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  #1  
Old 12-05-2010, 11:17 AM
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Run-Flat Replacement

Hello Everyone, and Happy Holidays!

I am in the process of making a decision and would like your opinions and past experiences in travelling down this road (no pun intended). I need to decide on whether to replace 2 worn tires with the same run flat tires speced with the car (Deuler H/L400RFT); or spend a bit more to replace ALL tires with a better suited tire.

I must say that being a previous X5 owner and new to the RFT tech, I haven't been impressed with the drive. The ride feels harsh and disconnected to me. I did have the optional 20" rim on my E53, but even the winter 17" rims I had exhibited a conneted feel during spirited driving. These seem to just push.

My issue here is that I have the third row, hence no spare tire option. Is it worth the risk or carry a "slime" option to run the better handling and cheaper to run non RFT? Do I always go RFT in my situation with the third row and just deal with it (even when I purchase 20" summer/fall tires)? What have you all done?

Also, generally, how do RFT's handle in the snow? They seem like a harder density rubber to me, is this the case? Will they be just as adept in snow as a non RFT tire?

Thanks in advance to your opinions/experience on the subject. This has been on my mind for a while and I need to make a decision soon, for safety's sake. Looks like another East coast winter is coming.

Have a great day!

-Sterling
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  #2  
Old 12-05-2010, 12:27 PM
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Thumbs Down on RFT

Sterling,

I had run flats on my Mini Cooper S and it was like driving a shopping car...at high speeds. The ride improved 1,000 percent after going to traditional tires.

My X5 also came with run flats and, while it's not quite as brutal as the Mini as far as ride, after 500 miles I made the decision to change to Michelin Latitude HPs (non-run flats). While I only have 400 miles on them, I drove the same route I had driven on the run flats, and again discovered a very marked improvement.

So then comes the issue of the spare. Well, first runflats aren't perfect...while at the BMW dealership I saw not one but two different BMW's arrive on a flat bed. The service manager said that both had run flats and they "shredded" -- so they were left stranded anyway.

I don't have a 3rd seat, but while I'll eventually source a spare rim for long trips, I've got a can of "tire seal" along with a great plug in portable tire inflator - both of which hid nicely in the side compartment on the left when your looking in the trunk. My AAA membership includes up to a 250 mile tow. While it's not a perfect solution, I've only had 3 punctures in 30 years of driving, and two of them had no air leakage at all.

It's a tough call, but that's the route I'm going.
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  #3  
Old 12-05-2010, 03:34 PM
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JCL JCL is offline
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JCL will become famous soon enoughJCL will become famous soon enough
Full disclosure: I don't have an E70. I have had three sets of run flat tires. RFTs tend to generate strong emotions, usually against.

IMO, early run flats tended to be very harsh. Each generation has improved, and recent RFTs can be very close to non-RFTs in comfort.

Manufacturers have also tuned suspensions in recent years, to reduce harshness. All that means is that harshness correlates to vibrations at a certain frequency, and they can tune the suspension to deal better with those specific frequencies.

The X5, particularly with larger tire sizes, already has very heavy wheels and tires. RFTs make it worse. It is also a heavy vehicle, and it isn't going to feel exactly the same as your E53.

Tire pressure can make as much of a difference as tire construction. If they seem harsh, make sure they aren't over inflated.

RFTs can shred, exactly the same as regular tires, if owners drive on them for long distances at high speeds when they are deflated. If owners ignore the low tire pressure light on the dashboard, they will end up on a flatdeck.

RFTs do not necessarily have harder rubber compounds, they have stiffer sidewalls. You can get RFT with hard or soft rubber compounds. I have summer performance tires on the 535, and a set of winter tires that perform very well in cold temperatures, and both are DSST (Dunlop's version of RFT).

RFTs are not all the same. Some are harsher, some are less harsh. Same as some tires corner better, and some tires wear more quickly. It is a gross generalization to say that all RFTs have any particular characteristic when compared to non RFTs.

RFTs have stiffer sidewalls, and that makes turn-in crisper. That is the same reason people buy larger tires with lower profiles, to get crisper turn-in.

I understand that some people don't like RFTs, and replace them. I was impressed enough with my Dunlop DSST tires that I purchased the same tires for winter, in a different tread pattern and rubber compound.

If you want to swap them, just decide if you are going to carry an inflation kit, or a cellphone.
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  #4  
Old 12-05-2010, 05:08 PM
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JCL,

Succinctly put and far better than my comments!
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  #5  
Old 12-05-2010, 06:18 PM
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Do a search and you will find a lot of info/opinions. I have 214's and third row. I switched to Conti DSW (non run flat tire). I have a compressor and sealant/patch ( and fingers crossed). I don't think any option non-RFT or RFT is ideal. Many places won't have a tire in these sizes in stock, so either way you might be stuck with a flat. Seems more likely that a non-RFT can be repaired.

I found the tire wear of the OEM Dunlops to be unacceptable for their cost. Conti's are all season (I am in Cinci) and while the turn in isn't as crisp, they are comfortable and tire wear has been great.

Good luck with your decision.
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  #6  
Old 12-05-2010, 10:11 PM
ard ard is offline
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Well, my M5 doesn't have a spare, just a air pump and slime.

After a pothole left me 50 miles from my destination and 110 miles from my home after midnight (and I rode in a tow truck to the hotel) I decided that maybe this whole "who needs a spare tire" bs was just BS. (Had I had runflats I would have been equally screwed)

Can you put a donut behind the 3rd row???

So I have a full size spare in the trunk, and have used it 4 times in the last 80k miles.
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  #7  
Old 12-05-2010, 10:57 PM
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BGM BGM is offline
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Quote:
Originally Posted by ard View Post
Well, my M5 doesn't have a spare, just a air pump and slime.

After a pothole left me 50 miles from my destination and 110 miles from my home after midnight (and I rode in a tow truck to the hotel) I decided that maybe this whole "who needs a spare tire" bs was just BS. (Had I had runflats I would have been equally screwed)

Can you put a donut behind the 3rd row???

So I have a full size spare in the trunk, and have used it 4 times in the last 80k miles.
ard--the real question is what were you doing so far from home after midnight ? Inquiring Minds Wanna Know .
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  #8  
Old 12-06-2010, 04:29 AM
ard ard is offline
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Had an early morning meeting in SF, and was going to be there three days- so drove down the night before. If I leave after 10PM I've made the drive in under 2 hrs
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  #9  
Old 12-08-2010, 11:32 PM
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I've complained about the Bridgestones before, mainly because of early wear and noise. But I will say they do fine in snow -- not as good as a snow tire, but fine in Minnesota winters for me.

My issue with them in the winter is noise and the harsh ride. The colder it is, the louder sounds are (hence the tires make seem louder). Also our roads tend to get bumpier during the winter from frost expansion and those little bumps can be brutal with the Bridgestones.

I have had non-RFTs on my previous E53 (I have an E70 now) and I agree with other posters, the non-RFT road smoother but turn in was a little looser. That said, I prefer the non-RFT ride and will be switching soon as my Bridgestones start to get louder.
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  #10  
Old 12-09-2010, 05:12 PM
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I'm switching to all-season regular tires this weekend. I also have 3rd row seats so I purchased an air compressor and slime bottle. I searched amazon for a high quality compressor so it can fill a fully deflated tire without overheating.
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