Run flat tyres
 

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[Closed] Run flat tyres

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I'm replacing two worn tyres on my car in the near future, any reason I can't put run flats on it? it has tyre pressure monitoring. Would having two run flats and two normal tyres be an issue? Any other problems/cons to think about?


 
Posted : 15/01/2015 10:02 am
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I wouldn't bother. Uncomfortable ride, more expensive than normal tyres, and unless your TPMS actively directly monitors tyre pressure from the valve, by the time it spots a flat you'll have destroyed the tyre. Ask me how I know. 😉


 
Posted : 15/01/2015 10:06 am
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Are you afraid of having your tyres shot out?

I seem to remember having read somewhere that run-flat tyres are not very good; my recollection is that they are heavy and not especially good. Why doesn't everybody use them?

Tyre pressure monitoring that works off the ABS is pretty good and should give you warning of a puncture.


 
Posted : 15/01/2015 10:07 am
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the price difference between normal and run flats isn't much so I thought it might be worth a punt but wanted some real world experiences before I spend money


 
Posted : 15/01/2015 10:25 am
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In general garages won't be comfortable with mixing run-flats and standard tyres on different ends of the car, you'd have to do all four at once.

Although from my experience you probably wouldn't want to - run flats give a bone hard, crashing ride and some very interesting handling! On some types of bump the whole car would 'bounce' six inches to the left/right which is a little unsettling (5 series estate).

Standard tyres and a good breakdown service for me (plus a can of tyre foam in the boot)...


 
Posted : 15/01/2015 10:45 am
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If you car isn't designed for run-flat tyres then they will have no benefits over standard ones other than poor comfort.

Wheels are designed slightly differently in the bead area to accommodate run-flats vs. std tyres to ensure a better seating if they go flat.


 
Posted : 15/01/2015 10:46 am
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Tyre pressure monitoring that works off the ABS is pretty good and should give you warning of a puncture.

You'd think so, wouldn't you? But it doesn't. It will eventually trigger but at that point the tyre's already a write-off. On my dad's Skoda Superb it took 90 miles to spot that he'd switched to the space-saver after clobbering a pothole on the A41.

I now have one that measures from the valve stems.


 
Posted : 15/01/2015 10:50 am
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Run flats are way better than they used to be.
But if it was me I wouldn't bother if you already have a spare wheel.
They are more expensive and if you do manage to get a puncture in them more often than not the tyre will need replacing where a standard tyre could possibly be plugged.


 
Posted : 15/01/2015 11:01 am
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I wouldn't - they are more expensive and have a habit of wearing unevenly. You also don't really want to be mixing run flats and non flats.

I've stuck with them on out 3 series because the car was deisgned to have them and there are enough people who havent been convinced about their cars handling after ditching them. To be honest, the ride isn't that bad on our car - no worse than my previous M Sport without run flats.


 
Posted : 15/01/2015 11:08 am
 timc
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Run Flats are designed to be scrapped after being driven with Zero pressure anyway, just a get you home alternative.

Personally Id stick to normal tyres if i were you.


 
Posted : 15/01/2015 11:36 am
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Run flats are terrible.

Get "normal" tyres andif you have no spare make sure you have AA/Green Flag.


 
Posted : 15/01/2015 11:39 am
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Run flats are fine as long as your car's suspension was designed for them. If not and you already have space for a spare I wouldn't bother.


 
Posted : 15/01/2015 11:43 am
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if you are on about BMW, you need to inform your insurance company if you replace the run flats with "Normal" tyres. This is to do with changing the car's spec.


 
Posted : 15/01/2015 11:49 am
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run flats give a bone hard, crashing ride and some very interesting handling! On some types of bump the whole car would 'bounce' six inches to the left/right which is a little unsettling (5 series estate).

What size wheels are you running? I also have a 5 series with run flats and find it very comfortable but we only have the SE with 17" wheels so we have quite a big tyre profile.


 
Posted : 15/01/2015 12:04 pm
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Run flats run on different wheels, they have a special bead/rim relationship to hold them on once flat. As said above, expensive, often run uneven (therefore not lasting as long), not as comfortable (they have harded sidewalls to give the tyre some structure with no air). They are better than they once were but as soon as mine wear out I replace them wth normals.

[i]

Normal wheel has a bead contour seat denomination of H2, which means double hump. RFT wheels are EH2, which means extended doube hump and makes sure the rft tyre sits well with its thicker sidewall and doesn't come off when run on flat.
The same tyre on a normal rim would not sit as secure, due to the different bead contour, which is the flaw in the "security" thinking, as it may come off when run on flat and then you are still stranded.
[i]


 
Posted : 15/01/2015 12:04 pm
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I have 225/50R17 RFT's on my car and they are no different in sensation to non-RFT's

For sure lots better than they were 5+ yrs ago
Cost isn't an issue either as it's a fully inclusive lease car

I guess the benefit only comes when you puncture & can drive home safely without having to become a target for sleepy truck driver 😉


 
Posted : 15/01/2015 12:29 pm
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On some types of bump the whole car would 'bounce' six inches to the left/right which is a little unsettling (5 series estate).

Ms njee20's Mini Clubman does that - very disconcerting! We'll be replacing them with 'normal' tyres once the runflats have worn, they give a very harsh ride. Not convinced at all.


 
Posted : 15/01/2015 12:36 pm
 timc
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njee20 - Member
Ms njee20's Mini Clubman does that - very disconcerting! We'll be replacing them with 'normal' tyres once the runflats have worn, they give a very harsh ride. Not convinced at all.

I've already been through the change on an E90, dont expect drastic differences.


 
Posted : 15/01/2015 12:42 pm
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Comparing a BMW 5 Series to a Mini is hardly like for like though is it?

From what I've read about them, RFTs usually ride harsher than std tyres and dont always handle as well.


 
Posted : 15/01/2015 1:39 pm
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@V8_shin_print - 245/40/18's, I'll admit it's not 'limo' like comfort now but you don't get the loud 'bangs' that reverberates around the cabin 🙂

I replaced mine with standard load rating tyres, the difference with reinforced 'XL' rated tyres might be less, many of the low profile tyres are XL anyway particularly at the budget end.

On my BMW the run flats were an option, so the same model may or may not have had them as OEM, so long as you're not going for aftermarket wheels the insurance company shouldn't be worried.

I also couldn't find any evidence for the suspension tune being different when run flats were fitted. And if it had been specially tuned then they made a rubbish job of it 😉

I had problems with the uneven wear issue too, stiff sidewalls and wide tyres isn't a great mix.


 
Posted : 15/01/2015 3:20 pm

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