E46 BMW Social Directory E46 FAQ 3-Series Discussion Forums BMW Photo Gallery BMW 3-Series Technical Information E46 Fanatics - The Ultimate BMW Resource BMW Vendors General E46 Forum The Tire Rack's Tire Wheel Forum Forced Induction Forum The Off-Topic The E46 BMW Showroom For Sale, For Trade or Wanting to Buy

Welcome to the E46Fanatics forums. E46Fanatics is the premiere website for BMW 3 series owners around the world with interactive forums, a geographical enthusiast directory, photo galleries, and technical information for BMW enthusiasts.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact contact us.

Go Back   E46Fanatics > Tuning & Tech > Motorsports & Track Forum by BimmerWorld

Motorsports & Track Forum by BimmerWorld
From Auto-X to Trackday to Racing and Professional Motorsports this is the place to discuss making BMWs fast
Sponsored by BimmerWorld

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 12-12-2009, 06:47 PM   #1
oofie
Registered User
 
Join Date: Jun 2004
Location: SD
Posts: 137
My Ride: 07 Fit
Send a message via AIM to oofie
Autocross...help

So my brother and I need new tires for his Z4 that we autocross. We have Falken Azenis right now but they're almost slicks right now. We're looking for some suggestions.

1) We have 235/40/17 right now on all four corners, will 245s or 255s help increase handling? Is it worth it to go from 235 to 245 or just go straight to 255s?

2) We're looking to get the Dunlop Direzza Z1 Star Specs. Is there anything else we should consider in that price range (about $140-160 per tire). How about the Kumho Ecsta XS? They're a bit cheaper than the Direzza, but since we're using this set strictly for autocross, we don't really mind spending if we're to get better tires.

Any help is greatly appreciated
__________________
oofie is offline   Reply With Quote
Ads by Google

Guests, get your FREE E46Fanatics.com membership to remove this ad.
Old 12-13-2009, 12:53 AM   #2
e46techtuner
Registered User
 
Join Date: Jun 2005
Location: USA
Posts: 718
My Ride: 2000 328i
I would get 255s, star specs. Haven't heard much about the xs.
__________________
e46techtuner is offline   Reply With Quote
Old 12-13-2009, 01:14 AM   #3
BruceWayne
OEM ///Member
 
BruceWayne's Avatar
 
Join Date: May 2008
Location: Annapolis, MD
Posts: 578
My Ride: 03 LSB ///M3
255s would be a different diameter and would be changing the ratios, 255/40/17 is too large and 255/35/17 is too small
__________________
AST 4200 | Vorshlag camber plates | Power Flex rtab & fcab | AFE stg. 2 | Auto Solutions SSK | Macht Schnell Studs | Stoptech stg. 2
BruceWayne is offline   Reply With Quote
Old 12-13-2009, 01:18 AM   #4
trippinbillies4
Registered User
 
trippinbillies4's Avatar
 
Join Date: Jul 2004
Location: Cincinnati, OH
Posts: 836
My Ride: '02 Mini, '13 FR-S
Changing the size ratio doesn't matter as long as you don't care if your speedo is off...

I ran RE-11's for a bit on mine, they do well at autox, especially after they're worn down to about 2/32". MY suggestion: get a second set of wheels and some A6's and be done with it. So much more fun!
__________________
__________________________________________________

'02 Mini Cooper #40HS, '13 Scion FR-S #40CS, '12 Ducati SF848
trippinbillies4 is offline   Reply With Quote
Old 12-13-2009, 03:05 AM   #5
bigjae1976
Registered User
 
bigjae1976's Avatar
 
Join Date: Dec 2003
Location: Earth
Posts: 11,471
My Ride: A car
Send a message via MSN to bigjae1976
I have the Dunlops Z1 SS's. Great tire even in occasional 35 degree weather. They grip pretty well when cold which I think is better for autocross. Only downside is a relatively small selection in sizes.
bigjae1976 is offline   Reply With Quote
Old 12-13-2009, 09:43 AM   #6
oofie
Registered User
 
Join Date: Jun 2004
Location: SD
Posts: 137
My Ride: 07 Fit
Send a message via AIM to oofie
Quote:
Originally Posted by trippinbillies4 View Post
Changing the size ratio doesn't matter as long as you don't care if your speedo is off...

I ran RE-11's for a bit on mine, they do well at autox, especially after they're worn down to about 2/32". MY suggestion: get a second set of wheels and some A6's and be done with it. So much more fun!
We're just running with BMW CCA and we'd like to stay in the stock class for now, so no R compounds for us. Are you running R compounds? We'd love those RE-11's but they're just too much for us right now (price wise).

So is 255/40/17 better than 255/35/17? And as trippinbillies4 said, we really don't care about the ratio, the set will be strictly for autocross.
__________________

Last edited by oofie; 12-13-2009 at 09:46 AM.
oofie is offline   Reply With Quote
Old 12-13-2009, 12:32 PM   #7
e46techtuner
Registered User
 
Join Date: Jun 2005
Location: USA
Posts: 718
My Ride: 2000 328i
Some people like using smaller diameter tires/wheels for better acceleration.

I would get 255/40/17. Its your choice though.

1010tires.com and discount tire both have a tire calculators you can use. The difference in diameter is very small.
__________________
e46techtuner is offline   Reply With Quote
Old 12-13-2009, 02:33 PM   #8
oofie
Registered User
 
Join Date: Jun 2004
Location: SD
Posts: 137
My Ride: 07 Fit
Send a message via AIM to oofie
Yeah, my brother and I are still debating if we would gain grip by going from 235 to 255. However, we'll probably just get the 255 since it's only about $14 more per tire, might as well try another size other than 235s. Thanks guys!
__________________
oofie is offline   Reply With Quote
Old 12-13-2009, 07:36 PM   #9
e46techtuner
Registered User
 
Join Date: Jun 2005
Location: USA
Posts: 718
My Ride: 2000 328i
you will definitely feel a difference in traction compared to 235s.
__________________
e46techtuner is offline   Reply With Quote
Old 12-18-2009, 07:45 PM   #10
trippinbillies4
Registered User
 
trippinbillies4's Avatar
 
Join Date: Jul 2004
Location: Cincinnati, OH
Posts: 836
My Ride: '02 Mini, '13 FR-S
With an open diff, you might take some of the camber out of the rear. Sounds crazy I know... I took my rear camber down to -1.4, toe'd out the back end 1/8". Makes a huge difference in getting the car to rotate.
__________________
__________________________________________________

'02 Mini Cooper #40HS, '13 Scion FR-S #40CS, '12 Ducati SF848
trippinbillies4 is offline   Reply With Quote
Old 12-22-2009, 01:47 PM   #11
murph1379
Registered User
 
Join Date: Nov 2006
Location: Minneapolis, MN
Posts: 483
My Ride: 2003 330i ZHP
I'm not sure where someone got the 255/35/17 size, but if someone made one I'd definitely buy that! (but they don't)

255 star specs all around will work well for you.
murph1379 is offline   Reply With Quote
Old 12-30-2009, 08:56 PM   #12
M3it
Registered User
 
Join Date: Mar 2006
Location: OC
Posts: 38
My Ride: '02M3,325it,330Ci
Quote:
Originally Posted by murph1379 View Post
I'm not sure where someone got the 255/35/17 size, but if someone made one I'd definitely buy that! (but they don't)

255 star specs all around will work well for you.
+1, Murph knows what he is talking about!

I ran Dunlops in the same 6 cyl stock group as your Z4 in SD, and was faster than the M cars.

Rick
__________________

Dunlop Tires / GreenFilter / ChaseCam in car video / Bilstein shocks / Enkei wheels
M3it is offline   Reply With Quote
Old 01-06-2010, 05:20 PM   #13
Activ3
Registered User
 
Join Date: Feb 2005
Location: Orlando/Miami
Posts: 6,360
My Ride: gets DRIVEN.
Send a message via AIM to Activ3
255 17s ftw. Check out the NT05 as well...
__________________
-David www.e46nonm.com | My Videos
2000 328i - Custom Turbo tuned by AA

Activ3 is offline   Reply With Quote
Old 01-06-2010, 05:21 PM   #14
Activ3
Registered User
 
Join Date: Feb 2005
Location: Orlando/Miami
Posts: 6,360
My Ride: gets DRIVEN.
Send a message via AIM to Activ3
Quote:
Originally Posted by trippinbillies4 View Post
With an open diff, you might take some of the camber out of the rear. Sounds crazy I know... I took my rear camber down to -1.4, toe'd out the back end 1/8". Makes a huge difference in getting the car to rotate.
What I also had to do was run 550lb rear springs with soft progressive ones up front. You can almost dial in off-throttle oversteer so that you can power on early to keep her straight.
__________________
-David www.e46nonm.com | My Videos
2000 328i - Custom Turbo tuned by AA

Activ3 is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Censor is ON





All times are GMT -5. The time now is 12:20 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
(c) 1999 - 2011 performanceIX Inc - privacy policy - terms of use