Run flat tyres

Jack Ratt

Jack Ratt

Zorg Expert (I)
Supporter
British Zeds
The West Country
Joined
Dec 3, 2013
Points
200
Location
TRURO, CORNWALL
Model of Z
2.8i AUTO and 2.8i MANUAL
Didn't want to hi jack Gaz's tyre thread so thought I'd start a new one. I've noticed a number of comments since I've been posting here since last December about run flat tyres and that a lot of people replace them with "ordinary" tyres rather than like for like.

Could you guys enlighten me as to why this is so.

One of the reasons I'm asking is because I've bought a set of BMW pattern 104 alloys that came off a Z4 and these are fitted with nearly new run flats. I only paid £120 for the set of 4 wheels including nearly new tyres so I was pretty chuffed but when I saw some of your comments I started to wonder whether or not I should change them.

As they are fitted as standard OEM parts they shouldn't be too bad so why do so many people dislike them? It would be interesting to get your thoughts.
 
The main issue with run flats is that they have reinforced sidewalls which tend to make the ride quite harsh compared to non-RFs.

I had 18" (style 108's) on my Z4 and to be honest I hated the ride, and at the first opportunity switched them to non-RFs and everything was much happier in my life.

There are other issues with RF's though, such as destroying the tyre by actually driving on it flat (which is the concept). I had one which deflated, and I didn't notice straight away (seriously they drive fine with punctures). By the time I made it to the tyre centre I had destroyed the sidewall so had to scrap the tyre.

For a pair of rear run flats on my Z4 I bought 4x Falken FK452 non runflats (that was when I switched!)

It's a personal thing and if you don't find the ride too bad then stick with them. I know other Z3 owners who have ended up with run flats for the same reason as you and didn't complain.
 
One thing worth noting Garry, is that most but by no means all, run flat tyres can't be repaired as a normal tyre can. They also contain a "goo" which is supposed to seal minor leaks. I took them off my wife's Eos as they needed replacing and fitted standard tyres. Better all round I think. TBH run flats were aimed at lady drivers who would not want to stop in the middle of no where either to change a wheel or wait for some one who would recover the car, or busy people in general who don't have time to waste and can drive on after the Tyre Pressure light comes on.

Tony.
 
GazHyde said:
The main issue with run flats is that they have reinforced sidewalls which tend to make the ride quite harsh compared to non-RFs.
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A lot of owners fit larger wheels with low profile tyres and with lowered suspension, surely this affects the ride as much or even more than running run flats?

On some of the roads around Cornwall it would be better if we had caterpillar tracks fitted. Now that's a thought, and they'd be proper run flats=))
 
Its also worth noting how much more expensive run flats are compared to non RFs.

Might as well use them until its time to buy a new set then go normal.

Lee
 
We've got runflats on the Z4 and, 7 years later after some initial negative views wouldn't change them in fact we'll shortly be coming up to the 3rd set of rears and 2nd set of fronts. Ours don't have any "goo" in them - well I didn't see any when they were being changed. Also one has been repaired just like a normal tyre although some tyre places will try and tell you that they can't be repaired. I did try the wheels from the Z4 on the Z3 but unfortunately the Z3 suspension was never designed for runflats so it just didn't feel right.
 
Iv got RF on the fronts...they tramline...I get under steer...and with the B8s and H&Rs....they can make your fillings fall out...I can't wait to get shut
 
t-tony said:
What mileage are you getting from your tyres?

Tony.
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The first set of rears lasted 20k but the car is on the lowered MTech suspension with increased camber angle and the tracking was out so they had excessive wear on the inside edge The fronts went to 30k but even though there was tread left she had hit a kerb and there was a bulge in the sidewall. For the first 5 years the car was my wife's daily car, 11 miles each way but now being retired it tends to do longer journeys and with keeping an eye on the tracking we should get 35 on the rears as the car has now done 53k and there is enough tread (>=5mm as I change at 3 to4mm) left at the moment. Hopefully we'll get around 40k, or even a bit more on the fronts.
 
Zed Carer said:
The first set of rears lasted 20k but the car is on the lowered MTech suspension with increased camber angle and the tracking was out so they had excessive wear on the inside edge The fronts went to 30k but even though there was tread left she had hit a kerb and there was a bulge in the sidewall. For the first 5 years the car was my wife's daily car, 11 miles each way but now being retired it tends to do longer journeys and with keeping an eye on the tracking we should get 35 on the rears as the car has now done 53k and there is enough tread (>=5mm as I change at 3 to4mm) left at the moment. Hopefully we'll get around 40k, or even a bit more on the fronts.
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That's way too many.more doughnuts needed:)
 
miller1098 said:
That's way too many.more doughnuts needed:)
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Got the Z3 for throwing around, and the tyres on that are much cheaper.

The Z4 gets runs like my 590 mile return trips to visit my son in St Andrews who, like me plays golf - in 6th, just under 3000rpm indicated 80 but probably 76'sh, 45mpg, small case, clubs and electric trolley all in the boot and very little wear on the tyres.
 
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