Run Flat limits
 

Has anyone had experience or heard of situations where someone has gone past the speed or distance limits of the run flat tire? I have searched and want to know what happens if I drive over the 50 speed and distance limits. Will my differential be reduced to a mess of molten metal? Will the tire disintegrate to the rims as I continue down the highway in a shower of sparks like on those cops shows? I hope these are precautionary limits and if needed I could for instance drive 80 mph or 100 miles distance without damaging my vehicle.

It's all related to heat in the tire. If you drive too fast for too long you will internally damage the tire then eventually it will come apart.

I know that. I was asking how fast and how far if anyone has tested those limits. The differential may also be damaged because of the disproportionate tire rotation speeds.

No experience driving on a 'de aired' RFT, but my guess is: the '50/50 limit' is the tire mfgers being overly cautious and figuring 'everyone' lives in the 'Burbs and can get to their local tire store for a new ~ $250+ tire, combined with barrister buzz words and liability limits...

Otoh, a cursory glance at RFTs on the net did not elicit much info or success in driving well past the '50/50' limit.

Fwiw, I have one car that came with RFTs, (our '02 VetteVert), but the OE tires were replaced by non-RFTs after the original tires wore out. 8 yrs and 35,000 miles later I have never had a prob with the non-RFTs, though I do pack a plug kit and compressor in the large trunk well, in that car.

All anecdotal, but I have had my share of tires going flat, but in the past decade and a half those low air situs have all come to my attention 'in the driveway/garage' and an easy patch/plug job has taken care of the situ. When was the last time one had a 'blow out' or flat on a trip? Happens, but so does getting a hole in one. :)

RFTs have some slight benefits, (mostly emotional), but are really designed for Buffy's piece of mind, imo. ;)
GL, mD

PS: My non tech opin is to not drive an AWD X on a de aired RFT for very far or very fast...

True enough MD. Though I've had my share of flats I have never been on the side of the road with one. I always look at my tires when I approach the car and if I see one getting soft I'll inspect it closely and usually find a nail or other slow leak. I once won a bet that I could see a 3 pound differential in air pressure in my tires.

The real object of my question is because on the freeways I travel on the actual speed limit is around 80 mph. Driving home at 50 would be unsafe with a 30 mph difference in speed. I wouldn't care about shredding a tire but would not want to sacrifice a differential.

As a final thought I believe that run flats will continue to become more popular and non run flat tires will go the way of tires with tubes. Buffy's everywhere rejoice.

On the car, I blew a front runflat tire 65 miles from home. I hit what looked to be a chunk of concrete that had popped up out of the roadway doing about 80 mph. With the speed limit being 70 mph for cars and 60 mph for trucks, I wasn't crazy going much below 55 mph. It was about 60 miles on the highway at 55 mph and then the last 5 miles is 40/35 mph through neighborhoods. It lasted me the drive home, but was definitely getting squirrely the last 10 miles or so and I definitely took it much slower off the exit ramp and turning in the neighborhoods.

Don't know what it would do to the X5, but that's why I have the spare tire kit and non-runflats now.

I have gone through 4 runflat tires in 2 years from the blowout, two sidewall punctures, and a pothole sidewall blowout. Prior to that, I think I have had 2 flat tires in probably 20 years. So far, just not impressed with the cost and frequency so I went with the spare tire kit and non-runflats which will all be put on next weekend.

Run flats are generally pretty terrible tires but they give housewives a nice false sense of security. I hope and expect they will continue to improve to a point where I'll consider using them.

I just switched out my 19" runflats for normal Michelin Latitude HPs. I was surprised that my ride on bumps is not significantly better. I live in FL with perfect roads so I was not exactly having road issues. The normal tires have taken the edge off the on center feel. It is now slightly mushy and not as laser sharp. I can't believe I am saying this, but I may switch back to run flats for my next set. The pricing is similar now although they won't last as long. The bottom line is the engineers tuned the suspension for runflats. I have Adaptive Drive so this may have made the switch more drastic for me.

No mater what, I always will have a spare and never drive on a run flat that is low.

I had the dash warning that my right rear was low, Stop or drive under 50 etc...

I slowly drove through curves and straights to have a feel for handling, ended up going about 25 miles at 75 mph. Tire shop found a screw dead center in the tread and was able to safely plug and boot the tire for $14.95. Reset TPMS and all is well. There was 0 damage to the tire other than the screw in the tread.

Echoing MD's comment,

PS: My non tech opin is to not drive an AWD X on a de aired RFT for very far or very fast...