Left front tire wear following track day. - New 2009 2010 BMW Z4

JumboJetDriver · 06-21-2011, 04:01 AM

Has anyone experienced scalloped tire wear on Bridgestone Run Flats following a track day event. My front left tire tread has scalloped wear on the outside edge only. All other tires do not have this type of wear. The car was run hard in 5, 20 minute sessions at Carolina motorsports park in high temperatures. The majority of turns are right hand turns. What causes this, is it incorrect pressure? A friend suggested it is from slight understeer coupled with the fact that the left front takes the most punishment in right hand turns. I am new to track driving and would appreciate any input. The car is a 2011 Z4 sdrive 35i.

Jordanpryce · 06-21-2011, 08:54 AM

Firstly, If you're going to run track days, I highly recommend a set of proper track tires. The run flats simply arent designed for this kind of use, and the feeling of the car with a good set of track DOT tires will make all the difference. Be prepared to go through tires on the track a lot faster than on the street. (brake pads too).

Tire pressure is vital. If there is a tire vendor at the track, ask him what pressures to run for the weather that day, they know best. Check the pressure on cold tires as well as when you get off the track. The pressure is always for cold tires, but it's good to know that running too soft will mean higher temps when hot, and vice versa. Usually you want to see a 4psi rise in pressure on a hot tire (depending on the tire).

As for the scalloping, I'm surprised the tires aren't roasted!

JumboJetDriver · 06-21-2011, 10:15 AM

So this is normal? I realize the tires are not the best choice, they are the factory installed bridgestone rft, and this was my first track event. I was just trying to determine if this scalloped wear just on that left front tire outer edge is indicative of anything else....other than wrong tire...I was wondering if something was out of alignment etc....thanks for your input. Does anyone have suggestions as to what tires would be good on my car for future track days? 2011 Z4 35i MT

Jordanpryce · 06-21-2011, 04:10 PM

The scalloping could be from running too soft of a pressure, or over-driving the tires.

richard in NC · 06-21-2011, 05:28 PM

I scalloped many a left front tire at CMP. Especially the e39 M5 which was a 4000 lb car with a good bit of understeer. I ended up with a set of Kuhmo R compound tires for track day. I could take them to the track in the back seat (in bags and blankets of course). Can't do that with the Z4.

A higher tire pressure helps as does more experience.

PS: I need to get my Z4 to the track.
PPS: I may look at the Pilot Super Sport tires. Expensive but I bet they are great for the track.

JumboJetDriver · 06-22-2011, 04:36 PM

Thanks for the reply and advice, I appreciate it.

DrewKo · 06-25-2011, 11:41 AM

Could also have something to do with your alignment/camber. Since the tires are run flat tires, tire pressure does not make as much a difference, because of the extremely stiff sidewall, in contrast to non-run flat tires, where tire pressure makes significant differences. It could be your camber, could also be that you hit a bad pot hole on the left and BMW's suspension reacts by doing to the tire what you have described (according to the mechanic where I take my Z4). If I had to bet, I think the least likely cause is tire pressure.

06-21-2011, 04:01 AM	#1
JumboJetDriver Registered Drives: 2011 BMW Z4 Sdrive 35i Join Date: Jun 2011 Location: North Carolina Posts: 3 iTrader: (0)	Left front tire wear following track day. Has anyone experienced scalloped tire wear on Bridgestone Run Flats following a track day event. My front left tire tread has scalloped wear on the outside edge only. All other tires do not have this type of wear. The car was run hard in 5, 20 minute sessions at Carolina motorsports park in high temperatures. The majority of turns are right hand turns. What causes this, is it incorrect pressure? A friend suggested it is from slight understeer coupled with the fact that the left front takes the most punishment in right hand turns. I am new to track driving and would appreciate any input. The car is a 2011 Z4 sdrive 35i.
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06-21-2011, 08:54 AM	#2
Jordanpryce Private Drives: 2011 Z4 30i Join Date: Mar 2011 Location: Brooklyn Posts: 97 iTrader: (0)	Firstly, If you're going to run track days, I highly recommend a set of proper track tires. The run flats simply arent designed for this kind of use, and the feeling of the car with a good set of track DOT tires will make all the difference. Be prepared to go through tires on the track a lot faster than on the street. (brake pads too). Tire pressure is vital. If there is a tire vendor at the track, ask him what pressures to run for the weather that day, they know best. Check the pressure on cold tires as well as when you get off the track. The pressure is always for cold tires, but it's good to know that running too soft will mean higher temps when hot, and vice versa. Usually you want to see a 4psi rise in pressure on a hot tire (depending on the tire). As for the scalloping, I'm surprised the tires aren't roasted! __________________ 2011 Z4 30i ///M Sport \| Sapphire Black \|Black Leather \|MT6 \| Carbon Trim \| Premium \| Comfort \| P-Sound \| Debadged \| Nav \| Black Kidneys Also Own: 04 Rover Disco G4, 00 VW Eurovan Westy, 10 BMW GS1200ADV Previous Cars: 11 328i, 09 Audi A4, 08 Audi A3, 71 Porsche 914-6, 65 Porsche 356, 88 VW GTI, 70 VW Type III, 99 VW Eurovan MV

06-21-2011, 04:10 PM	#4
Jordanpryce Private Drives: 2011 Z4 30i Join Date: Mar 2011 Location: Brooklyn Posts: 97 iTrader: (0)	The scalloping could be from running too soft of a pressure, or over-driving the tires. __________________ 2011 Z4 30i ///M Sport \| Sapphire Black \|Black Leather \|MT6 \| Carbon Trim \| Premium \| Comfort \| P-Sound \| Debadged \| Nav \| Black Kidneys Also Own: 04 Rover Disco G4, 00 VW Eurovan Westy, 10 BMW GS1200ADV Previous Cars: 11 328i, 09 Audi A4, 08 Audi A3, 71 Porsche 914-6, 65 Porsche 356, 88 VW GTI, 70 VW Type III, 99 VW Eurovan MV

06-21-2011, 05:28 PM	#5
richard in NC Major Drives: 2009 Z4 35i Join Date: Jul 2009 Location: Charlotte, NC Posts: 1,173 iTrader: (0)	I scalloped many a left front tire at CMP. Especially the e39 M5 which was a 4000 lb car with a good bit of understeer. I ended up with a set of Kuhmo R compound tires for track day. I could take them to the track in the back seat (in bags and blankets of course). Can't do that with the Z4. A higher tire pressure helps as does more experience. PS: I need to get my Z4 to the track. PPS: I may look at the Pilot Super Sport tires. Expensive but I bet they are great for the track. __________________ 2013 X3 35i, Vermillion Red/Sand Beige: MSport, Premium, Technology, Premium Sound, Hud, More... 2012 335is, Space Gray/Oyster-Black: DCT, 19s, Premium, Convenience, Nav, Heated Seats, More... Gone '11 X5 50i, '09 Z4 35i, '08 550i, 06 X3, 06 650i, '02 M5, '99 540i

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06-21-2011, 10:15 AM	#3
JumboJetDriver Registered Drives: 2011 BMW Z4 Sdrive 35i Join Date: Jun 2011 Location: North Carolina Posts: 3 iTrader: (0)	So this is normal? I realize the tires are not the best choice, they are the factory installed bridgestone rft, and this was my first track event. I was just trying to determine if this scalloped wear just on that left front tire outer edge is indicative of anything else....other than wrong tire...I was wondering if something was out of alignment etc....thanks for your input. Does anyone have suggestions as to what tires would be good on my car for future track days? 2011 Z4 35i MT

06-22-2011, 04:36 PM	#6
JumboJetDriver Registered Drives: 2011 BMW Z4 Sdrive 35i Join Date: Jun 2011 Location: North Carolina Posts: 3 iTrader: (0)	Thanks for the reply and advice, I appreciate it.

06-25-2011, 11:41 AM	#7
DrewKo Lieutenant Colonel Drives: 335i Montego Blue Saddle Brown Join Date: Jan 2007 Location: Atlanta, GA Posts: 1,569 iTrader: (4) Garage List 2007 335i [0.00]	Could also have something to do with your alignment/camber. Since the tires are run flat tires, tire pressure does not make as much a difference, because of the extremely stiff sidewall, in contrast to non-run flat tires, where tire pressure makes significant differences. It could be your camber, could also be that you hit a bad pot hole on the left and BMW's suspension reacts by doing to the tire what you have described (according to the mechanic where I take my Z4). If I had to bet, I think the least likely cause is tire pressure.