[seenthelight!]

hi all, have a 2017 435d xdrive, and new owner, so apologies for the (maybe) daft question.
it has the standard run flats on, and when it comes to replacing them, do i have to do all 4 at once ? if yes, why ?
never had run flats before, and always replaced worn tyres as an axle pair (once replaced just one, but that was due to an irrepairable puncture, and the opposite one was hardly worn).
most of you guys seem to agree to replacing the runflats asap, but why, when the car comes with them as std ?
i can see the benefits of runflats, but with all the negative hype, there must be outweighing negatives.
so, over to you guys.
btw, seems a great forum, with a fair bit of knowledge offered by members

[teaston]

Replace them in pairs, either with rft’s or non rft’s, but preferably non rft’s.

[A15X]

I’ve just ditched the Runflats this morning for a full set of MPS4s on my 430d vert and must say it rides so much better! Very happy with my purchase

[Alscoob]

I've ditched the run flats and on Goodyear Assy 3's much better.

S drive replace by axle in pairs as above

But are you x drive being 435d ? that makes a difference as there is a limit on tread depth variation front to rear so you don't wind up the centre diff.

To answer your question, non runflats give a much better ride, are quieter and depending on the type, better grip in wet & dry. Runflats are just so hard and bang and crash around.

[Jeff123]

Non runflats are also much cheaper.

[lethbridge]

Originally Posted by seenthelight!

hi all, have a 2017 435d xdrive, and new owner, so apologies for the (maybe) daft question.
it has the standard run flats on, and when it comes to replacing them, do i have to do all 4 at once ? if yes, why ?
never had run flats before, and always replaced worn tyres as an axle pair (once replaced just one, but that was due to an irrepairable puncture, and the opposite one was hardly worn).
most of you guys seem to agree to replacing the runflats asap, but why, when the car comes with them as std ?
i can see the benefits of runflats, but with all the negative hype, there must be outweighing negatives.
so, over to you guys.
btw, seems a great forum, with a fair bit of knowledge offered by members

I'd say only change out of run flats if they aren't working for you - I always kept mine and was quite happy with them. If you keep to rfts then just change tyres as you would normally - ideally in pairs as you say. If you change off of rfts you would probably be best to do the set though I doubt it would matter too much as the squishier non-rfts would probably be offset by the part worn rfts on the other axle. Just need to aim to keep rolling circumference similar to avoid stressing the transfer box - my view is it will be designed to at least cope with fully worn on one axle and new on another or there would be forever reports of xfer box failures - they appear to be rare...

[Richard52]

RFT - the devil's tyre

[Alice Coupe]

Originally Posted by Jeff123

Non runflats are also much cheaper.

That’s not necessarily so.
Michelin non run flats are expensive, you can get Goodyear RFTs cheaper. However, Bridgestone are more expensive.

Guess it depends on sizes too.

[cfm56d7b]

My experience with run flat tires ranges from "when can I replace these" - Bridgestone Potenza S001 to "these are much better" - Pirelli P Zero.

Run flat tires are very convenient but tend to become noisier as the tread wears down.

I actually like Pirelli P Zero and a slight road noise is acceptable.

Michelin Pilot Super Sport tires are simply great tires, ignoring the non run flat design.

[Jonesy72]

Originally Posted by seenthelight!

hi all, have a 2017 435d xdrive, and new owner, so apologies for the (maybe) daft question.
it has the standard run flats on, and when it comes to replacing them, do i have to do all 4 at once ? if yes, why ?
never had run flats before, and always replaced worn tyres as an axle pair (once replaced just one, but that was due to an irrepairable puncture, and the opposite one was hardly worn).
most of you guys seem to agree to replacing the runflats asap, but why, when the car comes with them as std ?
i can see the benefits of runflats, but with all the negative hype, there must be outweighing negatives.
so, over to you guys.
btw, seems a great forum, with a fair bit of knowledge offered by members

if you change to non runflats you will have to change all 4 at the same time

[Jeff123]

You just need to keep each axle the same and can change two at once.

[TouringPleb]

Originally Posted by teaston

Replace them in pairs, either with rft's or non rft's, but preferably non rft's.

Why have they got to be replaced in pairs?

[teaston]

Originally Posted by TouringPleb

Why have they got to be replaced in pairs?

They don't, you could replace all 4 but no point if one of the pairs still has plenty of tread.

[madlad2000]

Personally, and the cheapest option is to just replace any tyre with its oem replacement.

The 435dx MSport doesn't have sport suspension, and one way of firming things up is getting the OEM runflats. It works out cheaper.

If everything has to be right, as a minimum you need ACS springs to make it closer to M Sport handling, which is pretty cheap, and then ditch / sell all runflats and go for non RFs... 6 months ago the best was michellin MPS4. I'd like to say the ride is superior in every way, however if you have SE suspension, rigid runflats may be ok, literally 'dampening' the floaty SE suspension.


BMW went through a short phase in their introduction and company improvement of runflats. When they came as standard with my 320i coupe a year before the 4 series, they were not fit for purpose. Many countries had lawsuits or recalls. In the UK they pretended it was an unusual surprise to hear your 5th allow wheel cracking in 6 months, whilst you heard the person on the adjacent seat saying the same thing. To find an uncracked allow and runflat from that time gap that hasn't bee refurbished costs more than the original.

Also, don't forget, for tye tred, its the inner tread length. BMWs are well known for totally wearing out the sides.Tracking is beneficia, an dif xdrive worth the extra to get done at bmw

[Skwirrel]

Switching from the original run flats to good quality std tyres is not just about the ride, there is significantly more grip on offer with Michelin PS4 or Super Sport tyres (other good brands are available too) verses the Bridgestone OEM fit tyres in wet or damp conditions, and significantly more subjective feel in the dry. Such is the difference in the snow and ice, the car wouldn't move off the drive on run flats but coped surprisingly well on performance "summer" tyres.

In twenty years of driving and 500k miles I have had 2 or 3 slow punctures so I'll take the perceived extra risk and higher tyre wear from a performance tyre for greater driving pleasure and a massively better ride quality. The Bridgestone run flat tyres are without doubt the worst performing tyres I have ever experienced with very poor grip in typical UK September to March conditions. The second worst tyres were some OEM Bridgestone fitted to our Fiesta ST. It was border line dangerous in the wet with massive tram lining and torque steer, the car was transformed with some decent Michelin fitted.

I've also used Goodyear Eagle F1 on several cars and been very happy with them. Usually a good chunk cheaper than Michelin equivalents, I would fit them to my car if they did a matching set as the fronts would be AS2 and the rear AS3 whilst the phase out one and introduce the new spec tyre in all sizes.

[Rhino at Work]

Would BMW Assist come out to you if you've ditched the run flats? Or maybe they'd come and then present you with a bill once they worked out what the situation was. Has anyone on non rfts ever had to call them out?

[jcdub]

BMW offer a non flat option when a new car is ordered. So I doubt they present you with a bill...

[doncarlyon]

Originally Posted by jcdub

BMW offer a non flat option when a new car is ordered. So I doubt they present you with a bill...

I'd hope non flat is the only option haha

[pcp1234]

- xdrive requires same thread for all tyres
- best switch to non run flat, i cant see point of having them; mine and will go non runflat once I need to change tyres

[4WDriver]

Originally Posted by pcp1234

- xdrive requires same thread for all tyres

How can that be true when front and rear are different tyre sizes?