Sponsored by The Tire Rack

[Rando]

The perfect set of 4 competitors would be:

Michelin Pilot Sport PS2 (non-RFT)
Michelin Pilot Sport PS2 (RFT)
Bridgestone Potenza RE050A (non-RFT)
Bridgestone Potenza RE050A (RFT)

Please do this so that all the BMW sport package people with the Bridgestones will have some guidance on whether to replace them or not!

Or, if someone can give some definite advice on various treadlife, handling, noise level, comfort, etc... characteristics of these tires, that info would be very useful.

So far the Potenzas I have are very comfortable, but I'm wary of them getting uncomfortable and noisy as they wear.

Thanks in advance for any guidance/advice/information.

[kdjohn72]

Bump....great idea....

[stressdoc]

+2

I suggest we mount a boycott until they do it...
j/k

[S4to335]

Originally Posted by stressdoc

+2

I suggest we mount a boycott until they do it...
j/k

Oh yeah...that small company called tirerack will be crushed to our knees.

[abc9475]

they did that test on a swedish car magazine....

http://www.automotorsport.se/biltest...617/061704.pdf


The RFT was not as good as BMW says in every point the regular one were better but the only positive thing was that in case of puncture its safer to have RFT

[poiney]

Originally Posted by abc9475

they did that test on a swedish car magazine....

http://www.automotorsport.se/biltest...617/061704.pdf


The RFT was not as good as BMW says in every point the regular one were better but the only positive thing was that in case of puncture its safer to have RFT

That looks generally true, but not in each category. Then again, I cant read a single word of this. Don't suppose there is a translation somewhere.

[S4to335]

Originally Posted by poiney

That looks generally true, but not in each category. Then again, I cant read a single word of this. Don't suppose there is a translation somewhere.

babblefish?

[spacedogg]

Neither Babelfish nor Google does translation from Swedish to English. This is the best I can get from another online translator:

Test of RFT - tire. With punkteringssäkra tire slippers husband reservhjul. But how good is RFT - tire , am comparing with usual tire? Nots versatile good , am exposing wart test!

Within däckindustrin has it brawl long , but now interacts the as if punkteringssäkra tire gotten a agile , common name RFT – Run Flat Tire , ors if husband so shall : ”tomkördäck”. That let autumn one fifth castor , as reserve , give several distributes. Including tool so is the a considerable viktbesparing as nots is so easily joke attain on second manner. But before all is the a securities for driver that defiance items kunna come home , ors to next shop istället for that compel halt and maybe become standings in expectation on help. Far away all am mastering of that exchange castor herself and sometimes had husband forgotten that collapse däcktrycket in reservhjulet and must anyway poll salvage. On minussidan able wes nots unexpectedly write up one upper price for they punkteringssäkra RFT-däcken. Calculate on circa 500 chronology extra pers tire. As RFT - tire must have a däcktrycksövervakning – otherwise able husband unavoidable wheel devoid däcktryck – so be added moreover costs for that sometimes exchange out sensor on rims. Batterilivslängden am spending match the tyre livslängd , except on sportdäck as able rip very fast. As bilägare am gaining husband thus in was growing safety and securities , but am defeating per bigwig driftkostnader. Find the multi aspects? Yes , really and the am going somewhat easily that test as both däcktyperna find in same dimension and performance. For that kunna wheel devoid lufttryck , but often nots fast than km h , had RFTdäcken a boost däcksida. The find second technic solution also , but rigid däcksida is usual. Here find wes most manifest disadvantage with RFT - the tyre and the is a deteriorate comfort. Especially lengthen ors borders in vägbanan feel appreciably evident with RFT - tire. But the rigid däcksidan contributing also to one stable and more förutsägbart behaviour in high speed , few better styrrespons wholly plainly On arid asphalt is the often badly that in övrigt feel any sämre characters with RFT-däcken. The allvarligaste contempt anti RFT - tire -a is yet their deteriorate våtegenskaper , am comparing with standarddäck. Bromssträckan deteriorate from km h with circa four metre for both Michelin and Bridgestones RFT - tire , am comparing with standarddäcken. Four metre is very in these coherence , the is differences among one toppdäck and one of they among the tyre in lower prisklass. On the våta handlingbanan stayed also terms sämre with RFT - the tyre but the most serious each that they were very more svårkörda than standarddäcken. Våtgreppet each appreciably sämre with RFT - the tyre but the stayed also a very more sudden transition from hold to ohejdat slip. Auto stayed accordingly more topmost and very bad that wheel at the frontier. Unaided of ESP - system is RFT - the tyre touch on trafikfarliga and they am claiming a very open-eyed driver. Ska husband then dissuade from RFT - tire? Nja , so drastic requires husband maybe nots product but in they case there the find a valmöjlighet so sheep husband attend to a rejäl muse on what as is important. In the future am arriving all multi bilmodeller that wholly be lacking in reservhjulsutrymmet and then must husband select RFT - tire. Tune ourselves then hope that development tagit prompt stride forth , for currently am delivering RFT - the tyre a good deal övrigt that desire.

Basically just looking at the diagrams and bar charts are more useful....

Dry Handling
Bridgestone RFT 1 minute 17.0 sec
Bridgestone 1 minute 19.4 sec
Michelin RFT 1 minute 17.4 sec
Michelin 1 minute 17.8 sec

Wet Handling
Bridgestone RFT 1 minute 49.3 sec
Bridgestone 1 minute 44.7 sec
Michelin RFT 1 minute 44.2 sec
Michelin 1 minute 42.5 sec

Dry Braking
Bridgestone RFT 36.7 meters
Bridgestone 37.9 meters
Michelin RFT 36.7 meters
Michelin 35.5 meters

Wet Handling
Bridgestone RFT 52.4 meters
Bridgestone 49.2 meters
Michelin RFT 54.3 meteres
Michelin 49.8 meters

I'm not swedish so excuse me as my translation may not be accurate.

[bnj]

I have seen this test before. What matters most to me is the dry handling. In summer the roads are dry most of the time. There might still be some people to whom it might be a bit of a surprise that Bridgestone RFT lap time is clearly (0.8s) faster than non-RFT PS2.

[Gary@TireRack]

A good idea and already in consideration.

However note the following :

There is no PS2 runflat in our market.

Our own testing cannot take street wear into account (we test over a period of days, not months).

Ride comfort changes between various tires (compared to each other) as they wear has not been significant. Noise levels *do* change, but again our tests can't do well in taking this into account due to the short testing period of time.

It is already well known that the runflat version or the 050A rides more stiffly than the non-runflat version.

That leaves 'handling' as the main reason for the test at this time, and it is already known that the extra weight runflat tires in general can result in longer lap times versus the non-rft tires. The 050A runflat is not very heavy relative to other tires in those sizes. At this point I doubt management would agree to spend many thousands of dollars in test tires, track time, and test drivers time to discover how many tenths of a second faster the non-rft tire is. I'm not saying that I wouldn't be interested to see the results (because I am!) but the cost versus amount of knowledged gained doesn't seem very convincing at this time.

[bnj]

Gary,
Your Swedish does not seem to be very good. However, being at the tire industry, it would not make any harm to understand some basics of which factors make a tire fast. One of the major factors is the tirewall stiffness. Just have a look at the graphs in the test and edit your post before people will read it. Credibility matters.

P.S. There is some useful info in tirerack.com. You will find out that the weights of RFT 050A and NON-RFT 050A are the same. I don't know how credible their info is, however.

[abc9475]

Test of RFT - tire. With punkteringssäkra tire slippers husband reservhjul. But how good is RFT - tire , am comparing with usual tire? Nots versatile good , am exposing wart test! LOL LOL

I will translate the first lines..

Test of RFT tyres. With Run flat tyres you dont need reserve tyre. But how good is RFT compared to regular tyres? Not good at all shows our test.

[spacedogg]

"slippers husband". Sigh. LOL.

[E90330iS]

Well in simple terms, I am sure the RE050A RFT is worse than RE050A in every aspect except the hazardous conditions and Michelin Pilot Sport PS2 does not offer RFT in the states so I am sure we have a better idea now..

[sdiver68]

Originally Posted by Gary@TireRack

I'm not saying that I wouldn't be interested to see the results (because I am!) but the cost versus amount of knowledged gained doesn't seem very convincing at this time.

Exactly what I've been saying the whole time, the 050A RFT is a good performance tire and every single objective test has shown it to be about equal to the beloved PS2 non-RFT in the dry.

Disagree? Prove it with an objective test.

[bnj]

Originally Posted by E90330iS

Well in simple terms, I am sure the RE050A RFT is worse than RE050A in every aspect except the hazardous conditions..

Sorry, you lost me. RE050A RFT is the fastest and best handling tire in the test in dry tarmac. So do you mean dry tarmac is hazardous?

[gIzzE]

These tests mean sod all.
What I want to know is does the car skip about at the back when pressing on hard?
How does the tyre let go when pressing on hard?? And by that does it hold on for a long time and then let go all of a sudden like GDS3's or does it let go alot earlier but let you have total control like PS2's??

I couldn't care less if one stops a metre quicker than the other, my reactions are slower than that in both the dry and the wet.
A track, where most tests are done, is generally a far better surface than most of our back roads, which is where I have fun with my car, and on a track the stiffer sidewalls of a run flat don't cause the same problems.

I have tried Bridgestone, Pirelli and Michelin run flats, the PS2 zero pressure is the only run flat I actually like, all the others have come off the car within weeks, I am sure for 90% of customers they are fine, but try proper tyres and the difference is like night and day.

[stressdoc]

At this point I am very happy with the new Pirelli P Zeros [non-rft]. For my driving style, they are faster and slightly more comfortable than the OEM Bridgestone rfts.