F30POST
F30POST
2012-2015 BMW 3-Series and 4-Series Forum
BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read
BMW 3-Series and 4-Series Forum (F30 / F32) | F30POST > Technical Forums > Tracking / Racing / Autocrossing > Time for dedicated autox tires! (Questions regarding dif. rim sizes)
Extreme Powerhouse
Post Reply
 
Thread Tools Search this Thread
      07-19-2019, 03:44 PM   #1
badbread
not good, but bad
United_States
296
Rep
395
Posts

Drives: 2013 335i
Join Date: Jun 2016
Location: Bay Area, CA

iTrader: (3)

Time for dedicated autox tires! (Questions regarding dif. rim sizes)

Hi all,

So I'm really enjoying autox in my F30.

Last week I was tearing it up, snagged 2nd place in B class (1st place was a '18 230i with wheels and suspension work, he beat me by about .4). A few of the other B-class guys were super surprised especially seeing I was on PS4S's. They unanimously said I need to get some RE71's (no point change) on my car and that's where I am now.

My plan is to go square with no other mods (ie camber, suspension, spacers, etc...) Well maybe spacers... 245 all around seems safe. I think I could go up to 255's all around without bumping myself into A class...

My budget is pretty tight (to tight to get new APEX rims) so I'm on the hunt for the least expensive/decent rims I can find.

I have a few questions, I'm finding a lot of OEM staggered setups from F3x's.

For example one BMWCCA facebook member sent me this:
Quote:
"18x8.5 ET45 and have brand new PS4s 245/35/18
Rears are 18x9.5 ET43 and have 595RSRR 265/40/18
So what happens if I go with different size rims for up front and back, from the very little I know about rims/tires 24(5)5's should still fit but what are the negatives of having different size rims? Does that offset the whole square concept, etc...? How big of a difference are we talking going up to 245/255's up front with RE71's? Any concern losing 10mm on the rear if I go down to 245's?

Thank you very much!
__________________
They are spelled BRAKES not breaks!!!! Oh FFS, not another spark plug thread!
BreadsBMW on Youtube
Appreciate 0
      07-22-2019, 01:06 AM   #2
RMachuca3d
Lieutenant
RMachuca3d's Avatar
238
Rep
468
Posts

Drives: F30 328i Msport
Join Date: Aug 2018
Location: WA

iTrader: (2)

Garage List
255's should fit depending on the offset of the wheels.

Currently i'm running 18x8.5 ET30 all around and have a nice flush fitment with a little room to spare for 245's or 255's up front. (currently using 235/45/18's, that size was on super duper liquidation, bought these tires to tear them up )

If you are looking to stay with 18's, I might sell my set of lightweight TRMotorsports C4's (aprox 20-21lbs per wheel).
Appreciate 0
      07-22-2019, 09:42 AM   #3
alohasurftoad
Colonel
United_States
1089
Rep
2,186
Posts

Drives: 428i gran coupe
Join Date: Apr 2015
Location: hawaii

iTrader: (0)

For decent cheap I suggest konig ampliform, 18x9.5 Et35 with 255/40/18 square.

If you want staggered, Sportline 8s, 18x8.5 ET32 with 245/40/18 front, 18x9.5 ET45 with 255/40(or265/40) rear.
Appreciate 0
      07-31-2019, 02:36 PM   #4
brigade24
Enlisted Member
Canada
12
Rep
43
Posts

Drives: 2013 335 Sportline with X-dive
Join Date: Jun 2018
Location: Canada

iTrader: (0)

I autox an F30 335 xdrive (SCCA class is STU). I'm running an 18x9.5 et35 with 265-35-18 RE71s. Plenty of clearance in the rear but i run a 3mm spacer to max track width. I have to run a spacer up front to clear the coilovers. My front fenders are not rolled.

The wheels I'm using are superspeeds RF003RR and they cost less than $1k Canadian so less 32% for US$ purchases or whatever the exchange rate is and you've got yourself a bargain. The RF003 wheels in 18x9.5 format weigh 18.7lbs each which is apex territory.

Here is shot of the car in hard transition...bare in mind that i'm "suspensioned" and hence, lowered about 1.2-1.4 inches in this pic.
Attached Images
 
Appreciate 0
      08-19-2019, 02:06 PM   #5
badbread
not good, but bad
United_States
296
Rep
395
Posts

Drives: 2013 335i
Join Date: Jun 2016
Location: Bay Area, CA

iTrader: (3)

So I got some rims! Found some ARC8's up here from another forum member...

After a NIGHTMARE... ABSOLUTE FUCKING NIGHTMARE at the tire shop, I finally got them mounted with RE71R's on Friday, a day before an AutoX event.

Probably took about 4 sessions for them to finally really start biting in and OMG what a difference. Absolute incredible tire.

Took 2nd place in B-class on Saturday, missed 1st by a good amount .567 seconds.

It was really windy and the tires never got above 80F, not sure how big of a difference that makes...
Attached Images
    
__________________
They are spelled BRAKES not breaks!!!! Oh FFS, not another spark plug thread!
BreadsBMW on Youtube
Appreciate 0
      09-08-2019, 09:07 AM   #6
brigade24
Enlisted Member
Canada
12
Rep
43
Posts

Drives: 2013 335 Sportline with X-dive
Join Date: Jun 2018
Location: Canada

iTrader: (0)

Quote:
Originally Posted by badbread View Post
So I got some rims! Found some ARC8's up here from another forum member...

After a NIGHTMARE... ABSOLUTE FUCKING NIGHTMARE at the tire shop, I finally got them mounted with RE71R's on Friday, a day before an AutoX event.

Probably took about 4 sessions for them to finally really start biting in and OMG what a difference. Absolute incredible tire.

Took 2nd place in B-class on Saturday, missed 1st by a good amount .567 seconds.

It was really windy and the tires never got above 80F, not sure how big of a difference that makes...
did you lower your tire pressures?
Appreciate 0
      09-10-2019, 11:56 AM   #7
badbread
not good, but bad
United_States
296
Rep
395
Posts

Drives: 2013 335i
Join Date: Jun 2016
Location: Bay Area, CA

iTrader: (3)

Quote:
Originally Posted by brigade24 View Post
did you lower your tire pressures?
I started around 37PSI and finished around 34... 34 PSI seemed to bite MUCH more though I'm not sure if that's because the tires wore the "release compound" out by that time or because of the change in tire pressure.
__________________
They are spelled BRAKES not breaks!!!! Oh FFS, not another spark plug thread!
BreadsBMW on Youtube
Appreciate 0
      09-10-2019, 03:35 PM   #8
brigade24
Enlisted Member
Canada
12
Rep
43
Posts

Drives: 2013 335 Sportline with X-dive
Join Date: Jun 2018
Location: Canada

iTrader: (0)

Quote:
Originally Posted by badbread View Post
I started around 37PSI and finished around 34... 34 PSI seemed to bite MUCH more though I'm not sure if that's because the tires wore the "release compound" out by that time or because of the change in tire pressure.
34 psi is what i ran when i was on 245 RE's. i would sometimes bump up the psi in the front to 36.
Appreciate 1
badbread296.00

      09-12-2019, 05:04 AM   #9
didisinned
Enlisted Member
3
Rep
31
Posts

Drives: 2014 BMW 428i
Join Date: Jun 2018
Location: Santa Clara

iTrader: (0)

RE71r's are just absolutely amazing. So easy to burn through them, and I hate the road noise (all the rocks it picks up like glue). But you can't beat those!
Appreciate 0
      09-13-2019, 12:02 PM   #10
MacklinUSOB
Captain
United_States
383
Rep
714
Posts

Drives: f30 328i 6MT Sport
Join Date: Jan 2017
Location: Connecticut

iTrader: (0)

Just to add I am running 18x8.5 et38 SM-10s with 245 Hankook RS4s all around. I also have F80 LCAs and TSs which widen the track. The 245 RS4s actually measure to about 256. First installed I had some serious rubbing issues on the outer fender and fender tab. Even after removing the tab and mildly rolling the fenders I can still rub when the wheel isn't straight but not often. I have camber plates on the way to hit my target -2.8 (at -1.8 now) and to get rid of the rubbing. Here's a shot under full compression with the current setup, it's real snug.

For anyone trying to fit 255+ tires make sure you are running a more narrow offset than I am.
Attached Images
 
__________________
Add 5 horsepower for every M logo

328i RWD | Sportline | CRed on MW | 6MT | Bootmod3 STG 1 | MPE | GPlus FMIC | KW V2 | F80 LCA/TS | APEX SM-10 | R-S4 | Hawk HP+ | RBF600 | SS Lines |
Past: E36 328is & E38 740i

Last edited by MacklinUSOB; 09-13-2019 at 12:09 PM..
Appreciate 0
      10-03-2019, 10:04 AM   #11
chaungo
=D
chaungo's Avatar
Canada
1041
Rep
1,820
Posts

Drives: 13' 335ix
Join Date: Sep 2015
Location: Quebec

iTrader: (4)

Garage List
Quote:
Originally Posted by badbread View Post
I started around 37PSI and finished around 34... 34 PSI seemed to bite MUCH more though I'm not sure if that's because the tires wore the "release compound" out by that time or because of the change in tire pressure.
I don't autox but I do a bunch of lapping and find that starting at 32psi all around works great as you'll normally finish at 36-37ish.

Also, you should look into getting a stud kit since you'll be taking off your wheels a lot, it'll save your hubs and it looks better. I bought some and wheels changes are a breeze and the nuts do not seize on, nor my wheels.

I run 18x9 ET30, 255/40/18 on PS4s lowered on dinan springs/shockware.

PS4s are great tires, but normally around 7-8 laps in a 1 minute track, it'll start to get greasy.
__________________
2013 335i xDrive
Bootmod3, Pure Stage 2, Pure Inlet, GFB DV+, AFE Pro Dry S Drop-in Filter, ER CP/TIC CP, ER Catless DP, ATM FMIC, Borla ATAK, Dinan Springs, Dinan Shockware, XHP ZF8AT Stage 3, xDelete
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

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 Off



All times are GMT -5. The time now is 09:19 PM.




f30post
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST