kinleysma

When I was researching the GLC for purchase the prospect of run flat (ahem extended mobility) tires didn't sit well with me. I was reassured by the salesman that it really wasn't such a big deal.
WRONG.
Here's the problem....in the throes of a rapid leak after picking up a nail today, I was told these tires can't be patched and that I needed to replace my tire. Mind you I was in a city, Phoenix, AZ. NO ONE in Phoenix or all of AZ has these tires in stock. What's more is that it takes several days to ship them. Because I live 120 miles from Phoenix and the maximum driving distance on a run flat tire is 50 miles I was faced with potentially not being able to make it home.
The service department at the dealership was of little use. They "were really busy" so they topped off my tire and said I should be fine as it "was a slow leak". They also couldn't sell me a tire as they don't stock them. An hour later when the tire was losing pressure and the service dept had closed, I tried mBrace roadside service. The nice lady Googled a tire shop for me (which I had already done on my own) then said the only thing she could do was send me a flat bed to take my car to the dealership. Where it would sit until Monday stranding me away from home for 2 nights.
I finally found a tire shop that proposed patching the tire. While I waited I called the sales dept @ the dealership and eventually got a call back. As the tire shop patched my tire the MB salesman told me that my tire was absolutely not patch able and that MB is well aware that these tires are not available. I asked why they didn't have a few on hand at the dealership if they knew this was an issue and was told that they can't even get them. It turns out they've been poaching the tires off their service loaners when faced with this situation. He suggested that I put a new tire (non run flat) on the car, keep my receipt, and call the dealership on Monday.
I made it home on my supposed unpatchable patched tire and have found that Tire Rack has the 19" Pirelli run flats in stock. It will take a few days to get it here, I hope the tire holds. What an asinine situation. What good is my $55k car if it can't be driven? Should we all keep a spare run flat around since they're so hard to come by? Or switch all tires to standard and roll without a spare? My car has 1800 miles on it and I was so frustrated today I contemplated getting my old Toyota back. If you've made it this far I apologize for the rant.
Stay away from nails. It seems that is the MB solution.

Penn

I carry a Slime smart spair tyre goo kit which comes with a small compressor to pump in the goo and allows you to drive home at normal speeds without destroying the tyre.

This is the kit I have purchased: http://www.supercheapauto.com.au/Pro...12-Volt/360557

Ddmccormack

Interesting thread.

BTW, i believe the Slime kit mentioned above can be had on In US on Amazon for $35 vs the $95 from the Australian link mentioned....

HotRodW

Run-flats are great ... in theory. In practice not so much. Not only is availability a problem, but they're heavy, expensive, cannot be repaired, and they're a detriment to ride and handling. While they will allow you to drive to safety if punctured, they are no help if you bend a wheel or bulge the sidewall after an encounter with a pothole. And you are more likely to those things with run-flats due to the unforgiving sidewall. Ironic that the device specifically designed to prevent you from sitting stranded on the side of the road can actually lead to that very thing.

jimbobboy

Your experience concerns me: I have a GLC set for early October delivery for the beginning of a 4,500 mile tour (wife and friends) and nails on the road are not rare. In your case, I would have expected M-B to provide a loaner to get you home and then deliver your repaired vehicle ASAP and claim their loaner. But that won't work if the milage to home is in four digits I expect. How quickly could Tire Rack get a tire to the relevant dealership on an expedited basis? Hope as your frustration fades your appreciation of your car returns.

mbchris

Run flats are patchable as long as they are on the tread. Check out the manufacturer recommendation. Benz etc. don't want the liability.

Large BMW dealerships carry their entire range of tires for RFT - not sure why Benz don't. Of course you will pay for that privilege.

thenew3

Probably because BMW has been using run flats on their entire range of vehicles for many years and have already gone through this learning cycle.

Mb's just started using run flats on their newer redesigned vehicles. Maybe in a few years they will learn and the dealers will keep those tires in stock.

gkw4815

It wasn't a deal-breaker - but I too am annoyed that run flats are mandatory from the factory. Just another complexity, like the stop-start system, to eke out another 0.2 mpg in the name of chasing fuel economy standards.

I'd be reluctant to travel in rural areas (and there are plenty of them in Texas, that are 100s of miles from a Mercedes dealer) with no spare. Plus I agree they rough up the ride. Our GLC has the most compliant option (18" wheels) and it still rides much worse than mom's 12-year-old Camry.

RedwinGV

I'll argue that sounds like a biased opinion; Unless you're saying the Camry is just a mushy marshmallow ride, and then I'll defer. The GLC is smoother than my 2015 Audi and is smother than my 2008 MDX that I just sold. And the handling of the GLC is better than the 08 MDX (really can't compare with the Audi... and it shouldn't be either.)

For the record, I'm not a fan of runflats, but I had no other option. I do wonder what I'll do when they need to be replaced. If I go without runflats, I'll be in a hurt if I do get a flat. Conversely, if I do stay with runflats, most situations will be be resolved by the run flat--cept some extreme ones. Who knows what the right answer is.

gkw4815

Sheesh, I said it rides worse (it does), I didn't say it handles worse (it definitely doesn't).

FWIW though, the Camry rides better than nearly all newer cars I've driven. Small wheels and huge sidewalls help. The GLC300 rides okay, just a touch less luxurious than we were expecting.

I'm wondering if, when we need new tires, I could just get a non-run-flat set, and then also purchase an extra wheel and tire to keep as a spare. Just to bring along on trips in isolated areas.

Teckno

It appears GLC's in Sth Africa run 18" normal tyres, with spare, Jack and wheel brace !
If you are considering replacing run flats, be careful, you may void your car insurance or worse ? Your new car warranty. Worth checking. Our diesel version cannot fit a spare in the wheel well, as it has been modified in manuf to accomodate the AdBlue feature. MB in Oz sell a spare wheel and Jack kit for close to $1900, but it takes up 90% of the rear cargo area.

gkw4815

Really? I've never heard of a warranty or insurance being voided by an aftermarket tire, as long as you don't drive it until it's past the minimum tread depth. At least in the US, the Magnuson-Moss Warranty Act would likely protect you.

TBH it's a moot point for us. We only drive 5-6k miles a year per vehicle, so we shouldn't need new tires until well after the warranty's expired.

Teckno

In Oz, we have Aust Design Rules, and various State regulations. The Insurance Council here hangs it hat on such rulings, yes minimal tyre depth is one, but if in an accident you can have your ins cover voided if the assessor determines the car is not to original spec. Tyres especially, fitting normal tyres to a Veh sold new with run flats is one as well as changing rim or tyre size and even mixing tyre pattern on the 4 wheels. You might get away with two the same on front and another two, both same, but different on rear, so two Pirelli Scorpion on front and two Goodyear F1 on rears.

Teckno

The following ref site is a commercial site in the US.
http://www.tirerack.com/tires/tiretech/tiretech.jsp
I highly recommend the site and the insights they provide for all topics tyres, incl MB MOE.
Extract :
DIRECT VS. INDIRECT
Direct Systems
attach a pressure sensor/transmitter to the vehicle's wheels. An in-vehicle receiver warns the driver if the pressure in any tire falls below a predetermined level. Direct systems are typically more accurate and reliable and most are able to indicate which tire is under-inflated.
Indirect Systems
use the vehicle's anti-lock braking system's wheel speed sensors to compare the rotational speed of one tire versus the others. If a tire is low on pressure, it will roll at a different number of revolutions per mile than the other three and alert the vehicle's on-board computer. Indirect systems (except for the TPMS on several 2009+ Audi models and 2010+ Volkswagen models) are unable to generate accurate readings in cases where all four tires are losing pressure at the same rate, such as the effects of time and temperature.

20% under-inflation reduces tire lifetime by 30%;
30% over-inflation reduces tire lifetime by 45%;
30% pressure lower looks like proper inflated tire

TPMS (Tire Pressure Monitoring System) monitor your tire situation, warn abnormal tire pressure early, reduce the failure rate and the risk of accidents, improve fuel efficiency, extend tire life.

I hope this helps.
There's are numerous sections on tyre pressure for wet driving, run flats, etc.
I have used Tpms in my other cars, to great success, I prefer the sensors inside the wheel, as opposed to the variety that screws onto the existing valve stem.

mpalsal

MB can offer a spare tire for purchase as an option but have not done so, don't know why.

kinleysma

Follow up....The Gen. Mgr from the giant dealership that I tried to get help from that day called to apologize, but also didn't really offer a solution for anyone in the same future predicament. My local dealership clarified that the Pirelli run flats CAN be patched twice as long as its on the tread. If you have the Continentals they CANNOT. My patch has held and the tire seems fine. It would have been really helpful that day for someone to just know that patching wasn't a cardinal sin.
I did go ahead and purchase the slime/inflator kit to keep in my car. I know that also isn't really supposed to be used on run flats either, but in the situation I faced I would have done it. Interestingly the same kit is an option from MB. It is mentioned in the manual. I went so far as to suggest they include it with their new car sales if they weren't going to stock any tires.
It seems like such a poor oversight for a brand I thought was supposed to be a cut above.

jimmykashmir

so looks like run flats come standard with a new GLC now, and we cannot opt for regular tires?

once we use the 40-50k miles of these tires, can we replace with regular tires for next time, or is it mandatory that only run flat's fit on this car now?

thenew3

You'll likely not get 40-50k miles out of a set of tires these days. Most are wearing out around 25-30k miles.

You can replace them with regular tires at any time. You just have to keep in mind that if you get a puncture, you don't have a spare. With a run-flat you can at least drive short distances to a safe/convenient area. With a regular tire, you're stuck.

ec_nova

MB absolutely does not recommend patching of ANY tire, runflat or standard. There is no way to know what kind of stress the sidewall went through due to not knowing: A- how long it was low, and B- how low it went. If it were my car, I would replace my tire. I didn't buy the safest car on the road just to shove a piece of rubber and glue into the one thing that marries it to the road. My family's/my safety is far more important than money. I'd rather be pissed off and inconvenienced than injured or dead.

Now once the run-flats are worn, I am absolutely not replacing them with run-flats. I don't like the handling characteristics or wear rate. Michelin pilot super sports go on all my vehicles.

Gee Spoolin

I wonder if the "wheel and tire protection plan" offered my Mercedes Financial would've made OP's ordeal less of a hassle?

Like if you've got this extra coverage, and God forbid your expensive run-flat gets damaged when no local tire shops have any in stock, can you just drop off the car at the nearest dealer and have 'em order a replacement right away with minimal downtime?

ec_nova

from what I've seen, absolutely. I've seen people put into loaner cars while tires are on order. But this may not be the case at every dealership, I can't say for sure.

URBassman

I held off buying a BMW because they fit run-flats. So what do I find on my new GLC? Bloody run-flats! Rather than have to replace all four for conventional tyres can I have two front conventionals and two rear run-flats when the fronts wear out?

vastok

Newbie here, I have ordered GLC 250 Air-body control with 20 run flat tire, if I choose 18inch will that make any difference to handling?

I don't know if I shall be travelling a lot, I usually don't and I live in Melbourne, But to have that peace of mind that if something goes wrong it can always be repaired anywhere.

Or is there any other benefit to 20inch run flat tires?

Mr. J

Actually, the driver is capable of knowing exactly how low the pressure went, and if paying attention, the interval too. The TPMS will display the pressure of all four tires on the display screen whenever any tires drops below recommended pressure.

It's only dangerous to patch a run flat that has been driven while running on the sidewalls. If you plug it before running on the sidewall, you are fine.

Most shops won't do this because they have no way to easily confirm whether you drove the tire on the sidewall or not. The solution, plug it yourself.

Mr. J

The 18" will offer a softer ride than the 20". Some of the difference will be offset by airmatic/air-body control but the 20s will still have a noticeably firmer ride.