[gembrain]

F31 335i currently with original staggered runflat setup, 18” wheels, and adaptive suspension. Time to replace and currently decided to go for the CrossClimate 2 as an all year round. They do the 225/45 18 in Runflat or non runflat. The 255/40 is only in non run flat.

All say that ride comfort is better with non runflat - but does that make it more bouncy? Current ride comfort with the 18s and adaptive is good. Some say that steering is better (more responsive) with the runflat?

So, do I go square with the runflat, or stay staggered with non?

Any thoughts and specific experiences much appreciated

Thanks

[danb1979]

Which 18" wheels do you have?

I run 18" 405Ms for summers, Style 397s for winters with 235/45/18s all round - Goodyear Assym 6s summers, Goodyear Vector Gen3 all seasons for winters. Alloys are 18x8 all round

I also run CC2s on my 130i staggered fitment as Ive staggered wheels

If your 18s are the same size all round; get the same sized tyres all round

You could go 235/45 or 245/40 18s

[MarsKy]

See my post:
https://f30.bimmerpost.com/forums/sh...&postcount=120

I don't find the CC2s bouncy and handling around bends is sharp and not wallowy. Still to try them in summer though.

[ian332isport]

I have 18" runflat CC2s on my winter wheels. I also have adaptive suspension. No complaints at all.

They were still on the car for the early part of the summer and were just as good in the warmer weather. I'll be fitting them back on the car in the next week or so.

[davethefish]

always had 18" non runflats on my E90, and went back to 19" non runflats on my F30.
Ride is night and day.
but you will always have some, that for whatever reason, prefer RFT.
I just don't get it though....
I've always preffered a staggered set though.

[ian332isport]

Originally Posted by davethefish

you will always have some, that for whatever reason, prefer RFT..

RFT tyres have improved massively over the first generation fitted to the e9x cars. Even over the life of the f3x they've improved a lot. BMW didn't help the situation by fitting Bridgestone S001 RFTs as original equipment. Horrible nasty things.

I've got 19" PS4 RFTs on my summer wheels and 18" RFT CC2s on my winters. No issues with either. That said, I stick with RFT tyres for convenience. Being able to drive off the motorway on a cold wet night is worth more to me than any marginal improvement in comfort. I appreciate that RFTs won't get you out of every situation, but the odds are on your side.

I think the adaptive shocks do help with comfort though. I find is surprisingly compliant in 'comfort' mode. Certainly softer than non adaptive sport suspension.

[TurboWeasel]

I use the PS4 runflat as well (18") and "for whatever reason" I just prefer them to non-runflats. Better steering and better cornering on the limit. It's just basic physics. Stiff sidewalls improve cornering feel and don't roll over on the rim so much when pushed, which is exactly the same reason why a sports non runflat tyre handles better than a crappy ditch finder non runflat.

As you say, the Michelin runflats are no where near as harsh as the shitty OE * Bridgestones and Pirellis.

[gembrain]

Originally Posted by MarsKy

See my post:
https://f30.bimmerpost.com/forums/sh...&postcount=120

I don't find the CC2s bouncy and handling around bends is sharp and not wallowy. Still to try them in summer though.

Thanks Marsky - very useful 😀

[sunnys1ngh]

I ran the Goodyear asy 2 RFT for a while and they were perfect. Think people base their opinions on the dreadful s001 from factory. Using other brands are fine tbh

[davethefish]

I can understand that for safety reasons runflats have an advantage.
But ime you are more likely to breakdown and be unable to get off a motorway, than get a puncture so severe you can't carry on driving and exit.

But then i've always wondered why M3 and M4 would come non runflats, if runflats are better for performance?

[Ennoch]

Originally Posted by davethefish

I can understand that for safety reasons runflats have an advantage.
But ime you are more likely to breakdown and be unable to get off a motorway, than get a puncture so severe you can't carry on driving and exit.

But then i've always wondered why M3 and M4 would come non runflats, if runflats are better for performance?

Depends where you live and where you regularly drive I'd say. No spare wheel in a car is a trend that needs to die as far as I'm concerned, it's an utterly stupid response to saving weight and marginally increasing boot space by, in the main, leaving a void under the boot floor that is impossible to access if you actually have anything in your boot. I'm not a great fan of the ride of RFT's, the way they feel to steer, or the lack of subtlety on greasy/low traction roads. But sadly I don't really have the choice as I'm not driving everywhere with a spare wheel taking up most of the boot space as the car is on the verge of being too small as it is, and I'm not being stuck at the side of the road with a blown tyre given where and when I do most of my driving. I'd suggest that the M6 and M25 have less potholes in total than just a few miles of the A9 north of Perth, or indeed many other rural roads.

Stiff side walled tyres need softer rubber to create the same amount of grip as you actually need tread movement to turn and brake. Track tyres like AD08's etc have very stiff sidewalls but very soft tread (even on the road I killed a set of ultra soft R888's in less than 2k miles) but for a road tyre sold to the masses you need harder rubber so they last a reasonable length of time. I've found winter run flats to be better predominantly I suspect because of the softer rubber that's generally used. A performance tyre isn't just about ultimate traction but feel and balance, and that's where non-RFT's have the advantage, as it's much easier to tune them without the premise that the sidewalls need to be drivable with no air in them for a decent period of time.

[davethefish]

I agree with that, wish i had the space in the boot under the mat to put my space saver.

But I do carry a space saver + scissor jack and brace, as i very rarely carry anything in the boot.

[cramsnik]

Sorry to jump on the thread but I wonder if I can get some thoughts on my conundrum?

I have a 340d x drive, currently with RF Bridgestone Potenza on the front at ~6.5mm and Turanza on the rear at ~3.5mm and I'm concerned that the difference is going to have an adverse effect on the transfer case, so I'm looking to replace the rears. Ideally I need to stay on RF, however I'm not too keen on replacing the Turanza like for like as the general consensus seems to be that they wear quickly.

If I wanted to change the rears to another brand of RF and keep the Potenza on the front am I asking for trouble? I'm thinking something along the line of Goodyear Eagle F1 Asymmetric 3 which are available * marked etc?

TIA

[Alscoob]

Originally Posted by cramsnik

Sorry to jump on the thread but I wonder if I can get some thoughts on my conundrum?

I have a 340d x drive, currently with RF Bridgestone Potenza on the front at ~6.5mm and Turanza on the rear at ~3.5mm and I'm concerned that the difference is going to have an adverse effect on the transfer case, so I'm looking to replace the rears. Ideally I need to stay on RF, however I'm not too keen on replacing the Turanza like for like as the general consensus seems to be that they wear quickly.

If I wanted to change the rears to another brand of RF and keep the Potenza on the front am I asking for trouble? I'm thinking something along the line of Goodyear Eagle F1 Asymmetric 3 which are available * marked etc?

TIA

Think you might have trouble, as different manufacturers will have different sizes, although within the same tollerance gaps the B/stones could be at one end of the scale and G/year at the other, therefore the % ratio allowed front to rear could be well out, although the sizes stampted on the walls are correct.

I would always stick with the same manufacturer / tyre type front and rear. So repace rears with same and next time round you just replace all 4 for tyre of your preference.

I had a similar situation RFT all round 6mm on all, 2 rear ones were mis-shapen so considered all options in the end replace the rears for same even though I dislike tye tyres and would go to non run flat and a different manufacturer, it served the purpose for the time. I now have a matched set of RFT with 6mm (still) fronts and rears on 6.5mm, so I have an option to sell a full set which someone my be looking for to offset the cost of some new rubber that is more to my liking, without the possible issue of transfer case issues.

[cramsnik]

Originally Posted by Alscoob

Think you might have trouble, as different manufacturers will have different sizes, although within the same tollerance gaps the B/stones could be at one end of the scale and G/year at the other, therefore the % ratio allowed front to rear could be well out, although the sizes stampted on the walls are correct.

I would always stick with the same manufacturer / tyre type front and rear. So repace rears with same and next time round you just replace all 4 for tyre of your preference.

I had a similar situation RFT all round 6mm on all, 2 rear ones were mis-shapen so considered all options in the end replace the rears for same even though I dislike tye tyres and would go to non run flat and a different manufacturer it served the purpose for the time. I now have a matched set of RFT with 6mm (still) fronts and rears on 6.5mm, so I have an option to sell a full set which someone my be looking for to offset the cost of some new rubber that is more to my liking, without the possible issue of transfer case issues.

Thanks for this, pretty much confirmed what I assumed. The car has 30k miles on the clock and recon the fronts were changed to get it through its recent MOT before going up for sale as an approved used. Shame that the rears, although at 3.5m, are well within the legal limit.

[cramsnik]

I asked about this on another forum and was pointed in the direction of this text, taken from the BMW TIS, apparently it's a few years old now...

[Ennoch]

Originally Posted by cramsnik

Sorry to jump on the thread but I wonder if I can get some thoughts on my conundrum?

I have a 340d x drive, currently with RF Bridgestone Potenza on the front at ~6.5mm and Turanza on the rear at ~3.5mm and I'm concerned that the difference is going to have an adverse effect on the transfer case, so I'm looking to replace the rears. Ideally I need to stay on RF, however I'm not too keen on replacing the Turanza like for like as the general consensus seems to be that they wear quickly.

If I wanted to change the rears to another brand of RF and keep the Potenza on the front am I asking for trouble? I'm thinking something along the line of Goodyear Eagle F1 Asymmetric 3 which are available * marked etc?

TIA

If you go * marked GY on the back then they'll be fine with the Bridgestone's on the front if they're also * marked as the BMW rating means they conform to BMW specs which are very specific, rather than a slightly vague gentlemans agreement as others are in normal spec sizing (Pirelli for instance come up noticeably narrower than Michelin like for like). Also, sticking new rears on with the older ones is a lot better than the other way round as oversized rears apparently have less impact on the transfer box than if the same difference in circumference existed with new ones on the front. You can also get * marked Pirelli PZ4 in RFT. I don't rate them at all but they're marginally better than the S001's. I can't say where they sit relative to the GY's though as I've not run them.

[TurboWeasel]

Originally Posted by davethefish

I can understand that for safety reasons runflats have an advantage.
But ime you are more likely to breakdown and be unable to get off a motorway, than get a puncture so severe you can't carry on driving and exit.

But then i've always wondered why M3 and M4 would come non runflats, if runflats are better for performance?

A busted tyre is a busted tyre whichever type you have.

I assume a runflat has to be binned anyway after making it to your destination, so you're in for a new tyre regardless. I don't think they can sustain running in 'flat' mode for many miles either? 50 or so max is it? At no more than 50mph or less? Can't remember the guidelines.

Horses for courses really. I had no issue carrying a can of goo when running non runflats, but call me crazy, I just prefer the feel of runflats. I'm not bothered about what they do when they go flat tbh!

Runflats are more for average Joes and a way for BMW to save money by not including spare wheels and widow maker jacks.

M division are way more focused with tyres on the M cars compared to the bread and butter cars, and are often made specifically for them. So it's a different kettle of fish with the Ms from tyres, to dampers to body bracing. All substantially different to the non Ms.

[goram]

Last week, I had a puncture on a dual carriageway. There was no hard shoulder, and it would've been bloody dangerous to try and change a wheel there, so I was really grateful for the RFTs, meaning I got home in one piece.

I had been planning on ditching the RFTs purely on the larger range of non RFTs available, but in the end I put on 4 Goodyear AS3 RFTs for £710, fitted by my local F1 Autocentre (young lads, and petrolheads so trustworthy).

The RFT v non RFT discussion will go on forever, but if anyone is thinking of putting these on their staggered 19"s, I'm really impressed with the GYs. It drives like a different car completely (although tbf I did have ditchfinders on the front). I've covered about 600 miles now, and in all aspects they are spot on.

[TurboWeasel]

Runflats like a lot of other things have improved over the years, so glad you found one that works for you.

What's it like driving with a flat runflat? Not experienced it yet, and hope not to either!

[goram]

Originally Posted by TurboWeasel

Runflats like a lot of other things have improved over the years, so glad you found one that works for you.

What's it like driving with a flat runflat? Not experienced it yet, and hope not to either!

A bit like walking with a clog on one foot!

TBH, not too bad though, didn't once feel as if the tyre was going to shred....

[Ruskie27]

I have gone from Michelin PS4 back to Pirelli RFT. Reason being I very rarely push the tyres anywhere near the limit or drive erratically so I was disappointed with 15k from all 4. Also the roads are in a shocking state and I couldn’t shake the feeling of needing recovery if I was far from home. Not noticed any significant difference so far.