Runflat tires on cars that didn' come with run flats
- Thread starter DaveSwan
- Start date
One of the first mods I did to my BMW was ditch the run flats. There is no real advantage in my opinion, only cons. They rode worse, were more expensive, shorter life span, fewer tire choices, and if they do go flat you have about 100 feet before they shred completely. I used to commute 100 miles/day, and have had a total of 3 flat tires. In all of those situations run flats would not have helped me, only a spare tire.
Of course but keep in mind suspensions can be tuned for RFT. Think progressive/variable rate springs vs constant rate. As for the pros'/cons I can offer some insight based on my own experience with them.
The highways around ATL and the SE in general are fairly easy on RFT. It's the surface streets around the City of ATL where things can get a little loud.
The Bridgestone Driveguard exists for exactly this purpose. Runflats for TPMS cars not originally equipped with them. They're supposed to be a huge step forward in runflat technology, even if they're not quite as good as regular tires.
Some people need them for those one way spike strips in parking lots.
There is a new pirelli cienturato - it looks a lot like a Michelin CC2, and it advertises a layer of gooey sealant on the interior to self seal from nail incursion. I may have owned a pirelli on a used 86 escort in high school, before I knew anything about anything, and haven’t owned one since. This particular tire, however, is intriguing.
I have runflats on my BMW, and I think they are much safer than non-runflats and do not have any downsides that I care about. I did have a blowout with them, and it resulted in a much safer situation all around.
I wish I could put runflats on my Expedition. But runflat wheels are made slightly differently than regular wheels to keep the tires on the wheel in a runflat situation. So, it is not a good idea, and I have not found anyone knowledgeable who recommends it.
Bridgestone Driveguards are pretty decent. Its really not a terrible idea depending on your reasoning. Many newer cars don’t have spare tires on board.
edyvw
$50 site donor 2025
Bridgestone is by far the worst RFT of all top brands. Michelin, Continental and Pirelli are much smoother.
edyvw
$50 site donor 2025
It is more than that.
BMW, for example, uses spongy parts in numerous spots instead of real rubber. One of the most popular and extremely cheap upgrades is replacing rear shock mounts (especially lower ones) with Monroe rubber ones ($7 for E90). OE are designed softer bcs. RFT.
On Toyota Sienna I had RFT bcs. The AWD version does not have a spare (the spare is located in the FWD version in the floor compartment that is utilized by the transfer case in the AWD model). Suspension is not changed for RFT, and oh boy does it rattle inside. I killed suspension by 85k, and RFT probably played some role in it.
I would ditch the run flats if you have space for a spare. On my old BMWs the jack that came with the car with notches into a specific portion of the unibody fram e rail and there is a wheel chock too. And a full sized spare. The E34 is steel but full sized and the E28 is alloy because it has the TRX wheels. When I have flat tires on both, changing tires is almost a fun experience - that is how nice the jack and the set up is on each car. And then you have a full sized spare so you can continue on - not with some stupid donut or a RF tire that may shred up on you. I believe the RFT may be better for certain applications - an elderly person who still drives for example - but I think eliminating the spare and the nice jack is one of the big cheap outs on a lot of newer cars. My 4Runner at least has a full sized spare but the overall set up and the quality of the jack is far inferior to what BMW used to provide. Honda had the nerve to put a donut with my wife’s prior car, a Pilot. That was downright negligent in my mind - that is a 5k pound SUV and no way it should be running a donut. I put a full sized on that I bought at the pick and pull. RFTs are just the latest way they cheap out but it is what it is.
Let's be a bit precise:
RunFlat tires CAN be used on wheels designed for regular car tires.
HOWEVER
If you don't have TPMS, then you might not notice when you have a flat.
If your car wasn't originally equipped with RunFlats, then the wheels won't have the features to help hold the tire on the wheels when it gets flat. The feature is called EH2 - Extended Hump version 2.
I go into more detail here: Barry's Tire Tech: RunFlat Tires
RunFlat tires CAN be used on wheels designed for regular car tires.
HOWEVER
If you don't have TPMS, then you might not notice when you have a flat.
If your car wasn't originally equipped with RunFlats, then the wheels won't have the features to help hold the tire on the wheels when it gets flat. The feature is called EH2 - Extended Hump version 2.
I go into more detail here: Barry's Tire Tech: RunFlat Tires
Conversely, you can run reg tires on run flat rims which is what I did with the MB because they rode so hard:
Barry's Tire Tech: Current RunFlat tires and EH2 wheels are compatible with regular tires and wheels.
That is, you can use regular tires on the EH2 wheels that came OE on cars equipped with RunFlat tires
Barry's Tire Tech: Current RunFlat tires and EH2 wheels are compatible with regular tires and wheels.
That is, you can use regular tires on the EH2 wheels that came OE on cars equipped with RunFlat tires
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Exactly. My car came with RE050A’s which surprisingly lasted 40k.
Theee drawbacks—shops should not repair. Idea is they have no way of knowing if driven on flat (if so, throw away). What if negatory, and you get a screw. You’d have to plug it yourself as I did. Who wants a $400+ disposable tire?
Next is the harsh ride. I got 2014 pilot super sports for cheaper than a re050A would have been.
Lastly, cost is higher.
The only thing I don’t agree with is they are designed to be driven on flat, not shred. About all this accomplishes is to not change a flat like we would do normally, when discovered. It also saves the mfg money as no jack and no spare.
When I replaced my OE Goodyear run-flats with Continental run-flats on my BMW last year, I had the tech throw the best old tire in the trunk. A few months ago, we were returning from a day trip on a two-lane country highway over 50 miles from our home when we heard a loud bang, followed by a message on the console that one of the tires had no air pressure anymore. The car’s behavior was unchanged by the blowout – no swerving, direction change, etc, which was a blessing on a two-lane highway. The highway had no shoulder and there was some traffic. Knowing that I had run-flats I decided that the safest thing to do was to continue driving at a reduced speed until we reached a place where it was safe to pull off the road and assess the damage. About a mile down the road there was a business on the side with an empty parking lot, so I pulled in and had a look. The passenger side front tire had a hole in the sideway that was around 3” by 3” with a flap. I could easily push my thumb into the tire through the flap. But the tire had held together and the wheel and car were undamaged. With that much sidewall damage and being far from home or a tire shop, I decided to call a local flatbed tow truck. Interestingly the driver took advantage of the run-flats by simply driving the car onto the tilted flatbed rather than using a winch. When I told the driver that I had an unmounted tire in my trunk, he told me that he had the equipment necessary to mount it and balance it at his shop and was willing to do that, despite the late hour. So, within an hour we were on our way on tires that I could have driven as far as I wanted. The next day I took the car to BMW and had them mount a new tire, once again throwing the old one in the trunk. They charged me only for mounting and balancing – Continental’s road hazard warranty paid for the new tire without any hassle whatsoever.
If I had not had run-flats, the car could have swerved potentially causing a head-on collision, the wheel and car may have been damaged, and I could have been run over while attempting to change the tire at dusk on an unlit country highway with no shoulder. That’s why I think run-flats are safer.
If I had not had run-flats, the car could have swerved potentially causing a head-on collision, the wheel and car may have been damaged, and I could have been run over while attempting to change the tire at dusk on an unlit country highway with no shoulder. That’s why I think run-flats are safer.
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