SaniDel

Our 2015 GL550 with stock Continental 295R40/21 tires at less than 13,000 miles is slowly getting noisy. It's tire noise and not engine or drivetrain noise as it's present even while coasting with the transmission in neutral and it increases in frequency with vehicle speed. So one or more of the tires is slowly going out of balance.

I'm trying to avoid what some owners have experienced, i.e., never solving the problem, but spending lots of time and money at the dealership on a futile quest for quiet tires! Would you recommend trying anyway or "throw in the towel" and start over with new tires?

fabbrisd1

Take a hard look at the tires you have now - and recheck yourself for any tell tale wear problems - and make a mental note of what tire pressure you have been running by-and-large.

If this size - options are fairly limited -

I have good "feel" reports from customers who have gone with the Cont Extreme Contact DWS 06 - which is "harder" rubber (UTQG at 560) and slightly "deeper" tread pattern.

SaniDel

I'll say this about Conti's ... they are the most airtight tires I've owned. Visually and by the TPMs they hold their air ... 2016 was the last time I had to add air.

I keep all tires at the same pressure ... 38 PSI cold so they stay under 42 PSI when hot and above 32 PSI when cold.

Thanks for the suggestion to visually inspect. Thanks also for the suggestion for the Conti alternative. If I decide to replace rather than to balance I'll consider them, but I would prefer Michelins ... if they were available in my size.

timannnn

I had an issue where my toe was slightly off and it caused inside "feathering" which caused kind of a growl from front tires. If you take your hand and feel the inside of tire, you may feel an "edge" when running your hand one way and not feel it the other way. I would take to reputable alignment shop and have 4 wheel. Make sure your toe settings are correct. Good luck.

SaniDel

I'll check for that when I do a visual inspection as previously recommended. Thanks for that suggestion.

The problem is slowly getting worse ... for the first year or so it wasn't apparent, but now is noticeable, especially on smooth roads. So, it seems the tires are slowly "wearing wrong" as you suggested.

SaniDel

I'm not sure what to look for, but I see nothing obvious when comparing these pictures of the four tires. I would appreciate your opinions.

Assuming the wear pattern is what is expected after roughly 13,000 miles the noise is presumably a balance issue rather than a tire wear issue.

dieseldoc

Rebalance and 4 wheel alignment as long as there is adequate wear left on the tires

SaniDel

Much as I wish I could solve the problem with new tires, it probably makes more sense considering how much useable rubber is left after only 13,000 miles to rebalance and 4 wheel align the old tires ... unless and until Michelin offers a suitable replacement!

ItalianJoe1

It's your rears, you can see the patchy wear on the inner blocks. Have them balanced and cross rotated, they should wear back normally. Unfortunately they will be just as noisy as they are right now and will take about the same amount of time to wear back round, so if the noise really bothers you, replace them.

Rotation/balancing at 5k miles is needed on a lot of these heavy trucks. The tires are just so big, that any little wear gets them out of balance enough to cause weird wear patterns. Gotta be rotated around to help it out.

Isawelvis

when you get your tires balanced make sure they use a Force Balance machine. Most people have them now. It is possible to balance the rim and then the tire and then match them up, high spot to low spots. I have had them move the tire around on the rim to make it more of a match. Force balance is also, supposed the balance the tire to match the car it is on, not just the tire and rim together. Its made by the Hunter company. Check it out. May help , not sure though

LIRS6

Anything embedded in the tires, i.e. stones or such?

SaniDel

That will be the first thing to check once it is up on the lift! It goes into the shop in three days ... will advise the outcome.

ItalianJoe1

Road force balancing will help compensate for rims that aren't perfectly straight or tires that are a little off, but a good, round rim and a quality tire should have very low road force variation. Often, match-balancing using road force is a way to keep a marginal tire from being a balance problem. New tires, it almost never is needed with high quality tires, unless you got an unlucky one with a hard spot in the tire.

It can't hurt though, and only takes a couple extra minutes when balancing tires to check, a lot more if you need to dismount/rotate the tires on the rims though.

SaniDel

I am hoping that whatever the problem it won't be necessary to unmounted the tires from the rims. These original Continental tires are truly airtight and I doubt they will remain this airtight if they get unmounted and remounted.

I'm hoping the problem can be solved by rotating mounted tires, balancing mounted tires or aligning the suspension and only unmount the tires if they find a defective tire or wheel, which seems unlikely as the problem is very slowly getting worse.

If a tire is defective, I might pull the trigger on new tires!

Isawelvis

Force balancing does not automatically mean they move the tire on the rim. Its one option, the thing is the balancing machine simulates the weight of the car on the tires as it balances them. They usually do it without ever having to move the tire on the rim.

I know from experience that on a Ford Contour my daughter had, the only way to get a good balance was force balancing.

Like I said they normally won't move the tire on the rim since it takes alot of extra time. I fact they really don't want to do it. You could tell them you do no want them to do it.

Keep us posted on your decision and results. Good luck.

SaniDel

You were all right ... thanks!

Our local dealership (MB of Wilmington, Delaware) didn't find what @LIRS6 described, but instead identified the problem with all four tires as what @timannnn described ... they even demonstrated it the same way. They also recommended against keeping the tires for the reason @ItalianJoe1 provided ... it would take as long to get them "back into shape" to get quiet ... I don't have time or patience for that.

They removed, photographed and will return two of the tires to MB to demonstrate the problem that @fabbrisd1 described. The Parts & Service Director intervened personally with MB and worked a reasonable deal ... MB would pay for two of the four new tires. That plus four-wheel alignment minus a 15% discount for renewing my MBoA membership got us back on the road for less than $1,000 ... including the use of a new C300 for the day.

Needless to say, the new tires are the same Continental 295R40/21 tires. The only alternative is Pirelli, but the dealership doesn't recommend them. The director advised that Continental has changed the rubber formulation and hopes we'll get 20,000 out of this set ... we'll see.

Lessons learned ... rotate the tires at every service, align all four 'corners' at every service ... and '*****' if not satisfied!

ItalianJoe1

Glad you got it handled, we see it all the time.

Options are very limited in that size, and yes the Pirelli is not as good as the Conti.

Alignment isn't really what causes that, it's balancing and lack of rotation. Moving them to the other side or other axle helps offset the wear to the other side of the tread blocks and keeps them from getting lumpy, which makes them noisy.