tease out of an old Range Rover) unless it was a alignment issues (F-ing Ford Company Car) or road hazard failure) 100K is my record.
I have found the same things as you running higher than listed pressures in 15-18 different cars, but this car at 5300 lbs on street tires seems to be bucking every bit of conventional and seat-of-pants wisdom that I've gleaned from 22 years of driving.




So far I an getting about what I expect.
Bought it with 3/4 used tires (Two replaced due to road damage) and now that it has another 18K miles, the other two are ready for replacement.
The two with about 16K miles look very good. (It is a GL320, so I am not ruining as wide a tire.)
P.S. About 4+K of the miles were towing.
http://gmtnation.com/forums/topic/54...rains-at-130k/




http://gmtnation.com/forums/topic/54...rains-at-130k/
I think you are missing the point.
Proper (cross) rotation is what most people do. How do you support that non-cross rotation provides better tire life?
Last edited by N_Jay; Jul 1, 2014 at 02:51 PM.
This article kind of explains my standing:
[Tire rotation is a simple matter, but like many things automotive it is also loaded with mis-information. The principle is to even out tire wear, between the front and rear of the vehicle. Tires are normally rotated between 5,000 and 9,000 miles. In theory this should provide longer tire service and there are four patterns in general use.] http://www.agcoauto.com/content/news/p2_articleid/94
If anyone can find a SAE publication advocating that cross-rotation tire patterns provide exceptional mileage, i'll make it into a poster and hang it in my garage.
Last edited by drgeeforce; Jul 1, 2014 at 06:50 PM.




If anyone can find a SAE publication advocating that cross-rotation tire patterns provide exceptional mileage, i'll make it into a poster and hang it in my garage.
So let me understand.
1) Just about every source recommends cross rotation for tires that can be. (Tire companies, Car companies, and Oil companies, and the government)
2) You have produced exactly ZERO links for your suggested rotation method.
3) You only will accept an SAE recommendation to concede you might be incorrect.
Do I have that right?
Last edited by N_Jay; Jul 1, 2014 at 06:55 PM.




http://www.nhtsa.gov/cars/rules/tire.../brochure.html
http://www.nhtsa.gov/cars/rules/tire.../brochure.html
The Society of Automotive Engineers is the Gold Standard. Care to wonder why they don't advocate ANY particular pattern?




I work with an industry standard group. There are lots of things unsaid.
I find your proof being the absence of a statement from one group as "interesting".
I know it's not a great result, but considering that the Conti 4x4 Contact has a really bad treadwear, I think am getting a "not to bad" results. I would like to try the Conti CrossContact LX20 but it isn't available for the size I need, 275/55R19.




