Are Run flat tyres really that uncomfortable?

[KwS 2425]

The 16s on my Mini are the first set of RFTs i have ever had, all my previous cars, BMWs included, have had any RFT swapped for normal tyres. TBH, with all the hype around how harsh RFTs ride, having just driven 800km across the country in the car, It rides no differently to any other car with similar size tyres. The bigger sidewall likely makes a difference, I can imagine a stiff sidewall RFT on 18s or 19s could be quite harsh, but Im still not convinced that they are the devil like the internet tries to tell me.

[NZ BMW 368]

So if you get a gash in the sidewall of a run-flat can you keep going?

I have gone the conventional tyre route with a kit of goo and a compressor (which I don’t even know works). I must admit when I went down to the west coast a couple of years ago and saw no cell reception in a few places I got a bit nervous... 

[kiwi535 538]

I beleive you can drive on an rft that is absolutely flat.That is the idea of them.You can drive for up to 80 km

 

[KwS 2425]

The owners manual for my Mini states you can drive up to 250km at a max of 80kph if you have 1 or 2 people and no luggage in the car. It drops to 50km with a full car load of people. Thats with the tyre at 0psi.

[M3AN 4016]

2 hours ago, NZ BMW said:

So if you get a gash in the sidewall of a run-flat can you keep going?

Good question, it might be too easy to say "yes" to this, run-flats depend on the integrity of the sidewall after all.

The only puncture I've had in the last 20 years is a sidewall gash. And on a brand new tyre! ?

[NZ BMW 368]

5 hours ago, M3AN said:

Good question, it might be too easy to say "yes" to this, run-flats depend on the integrity of the sidewall after all.

The only puncture I've had in the last 20 years is a sidewall gash. And on a brand new tyre! ?

Exactly, I notice the comments above all saying “yes” but I am not convinced that if the sidewall is compromised you can drive on them safely.

It appears you can in some circumstances but I don’t know how confident I would be in some tyres and in certain types of damage:

https://www.boston.com/cars/car-guides/2018/07/30/can-i-still-drive-with-a-damaged-run-flat-tire

https://f30.bimmerpost.com/forums/showthread.php?t=1398649

[E30 325i Rag-Top 2960]

I would have thought it would be well nigh impossible to get a gash in the side of a run-flat as they are bloody solid through their design.

Chopping and changing cars often I have driven on a variety of ultra-low profile high performance (Pirelli / PSS4) and similar run flat (Bridgestione, Continental) tyres a number of times, over some pretty awful road surfaces - SH2, SH27, SH5, etc. Whilst I have never done a full-on back-to-back test with different tyres on exactly the same car, I would suggest that they are comparable enough to draw some viewpoints...

For road-noise, the noisiest tyres would have to be the PSS4 on the M3. Noticeably louder than the run-flats, especially on the coarse-chip stuff that apparently passes as an acceptable road-surface these days. Even with the louder exhaust and engine note the tyres were almost to the point of being a nuisance, especially on a long drive where long sections were on the coarse chip.

In terms of the ride quality, very little to choose between them to be honest. Trying to make a correction between the "comfort" M setting and the "Comfort" M Sport settings, it would have to be pretty close. The fact that the wheels would be 19s or 20s with very narrow side walls would be a big reason for that, with such little effective sidewall to make a difference in the overall movement of the whole suspension system. However, I briefly drove a 3-Series on non-RFT 18s the other week and it wasn't immediately obvious to me what tyres it was running, only the mobility kit in the boot notified me of the difference. Admittedly this was only pootling around town on the daily commute and errands and no spirited drive around the back roads was involved.

Handling and performance, to be honest I have run out of ability and bravery well before any of the tyres have run out of grip or started protesting too much and this is in a variety of weather conditions and temperatures. Whilst I possibly don't drive as fast as some on the public roads, the tyres do get a fairly reasonable work out on the twisty bits of SH5.

So overall, hmm, yes, there probably a difference between the two types. Is it as bad as people say? To my not overly sensitive arse-ometer, probably not. Like all tyres, there are some runflats that are better than others. If it were my choice of tyres, would I go for RFT, yes I would primarily due to the amount of open road and longer distance driving I do and the increased peace of mind. These factors change for all of us, so the answer probably also changes as to what is "best" for us.

[325_driver 422]

On 7/2/2020 at 4:19 PM, E30 325i Rag-Top said:

For road-noise, the noisiest tyres would have to be the PSS4 on the M3

Big thanks right there ^ you've essentially answered my question, I've driven on Pilot sport 4's before in the 225/40/18's and did think they were also noisey, so I wondered just how bad could run flats be.

I think i'm going to use RFTs on the e90, they will obviously be noisy'er, but they can't be that bad