Losing confidence in grip
12-10-2008, 11:11 AM
#11
Contributors
Join Date: Jan 2005
Location: San Jose, California, USA
Posts: 4,119
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 2008 Porsche 911 Carrera S Convertible. Midnight Blue, 6 Speed.Retired - 2007 997 Carrera S, Midnight Blue, Grey leather, premium audioRetired - 2007 550i, Monaco Blue over Beige, Navigation, Logic 7, Cold Weather Pack, Comfort Access, Sport Package
Model Year: 2008
The OEM runflats on my 550 (Bridgestones) suffered from poor grip in the wet or when cold but were very good in the dry. I think RFT's in general suffer from these issues, and I quickly replaced the OEM runflats with better tires. In your case, it could well be that the tire's characteristics are being exaggerated a little due to December weather. If you're finding that the back end comes out or breaks loose as you corner that's actually oversteer and not understeer (which is where the nose pushes in the direction of travel when you try to corner). It's not just tires that could cause this, you may also have alignment issues. Tire pressures can also have an impact. Either way, I'd certainly suggest you consider switching the RFT's out for better tires, Let us know how it turns out!
12-10-2008, 11:13 AM
#12
Contributors
Join Date: Mar 2007
Location: Kuala Lumpur, Malaysia
Posts: 1,056
Likes: 0
Received 1 Like
on
1 Post
My Ride: G30 530i M-sport
Model Year: 2018
Mine is a non-sport car, but with the factory-fitted M-tech suspension and drop, running Dunlop SP Sport RFTS on 17" OEM wheels. Have not noticed any issues with cornering and grip (and I love the looks on the boy racers' faces when they slow for motorway cloverleaf exits and I zip past them without bleeding off too much speed).
All that said, the car can be VERY skittish when it encounters gusty crosswinds and unfortunately, in this country, that is most days this time of year.
All that said, the car can be VERY skittish when it encounters gusty crosswinds and unfortunately, in this country, that is most days this time of year.
12-10-2008, 01:26 PM
#13
Contributors
Join Date: Nov 2006
Location: Idaho
Posts: 349
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 07 550 i, mystic blue, black leather, cold weather package, nav, sport, shades, bags, rear heat, V1 hardwired.
05 F350 TD Crew Cab
04 Range Rover HSE
91 964 C4 Cabrio
07 997 Turbo Cabrio
A while back we were talking about tire grip and runflats, and Rudy made some mention that the run flats loose grip in colder weather. Yesterday, bringing the kids home from school, they asked me to "stomp on it dad." I shut off the traction control, power braked, and then WOW, the rear tires lit up like a prom queen at homecoming. The weather here is in the low 40's, and getting the tires to break loose with the RFTs is impossible in the summer months, so I stand corrected based upon first hand research.
12-10-2008, 02:26 PM
#14
Contributors
Join Date: Mar 2005
Posts: 2,573
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 2006 530i Sport
Silver Gray - Black Leather - Anthracite Maple
Manual Transmission
Premium Audio
Cold Weather Package
Rear sunshade
Sirius Radio
Autobahnd Roadblock (3M) film kit
Originally Posted by studavis' post='742485' date='Dec 10 2008, 05:26 PM
A while back we were talking about tire grip and runflats, and Rudy made some mention that the run flats loose grip in colder weather. Yesterday, bringing the kids home from school, they asked me to "stomp on it dad." I shut off the traction control, power braked, and then WOW, the rear tires lit up like a prom queen at homecoming. The weather here is in the low 40's, and getting the tires to break loose with the RFTs is impossible in the summer months, so I stand corrected based upon first hand research.
Car and Driver tested the 530i Sport (US) with Dunlops to round the skidpad at .90g. I have absolute faith in them. However, a cold tire is always going to break loose more than a hot one.
It is also good to remember that tires age. The compounds stiffen and grip can be lost.
A hot tire is a stickier tire, which is why drag racers do "burnouts", to heat the tire up (and also burn off any crud they may have picked up). It's also why you see F1 cars weaving at low speeds.
12-10-2008, 03:21 PM
#15
Contributors
Join Date: Oct 2007
Location: Thousand Oaks, California
Posts: 11,084
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 2008 550i Jet Black on Black Leather, SAT with Paddles, Logic 7, Comfort Seats, NAV, Sport Package, PDC, Xenons, Sirius, Trinity 12W LED Angel Eyes, RPi GT Exhaust, M rear spoiler, ACS Roof Spoiler, Tinted Tail Lights, Bimmian Carbon Fiber Pillar Trim, Bimmian Shadow 550i emblem, RPi Scoop, E60 Forum Cling, Mtec bulbs in fog lights, Mtec 2W LED for License Plate Light Bulbs, K&N Filter, Bimmian LED Smoked Side Markers, Blackout roundels, Carbon Fiber Kidney Grills.
Retired Rides - 1989 325i convertible, 1995 M3, 2002 X5, 2005 545i, 2008 X5 (Lemon)
One of the many reasons we part with RFT's!! 
12-10-2008, 05:50 PM
#16
Contributors
Join Date: Jan 2005
Location: San Jose, California, USA
Posts: 4,119
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 2008 Porsche 911 Carrera S Convertible. Midnight Blue, 6 Speed.Retired - 2007 997 Carrera S, Midnight Blue, Grey leather, premium audioRetired - 2007 550i, Monaco Blue over Beige, Navigation, Logic 7, Cold Weather Pack, Comfort Access, Sport Package
Model Year: 2008
Originally Posted by UUronL' post='742513' date='Dec 10 2008, 03:26 PM
Car and Driver tested the 530i Sport (US) with Dunlops to round the skidpad at .90g. I have absolute faith in them. However, a cold tire is always going to break loose more than a hot one.
12-10-2008, 07:07 PM
#17
Contributors
Join Date: Oct 2008
Location: Ft. Lauderdale, FL
Posts: 946
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 2004 545i, Sport and Premium package, Titanium Silver with Black Dakota Leather interior
Not to highjack the thread but... I am looking for performance plus value (treadwear, grip, road noise etc). From my research, Sumitomo may provide best bang for the buck. What are your experiences and recommendations?
12-11-2008, 01:25 AM
#19
Senior Members
Thread Starter
Join Date: Aug 2008
Location: London, UK
Posts: 277
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 2005 BMW 525D M-SPORT // Grey // SB attached
wow, some excellent analysis and views there.
Given RFT's are not cheap (?210 per tyre here in the uk!), I might just change to some normal tyres.
Can the same alloy be used with normal tyres ? I want to simply take off the RFT's off the 166 and put on normal tyres ... hope thats possible!
Given RFT's are not cheap (?210 per tyre here in the uk!), I might just change to some normal tyres.
Can the same alloy be used with normal tyres ? I want to simply take off the RFT's off the 166 and put on normal tyres ... hope thats possible!
12-11-2008, 05:55 AM
#20
Contributors
Join Date: Jan 2005
Location: San Jose, California, USA
Posts: 4,119
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 2008 Porsche 911 Carrera S Convertible. Midnight Blue, 6 Speed.Retired - 2007 997 Carrera S, Midnight Blue, Grey leather, premium audioRetired - 2007 550i, Monaco Blue over Beige, Navigation, Logic 7, Cold Weather Pack, Comfort Access, Sport Package
Model Year: 2008
Originally Posted by nudda' post='742890' date='Dec 11 2008, 02:25 AM
wow, some excellent analysis and views there.
Given RFT's are not cheap (?210 per tyre here in the uk!), I might just change to some normal tyres.
Can the same alloy be used with normal tyres ? I want to simply take off the RFT's off the 166 and put on normal tyres ... hope thats possible!
Given RFT's are not cheap (?210 per tyre here in the uk!), I might just change to some normal tyres.
Can the same alloy be used with normal tyres ? I want to simply take off the RFT's off the 166 and put on normal tyres ... hope thats possible!