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jonoe30

Best Run Flats

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My little brother needs to replace the RFTs on his E91 Motorsport (staggered 17" alloys). I can see threads from a few years ago saying that Pirelli's were probably the best bet.

Just thought I'd recheck and see if people are still fitting these or if there are newer versions out and opinion has changed.

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I would not buy RFTs to replace. 

I haven't driven the Pirelli's but at least they sound better that the Potenza.

The Potenza perform pretty well, but the wear rating is very low and the ride is so hard/harsh. 

You can get way better tyres that will last longer, perform better and ride nicer, for cheaper than RFT.

 

 

 

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Yeah I know the arguments against getting them, and if it were me I wouldn't keep them, but to be honest in the nicest possible way he's not the kind of person who's going to fiddle around with a goo pumping solution ("M Mobility" style) on the side of the road, or carry a spare in his boot (I thought we might have been able to fit a space saver in the cavity under the boot, but it's way to small), so have decided to continue down the RFT path.

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Tire Rack won't ship Pirelli to NZ so your options may be limited. 

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I am noticing a few times now with this wet weather at 50km/h speeds that I am getting the DTC warning light flashing a few times per day with driving on wet roads.  I don't really feel confident driving them in the wet because of that, so am considering changing my tyres well before the tread depth requirement.

They may still have the original tyres that they were important with from Japan, so I am not sure the age and tyre rubber can 'age' I believe, so having new tyres with more grip might better sooner rather than later.

I still want to go with RFT anyhow, so I have read some reviews and Pirelli or Bridgestone mat be the better option.  And leaning towards Bridgestone as they seem to be more readily available.

http://www.bridgestonetyrecentre.co.nz/tyre/t290/Passenger/

Online reviews seem to indicate that they are quite a poor option.

The Pirelli's seem harder to get ?

Requested a quote from - http://www.tyrepower.co.nz/

 

 

 

 

 

Edited by KiwiTT

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I had Bridgestone RE050 RFT's on my old E60 and while the stiff sidewalls did nothing for ride comfort the car was very composed at speed. 

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Best run flats. Sounds like an oxymoron! 

Just tell him to get decent tyres, and have a spare.

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I forgot to follow up with the outcome... he ended up getting Pirelli P Zero run flats to replace the OEM Bridgestones (which may have been the originals or second set, they were overdue for replacement wear wise)... was about $1650 all up including alignment which I thought was very reasonable (225 front and 265 rear fitment I think).

I've been borrowing the car since December and have done around 5000km on them... they are much more forgiving, more like normal low profile tires, don't tramline like the Bridgestones did and in the recent downpours have been very compliant and not too prone to aquaplaning. Wear seems to be good so far.

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I have got a quote for Pirelli P Zero - BMW fit for the same price as above - $1650, but I can also get Bridgestone OEM RE0050A RFTs for $1247 (currently 4 tyres for the price of 3) special until 17 March.

Is it worth the extra $400?

 

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My car came with those Bridgestones and I thought they were awful. Terribly harsh, prone to tram lining, made my arms tired on long drives from all the steering effort needed on bumpy roads.

Grip in the wet was terrible. Wheelspin in 3rd gear on a stock 335i. On my Goodyear Eagls F1s I can only break traction in 1st in the dry and 2nd in the wet - but I have to try, it doesn't happen by accident. 

Maybe on a 325i or lower they would be acceptable for grip. Just not in 19-inch unless you like having your bones shaken.

Edited by Matth5

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Aren't the RE050s what they shipped with? Whatever it had on it I found them very harsh... unfortunately all tire/suspension opinions are very subjective... I usually drive an E30 with Toyos which have much bigger side walls so take my opinion with a grain of salt :) 

Edited by jonoe30

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26 minutes ago, Herbmiester said:

The Re050A has always had a good reputation.

I drove some on that 330i that I nearly purchased and thought them average (comparing against RE003 is maybe unfair?); today I drove some on an e60 (245/40R18) and found them good (grippy enough, stiff sidewalls)... on the UK tyre review website, they rate reasonably well.  My interpretation is "appreciated bordering on well regarded".   http://www.tyrereviews.co.uk/Tyre/Bridgestone/Potenza-RE050A.htm

HTH

Edited by Olaf

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I have driven several thousand km in rental Holden SV6s with the non-runflat version of the tyre and those were perfectly fine. Still not as grippy as the best, but comfortable and suited that car just fine. I think it's those stiff runflat sidewalls that make a major difference. 

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The other thing I have thought is from what I have read is that the suspension has been calibrated for the RFT stiffer sidewalls.

This is what I read also in the BMW 3 Series development book.

 

 

Suspension system designed for run-flat tires

Benefit

• Optimum riding comfort

The relatively stiff sidewalls and greater weight of run-flat tires call for specific suspension tuning. On vehicles where both regular and run-flat tires are offered, riding comfort may be somewhat compromised with the run-flats. Because the new 3 Series is engineered “from the ground up” for run-flat tires, its suspension is optimally calibrated for them.  This means that riding comfort is optimum; in other words, the new 3’s ride”

 

So I may notice other issues if I change from the OEM setup.

 

 

330i_Book.pdf

Edited by KiwiTT

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On ‎12‎/‎03‎/‎2017 at 5:18 PM, Michael. said:

Best run flats. Sounds like an oxymoron! 

Just tell him to get decent tyres, and have a spare.

True  it's a bit like asking what is the best junk food - runflats  are not a technical innovation  and do not improve the driving experience- they are just another aid to cover  ( driver / owner) incompetence.

P.S. if you want products from the U.S. from companies that don't ship here just use one of the numerous US based NZ shipping entities - we use mainfreight you generally get free internal shipping and then pay sensible international shipping costs not rip off American rates.

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I wouldn't worry about the suspension setup especially if you are changing from one type of run flat to the other. Plus all of BMW's marketing around RFTs was designed to sell the idea that they were for better performance and convenience and not that they were a cost saving and economy improving measure (which would have been the main drivers for the switch). I would hazard a guess and say the calibration for RFTs is relatively subtle... slightly different spring and damper rates, as people regularly switch to non-RFT's without issue.

Going back to your original post KiwiTT, what tires does the vehicle have on it now? Apart from the DTC warning activating (it's hard to say whether this is happening too often without driving with you, though at 50km/h I'd expect you'd have to be turning some very tight corners or braking very sharply on slippery surfaces to activate it) do you have any other issues with them?

Edited by jonoe30

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On ‎12‎/‎03‎/‎2017 at 2:18 PM, KiwiTT said:

I am noticing a few times now with this wet weather at 50km/h speeds that I am getting the DTC warning light flashing a few times per day with driving on wet roads.  I don't really feel confident driving them in the wet because of that, so am considering changing my tyres well before the tread depth requirement.

 

You can use a very simple rule  for tyre age:  0-4 years good to use on a road wheel 4-6 years  marginal on a road wheel - better as a spare,  post 6 years ditch them.

If you cannot verify the age by using the date code on the tyre  then go by the age of the vehicle and odometer reading. My NZ new 328 had 29,000km on the clock and the tyres were 6 years old ( very nice Contis in mint "looking condition" ) but they were past their use by date - spun easily in the wet (no DTC)

It sounds like yours are also past their use by date ?

P.S also check the wear figure  anything over 500 won't stick in the wet

100-250 is a sticky tyre

250-400 is a touring tyre

500 plus is something to stop the chassis dragging on the ground.

 

Edited by 3pedals
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14 minutes ago, 3pedals said:

You can use a very simple rule  for tyre age:  0-4 years good to use on a road wheel 4-6 years  marginal on a road wheel - better as a spare,  post 6 years ditch them.

Sage advice :)

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22 minutes ago, 3pedals said:

P.S also check the wear figure  anything over 500 won't stick in the wet

100-250 is a sticky tyre

250-400 is a touring tyre

500 plus is something to stop the chassis dragging on the ground.

 

FYI - according to Tire Rack the Bridgstones are 140 and the Pirelli's are 400
https://www.tirerack.com/tires/tires.jsp?tireMake=Pirelli&tireModel=P+Zero+Nero+All+Season+Run+Flat

https://www.tirerack.com/tires/tires.jsp?tireMake=Bridgestone&tireModel=Potenza+RE050A+RFT
 

Some additional info for those interested: https://en.wikipedia.org/wiki/Uniform_Tire_Quality_Grading

Edited by jonoe30

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Going back to the original question posed, what are the best run-flats, whilst I won't suggest a specific brand as a lot of the decision is down to personal taste and driving style, I would just emphasize the fact that the design(s) used in run-flats have been developed over the years and the latest "generation" of tyres are significantly better in regards to the problems most associate with run flats. I am not 100% on how things have changed, or if you can even still buy the older generations, but would suggest that your brother really only look at the latest generation IF they can be fitted on the E91. It's been a while since I drove and E91 but I can't remember the ride being overly harsh even with 19's and M-Sport suspension on the RFTs, and pretty sure they were Bridgstones.

Of the tyres coming from the factory now the Bridgestone is certainly the most widely fitted, but it is hard for me to tell the difference between those and the Contis.

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I have decided to go with the Bridgestone RE050A RFT as these are the ones that BMW specify, and as I have a 4 year Autosure warranty, and should I develop a suspension fault in those 4 years (the likely life of my tyres - I do about 7,500km a year), they won't have an 'out' because I have non-OEM tyres.

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The evolution of run flats has related more to the rim they fit on than the design of the case structure. Initially they could only be used on certain rims now run flats and non run flats are largely interchangeable on most rims.

They are now a bit lighter because they use smarter materials , but the core problem with a run flat is the fact that the case has to do the supporting work the air would have done so it has to be far more rigid. Having said that the current range of run flats have more tread base compliance to introduce some flex above the case and ease the ride quality.

So in answer to the original question - any of the latest technology run flats from a reputable manufacturer e.g. Bridgestone, Continental, Michelin or Pirelli

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Just out of curiosity I checked exactly which Bridgestones are on the current car, answer Potenza S001s. +++would recommend*

* - caveat, only if suitable for your application.

 

 

 

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4 hours ago, KiwiTT said:

I have decided to go with the Bridgestone RE050A RFT as these are the ones that BMW specify.

Interesting, I have never seen a BMW tyre specification include a brand / variety for anything other than the high- performance models, M cars and M140i / M240i, etc.

i can understand your view, those "mechanical insurance" policies look for any thing to avoid paying out.

 

 

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