Wondering if run flats are as bad as some people say they are?

 

Depends what you're referring to. They cost more, tend to have a harsher ride, and don't have a great selection.? However, given that there's no spare in my wife's GL350 a few(and there wasn't one in her old Toyota Sienna), I wouldn't go without them. We have had a few times where we'd have been stranded without them. Unless you're adding a spare, you're taking your chances.

 

I'm concerned only about the ride characteristics, and how much "stiffer" the run flats are than the standard non run flat 20" tire.

 

If you go to the BMW boards, people are complaining non stop about the runflats. That hasn't been the case here and they have been installed on probably half of all GL's (all diesels and 450s with appearance package) since 2009.

The bad:
1. No spare.
2. Limited supply of replacement tires which could interrupt your trip if you are out of town. If you are not out of town, in theory, you should be able to call a shop when you get a flat and drive there the next day to have them install a new tire. Again, check with your local dealer/tire shop as to the availability. Most shops can have their wholesaler ship next day.
3. Stiffer sidewall. It is a 20" wheel though so if you are looking for a super soft ride, 20" wheels probably aren't for you. Having said that, many of the early BMW runflat complaints were a result of harsh rides. Bridgestone is on their 3rd generation tire (or something like that) and the sidewalls are not as hard as they used to be. Also, the GL has air suspension and absorbs minor road defects better than the typical BMW setup. The roads where I live are pretty good. If they were in poor condition with lots of pot holes, I might be hesitant to go with runflats.
4. Cost. The Goodyear tires are much more expensive (than OE 19") but are repairable when damaged by nails in the tread area (not sidewall damage) per Goodyear and per my MB Dealership. Some dealerships will repair the tires, some will not. The Bridgestones are much cheaper but have a warning placed on them that they are not repairable. I have the Goodyear tires and I carry a small compressor and tire plug kit in the tool compartment.

Good
1. A major safety concern with SUV's is the risk of rollover following a flat tire due to a loss of control. With a runflat tire, supposedly it is difficult to discern between a flat and fully inflated tire in terms of handling (at least this is the marketing line).
2. Only in rare occasions should you ever be stuck on the side of the road due to a flat tire.
3. The Goodyear tires while expensive, seem to have a tread life that is almost twice (35,000-40,000) that of the 19" OE tires. I don't know how long the Bridgestone tires last. Replacing tires is a hassle. Fortunately, I'll only have to do it once while owning my GL.
4. The Goodyear tires are vibration free and are very smooth on well maintained roads even at high speeds.

In a perfect world, I would probably have runflats on my GL with a spare hidden in a storage area in back. I'm hoping Mercedes moves the Adblue tank for the next gen GL.

As far as your tire stiffness concern, if I were you, I would test drive a GL on the roads you typically use to see if they work for you.

 

Thank you 43221B.
The roads in Hawaii are aweful. I've test driven the 450. Unfortunately, there aren't any 350s around to test drive so I can't compare the ride differences. When ordering the GL, I'd like to have nothing smaller than 20"s, so....... I think I'm ok.

 

You shouldn't have to drive a 350 to find out how the 20" runflats ride. The appearance package on the 450 has the same wheels and runflat tires as those that come standard on the 350.

 

Got it! Thanks for the clarification. So, either way I look at it, I was going to get that package in the 450.

 

Just replaced my R's run flats with standard tires, and I will never go back. The difference is absolutely mind-blowing! I weighed all pros and cons and decided I will never be out of AAA or MB Roadside area and my wife wouldn't change the tire anyhow. Plus my mileage has increased about 1.5 mpgs. Good luck with your choice.

 

I will have the same dilemma soon. So...do you drive without spare ?

 

My advisor promised I would be happy I gave up the spare and got the ride of reg tires-he was so right. There is a kit out there that is somewhat better than fixaflat in a can, but I figure it will ruin the tpms sensors...so yes, driving without a spare. Stupid adblue tank!

 

I did the same thing on my X5..the difference was huge and I used to carry air compressor in the trunk. My GL now has about 4K miles and I think I will change tires before 10K. Can't take them anymore.

 

Damn run flats

 

You nailed it! We got out of run flats on my wifes X5 and the ride got WAY better... still too bumpy for this GL'er, but way better. Run flats are a joke.