Run Flat Tyres ... Yes or No
Run Flat Tyres ... Yes or No
Author
Discussion

warrenosment

Original Poster:

9 posts

181 months

Sunday 23rd September 2012
quotequote all
I'm interested in the pros and cons in general, but specifically for a BMW M135i as I'm confused:

> I understand the car was developed with some specific tyres in mind...what were they, RF or not?
> WHATCAR? says "Just as crucially, though, a lowered ride height, specially selected springs and dampers, and the M division's insistence on fitting high-grip, non-run-flat tyres means you can place the car on the road with supreme accuracy"
> RF's are a £0 cost option...ominous
> what are the standard factory fitted Brand of RF and 'normal' tyres?
> if I buy RF and dislike them can I change to normal tyres...or are the wheel rims and/or suspension setting s different in some way(s)?
> what do BMW and knowledgable drivers recommend? what are the differences

All inputs will be read with interest. Thx

Drek

609 posts

194 months

Sunday 23rd September 2012
quotequote all
Mate, there's stloads of threads about RFTs on this forum and others. Might be worth your while acquainting yourself with Google, you may well find the answers you're looking for.

islander

371 posts

275 months

Sunday 23rd September 2012
quotequote all
Run flats on a 5 series M sport will add 3p a mile to your running costs!

Monty Python

4,813 posts

226 months

Sunday 23rd September 2012
quotequote all
islander said:
Run flats on a 5 series M sport will add 3p a mile to your running costs!
How do you work that one out?

davepoth

29,395 posts

228 months

Sunday 23rd September 2012
quotequote all
Monty Python said:
How do you work that one out?
I'm guessing a combination of the higher cost per mile of the run-flat itself (they're pricier than a normal tyre and they last the same number of miles), and possibly an increase in fuel consumption; I don't know about the fuel consumption.

Storer

5,024 posts

244 months

Sunday 23rd September 2012
quotequote all
They are also crap in the winter with no grip on snow and ice unless you get the winter tyres as well.

gaz1234

5,233 posts

248 months

Sunday 23rd September 2012
quotequote all
according to most petrol heads they are crap, but i have them and not bad. would rather lose a bit of high end grip than having a blow out at 120+ with non-run flats

sodslaw

189 posts

168 months

Sunday 23rd September 2012
quotequote all
gaz1234 said:
according to most petrol heads they are crap, but i have them and not bad. would rather lose a bit of high end grip than having a blow out at 120+ with non-run flats
'not bad' and cost more offset how much better they would be in case of a blowout for me

matthias73

2,901 posts

179 months

Sunday 23rd September 2012
quotequote all
sodslaw said:
gaz1234 said:
according to most petrol heads they are crap, but i have them and not bad. would rather lose a bit of high end grip than having a blow out at 120+ with non-run flats
'not bad' and cost more offset how much better they would be in case of a blowout for me
Do all tyres blow out at 120mph? Might have to invest in some run flats.

gaz1234

5,233 posts

248 months

Sunday 23rd September 2012
quotequote all
not as grippy as ps2 and contis for example. also a bit noisey.
but i think there was a gtr on fifth gear that had a blow out at 150mph...

Leins

10,441 posts

177 months

Sunday 23rd September 2012
quotequote all
sodslaw said:
'not bad' and cost more offset how much better they would be in case of a blowout for me
But they also have a tendency to "bubble" in the sidewall if you hit any potholes, well Potenzas did anyway. Never kept them on long enough afterwards to find out whether they would blow-out as a result (?)

Plus I'd also take the risk of a blow-out in a standard tyre, which incidently I had at 50mph earlier in the year, compared to the shocking grip levels of RFTs when they get cold

SLCZ3

1,293 posts

234 months

Monday 24th September 2012
quotequote all
A pal of mine who has a body repair shop, and does aluminium welding, tells me he has had alot of 3 and 5 series 19 inch wheels, with runflats, coming in for cracking appearing in the rims.

Edited by SLCZ3 on Monday 24th September 13:25

SLCZ3

1,293 posts

234 months

Monday 24th September 2012
quotequote all
A pal of mine who has a body repair shop, and does aluminimu welding, tells me he has had alot of 3 and 5 series 19 inch wheels, with runflats, coming in for cracking appearing in bthe rims.

Edited by SLCZ3 on Monday 24th September 13:39

Dave Hedgehog

16,331 posts

233 months

Monday 24th September 2012
quotequote all
we had a 3 series earlier in the year with them on, the ride was horrific, very crashy

scotty_d

6,795 posts

223 months

Monday 24th September 2012
quotequote all
I had them on our Mcs, harsh ride, Noisy, tram line badly , Expensive. those are the down sides.

Great if your other half has the car and can just drive it home or to the closest garage with out waiting for hours for rescue on her own. Handle pretty well with a stiff side wall. And that's about it for them.

I binned them and moved on to standard tyres and it is a much better car for it.

CO2000

3,177 posts

238 months

Monday 24th September 2012
quotequote all
scotty_d said:
I had them on our Mcs, harsh ride, Noisy, tram line badly , Expensive. those are the down sides.

Great if your other half has the car and can just drive it home or to the closest garage with out waiting for hours for rescue on her own. Handle pretty well with a stiff side wall. And that's about it for them.

I binned them and moved on to standard tyres and it is a much better car for it.
Same as above for me, just go with a normal tyre with stiff side walls or it will feel strange.

Ozzie Osmond

21,189 posts

275 months

Monday 24th September 2012
quotequote all
Storer said:
They are also crap in the winter with no grip on snow and ice.
In my experience of runflats that's not true. Grip is generally comparable with a conventional tyre. Why wouldn't it be?

Where runflats can fairly be criticised is for harsh ride (due to stiffer side-wall) although the most recent tyres are better than a decade ago. The same stiffness can also affect handling grip bumpy cornering.

Absolutely the last thing you want is runflat tyres in combination with a sports suspension set-up.

Sonic

4,008 posts

236 months

Monday 24th September 2012
quotequote all
My understanding is that the M135i is designed and tweaked to work without RF tyres.

I have RF as standard on my F20 125i, and to be honest they're no-way near as bad as i was expecting. I think they've made some improvements since the e87's.

That said, given the choice, and given that the M135i is designed to work without them, i wouldn't bother with RF and would go for standard.

larrylamb11

690 posts

280 months

Monday 24th September 2012
quotequote all
My experience of run-flats on a 1-series was an eye opener for me. We test drove an SE, then bought a Sport and the difference was staggering - the SE drove like a really nice normal car, the Sport was overly harsh and crashy. It tramlined really badly on the motorway and laid waste to the tyre tread at alarming speed - wearing the edges of the fronts and the centres out of the rears. I got so sick of the ride I actually ended up buying a set of smaller diameter wheels to increase the aspect ratio, which did improve the ride. I also found the expense of replacement tedious after a while. I found the ride with low profile run flats was so skittish that it didn't inspire enough confidence to push on, particularly with a passenger in the car. It put me off run-flats and particularly the ultra-stiff suspension manufacturers seem hell-bent on installing on modern 'sports' cars.
As for using normal tyres, thats fine 'til you get a puncture. The reality is even when my wife punched a flint right through the tread of one of the run-flats it still got her home - there was no way you could have done that with a can of tyre foam. That is the only advantage that I could see.

sodslaw

189 posts

168 months

Monday 24th September 2012
quotequote all
Leins said:
sodslaw said:
'not bad' and cost more offset how much better they would be in case of a blowout for me
But they also have a tendency to "bubble" in the sidewall if you hit any potholes, well Potenzas did anyway. Never kept them on long enough afterwards to find out whether they would blow-out as a result (?)

Plus I'd also take the risk of a blow-out in a standard tyre, which incidently I had at 50mph earlier in the year, compared to the shocking grip levels of RFTs when they get cold
I meant I would ditch the runflats ^ biggrin