Run flat blow out fix

R

raymond.harper

Senior member
I always worry about runflats. Our Z4 and Mini have them but what happens if they suffer a total failure? Rather than trailer you to a garage for a new tyre assuming the garage is open the A.A. carry a 17 inch universal run spacesaver. If your tyre is destroyed they will fit the spacesaver and you will be on your way along with your old wheel. Hopefully there is enough space in the car for the wheel. Then you go to your tyre depot in your own time and get a new tyre placed and the depot will take away the spacesaver and it gets sent back by courier to the A.A
 
A 17" universal spacesaver tyre isn't going to be universal though!

It wouldn't fit over any car's front discs if they've got large brakes (e.g. 355mm or bigger).

In my case, the car was trailered to a garage to have the tyre replaced - and it took them 5 hours to get me from Suffolk to near Heathrow. it should take less than 2 hours at my normal time (5am), but due to the puncture and delay in waiting for recovery, we were travelling in peak time.
 
I am assuming he means that switching to non-runflats there is an element of what if....
A space saver is obviously one way of getting you on the road againbut its still a legal requirement to have the means to fix a flat tyre whether its a spare or tyre sealant and an inflator.
We had a space saver for our mini, it came in a kit that fitted under the car on the opposite side to the exhaust. Could only be fitted to no-S models as their pipe ran down the centre and left no room.
If you had a puncture with a front tyre, you would have to fit the pace saver on the rear and move the ok rear onto the punctured front as the 17" space saver would not fit over the brakes.
This could possibly be done with a lot of cars except ones with staggered fitment.
 
I'm not with the AA so that might be a problem :) plus I would like to see them try and fit a spacesaver over the M140s 4 pot calipers. If the runflat fails completely then it woud be a trailer job. I never worry about it to be honest.

The Z3 I had was always slightly ridiculous with punctures as it had a spacesaver strapped to the underside of the car but the flat woud never have fitted in the boot :roll: Great thinking by BMW.

Always reminds me of this tragic story,

http://www.dailymail.co.uk/news/article-1263095/U-S-Air-Force-captain-Jenna-Wilcox-holiday-Scotland-dies-freak-accident-sports-car-tyre-explodes-lap.html

Tim.
 
raymond.harper said:
I always worry about runflats. Our Z4 and Mini have them but what happens if they suffer a total failure? Rather than trailer you to a garage for a new tyre assuming the garage is open the A.A. carry a 17 inch universal run spacesaver. If your tyre is destroyed they will fit the spacesaver and you will be on your way along with your old wheel. Hopefully there is enough space in the car for the wheel. Then you go to your tyre depot in your own time and get a new tyre placed and the depot will take away the spacesaver and it gets sent back by courier to the A.A
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Are you suggesting the recovery companies should carry space savers? That would be dozens to cover all wheel sizes, stud number, PCD, etc. For all members cars. Quite unrealistic expectation, except perhaps one or two common car sizes

I saw somewhere the average puncture is 1 per 90,000 miles, so not really an issue to worry about. Most of those will show up on the driveway or car park when left.. Total failure is rare and breakdown more likely to be battery or key loss/failure...
 
While the AA/RAC DO carry a "universal" spacesaver, as said I'm not sure about it fitting our Zeds, especially those with bigger brakes.

Having recently ditched my RFT's, I don't really give it a thought. I still carry my "Stork Ranger" tubeless tyre repair (plug) kit in the boot, along with a small £10 Aldi compressor, as I do in all my vehicles.

Probably had to use them about a dozen times over the last 15 or so years, and approx 750,000 miles that I've driven. IMO, if you keep an eye on your tyres, a puncture is normally easily spotted, even if a tyre picks up a screw/nail, you can usually hear it as it hits the tarmac on every revolution. Tyres nowadays are pretty strong and actual blowouts are fairly rare (I'm talking about premium brands, not the cheap Chinese ditchfinders) Of course, there is always the scenario where you can't avoid an object/debris in the road, but if it's serious enough to cause a blowout in a std tyre, it probably would do the same to a RFT.

I'm sure I read recently that the number one cause of a blowout is still under inflation, causing the tyre to overheat and delaminate, literally falling apart, but again I'd like to think I'd hear/feel this before it got to a critical stage.

Just my 2p.

Mike
 
Blowouts do occur and can happen with premium tyres too.
Nicki had a blowout on the motorway with the X6 with Bridgestone runflats fitted.
Front tyre instantly lost all air as something on the motorway punctured the sidewall.
Might not be a normal blowout but this sort of thing would knacker any tyre whether budget or premium.
 
First hand experience of this in an E90. Bang and im pulling on to the hard shoulder with a destroyed sidewall of the OSF tyre. The AA showed up and recovered me to wherever I wanted to go in the UK, in this case about 30 miles. N9t sure what would have happened if I didn't have the nationwide recovery element, always had it so never considered it. But I guess with the basic cover I would have thought it would be just like any other mechanical breakdown, they'll take you to the nearest garage or tyre contractor in this case, whether they're open or closed and leave the car there. Once there it's on you to sort yourself.

If anything these days blowouts are more common on RFT than non runflats. Their internal structure is more prone to damage and tyre bulges are much more common, basically its the same issue with runflats that causes wheel cracking/buckling no give whatsoever so one decent pothole... Left unchecked or unnoticed these bulges can lead to a catestrophic tyre failure. Just ask any decent MOT tester how many bulging runflat tyres they see compared to non runflats. All brands as well, had recent personal experience of this with a Goodyear F1 RFT on a company vehicle, went unnoticed as well till the tyre was due to be replaced as it was on the inner wall.
 
Roads round Trafford are awful for a bludge on my mini JCW in the first 500 miles 🤬

Only the second car I’ve had them on and tbh even with the new tech they are still crap but don’t want to fork out another £800 for some nice normal tyres.
 
jimmybell said:
Surprised they fit RFT to a JCW model!
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Exactly. I tried to argue the point but we got a good deal with nearly 10k off list so they wouldnt budge on putting more performance tyres on it.

It was a pre reg so it had almost every option and run flats are an option...
 
I thought Run Flat Tyres meant just that. Get a blowout and you can drive on the tyres still - albeit with reduced enthusiasm. Do they suffer from complete collapse like a standard tyre would??
 
Problem is in most cases is if you have a slow puncture and still drive on it like most people do the sidewall collapses meaning you cant put any air in it at all and they are just as useless as normal tyres in puncture respect.
 
tomscott said:
Problem is in most cases is if you have a slow puncture and still drive on it like most people do the sidewall collapses meaning you cant put any air in it at all and they are just as useless as normal tyres in puncture respect.
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No sure that's right Tom or perhaps I'm missing your point. If the air comes out of the tyre to zero psi then you can dive at least 50 miles at max 50mph. The entire design is to run with no air. I'd bet you could drive them happily with a 2" hole in the wall too given the design of rim and bead
Drive 500m on a normal tyre with with no air an it'll likely cost you the rim too

I'm no fan of them, but they are way better for the average muppet and save a huge amount of weight and space in cars
 
Didnt quite explain correctly. People still treat them as usual tyres.

If you have a slow puncture on a runflat and you drive on it, it weakens the sidewall so if you keep pumping it up (as most people do as they think its a normal tyre) then as it runs down it runs on the sidewall. After driving on the runflat for the 50 miles the sidewall collapses and the tyre is as done as a normal flat no longer holds the weight.

Happened to a girl at work who had no idea and she ended up stranded im sure she had run it for an extended period. Given that you know how they work they can positive but many people dont and end up in the same position as you would with a normal tyre.

My first mini in 2007 was the first car I had with RF. I had them removed pretty quick as they made the car handle so badly it was all over the place they were only 16" so replacing them was cheap. Now unfortunately have them again but 10 years later but 19s 225 35s all round :headbang:

Thing that annoyed is the mini is brand new and have been treating it as such. I have avoided everything I could apart from one little pot hole that I admit I didnt see. Ditdnt think anything of it as it was really small. The car had another small issue with some stitching on the passenger seat so went in to be sorted and on the inspection they found a great bulge on the inside of the passenger side tyre sidewall. It obviously doesn't take much to ruin them, im pretty sure a normal tyre would have taken it as they have more give.

Where I work in Trafford park, its awful atm they are installing the new metro link and most of the main roads are closed. So all the little back streets are getting hammered and as its an industrial area there are loads of haulage trucks and heavy machinery. Some of the roads in the middle of Africa were better.

The car also feels like its on rails, corner hard and its like the tyre moves under the wheels. Strange sensation and completely ruins the car.
 
Ok but your talking of an unusual circumstance of slow puncture and of course ignoring the usual pressure warnings from the TPS and similar and just reinflating. Of course people abuse tyres and pay the penalty, with runflats it’s that the wall deteriorates when run flat or very low, but of course so does a normal tyre which doesn’t last long at all

You’ll get no argument from me which I prefer, but I remain convinced that for most drivers the ability to drive home or garage beats wheel changing and spares or recovery and in most normal driving they are safer
 
I guess the real question is are the benefits of RFT worth it against the likely frequency of a puncture that immobilises you. In 25 years and god knows how many miles but must be well in excess of 700,000 I've only had three immobilising tyre issues and one of them was a blowout on a runflat anyway. For me I'll take the benefits of the non runflats for the once in a bluemoon occurrence where I get an immobilising puncture and an inflation kit won't cut it. At the end of the day lots of manufacturers including the likes of Porsche's only give you an inflation kit these days anyway.
 
Interesting thread!

Mrs Tidy bought a new Mini One in 2003 and had the choice of run-flats or non-RFTs and a spacesaver - not knowing much about RFTs then we went for non-RFTs and the spacesaver. Luckily she never had a puncture anyway, but looking back I think RFTs might have been a better idea.

I bought a 320td (so non RFTs) in 2005 and only had 1 puncture in that on a sunny summer's day, so putting the spacesaver on wasn't an issue.

I replaced it in 2008 with a 123d on RFTs. I had 2 punctures in that and both times it was snowing, so being able to just drive home was really handy!

So that was 3 punctures in 124K miles. I just seem to be lucky. :(

Now I'm planning to put my Z4 on non RFTs, so in anticipation of that I bought a 17" spacesaver, jack and wheel-brace from a forum member (although I've also got an Aldi compressor and some Holts goo)!

At the end of the day if the sidewall gets ripped it doesn't really matter if it is an RFT or not, you're not going any further on it!
 
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