RFT vs Non-RFT cornering

accel · 07-13-2011, 05:21 PM

As a lot of folks here I'm going buy non-RFT set of tires
when my current set of RFTs will be due to replacement. Difference
in cost is going to allow me to buy compact spare tire as well.

I'm pretty much OK with RFT + ZSP stiffness and ride quality, so
thats't not the issue. The main reason for going non-RFT is extreme
inconvenience of potential interruption of the trip due tire
replacement in the shop. Also, I really doubt appropriate RFT tire will
be available (as well as nearby tire shop) in given circumstances
due to Murphy's law.

My question is regarding slightly different matter though. I like BMW's
handling specifically in tight and fast turns, but noticed one scary
feature - in case of road imperfections the car might shift outside
of the turn abruptly. I think this feature might be partially due to
stiff RFT sidewalls. So here's the question: will the car be less
prone to this shift with non-RFTs, or this is not related?

'Cause I used to have the car with custom suspension that was even stiffer
than my current ZSP, but it didn't have such behavior. So I wouldn't blame
suspension stiffness alone.

captainaudio · 07-13-2011, 05:57 PM

Quote:

Originally Posted by accel

As a lot of folks here I'm going buy non-RFT set of tires
when my current set of RFTs will be due to replacement. Difference
in cost is going to allow me to buy compact spare tire as well.

I'm pretty much OK with RFT + ZSP stiffness and ride quality, so
thats't not the issue. The main reason for going non-RFT is extreme
inconvenience of potential interruption of the trip due tire
replacement in the shop. Also, I really doubt appropriate RFT tire will
be available (as well as nearby tire shop) in given circumstances
due to Murphy's law.

My question is regarding slightly different matter though. I like BMW's
handling specifically in tight and fast turns, but noticed one scary
feature - in case of road imperfections the car might shift outside
of the turn abruptly. I think this feature might be partially due to
stiff RFT sidewalls. So here's the question: will the car be less
prone to this shift with non-RFTs, or this is not related?

'Cause I used to have the car with custom suspension that was even stiffer
than my current ZSP, but it didn't have such behavior. So I wouldn't blame
suspension stiffness alone.

I found the same thing. On bumpy turns the RFTs would bounce around and loose contact with the road surface and the rear end would start to step out. I believe it was due to the stiff RFT sidewalls and in my case replacing them with non-RFTs greaty reduced the problem.

CA

username604 · 07-13-2011, 06:30 PM

I totally get that bouncing around feeling over road imperfections.
The first time it happened i nearly shite myself (2 lane left turn, don't wanna be losing traction in the midst of other cars).

chromisdesigns · 07-13-2011, 07:50 PM

Yep, that "demented bunny rabbits on meth" hopping will be gone once you ditch the runflats. That crap is dangerous, IMHO. I was so glad to be rid of it!

1bad335 · 07-13-2011, 07:55 PM

Quote:

Originally Posted by captainaudio

I found the same thing. On bumpy turns the RFTs would bounce around and loose contact with the road surface and the rear end would start to step out. I believe it was due to the stiff RFT sidewalls and in my case replacing them with non-RFTs greaty reduced the problem.

CA

Absolutely dead on. The added protection of being able to drive on a flat tire was not worth it to me at all. I replaced my nearly brand new RFT's with Conti DWS all seasons and have not looked back. I feel my car handles great and the ride is like night and day better. On these NY roads the RFT's would rock the fillings out of my mouth. Bought a nice 5 series spare which fits the 335 perfectly and I'm a happy camper now.

CJ421 · 07-13-2011, 08:07 PM

Yeah that's RFTs for you. They have a sharp turn-in feel but don't conform at all to the road surface, so you skip over it ... yuck.

Tortfeasor 335xi · 07-13-2011, 08:13 PM

Even increasing the diameter of the wheel from 18 to 19, my non-rft summer tires have a better ride than my factory wheels and tires did.

MissMyE30 · 07-13-2011, 10:01 PM

I was amazed at the difference. Never going RFT's again. BTW I just got back from tossing my E90 hard at the dragon. No issues at all, felt rock solid and predictable. I have a ZSP w/ stock wheels and Michelin Pilot Sport A/S + 's.

richb811 · 07-13-2011, 11:09 PM

For all their advantages, I still feel runflats detract from the driving experience.

I'd rather keep a compressor and a can of fix o flat in the back than be able to drive my ass 20 miles on a flat.

driverman · 07-14-2011, 01:15 AM

Quote:

Originally Posted by captainaudio

I found the same thing. On bumpy turns the RFTs would bounce around and loose contact with the road surface and the rear end would start to step out. I believe it was due to the stiff RFT sidewalls and in my case replacing them with non-RFTs greaty reduced the problem.

CA

+1

I had the same experience.

07-13-2011, 05:21 PM	#1
accel First Lieutenant 45 Rep 335 Posts Drives: e90 328i MT ZSP Join Date: Jan 2010 Location: SF Bay Area, CA iTrader: (0)	RFT vs Non-RFT cornering As a lot of folks here I'm going buy non-RFT set of tires when my current set of RFTs will be due to replacement. Difference in cost is going to allow me to buy compact spare tire as well. I'm pretty much OK with RFT + ZSP stiffness and ride quality, so thats't not the issue. The main reason for going non-RFT is extreme inconvenience of potential interruption of the trip due tire replacement in the shop. Also, I really doubt appropriate RFT tire will be available (as well as nearby tire shop) in given circumstances due to Murphy's law. My question is regarding slightly different matter though. I like BMW's handling specifically in tight and fast turns, but noticed one scary feature - in case of road imperfections the car might shift outside of the turn abruptly. I think this feature might be partially due to stiff RFT sidewalls. So here's the question: will the car be less prone to this shift with non-RFTs, or this is not related? 'Cause I used to have the car with custom suspension that was even stiffer than my current ZSP, but it didn't have such behavior. So I wouldn't blame suspension stiffness alone.
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07-13-2011, 06:30 PM	#3
username604 Colonel 130 Rep 2,554 Posts Drives: bmw Join Date: Sep 2010 Location: repair shop iTrader: (0) Garage List 2008 BMW 335i [10.00]	I totally get that bouncing around feeling over road imperfections. The first time it happened i nearly shite myself (2 lane left turn, don't wanna be losing traction in the midst of other cars).
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07-13-2011, 07:50 PM	#4
chromisdesigns Lieutenant Colonel 47 Rep 1,753 Posts Drives: 2008 BMW 335i sedan Join Date: Jan 2010 Location: San Francisco iTrader: (0)	Yep, that "demented bunny rabbits on meth" hopping will be gone once you ditch the runflats. That crap is dangerous, IMHO. I was so glad to be rid of it!
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07-13-2011, 08:07 PM	#6
CJ421 Brigadier General 2059 Rep 4,266 Posts Drives: BMW G80 M3 Join Date: Feb 2011 Location: PA, USA iTrader: (1) Garage List 2024 BMW M3 Sedan [9.67]	Yeah that's RFTs for you. They have a sharp turn-in feel but don't conform at all to the road surface, so you skip over it ... yuck. __________________ 2024 BMW M3 Sedan Frozen Pure Grey II/Fjord Blue, 6MT Past: 2021 Z4 M40i Frozen Grey II/Black Alcantara \| 2017 F30 340i Mineral Gray/Coral Red, 6MT \| 2011 E92 335i Le Mans Blue/Black, 6MT
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07-13-2011, 08:13 PM	#7
Tortfeasor 335xi Corporate Hack 4 Rep 288 Posts Drives: '08 335xi Coupe Join Date: Mar 2008 Location: Princeton, NJ / Philly, PA iTrader: (0)	Even increasing the diameter of the wheel from 18 to 19, my non-rft summer tires have a better ride than my factory wheels and tires did. __________________ New Car: 2008 335xi Coupe Earlier Car: 2004 STi (got stolen) Earlier Earlier Car: 1995 Mustang GT (416 whp and a blown engine) Really Much Earlier Car: 1988 Mazda 626 TURBO
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07-13-2011, 10:01 PM	#8
MissMyE30 Private 0 Rep 63 Posts Drives: E90 330i Join Date: Dec 2010 Location: Richmond VA iTrader: (0)	I was amazed at the difference. Never going RFT's again. BTW I just got back from tossing my E90 hard at the dragon. No issues at all, felt rock solid and predictable. I have a ZSP w/ stock wheels and Michelin Pilot Sport A/S + 's.
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07-13-2011, 11:09 PM	#9
richb811 506 Rep 4,590 Posts Drives: 2020 G20 330i M Sport Join Date: Dec 2010 Location: NJ iTrader: (21)	For all their advantages, I still feel runflats detract from the driving experience. I'd rather keep a compressor and a can of fix o flat in the back than be able to drive my ass 20 miles on a flat.
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