Auto-X Tire Pressures: Staggered 335xi

satakal · 07-07-2009, 05:54 PM

I can't wait to drive Watkins Glenn and The Ring. OMG, the ring! In 1080!

no clue on release date. We should have a Prologue / beer / bbq at my house next weekend. Or, we could beg the cool guys in the local PCA to let is "crash" their AX. http://www.motorsportreg.com/index.c...2F095C54DE7424

Ramos · 07-07-2009, 06:05 PM

Quote:

Originally Posted by Chowbow

Up to a point, it works. Try it. Street pressures on the stock staggered 18s is something like 32F/36R. Go up to 43F/42R and the car is more neutral. At least on my setup, for me, with my driving style, it is.

On my 19s, I run 44F/41R at the autoX (hot pressures) and it works best for me. I'm on Eibach ProKit springs with Bilstein HD shocks, 19" CSLs with 235/265 tire setup. This is on regular old street tires though, things change a lot with R-compounds and slicks.

I think the reason your car is more neutral is because you run such insane pressures up front that you are past the point of grip all together...
Seriously though, I have never heard anyone run such high hot pressures.. Are you sure this is helping you? Last time I was at a track day, on one of the runs, the car was getting very sloppy and sure enough I was at 42 PSI at the front... Dropping it to 38 front and 40 rear hot helped a lot

Ramos · 07-07-2009, 06:06 PM

Quote:

Originally Posted by satakal

I can't wait to drive Watkins Glenn and The Ring. OMG, the ring! In 1080!

no clue on release date. We should have a Prologue / beer / bbq at my house next weekend. Or, we could beg the cool guys in the local PCA to let is "crash" their AX. http://www.motorsportreg.com/index.c...2F095C54DE7424

I'm in either way

200Duece · 07-07-2009, 06:12 PM

Quote:

Originally Posted by satakal

no clue on release date. We should have a Prologue / beer / bbq at my house next weekend. Or, we could beg the cool guys in the local PCA to let is "crash" their AX. http://www.motorsportreg.com/index.c...2F095C54DE7424

me might have to roll through Tech backwards to make them think our engines are in the right place

Chowbow · 07-07-2009, 06:17 PM

Quote:

Originally Posted by Ramos

I think the reason your car is more neutral is because you run such insane pressures up front that you are past the point of grip all together...
Seriously though, I have never heard anyone run such high hot pressures.. Are you sure this is helping you? Last time I was at a track day, on one of the runs, the car was getting very sloppy and sure enough I was at 42 PSI at the front... Dropping it to 38 front and 40 rear hot helped a lot

I chalk marked my tires, even at 40, I was still getting rollover down to the markings on the sidewall. These are on GS-D3s. The rears which are much lower profile (30 series) are less prone to the roll over though. I strive to scrub down to the tip of the triangle on the tire.

This is the first set of wheels/tires I've run such high pressures on actually. I've typically ran in the high 30s or at about 40 on most of my other cars. I co-drive my friend's evo and it works great at 32psi hot. I really think it's just the setup I have now and it works OK. I'm not quite a n00b to autoXing either, been doing it on and off for 10 years now so I hope I'm doing it right...

Chowbow · 07-07-2009, 06:19 PM

Oh, and these are only for autoX. On a road course I run lower pressures, 40F/40R, and of course I don't push it quite as hard.

Ramos · 07-07-2009, 06:36 PM

Gotcha... Makes sense..

I just think that you are sacrificing way too much grip to avoid rolling on the tires..
Do that really cure your understeer? That's why I said in my first post that I don't think tire pressure can really cure understeer on our cars running staggered.

At least you save rubber by running such high pressures..

Chowbow · 07-07-2009, 06:45 PM

It's definitely slippery when there's a lot of rollover, and hard to control at the limit. I'll try running some lower pressures again and see what happens. I've consistently tested and had to add air until now but no harm in trying to go back down. I should be going this Sunday and I'll check it out.

Ramos · 07-07-2009, 06:51 PM

Try 38 Front 42 rear next time and see what that does...
HAve you ever tried square though? I am telling that makes a bigger difference than any pressure adjustment you can come up with

JoosyJoos · 07-10-2009, 12:21 PM

I'm autoxing on my Volks for the first time tomorrow. I had been using the stock rims with the Bridgestone RFTs. Not really sure where to start out the tire pressure but I'll probably try around 36 front, 38 rear and tweak from there.

Inflating the RFTs up to 38-40psi makes them incredibly hard to drive on in my opinion. The car feels more responsive but it comes at a cost of grip.

I'll be running on Kumho Ecsta MX tires.... so if anyone has used these in an autox setting let me know.

nicknaz · 07-10-2009, 12:47 PM

Quote:

Originally Posted by JoosyJoos

I'll be running on Kumho Ecsta MX tires.... so if anyone has used these in an autox setting let me know.

my old WRX seemed to be happy with 38psi hot pressure front and rear with 225/50/16 kumho MX. seemed like grip really dropped off when I went past 40psi on those tires. no experience on E9X sorry.

Chowbow · 07-10-2009, 01:33 PM

I ran the MXs in a 225/40/18 on my S4 for a season, I believe I ran at 40ish hot. YMMV though, especially if you're running a lower profile tire. The lower the profile, the higher the pressure GENERALLY. But don't take that as a rule.

JoosyJoos · 07-10-2009, 09:13 PM

Thanks guys... I've got them pumped up around 40psi right now waiting for tomorrow. Its always easier to drop pressure than to add it so I went high. I'll report back here tomorrow with results.

JoosyJoos · 07-12-2009, 02:44 PM

Okay, thought I would report back since the autox was last night. First let me say that night autoxes are pretty tough when their isnt adequate lighting lol.

Litte background... I'm running Volk CE28N's with 235/40/18F and 265/35/18R with Kumho Ecsta MX tires (which are very worn at this point). I had them pumped up to 40psi front and 38psi rear. It was my first time doing an autox on these tires and let me say what it difference it meant compared to the original RFTs. I think I had the ideal tire pressures set because understeer was largely nonexistant (given the car we drive I'd say it was good for a 3500lb porker). So I just thought I would let people know for those of you running a similar setup.

nicknaz · 07-12-2009, 08:28 PM

Quote:

Originally Posted by JoosyJoos

Kumho Ecsta MX ...

It was my first time doing an autox on these tires and let me say what it difference it meant compared to the original RFTs. .

You autoX the original RE050A as well and preferred the MX to those tires?

JoosyJoos · 07-12-2009, 10:24 PM

The Kumhos are light years ahead of the RE050A's imho. My friend runs the XS series while I have the older compound MX tires. They have both received praise from Tirerack as well as Grassroots comparison tests. Additionally they are pretty cheap performance tires when compared to things like the Bridgestone RE01R and RE11s. My only gripe is that compared to my brothers Bridgestone RE01Rs on his 318ti, the Kumhos arent nearly as good in the wet.

nicknaz · 07-13-2009, 12:25 AM

wow, that's really interesting! I wonder how much difference there is between the RE050A and RE050A II compounds.

I used to do HDPE on Kumho MX and I prefer the RE050A II on my 328 to the Kumhos (which I thought had mushy sidewalls, less grip and less tolerance for heat)

glad you found some tire pressures that worked well for your setup!

Chowbow · 07-13-2009, 12:33 AM

I was looking to try out some new pressures today but ended up co-driving somebody's Evo instead. At least I got to beat up someone else's car instead of mine.

Will have to wait for the next one to see what works.

The HACK · 07-13-2009, 01:01 PM

Quote:

Originally Posted by Nick Nazareno

wow, that's really interesting! I wonder how much difference there is between the RE050A and RE050A II compounds.

I used to do HDPE on Kumho MX and I prefer the RE050A II on my 328 to the Kumhos (which I thought had mushy sidewalls, less grip and less tolerance for heat)

glad you found some tire pressures that worked well for your setup!

There are several different 050As, make sure you've got the right ones.

There's the regular Bridgestone RE-050A, which is an inferior, 2 generation old compound. Then there's the Bridgestone RE-050A Pole Position, which is a far superior compound to the RE-050A. Both use the same tread pattern, the only way to tell is by the UTQG tread wear rating and the sidewall, the good '050A' says 'Pole Position' on it.

After having tried just about every iteration of the Bridgestone "050" variant, plus the Kumho MX, my PERSONAL OPINION is that the 050A Pole Position is much better than the MX and lightyears better than the 050, 050A, and the 050A Run-flat. The 050A Pole Position is just maybe a hair/notch below the Toyo R1-R in dry grip and SUPERIOR in wet-grip to Michelin PS2, which has amazing wet grip to start with.

Rumor has it the Kumho XS might as well be an R-Comp.

nicknaz · 07-13-2009, 01:26 PM

Quote:

Originally Posted by The HACK

There are several different 050As, make sure you've got the right ones.

There's the regular Bridgestone RE-050A, which is an inferior, 2 generation old compound. Then there's the Bridgestone RE-050A Pole Position, which is a far superior compound to the RE-050A. Both use the same tread pattern, the only way to tell is by the UTQG tread wear rating and the sidewall, the good '050A' says 'Pole Position' on it.

After having tried just about every iteration of the Bridgestone "050" variant, plus the Kumho MX, my PERSONAL OPINION is that the 050A Pole Position is much better than the MX and lightyears better than the 050, 050A, and the 050A Run-flat. The 050A Pole Position is just maybe a hair/notch below the Toyo R1-R in dry grip and SUPERIOR in wet-grip to Michelin PS2, which has amazing wet grip to start with.

Rumor has it the Kumho XS might as well be an R-Comp.

The tires on my car are "050A II". Your post prompted me to do some goolging and according to NASIOC.com these "050A II" slot in between the "050A" and "050A Pole Position" in terms of dry grip. Maybe that's why everyone with a 335 hates the stock tires (it comes with "050A") and I am ok with them (328 comes with "050A II")

Damn you are right about the Kumho XS

http://www.tirerack.com/tires/tests/...y.jsp?ttid=118

check out the average cornering force chart at the bottom of that page. over 1g on a stock '08 E92 328 just from swapping to the Kumho XS

Jeffrolite · 07-29-2011, 10:21 PM

Have you considered adjusting your driving technique? Trail brake a little more into the turns to add weight over the front tires. The added forward weight will give you more front end grip and reduce over steer. If you release braking prematurely then turn, the weight will be rearward again, giving more traction to the rear than front. I'll be autocrossing tomorrow with stock RFT staggered set up and will start with 38 psi front and 42 psi rear. Although, I can't wait to buy another set of rear wheels for the front...added bonus you can rotate the tires!

07-07-2009, 05:54 PM	#23
satakal Major 95 Rep 1,476 Posts Drives: e46 Join Date: Nov 2007 Location: socal iTrader: (2)	I can't wait to drive Watkins Glenn and The Ring. OMG, the ring! In 1080! no clue on release date. We should have a Prologue / beer / bbq at my house next weekend. Or, we could beg the cool guys in the local PCA to let is "crash" their AX. http://www.motorsportreg.com/index.c...2F095C54DE7424
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07-07-2009, 06:19 PM	#28
Chowbow pew pew 166 Rep 6,781 Posts Drives: 三三五i Join Date: Aug 2007 Location: CA iTrader: (6) Garage List 2015 BMW 328i wagon [0.00] 2007 BMW 335i sedan [10.00] 1997 BMW 328i track ... [10.00]	Oh, and these are only for autoX. On a road course I run lower pressures, 40F/40R, and of course I don't push it quite as hard. __________________ CSL replicas are now CSL counterfeits. Jesus saves, like Valentine1.
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07-07-2009, 06:36 PM	#29
Ramos Colonel 863 Rep 2,897 Posts Drives: G20 2020 M340 Join Date: Nov 2007 Location: So-Cal iTrader: (6)	Gotcha... Makes sense.. I just think that you are sacrificing way too much grip to avoid rolling on the tires.. Do that really cure your understeer? That's why I said in my first post that I don't think tire pressure can really cure understeer on our cars running staggered. At least you save rubber by running such high pressures..
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07-07-2009, 06:45 PM	#30
Chowbow pew pew 166 Rep 6,781 Posts Drives: 三三五i Join Date: Aug 2007 Location: CA iTrader: (6) Garage List 2015 BMW 328i wagon [0.00] 2007 BMW 335i sedan [10.00] 1997 BMW 328i track ... [10.00]	It's definitely slippery when there's a lot of rollover, and hard to control at the limit. I'll try running some lower pressures again and see what happens. I've consistently tested and had to add air until now but no harm in trying to go back down. I should be going this Sunday and I'll check it out. __________________ CSL replicas are now CSL counterfeits. Jesus saves, like Valentine1.
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07-07-2009, 06:51 PM	#31
Ramos Colonel 863 Rep 2,897 Posts Drives: G20 2020 M340 Join Date: Nov 2007 Location: So-Cal iTrader: (6)	Try 38 Front 42 rear next time and see what that does... HAve you ever tried square though? I am telling that makes a bigger difference than any pressure adjustment you can come up with
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07-10-2009, 12:21 PM	#32
JoosyJoos Major 113 Rep 1,347 Posts Drives: 2011 335d Join Date: Apr 2007 Location: Atlanta, GA iTrader: (1) Garage List 2008 BMW 335i [0.00]	I'm autoxing on my Volks for the first time tomorrow. I had been using the stock rims with the Bridgestone RFTs. Not really sure where to start out the tire pressure but I'll probably try around 36 front, 38 rear and tweak from there. Inflating the RFTs up to 38-40psi makes them incredibly hard to drive on in my opinion. The car feels more responsive but it comes at a cost of grip. I'll be running on Kumho Ecsta MX tires.... so if anyone has used these in an autox setting let me know. __________________ 1997 M3 Coupe - BMWCCA I-Prepared #22 2006 M Roadster - 23,000 miles and slowly counting
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07-10-2009, 01:33 PM	#34
Chowbow pew pew 166 Rep 6,781 Posts Drives: 三三五i Join Date: Aug 2007 Location: CA iTrader: (6) Garage List 2015 BMW 328i wagon [0.00] 2007 BMW 335i sedan [10.00] 1997 BMW 328i track ... [10.00]	I ran the MXs in a 225/40/18 on my S4 for a season, I believe I ran at 40ish hot. YMMV though, especially if you're running a lower profile tire. The lower the profile, the higher the pressure GENERALLY. But don't take that as a rule. __________________ CSL replicas are now CSL counterfeits. Jesus saves, like Valentine1.
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07-10-2009, 09:13 PM	#35
JoosyJoos Major 113 Rep 1,347 Posts Drives: 2011 335d Join Date: Apr 2007 Location: Atlanta, GA iTrader: (1) Garage List 2008 BMW 335i [0.00]	Thanks guys... I've got them pumped up around 40psi right now waiting for tomorrow. Its always easier to drop pressure than to add it so I went high. I'll report back here tomorrow with results. __________________ 1997 M3 Coupe - BMWCCA I-Prepared #22 2006 M Roadster - 23,000 miles and slowly counting
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07-12-2009, 02:44 PM	#36
JoosyJoos Major 113 Rep 1,347 Posts Drives: 2011 335d Join Date: Apr 2007 Location: Atlanta, GA iTrader: (1) Garage List 2008 BMW 335i [0.00]	Okay, thought I would report back since the autox was last night. First let me say that night autoxes are pretty tough when their isnt adequate lighting lol. Litte background... I'm running Volk CE28N's with 235/40/18F and 265/35/18R with Kumho Ecsta MX tires (which are very worn at this point). I had them pumped up to 40psi front and 38psi rear. It was my first time doing an autox on these tires and let me say what it difference it meant compared to the original RFTs. I think I had the ideal tire pressures set because understeer was largely nonexistant (given the car we drive I'd say it was good for a 3500lb porker). So I just thought I would let people know for those of you running a similar setup. __________________ 1997 M3 Coupe - BMWCCA I-Prepared #22 2006 M Roadster - 23,000 miles and slowly counting
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07-12-2009, 10:24 PM	#38
JoosyJoos Major 113 Rep 1,347 Posts Drives: 2011 335d Join Date: Apr 2007 Location: Atlanta, GA iTrader: (1) Garage List 2008 BMW 335i [0.00]	The Kumhos are light years ahead of the RE050A's imho. My friend runs the XS series while I have the older compound MX tires. They have both received praise from Tirerack as well as Grassroots comparison tests. Additionally they are pretty cheap performance tires when compared to things like the Bridgestone RE01R and RE11s. My only gripe is that compared to my brothers Bridgestone RE01Rs on his 318ti, the Kumhos arent nearly as good in the wet. __________________ 1997 M3 Coupe - BMWCCA I-Prepared #22 2006 M Roadster - 23,000 miles and slowly counting
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07-13-2009, 12:25 AM	#39
nicknaz Lieutenant General 3188 Rep 10,509 Posts Drives: C6Z Join Date: May 2008 Location: NorCal iTrader: (0)	wow, that's really interesting! I wonder how much difference there is between the RE050A and RE050A II compounds. I used to do HDPE on Kumho MX and I prefer the RE050A II on my 328 to the Kumhos (which I thought had mushy sidewalls, less grip and less tolerance for heat) glad you found some tire pressures that worked well for your setup!
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07-13-2009, 12:33 AM	#40
Chowbow pew pew 166 Rep 6,781 Posts Drives: 三三五i Join Date: Aug 2007 Location: CA iTrader: (6) Garage List 2015 BMW 328i wagon [0.00] 2007 BMW 335i sedan [10.00] 1997 BMW 328i track ... [10.00]	I was looking to try out some new pressures today but ended up co-driving somebody's Evo instead. At least I got to beat up someone else's car instead of mine. Will have to wait for the next one to see what works. __________________ CSL replicas are now CSL counterfeits. Jesus saves, like Valentine1.
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07-29-2011, 10:21 PM	#43
Jeffrolite Enlisted Member 0 Rep 33 Posts Drives: 2008 335xi e90 Red MT Join Date: May 2011 Location: Morgantown, WV iTrader: (0)	new post to a very old thread Have you considered adjusting your driving technique? Trail brake a little more into the turns to add weight over the front tires. The added forward weight will give you more front end grip and reduce over steer. If you release braking prematurely then turn, the weight will be rearward again, giving more traction to the rear than front. I'll be autocrossing tomorrow with stock RFT staggered set up and will start with 38 psi front and 42 psi rear. Although, I can't wait to buy another set of rear wheels for the front...added bonus you can rotate the tires!
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