To Run flat or not to Run flat, that is the question.

Thursday, July 9, 2009 by Gus Liszewski

     Run flat tires are becoming a hot topic of conversation.  With most of the new BMW, Mini, Chevrolet Corvettes, and even Toyota Sienna AWD models coming without a spare tire, it leaves owners with limited options.  While run-flat tires do provide extended mobility, there are mixed reviews on their ride quality, durability, cost, and overall value.  

    If I was putting my wife in a car and sending her across country in a vehicle without a spare tire, I would most definitely see the value in the run flat tires.  Now as a performance junkie, I would have to say that I am not the most impressed with the way some of these tires handle or ride.  

    Lets start with an explanation of how the run flat tire actually works, and what is different between these and a conventional tire.  The major difference is in the construction of the sidewall of the tire.  In the illustration below you will see the difference in the thickness of the sidewall and the way it is constructed.  The top section is of a standard tire with normal sidewall construction.  The second section is of a run flat tire, you will notice that the sidewall is almost twice as dense.

      

    So what does this mean?  Well twice as much rubber is twice as hard to flex.  So the driver ends up feeling every bump in the road.  I personally like to feel connected to the road, but even I have my limits.  I talk to Chev Corvette owners regularly, and I can't remember a single one that was happy to pay the premium for run flats, and didn't complain about the wear factor and ride quality....or lack there of.

   When the tire loses pressure, the weight of the vehicle actually rests and runs on the sidewall.  Think about it!  The entire weight of the car is running on the sidewalls!  The gotta be stiff to support that!

    Where does this leave me on run flat tires? If you are willing to make the swap and take the risk of needing to call a tow truck or flat bed in the event of a flat,  you will open up a lot more options at a lower price point, that are superior performing tires, and better riding tires!  This is a decision you have to commit to pretty whole heartedly, but if you love to drive, your car will thank you!

    But wait!  There is a solution that might help!  Continental Tire has developed and marketed the Continental Conti Comfort Kit.  Say that fast five times!  This is an inflation system that is designed to be carried in the trunk that is a combination of a 12v compressor and a high grade can of sealant.  This is not intended to be a permanent fix, but will get you off the road if there is a simple puncture.

    
    

Comments on To Run flat or not to Run flat, that is the question.

Saturday, February 27, 2010 by Juan Z:
Just got a new Mercedes ML 350 Blue Tech and it comes with RFTs. How long can I drive if I get a flat without using the Continental Kit? Also, can i use standard tires on the factory rims?
Sunday, April 18, 2010 by Gary Applebaum:
I have a BMW 04 645ci equipted with run flats. During a fast S turn I feel the tire flatten out at the transition point Any comments ?
Wednesday, July 14, 2010 by DAVE HANSEN:
Can a run flat tire be repair on simple nail in the center of the tread ? Run flat tires SUCK in every way....
Thursday, July 15, 2010 by Gus @ Tire Rack:
Run flat tires should not be repaired. They are only rated for 50 miles with no or low air pressure. It is hard to know how many miles were actually traveled before the repair was done. If the same situation was to arise again, you are now driving on a tire that no one knows how long it may last before it were to fail. That is bad news at 65 mph!
Sunday, July 25, 2010 by Peter Bancheri:
Do you offer compact spare tires and wheels for a BMW335i with a sport package? I have air pump that plugs into the cigarette lighter. Is there a temporary spray repair fluid that would work with my air pump. Run flat tires would cost $1000s of dollars for a rarely used benefit over the life of my car. Plus, they don't handle very well.
Monday, July 26, 2010 by Gus:
We do not carry anything in a compact wheel or tire application for this vehicle. We offer the same mobility kit that you have now, or you could opt for a full size tire and wheel, but trunk space will be scarce.
Saturday, August 14, 2010 by kenny prokop:
can run flat tires be replaced with standard tires? I own a 2007 BMW 328xi,and My BMW dealership has advised against this,stating that it would significantly alter the handling of the car,because the suspension of the vehicle has been designed for these tires and these tires only.What are my options?
Wednesday, September 1, 2010 by Eve:
I agree with previous comments, RFT offer the worst handling ride and their wear/life is short too...what the options for replacement on a Mini? options for
Wednesday, September 1, 2010 by Gus @ Tire Rack:
What do you have on the Mini Cooper? Are you running 16" or 17" wheels. When it comes to non run flat tires, there are a number of options in both sizes. It depends on what you are looking for. Comfort, responsivness, noise quality, wear, etc. Feel free to call me directly if I can help you make some decisions!
Sunday, October 24, 2010 by gino:
I have just bought a 2000 c5 corvette with only 21,162 miles and the rft have very little tread on them,is this normal for the tires.can they be replaced with a high quility tire? (carrying a puncher kit and a 12 volt compresor, any help would be appreciated.
Wednesday, November 10, 2010 by Garry:
Ok Gus, how about this scenario. I have run flats on my MINI that I keep inflated to 35 psi. The front right tire gets a screw in it and goes down to 28 psi at the lowest. If the screw is in the 'safe' area for repair of the tread, is it ok to patch the tire?
Friday, November 26, 2010 by arie:
I have bmw x5 2007. Do i have place to keep fool size 255/55/18 tire under cover in trunk.Thank You
Wednesday, December 1, 2010 by Mike:
Can you use a sealant with a RFT, I have a 2007 328i and the dealer indicated that a flat usually ends up costing about $1000 becuase the rim will get damaged when the tire deflates. I was wondering if using a sealant shortly after getting flat would save the rim.
Monday, December 6, 2010 by Mark:
Looking for a compact spare (donut) for a lexus sc430. Do you carry anything?
Saturday, January 1, 2011 by Carl:
Have a 2011 mustang v6 with 235/50/18 tires, preferably compact looking for a spare wheel and tire,
Monday, January 3, 2011 by Gus:
Don't carry any spare comact wheels, just the spare tires. We could do something full size, but there is going to be some trunk space given up. Did this vehicle no come with a spare?
Tuesday, January 4, 2011 by Albert:
Will the Continental Kit ruin the TPMS on a 2008 BMW 335i Coupe (w/ sport package)? Is there another brand that will not?
Friday, March 4, 2011 by Michael:
I am tired of buying run flats for our 2005 Toyota Sienna. In the snowy mountains for Colorado, we hardly get 14,000 miles. We are willing to buy reg. tires, but need a donut spare to throw in the back on long trips. Can you help me locate the right one for our car?
Wednesday, June 8, 2011 by Ed Chaback:
I have a 2005 Lexus SC430 and would like to get rid of my run flats. Do you have a donut tire on a rim to use as a spare? If not what would you suggest?
Wednesday, June 8, 2011 by Gus @ Tire Rack:
I do not carry a spare wheel and tire setup for the vehicle. If you are looking to move away from the run flat tires, I would tell you the best option that I can offer is the Continental Comfort Kit. It will help in the case of a puncture, it will not help in the case of a major tire failure however. So if you are ok making the commitment to calling a tow truck if you get a flat (worst case scenario if the Conti Kit can't help) then that is the way I would go.
Friday, June 17, 2011 by lauren:
I have a BMW 328i and replaced the tires 6 months ago. Now rear tires are completely bald(again).. Do you know what is causing this? Should I try a different tire other than run flats. I have 205/55 16 now.
Sunday, July 24, 2011 by R Missle:
Drove to Fl. Had 15m Miles on Bridgestone Rf's. Thanksgiving Day went
on Fl Trpk...got a blowout , drove 30 miles to exit, got off, called AAA
and 15 minutes later..I was on my way. P.S. Had tire coverage, sent in
paperwork and 10 daysw later I rec'd my check. You don't get as much mileage but when my wife if out driving, I have a comfort zone.
Sunday, August 7, 2011 by matt :
I plan on purchasing a 2 rear used Conti run flats for my BMX X5.I have nonrunflats on the front...is this ok?
Thursday, September 1, 2011 by Melelani:
Hi Gus, I have a 2006 BMW 325i with sport package. I have replaced my complete set of RFTs three times now since I own the car. Sick of the paying the premium and ready to switch to regular tires. I'm okay with calling a tow truck or buying a ContiKit, but I'm told that CA state law requires that I have a spare. My tires guy can't install my non-RFTs unless I can show him I have the spare. Is this true? And if so, how can I get around it. I don't want to drive around with a spare in my already-tiny trunk. Please help with any suggestions. Thank you
Monday, September 19, 2011 by Sherry Ayres:
I purchased a 2011 MINI Countryman at the end of January. I discovered several weeks ago that I have a nail in my RR runflat tire (2800 miles)! After doing the research, I have decided that I do NOT want to continue using runflat tires. I am waiting for the Merchant dealer in my area to get my tire in stock (apparently, my MINI has non-standard size tires that are hard to find!). Once I replace the tire, I will be making a trip to the MINI dealer 200 miles away so that they can replace all four tires with non-runflat tires. BTW, I was told that the (goop in the) ContiKit will damage the pressure sensor, so if I use the goop I will not only be replacing the tire but ALSO the pressure sensor monitor. Is there any truth to that?
Saturday, October 15, 2011 by Peggy:
I have a 2009 BMW 328xi with run flats and am having the same problem described above. I actually talked to a really honest guy at my local BMW parts department today and he indicated that the auto industry was sold a bill of goods on run flats and now everyone's finding out they're no good. Doesn't do me (us) much good. Options seem to be: (1)buy crappy run flat tires twice as often as regular tires at a premium price, or (2)buy "regular" tires and either get a spare/donut to roll around in the trunk along with your groceries or get, in BMW parlance, a mobility kit ($150). I keep my cars a long time, my last one was 17 years old, so this is a long-term sucky problem for me.
Saturday, November 26, 2011 by Ted Janacek:
looking for a spare for 2008 BMW 328xi, I am using standard tires, not run flat. You were recommended on Bimmer site, thanks, TEd
Saturday, February 25, 2012 by B Watts:
Looking to replace RFT on 2009 Mini S w/ standard tires. Will standard tires work with OEM Mini wheels? Thanks
Thursday, March 15, 2012 by Mike:
I have an '08 BMW 535xi SportWagon that came with terrible Goodyear NCT runflats. Thank God the car came with a compact spare and jack. The tires were replaced after 1,500 miles with standard Michilins after one of the tires developed a bubble in the sidewall.

Now, the dealer tells me that BMW has gone "all in" on runflats (no spares, or inflation kits). I was thinking of swapping for a '12 X3. But, no more, that's a "deal breaker". How'd you like to be in a new BMW on a non-interstate road in the Western US with a flat runflat, with no spare?

We'll see where this ends up in a few years.
Monday, April 2, 2012 by Steve:
I've used conventional tires on my 06 sienna awd for 65,000 miles.
I carry a full size spare on a wheel tied down in the rear
Has worked well .
Yokohama avid's ate a good chioce
Friday, April 6, 2012 by Mechanic1:
I want comfort with little noise,
I will buying new rims and tires on my 2012 mini cooper countryman what tires do you suggest for that set up
Thanks in advance for your help love this site
Thursday, May 10, 2012 by yashar:
Hi every body.

I got a 2008 bmw 328 i, coupe,, with sport suspension,,, running on RFT. the bridgeston potenza... ride is horrible, and too expensive,,, dealer keeps telling me if i switch to Michelin super sport summer tires, it will mess up my handling,,, is that a true case? cuz iv heard michelin super sport is a great performance and comfort tire. could that be a replacement for my rn craps?

thank you
Wednesday, May 16, 2012 by Gus:
Yashar:

Like I mentioned in my blog, the largest trade off will be the fact that you do not have a spare. We use the BMW 3 series platform for our test vehicles and have no issues with the handling. I think that you will also find that many people have made the change to non run flats and have felt that it has improved the vehicle's handling. It will all be personal opinion and feel. There is not a magic answer, but I would say that from my experience it will not Negatively effect the handling.
Sunday, July 29, 2012 by Bryan:
Hello,
I have a 2006 Toyota Sienna LE AWD. My tires need to be replaced and I am considering moving to a non-RFT solution. The dealer has told me that I can't mount a non-RFT to the RFT rims. I've read conflicting reports on the web. Can anyone tell me if I can mount a non-RFT tire on the Sienna RFT rims? I know this would leave me without a spare but am considering a can of tire repair and a 12v compressor. Any recommendations on a compressor? Thanks!
Monday, July 30, 2012 by Gus:
The dealer is incorrect. There is an additional "safety hump" that is designed to help keep a run flat tire on the wheel when it is being run in a zero pressure situation, but those wheels can accommodate a conventional tire with no problem. As for the compressor option, I would strongly suggest the Continental Comfort Kit, it can be operated as just a compressor, or also used in combination with the sealant when needed.
Thursday, August 23, 2012 by Gene:
I own a 2007 BMW 328xi and changed out the Rfs for non due to wear. I've been running softer Goodyear tires for about a year now and so far so good. Better handling, softer ride. Find a spare extra wheel, pop a tire on it, stick it in the trunk and quit over thinking all this run flat or non nonsense.
Wednesday, October 10, 2012 by Robert:
I'm trying to find a mini spare for a 2010 AWD Toyota Sienna XLE. (I'm replacing the OE RFT's with regular tires.) Does such a thing exist?
Tuesday, January 8, 2013 by Jim:
Very helpful information.
Tuesday, February 12, 2013 by Ronnie:
Was wondering if I could use a doughnut tire on my 2002 corvette instead of purchasing rft. What type of car would I need to get the spare off of. I was told a 2002 camero or firebird.
Tuesday, February 12, 2013 by Marshall @ Tire Rack:
Ronnie,
We do not sell any spare tire kits for this vehicle. You may be able to use one off of another vehicle, however I would question whether or not it offers adequate brake clearance.
Saturday, May 11, 2013 by Cynthia:
I'm sick of buying RFT's every year. Can I change to regular tires on my Lexus sc430? If so, how difficult will it be? Which tires will work best?

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