BMW run flat tyres

[mr_tony]

Anyone out there (Apart from EVO!) taken the run flats off their BMW and gone for a non run flat brand tyre?

IF so - how did it change the feel of your car?

The Aero is on run flats at the moment which I expect to wear out in the next 3-4k of driving around Europe in the coming weeks and I'm wondering if it's worth dumping the run flats if it'll give an improvement in grip / handling / progressiveness?

[LuS1fer]

In EVO this month, I recall reading that dumping runflats saved 1kg of unsprung weight at each corner on some car or other.

[r988]

LuS1fer said:

In EVO this month, I recall reading that dumping runflats saved 1kg of unsprung weight at each corner on some car or other.

How much weight does a spare tyre add? or do you carry around one of those cans of foam and hope

[mr_tony]

Anyone else?

Results on the last car evo had that took these off (645i?) was IIRC a better ride (sidewalls on runflats kevlar so v stiff) more grip, and more progressive sliding. I think the feeling was that the hard sidewall made for less predictable / smooth behaviour around the limit of traction...

Anyone confirm this?

[Raify]

On a MINI Cooper S works:

With runflats:
Incredibly harsh ride, poor grip in dry dreadful in the wet.
No way of repairing nails / bolts in the tyre
Almost twice the price to replace (quoted £160 for 195/50*16 from BMW)
Heavier
Wear faster

With proper tyres:
Much better ride, fantastic grip in dry and wet
£15 to repair a nail / bolt
Cheaper to replace (approx £80-100 depending on brand)
Lighter
Much longer life.

It's a no-brainer. Get rid of them, why do you think that all the 'M' cars have proper tyres?

[mini_ralf]

Another Cooper S owner...

I got rid of the run flats last week. They were shoddy in the dry. Damned dangerous in the wet and the ride was probably only just be better than a 16th century horse and cart for ride.

The new 'ordinary' tyres are lovely. Grippy in the dry. (Haven't tried them in the wet yet). Much quieter and they absorb bumps more smoothly.

I would honestly suggest that you change as quickly as you can.

[mr_tony]

I'm keepign the runflats for now as I'm off to the South of France for 2 weeks in the car - so the runflats may yet prove themselves useful!

HAving said that as soon as I'm back I'm keen to get some proper rubber on there and the feedback from tyou MINI owners if just confirming my suspicious.

I would say though that on the Mog the ride is fine= and the grip is prodigious anyway. Even more grip can't hurt, but I'm looking for a tyre with a progressive behaviour at the limit - these are a bit snappy IMHO.

Thing some cut slicks will be the way forward. (like the ones fitted to the lotus 340R etc)....

[mini_ralf]

These tyres came highly recommended to me.. Although I've only done about 200 miles on them so far I have been quite impressed.

www.federaltyres.com/ They can be bought in the UK from www.camskill.co.uk/products.php?plid=m4b0s0p0

[bosshog]

r988 said:

LuS1fer said:

In EVO this month, I recall reading that dumping runflats saved 1kg of unsprung weight at each corner on some car or other.

How much weight does a spare tyre add? or do you carry around one of those cans of foam and hope

I think you missing the point - its unsprung weight. Very different to just weight/number of burgers you've just eaten..

[Fat Audi 80]

Anybody had a puncture in a run flat?? Are they worth it???

Seem a bit of an uneccesary compromise to me. Worse handling ALL the time. Will help you avoid a blowout or all you to drive to a garage in the rare event that you get a bad puncture. You will still pay twice a much to replace it anyway.... :scratch:

[mr_tony]

I think the key with a runflat is that the tyre won't 'shred'.
Spoke with my mechanic this am, he'd been driving a Bimmer on track when he clipped a curb and literally ripped a tennis ball sized chunk out of the sidewall, tyre stayed together, and was still completely drivable! He filled it up with foam as best he could and drove it to a garage...

The unsprung weight saving would be considerable for me with 18" wheels I figure, and on a car as light as the Aero that could actually make a significant difference to the handling...

[Raify]

Fat Audi 80 said:

Anybody had a puncture in a run flat??

Fat Audi 80 said:

Are they worth it???

No

Fat Audi 80 said:

Seem a bit of an uneccesary compromise to me. Worse handling ALL the time. Will help you avoid a blowout or all you to drive to a garage in the rare event that you get a bad puncture. You will still pay twice a much to replace it anyway.... :scratch:

Exactly, you gain nothing:

1. Blowout
Runflat - you're screwed. No amount of sidewall re-enforcement will help you. And you have no spare / gunk
Normal + gunk - you're screwed. Gunk will just drain out.
Normal + spare - Hurrah!

2. Nail / bolt embedded in tyre
Runflat - Screwed. No garages will fix them (although it's technically possible). Only option is to replace
Normal. Might not even need gunk to get to garage. £15 to repair (providing it's not near edge). If it's a replacement, the cost is nearly 40-50% less than runflats.

3. Non-catastrophic puncture
Runflat - You can drive to the garage without even getting your hands dirty. Hurrah! Replace at inflated (sorry) prices. Boo!
Normal + gunk - Fill tyre, go to garage. Replace at normal prices
Normal + spare - Fit spare, Sort puncture at your leisure.

I've never experienced so many punctures as when I had runflats on the MINI. They attract nails like magnets.

[baSkey]

i still have mine (MCS) cos i am not about to waste tyres just for the sake of it!

in my experience i don't have especially poor wet weather grip but the traction seems to go out of the window..! in a way it helped me cos (i have the LSD) it was pulling all over the shop in the greasy wet roads of february and it led me to the garage where i discovered my geometry was out. improving the geometry lessened the effect but nonetheless tyre traction was below par for the level of other 'mechanical' traction.

[F355SPIDER]

my run flats are a bloomin nuisance in the warm weather - it mucks about with the sensor and tells me i have a flat when i havent - but then how do you know because its a run flat Twice its said it was flat and it wasnt - thank god the tyre centre was trustworthy.

[djfaulkner]

Question about run flat tyres.....

If for example - Someone had nicked the car and the police used the stinger.
Could they just keep on running?

[cjm]

I would have thought with the Aero it would be worth giving the factory a call and seeing what other tyres they have tried and what sort of effect they have?

Colin

[LuS1fer]

Chevrolet put the 2001-2004 C5 Z06 on Goodyear Supercar tyres where the rest of the Corvettes ran on run-flats. Switching to ordinary tyres vastly improves the car. Interestingly, given the very good reviews of the handling of the C6 Z06 which DOES run on run-flats, I for one would like to see one run on normal tyres as it would be even better.

[Fat Audi 80]

Raify said:

Fat Audi 80 said:

Anybody had a puncture in a run flat??

Fat Audi 80 said:

Are they worth it???

No

Fat Audi 80 said:

Seem a bit of an uneccesary compromise to me. Worse handling ALL the time. Will help you avoid a blowout or all you to drive to a garage in the rare event that you get a bad puncture. You will still pay twice a much to replace it anyway.... :scratch:

Exactly, you gain nothing:

1. Blowout
Runflat - you're screwed. No amount of sidewall re-enforcement will help you. And you have no spare / gunk
Normal + gunk - you're screwed. Gunk will just drain out.
Normal + spare - Hurrah!

2. Nail / bolt embedded in tyre
Runflat - Screwed. No garages will fix them (although it's technically possible). Only option is to replace
Normal. Might not even need gunk to get to garage. £15 to repair (providing it's not near edge). If it's a replacement, the cost is nearly 40-50% less than runflats.

3. Non-catastrophic puncture
Runflat - You can drive to the garage without even getting your hands dirty. Hurrah! Replace at inflated (sorry) prices. Boo!
Normal + gunk - Fill tyre, go to garage. Replace at normal prices
Normal + spare - Fit spare, Sort puncture at your leisure.

I've never experienced so many punctures as when I had runflats on the MINI. They attract nails like magnets.

Thought so!

Cheers,

Steve