macfactor

I have come to the conclusion that the only real issue I have with my 4 month (4K miles) old GLC300 is the run flat tires. Yes I have a couple of small issues, like screeching breaks in reverse, but overall I love the car. My major issue is with the run flats and I am not sure if they can be replaced with a more traditional tire.

The car was delivered with the tires over inflated and the ride was very skippy when hitting potholes or bumps in the road. I reduced the pressures and the ride became much more compliant. Now that the weather in Texas has turned a little colder the run flats have become a real pain as they lose considerably more pressure with sudden temperature drops than any standard tire I have ever had. As is usual here the temperature went from 35 one day to 75 the next and the tires gained way more pressure than I am used to on this warm day. They went up 6 PSI and once again the ride became jittery. Seems to me that this will be a constant battle and the run flats just are not a good tire overall.

At this point I am thinking of replacing them and getting a pump/goo kit at the same time in case I get a flat in the future.

So has anyone replaced theirs and what were your results?

Thanks in advance for your feedback.

dieseldoc

You can definitely replace with regular tires. You will still have issues of pressures changes with change in temperature. I have had this problem with all of my cars irregardless of tire type or make.

macfactor

Agree with your statement about pressure changes and temperature. However the variances appear to be much greater with these run flats and due to this the ride quality suffers greatly. Feel like I will be constantly chasing my tail trying to keep the pressures at required levels and then not affecting the ride so much.

My experiences with these tires has been eye opening as I have never had them before. The stiffer sidewalls seem to be the issue and I get the feeling the bead does not lock as well as a normal tire.

Would really like to see if anyone has switched them out and if their experience has been improved.

larrypmyers

As Jeff posted above you can change to conventional tires with no problem. However, you should know that outside air temperature change affects conventional and extended mobility tires in the same manner. A general rule of thumb is for every 10 degrees of outside temp. change one will see a one degree change in tire inflation pressure.

The best way to combat large changes in tire pressure is to inflate your tires with nitrogen which is unaffected by outside air temp. changes.

I've been driving on extended mobility tires since 1999. During that time have experienced two punctures, both of which, without interruption, was able to drive on to a tire shop, where, in both instances, the affected tire was repaired and reinstalled

Driving on extended mobility tires gives me a warm fuzzy. Why? I know that I won't find myself immobilized on the freeway hard shoulder with traffic whizzing by at speed just a couple of feet away.

Early on extended mobility tires were noisy, hard riding, expensive and sometimes hard to find. However, todays tires possess none of those early deficiencies. Driving on todays extended mobility tires its nearly impossible to ascertain what kind of tire is on the vehicle.

Flubadub

I have to disagree with you on this. Laws of physics don't care what the gas is. Boyle's Law applies to nitrogen as well as other gases. When temperature changes, pressure changes. You are correct on the rule of thumb, but it is not different for nitrogen vs air filled tires. Most people don't know that the air we breath is almost 80% nitrogen.

larrypmyers

Like ethanol in gasoline, extended mobility tires are becoming ubiquitous.

larrypmyers

Ahh, my bad. Brain dump in effect. Your absolutely correct.

Outside temperature change affects tire pressure in the same manner without regard as to whether they are filled with compressed air or nitrogen.

Beer is on me.

johara

The concept of the run-flat tire is appealing, but for me one of their drawbacks has bitten me in the ***, twice.

If you don't already know, in the event of a flat tire most run-flats are supposed to be replaced (depending on the recommendations of the manufacturer and the conditions of the the flat tire). So when I found a large screw in my tire, the only option was to replace the tire. Then two weeks later when a rogue nail found its way into another tire, this too had to be replaced. Had these been non-run-flat tires these punctures would have been patchable.

It's clear that I have been a bit unlucky, but $700 later I wonder if using non-runflat tires and using MB's road service makes more sense.

larrypmyers

Holy cow, you've had as many punctures in two weeks as I've had in 17 years. Maximum bad luck.

Maybe consider hanging a full width magnet beneath your front bumper.

Am aware there are manufactures that advise not repairing their extended mobility tires. And Pirelli is one of them. That said, repairing a routine puncture would be very tempting. I'll cross that bridge when I come to it.

Of the two punctures I had, one was a Goodyear and the other a Michelin. Neither manufacturer had a restriction on repairing their tires.

Based on your lousy luck perhaps, as you say, conventional tires work for you.

bips

Like the OP, I'm seriously thinking about making the switch for the reasons outlined. I opened this thread hoping to read of the experience of anyone who had switched from run-flats to regular tyres, but I don't see any. I guess the GLC is too new for that. You'd have to be desperate to ditch such expensive tyres while they still had some life in them, rather than at their EoL.

This isn't the first thread where we've had these repair vs replace & nitrogen debates. Not much new here. That said, and FWIW, I had a nail in my run flat repaired via a plug. The MB said they could do it, but it would be faster and cheaper to have a tyre dealer do it, so I did.

As I understand it, the difference between a run-flat and a regular tyre is the sidewalls. Isn't the tread much the same? Why would a nail in the tread of a run-flat be any different to a nail in the tread of a regular tyre? I can't see the difference. Neither my MB dealer nor local tyre shop could either, apparently.

HotRodW

We don't have our GLC yet, but I'll be mounting conventional winter tires as soon as I get it home. We'll give the run-flat all seasons a chance once the weather breaks, but I'll likely replace them with conventional rubber if we notice a substantial decrease in ride quality when the winters come off. I made the change with my BMW and never regretted it.

Flubadub

I never turn down a free beer! Next time you are in East TN, just let me know.

Flubadub

Based on my research, only Yokohama says repair is not to be done. The concern seems to be that driving a fully uninflated tire damages the internal integrity, so even though you could repair the puncture, you would be driving on a dangerous tire. Driving the on the tire to a repair shop pretty much means you need a new tire. I think your best bet is to call for roadside assistance, AAA or carry a plugging kit if you are driving outside metro areas.

fearyoda

GLC I have is at 2k miles and I'm honestly on fence if I should replace the run flats too.

zhenyaf

How do you guys feel about driving on regular tires with no spare? At least with run flats you can get to a tire shop

fabbrisd1

Note - "Extended Mobility" tires are the wave-of-the-future - and their construction gives sidewalls strong enough for "upt-to-50-miles-at-reduced-speed" .. the original "run-flats" using aluminum inner-disc technology taken from truck technology were horrible ride/horrible-wear.

1) Tire inflations - 2 psi either way - can give you different ride feel - as noted inner fuel filler door gives you MB recommended

2) I have not had customer feedback - yet - on tread life for extended mobility

3) Most customers have no complaint - and don't even notice - they are driving on a new extedned mobility tire as compared to standard tires they are coming from on most prior vehicles

4) A good bet is to have tire "goo" in the trunk

5) There is unclear-direction from most manufacturers on extended mobility flat repair - like ALL tires sidewall repair NOT allowed - what gets unclear from tire manuf is whether tread punctures can be repaired or not - usually on a "full road flat" where the tire has been driven on the sidewalls manuf would say tread repair not allowed since you end up with bad-sidewall tire.

6) On new vehicles - a good reason to consider wheel/tire protection/insurance - which can only be offered when the car is sold - and not avail after sale.

Keep the beat !