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[SCA]

Originally Posted by WolfsburgerMitFries

"Designed" for runflats? That's just how BMW markets it and sells you on the idea of runflats. Not everything you hear in the world is true my friend. Take any BMW with runflats and put normal tires on and suddenly it will handle better, ride smoother, get getter gas mileage, stop faster. That's because you're dumping a BUNCH of unsprung rotating weight and loosing those absurdly stiff sidewalls. Runflats=crap and the first modification most enthuisasts in here plan on doing when they get their car is to dump their runflats faster than last nights dinner, then adding what's known as a "tire mobility set" in Europe...which means a can of fix-a-flat and a quality 12V air compressor. I also recommend a tire plug set because its not hard to do.

So true, many E90 owners dumped their RFTs.

[maq]

Originally Posted by WolfsburgerMitFries

"Designed" for runflats? That's just how BMW markets it and sells you on the idea of runflats. Not everything you hear in the world is true my friend. Take any BMW with runflats and put normal tires on and suddenly it will handle better, ride smoother, get getter gas mileage, stop faster. That's because you're dumping a BUNCH of unsprung rotating weight and loosing those absurdly stiff sidewalls. Runflats=crap and the first modification most enthuisasts in here plan on doing when they get their car is to dump their runflats faster than last nights dinner, then adding what's known as a "tire mobility set" in Europe...which means a can of fix-a-flat and a quality 12V air compressor. I also recommend a tire plug set because its not hard to do.

You are missing the point. No where in my post did I say run flats ride and handle better than non RF tires. I was pointing out the E82 was developed with RFTs and that's a fact. Do you think BMW, knowing their car would be sold and used with RFTs, would develop the suspension around non-RF tires? However, that doesn't mean non-RFs can't improve ride and handling in the same sense that your BMW's suspension is designed to work with road-legal tires, but R-compond can still improve things.

I co-drive a Porsche and an Alfa and prepare an E36 in club racing, so I think I know my tires better than you do.

[emm3tt]

Originally Posted by maq

You are missing the point. No where in my post did I say run flats ride and handle better than non RF tires. I was pointing out the E82 was developed with RFTs and that's a fact. Do you think BMW, knowing their car would be sold and used with RFTs, would develop the suspension around non-RF tires? However, that doesn't mean non-RFs can't improve ride and handling in the same sense that your BMW's suspension is designed to work with road-legal tires, but R-compond can still improve things.

I co-drive a Porsche and an Alfa and prepare an E36 in club racing, so I think I know my tires better than you do.

I agree with your initial point about BMW designing the cars with runflats, but are you suggesting that the car should only run with runflats?

[maq]

Originally Posted by emm3tt

I agree with your initial point about BMW designing the cars with runflats, but are you suggesting that the car should only run with runflats?

Absolutely not. I wasn't suggesting anything in any of my posts, but if you ask me I'm all for non-RF. I run Michelin PS2s on all my cars.

I didn't want to get into the whole RF vs non-RF thing because it was off-topic and kind of like beating a dead horse. But apparently it's a sensitive subject here, you mention the word "RFT" and someone will give you a lecture.

[inTgr8r]

Originally Posted by maq

You are missing the point. No where in my post did I say run flats ride and handle better than non RF tires. I was pointing out the E82 was developed with RFTs and that's a fact. Do you think BMW, knowing their car would be sold and used with RFTs, would develop the suspension around non-RF tires? However, that doesn't mean non-RFs can't improve ride and handling in the same sense that your BMW's suspension is designed to work with road-legal tires, but R-compond can still improve things.

I co-drive a Porsche and an Alfa and prepare an E36 in club racing, so I think I know my tires better than you do.

So was the Z4 "developed for RFs" (modified when RFs introduced)
...they're still crap & the suspension works better with normal tires.

Sooooo what's the import of the statement "developed for RFs"?
- nothing, zip, nadda, .....all marketing BS

[cncmastr]

Originally Posted by inTgr8r

Yep...
MANY Z4 owners that I know, have complained about tire issues, especially tramlining...
The problems magically disappeared when they ditched the RFs.
The car handled better & the ride was smoother as well.

Most if not all high-perf tires will tramline, not just RFTs

[hector]

Originally Posted by Klinn

Quite true, and at the opposite end of the tire spectrum, it seems likely my E46's current 17" wheel + snow tire package will also fit the 135i. They've still got lots of life and I was hoping I wouldn't have to buy another set.

i was wondering the same thing. my e46 17" package wouldn't fit the e92 335 so i had to get new but maybe it will fit the 1er. they've only got a few thousand miles on them.

[maq]

Originally Posted by inTgr8r

So was the Z4 "developed for RFs" (modified when RFs introduced)
...they're still crap & the suspension works better with normal tires.

Sooooo what's the import of the statement "developed for RFs"?
- nothing, zip, nadda, .....all marketing BS

Jeez we have some serious RFT haters here. I get it that you like your normal tires, OK? But we are not exactly discussing that here. The guy said E82 had to have RFTs because there was no room in the trunk, I was simply responding to that by stating the E82 was designed to work with RFT - which, you can't prove otherwise unless you have a pic of a test mule on non-RFTs. I didn't say "RFTs actually work on E82" or "RFT FTW." Start a damn "I hate RFT" thread in the tires section if you'd like to continue the RFT vs nonRFT dicussion.

[Garrett]

Originally Posted by maq

Absolutely not. I wasn't suggesting anything in any of my posts, but if you ask me I'm all for non-RF. I run Michelin PS2s on all my cars.

I didn't want to get into the whole RF vs non-RF thing because it was off-topic and kind of like beating a dead horse. But apparently it's a sensitive subject here, you mention the word "RFT" and someone will give you a lecture.

Whats it matter, their on BMW's..! Get a flat tire and how is that your problem, I have a 1-800 I call and some nice gentlemen comes and fixes it for me...!

So why argue about a spare tires...??





-Garrett

[adc]

Originally Posted by inTgr8r

Sooooo what's the import of the statement developed for RFs

It is true. The suspension on E9x cars was calibrated specifically for runflats. Designed here means just that - the calibration, not the entire geometry design and concept.You can tell that if you drive an E92 Sport Package, which rides very stiffly over minor imperfections - as stiffly as an E46 SP - but floats over the big stuff. That means that the stiffness of the damping was dialed back a bit, say 10-20%, which is compensated for by the extra stiffness of the RFT sidewalls. (I'm making up the actual percentages here, they may be different in real life).If you take an E92 and throw away both the runflats and suspension, you can make it handle just as well as any previous generation bimmer.

[inTgr8r]

Originally Posted by maq

Jeez we have some serious RFT haters here. I get it that you like your normal tires, OK? But we are not exactly discussing that here. The guy said E82 had to have RFTs because there was no room in the trunk, I was simply responding to that by stating the E82 was designed to work with RFT - which, you can't prove otherwise unless you have a pic of a test mule on non-RFTs. I didn't say "RFTs actually work on E82" or "RFT FTW." Start a damn "I hate RFT" thread in the tires section if you'd like to continue the RFT vs nonRFT dicussion.

LOL.. I don't disagree with you.
It just gets me when the marketing people make things sound magical

[Propagator]

Originally Posted by adc

It is true. The suspension on E9x cars was calibrated specifically for runflats. Designed here means just that - the calibration, not the entire geometry design and concept.You can tell that if you drive an E92 Sport Package, which rides very stiffly over minor imperfections - as stiffly as an E46 SP - but floats over the big stuff. That means that the stiffness of the damping was dialed back a bit, say 10-20%, which is compensated for by the extra stiffness of the RFT sidewalls. (I'm making up the actual percentages here, they may be different in real life).If you take an E92 and throw away both the runflats and suspension, you can make it handle just as well as any previous generation bimmer.

Wait, I thought the special RFT design also included the anti-gravity ray gun for the added unsprung mass. :mad:

[mikeo]

TheUltimateDriver,
I took the liberty of adding offset info to your original post. Hope you don't mind.

[Dave]

thanks for the addition mikeo 8)
go to work tirerack!

[SCA]

Originally Posted by mikeo

TheUltimateDriver,
I took the liberty of adding offset info to your original post. Hope you don't mind.

Great Work! :thumbup:

[SF_VR6]

Do I pay attention to the Bolt Circle numbers or just the size and ET?

What does ET stand for?

Here is what I want:

http://www.bbs-usa-appguide.com/publ...m?CLID=15&WF=4

:iono:

[mikeo]

ET refers to offset, which should be somewhere between 38 - 45 (THAT IS JUST A GUESS UNTIL WE HAVE THE CARS TO TEST FITMENT).

Bolt circle must be 5 - 120, Center Bore (CB) 72.5

[juniormint]

awesome I will be getting my 135i from the factory with the 17's. Buying a set of SSR lightweight wheels and some performance tires. Than slapping Blizzak snow tires on the 17's for the winter

[adc]

Originally Posted by JuniorMint

awesome I will be getting my 135i from the factory with the 17's.

Only if you stay away from the Sport Package, I think... otherwise you get the staggered 18's.

[ersatzS2]

More clues on tire fitment via the Hartge website. They are suggesting with a 40ET you can get 235/35s on an 8" wheel up front.

37 87 2380 JHARTGE CLASSIC 2 wheel set
8 x 19" offset 40 with 225 / 35 ZR 19 front
9 x 19" offset 46 with 225 / 35 ZR 19 reara37462380 = '
1 2 3
'37 46 2380 JHARTGE CLASSIC 2 wheel set
8 x 19" offset 40 with 235 / 35 ZR 19 front
9 x 19" offset 46 with 235 / 35 ZR 19 reara37872390 = '
1 2 3
'37 87 2390 JHARTGE CLASSIC 2 wheel set
8 x 19" offset 40 with 225 / 35 ZR 19 front
9 x 19" offset 46 with 255 / 30 ZR 19 rear

[ersatzS2]

Originally Posted by maq

I'm all for non-RF. I run Michelin PS2s on all my cars.

Originally Posted by maq

I was pointing out the E82 was developed with RFTs and that's a fact. <snip> I co-drive a Porsche and an Alfa and prepare an E36 in club racing, <snip>

I agree with the conjecture that since BMW is configuring the car around rfts, then it is logical to suppose that spring rates, shock rebound, and alignment specs are all tailored for those tires and adjustments will be needed for non-rfts. How big an adjustment, who knows.
My experience is that any street setup is going to destroy the tires on the track anyway, not nearly enough camber up front and too much weight transfer too quickly for the rears to work right.

It's my wife's car so I can't go crazy, but I do intend to borrow it for trackdays, so the plan is to install camber plates and adj ARBs. Leave the springs as they are, but at least give the outer halves of the front tires a fighting chance for survival.
All this means dedicated track tires, and since you've used those fancy PS2 street tires and also race, I'd be interested in your opinion. I've been planning to buy one of the harder wearing R-compounds, eg Toyos or PS Cups. However this isn't competition and the suspension will be far from optimized for these things even with a few degrees of camber. How would a set of PS2s compare for longevity and grip as an alternative to Rs?

[adc]

Originally Posted by ersatzS2

I agree with the conjecture that since BMW is configuring the car around rfts, then it is logical to suppose that spring rates, shock rebound, and alignment specs are all tailored for those tires and adjustments will be needed for non-rfts. How big an adjustment, who knows.

If it follows the 335 (E92) example, none. The ride on the 335 was improved by swapping to non-RFT tires, as was dry, wet and snow traction. Turn-in remained the same.

My experience is that any street setup is going to destroy the tires on the track anyway, not nearly enough camber up front and too much weight transfer too quickly for the rears to work right.

As long as you drive the PS2 equipped car thoughtfully, they will accomodate say 2 events per year. If you start pushing the car, the tire temps will quickly go up (pressures too) and you can ruin them in a day. That being said, I think they behaved on track much better than their predecessors (PS) - they will work with you for longer and not become quite as greasy when they quit. That was my direct experience...

I think I'll go a different route with the 1, because the PS2's are very expensive. Perhaps throw in a set of those inexpensive Azenis RT615, use for street and track and replace as needed.


BTW, I think PS2 runflats may soon become available.