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[NCTim4]

I did some searching for Runflat replacements as my Potenzas are approaching 25k. There seems to be a known issue with the Turanza with regards to cupping. My Potenzas showed some cupping at about 10k and became noisier. BMW said the pressure was low and I've been watching it more closely since then. The cupping hasn't worsened and the noise hasn't worsened or improved. Is Bridgestone offering some discounts for replacements of the Potenzas or just the Turanza's?

I've read the ongoing Runflat vs. non Runflat debate since I bought my car and I want to stick with the Runflats, but there doesn't seem to be a large selection of replacement Runflats. The Potenza's appear to be available. I read some posts about Contis (had good experience with Contis on my E46), but don't see them as an option at TireRack; do I need to be looking somewhere else? Clearly the non-runflat contingent likes PS2s and F1s, but is there a consensus preference for runflats?

One final question: if I were to switch to non-runflats, would I have to ditch my 162 wheels or can I have non-runflats mounted to these wheels?

NCTim

[Ruff Rider]

I put non run flat tires on my 162 wheels. Any tire will work on the 162 wheel as long as it is the right size.

[varkdriver]

I just took delivery of my 335i and replaced the Bridgestone Runflats at 75miles. I was planning on putting them on Ebay, but if you are interested, contact me. Make you a good deal... They are essentially new.

[klinkerklu]

We had the Turanza's replaced with Conti's, and after 1K, we've both agreed we don't like them as well.
They are a nicer touring tire, but overall they don't grip as well. On tight corners we feel traction control kicking in, when it never used to. Overall they are a cushier ride.
It really feels like we ended up with a higher profile, narrower tire even though they are the same size.
The Turanza's definitely felt sportier, (if you could call RFT's sporty) they just wore like crap.

[txusa03]

Originally Posted by klinkerklu

Overall they are a cushier ride.

I would not buy a car with sport suspension and get a cushier tire. That does not make any sense to me. I like the potenza rft and I really think the 330 is designed for the potenza rft. They are solid in dry and good in wet. I could be the only person who feel this way about my 330 and the rft potenza. In that case, this car was definitely built for my taste.

I know some of my passengers complain of rough ride but the car is not a cadilac and it is not a porsche/s2000. It is somewhere in between. But that is just my opinion.

[klinkerklu]

Originally Posted by txusa03

I would not buy a car with sport suspension and get a cushier tire. That does not make any sense to me.

Right, thus why we aren't happy with them.
However, given the wear issues that Bridgestone is having, we weren't sure if it would be better to replace with the same crappy tires we had, or try something new.
These tires are just tiding us over anyway until we find a new set of wheels.

[txusa03]

Originally Posted by klinkerklu

Right, thus why we aren't happy with them.
However, given the wear issues that Bridgestone is having, we weren't sure if it would be better to replace with the same crappy tires we had, or try something new.
These tires are just tiding us over anyway until we find a new set of wheels.

Your conti is not rft so what you have plan should you get a flat?

[smellthebeans]

MG

I have to agree with your observation on the RFT & performance issue. (I am still not sure there is even one issue) My Protenzas have 21K on them. the fronts are good for at least another 6K, the rears have maybe 1.5 to 2k left tops.

I have seen several references to BMW engineers adressing the issue of handling given the stiffer side walls of the kevlar reinforced RFTs. Seems to me the car is designed specificly to roll on RFTs. Rolling a non RFT may change the handling of the vehicle.

These cars are incredibly complex pieces of engineering. I am not prone to mess with somthing...I would love to test drive a 330/335i ZSP car on NON RFTs to make up my mind for myself

The big down side is we are stuck with only one option of RFTs when you have the ZSP package.

[UncleWede]

I have a 325, but got the Contis as replacement. Yesterday I got a loaner '07 328 with the Potenzas back on, and just going stright down the freeway my teeth were on the edge of chattering from the vibration. So I don't think Bridgestone was re-designed anything. The Contis seem much better in cornering with any amount of road surface irregularity, just because they are slightly softer and will "take" some of that hit.
I still want to get my hands on a 325 with non-RFT, or even just go on a little cruise with someone with such a setup, so I can see if its really that much better.

[KevinC]

Originally Posted by smellthebeans

Rolling a non RFT may change the handling of the vehicle.

It has a HUGE effect on the handling of the car - all for the better, let me assure you firsthand.

Don't buy into all that marketing crap about RFT's.. "engineered for runflats" is a load of horseshit. All it means is that they used softer bushings and springs and not-so-desirable techniques to tame the brutally stiff sidewalls. Switching to a better "real" performance tire doesn't cause any ill effects at all.. in fact when some of those compromises come into play with a great tire, the result is awesome handling and increased comfort, which ain't a bad thing at all for a daily driver.

[d3l0n]

Originally Posted by txusa03

I would not buy a car with sport suspension and get a cushier tire. That does not make any sense to me. I like the potenza rft and I really think the 330 is designed for the potenza rft. They are solid in dry and good in wet. I could be the only person who feel this way about my 330 and the rft potenza. In that case, this car was definitely built for my taste.

I know some of my passengers complain of rough ride but the car is not a cadilac and it is not a porsche/s2000. It is somewhere in between. But that is just my opinion.

I hear what your saying...

I love the idea of RFT, but... i always had a question of my turns with my rear feeling like it was sliding, before if necessary that DSC would kick in. It was obvious because of it begin so hard just as it is feeling all the bumps.

for a 40k+ car... we all know BMW's are, if not thee best, one of the best with sports/luxury/safety combination. Thats why i chose this automaker to being with then.. the model. I was hard headed and was like F what the passengers think, but I also wanted a smooth ride.

So i got rid of my tires when the snow came down(they had wear on them), got some non-rft.. cheap Sumitomo tires (embarassed lol, i never heard of them) and the road feels soooooo smoooth. NOW, i feel like i am driving on cream filled roads . It's a great feeling. I just have to brace myself for a flat, but I am calm person so it shouldn't phase me. This is not my first car.

Now i feel much better grip to the road, i just have to find the speed rating and make sure I don't go over the limit too much . Plan on getting new wheels in the near future anyway.

[bnj]

Bmw uses Rft's for a reason. I have e92 335 that has perfect handling. Magazines seem to agree. Bmw mates the suspension to RFTs. You compromize the handling by altering tirewall stifness. Have another car if you want just a comfortable ride.

[KevinC]

Originally Posted by bnj

Bmw uses Rft's for a reason. I have e92 335 that has perfect handling. Magazines seem to agree. Bmw mates the suspension to RFTs. You compromize the handling by altering tirewall stifness. Have another car if you want just a comfortable ride.

Ridiculous statement.

The runflats are heavy and crash over bumps, and don't stay planted as well as a "real" performance tire. Leave your suspension alone and replace those crappy tires with PS2's and then try to tell me your car doesn't ride AND handle better with the new tires. Not only are both improved, but the difference is dramatic. Ask ANYONE who has done this and you'll get the same answer.

[bnj]

Originally Posted by KevinC

Ridiculous statement.

The runflats are heavy and crash over bumps, and don't stay planted as well as a "real" performance tire. Leave your suspension alone and replace those crappy tires with PS2's and then try to tell me your car doesn't ride AND handle better with the new tires. Not only are both improved, but the difference is dramatic. Ask ANYONE who has done this and you'll get the same answer.

Just out of curiosity, what part of my statement is ridiculous? Do you claim Bmw is not using RFT's for a reason? Do you mean that in reality magazines bash the handling of e92 335? Do you mean Bmw is very unreliable in their statements? Or do you think that having a floppy tirewall perhaps increases the accuracy of steering and overall handling precision? Perhaps you think Mercedes S-class would not be any more comfortable? Now I know! You don't believe I drive 335i!

[Ghunger]

Originally Posted by bnj

You compromize the handling by altering tirewall stifness.

Pretty sure this is the part he was calling rediculous, based upon his response.

[epiphone3]

switching to non-runflats significantly reduces the weight of the wheel-tire combination. With the reduction in unsprung weight and rotating intertia, the car doesn't have choice but to perform better.

This only benefits handling... further, the super stiff sidewall of RFT tires reduces the vehicle stability when traveling through corners with uneven pavement and bumps.

Yes the E90 handles well with RFTs out of the box, but put 30000 km on a set and let me know how you feel about RFTs once they've worn a bit.

I haven't switched to non-RFTs yet, but am planning on doing so.

As was said before, BMW tamed down the ill effects of the RFT tires... ill effects still remain despite their efforts. It is impossible for the cars handling to suffer by switching to non-RFT tires of OEM quality. It is the laws of physics!

[bnj]

Originally Posted by epiphone3

switching to non-runflats significantly reduces the weight of the wheel-tire combination.

I'll begin with your first claim: How much is a significant weight reduction? Then, how much is exactly the weight reduction in a tire that is exactly the same, except being non run-flat instead of run-flat? Take for example potenza RE050A vs RE050A RFT 225/40-18 (typical tire in a Bmw from factory).

[KevinC]

Originally Posted by bnj

Just out of curiosity, what part of my statement is ridiculous?

What part? The entire thing.. especially the last line, which is just over-the-top ridiculous: Have another car if you want just a comfortable ride.

Look, you guys who like and defend runflat technology - more power to ya. But please don't tell the rest of us that these tires perform as well as non-runflats - because it just ain't true.

[d3l0n]

umm.. can some one carefully explain to me how the car's suspension is built for these tires. I kinda get it to a certain degree. I guess at a general sense, not too detailed. in the explaination, explain the comparison with a car who's suspension is built for non-rft. (sorrry for the essay question)

[epiphone3]

Originally Posted by bnj

I'll begin with your first claim: How much is a significant weight reduction? Then, how much is exactly the weight reduction in a tire that is exactly the same, except being non run-flat instead of run-flat? Take for example potenza RE050A vs RE050A RFT 225/40-18 (typical tire in a Bmw from factory).

To be honest, I don't know the exact weight difference... but I do know that it is significant and on the order of several pounds.

You should be aware that since it is weight located at the outer most area of each wheel, this extra weight will generate a lot of intertia (think of how fast the wheel rotates at, say, 60 mph). Losing rotating weight is one of the effective ways to improve your car's performance both in a straight line and in corners. In addition, the reduced weight will give the suspension a better ability to react to changes in the road surface hence improving handling, feel, and ride quality.

[epiphone3]

Originally Posted by d3l0n

umm.. can some one carefully explain to me how the car's suspension is built for these tires. I kinda get it to a certain degree. I guess at a general sense, not too detailed. in the explaination, explain the comparison with a car who's suspension is built for non-rft. (sorrry for the essay question)

It was mentioned above... basically BMW use softer damping rates and bushings, etc. to tame the effects of having a practically rigid side wall that run-flat tires have.

Cars made to run with non-RFT tires will assume a certain level of tire side-wall flex in design and can therefore use stiffer versions of some of the other suspension components without compromising ride quality too much.

[Richwm]

Buy PS-II over stock RFT's

Pro's

1-Loose 12 Lbs of unsprung weight
2-Better gas mileage ( +2 mpg for me)
3-faster acceleration ( less unsprung weight)
4-higher cornering limits (.95 g's stock .98 with PS-II's)
5-better wet and dry traction
6-longer tire life
7-less replacement costs
8-better ride quality

Con's

1-no spare

So thats 8 to 1 any questions
read the compare at tirerack
http://www.tirerack.com/tires/Compar...speed_rating=Y