BMW 1 Series Coupe Forum / 1 Series Convertible Forum (1M / tii / 135i / 128i / Coupe / Cabrio / Hatchback) (BMW E82 E88 128i 130i 135i)
 





 

Post Reply
 
Thread Tools Search this Thread
      01-16-2013, 10:26 AM   #1
kb135
Private First Class
kb135's Avatar
Australia
5
Rep
120
Posts

 
Drives: 135i Alpine white
Join Date: Dec 2011
Location: Brisbane, Australia

iTrader: (0)

Does added negative toe (in) increase traction at rear?

As the title says, does adding more toe in at the rear (say 1mm to 2.5mm per side) increase your traction on take-off? Reason I ask is, just two weeks ago when I had my 18"MPSS (225/255) and 1mm toe in rear, I could spin wheels in 1st and 2nd gear while rolling at 40km/h. Now with my 19"MPSS and 2.5mm toe in (same 225/255 widths) I am finding it very difficult to even spin in 1st while rolling. (Obvious factors have been checked, DTC completely off, boosting healthy etc.)
Any ideas?
Appreciate 0
      01-16-2013, 11:04 AM   #2
DRedman45
First Lieutenant
DRedman45's Avatar
4
Rep
391
Posts

 
Drives: 07 e86 //M coupe
Join Date: Oct 2012
Location: Northern va

iTrader: (0)

yes it does, but added weight of 19's also makes a huge difference
Appreciate 0
      01-16-2013, 08:12 PM   #3
kb135
Private First Class
kb135's Avatar
Australia
5
Rep
120
Posts

 
Drives: 135i Alpine white
Join Date: Dec 2011
Location: Brisbane, Australia

iTrader: (0)

Hmm. Did some checking and turns out both the 261M 18"and V710 19" wheels weigh the same? Has my research failed me?

Will do my own weighing this weekend.
Appreciate 0
      01-17-2013, 05:20 AM   #4
RimasRS
Colonel
RimasRS's Avatar
28
Rep
2,397
Posts

 
Drives: 135i MT 2009 AW
Join Date: Sep 2010
Location: Europe

iTrader: (0)

Quote:
Originally Posted by kb135 View Post
Hmm. Did some checking and turns out both the 261M 18"and V710 19" wheels weigh the same? Has my research failed me?

Will do my own weighing this weekend.
Interesting to know difference. Please post results.
Appreciate 0
      01-17-2013, 08:26 AM   #5
IGoFast1589
Captain
IGoFast1589's Avatar
12
Rep
654
Posts

 
Drives: 08 135i
Join Date: Nov 2010
Location: NY

iTrader: (2)

When you take off the rear end of the car will squat down and your dynamic toe settings will change from what they are when static.
Appreciate 0
      01-17-2013, 08:36 AM   #6
kb135
Private First Class
kb135's Avatar
Australia
5
Rep
120
Posts

 
Drives: 135i Alpine white
Join Date: Dec 2011
Location: Brisbane, Australia

iTrader: (0)

Quote:
Originally Posted by IGoFast1589 View Post
When you take off the rear end of the car will squat down and your dynamic toe settings will change from what they are when static.
Ah yes thats true. Have you got any idea if it becomes more toe-in/out? I am guessing out?
Appreciate 0
      02-15-2013, 10:19 PM   #7
kb135
Private First Class
kb135's Avatar
Australia
5
Rep
120
Posts

 
Drives: 135i Alpine white
Join Date: Dec 2011
Location: Brisbane, Australia

iTrader: (0)

Did some weighing:

Turns out
Stock 261M in 18x8.5 with 255/35/18 MPSS = 23.2kg
VMR V710 19x9.5 with 255/30/19 MPSS = 23.2kg
Not an error with scale. I triple-checked these. Just co-incidence.

So i guess tightening up my rear end with subframe bushings and altering camber to -2.0* has given me much more traction on rear? Because its quite hard to break traction in 2nd gear in a straight line, and slight to moderately difficult in 1st, from a roll that is. Used to spin like mad in 1st and break traction at 40km/h in 2nd prior to rear end mods. Logs show it's boosting fine... . Will still check for boost leaks anyway, and maybe attend a dyno day and compare. Butt dyno says all is well though Thats what matters most right?
Attached Images
  
Appreciate 0
      02-17-2013, 02:18 AM   #8
John_01
Colonel
John_01's Avatar
Australia
24
Rep
2,051
Posts

 
Drives: E90 325i, E82 135i
Join Date: Mar 2009
Location: Sydney, Australia

iTrader: (0)

Do you think the new tires may have more grip now they are broken in and started to get some wear?

The rear suspension will gain toe-out when it is compressed. I prefer to call it bump steer.
Appreciate 0
      02-17-2013, 02:29 AM   #9
BMW86
Major General
Australia
138
Rep
8,958
Posts

 
Drives: 135i CLA45 AMG Ninja
Join Date: Jul 2008
Location: Australia

iTrader: (0)

I think you need to factor in these variables:
- condition/wear of both sets of tyres
- the road you did the test on
- road surface temperature and conditions (ie. if it has been raining, for how long or how long ago etc)
- tyre pressure
- tyre temperature

From first hand experience these factors can have a noticeable effect
__________________
BMW 135i N54
MERCEDES CLA45 AMG
Appreciate 0
      02-17-2013, 09:16 AM   #10
Pig Farmer
Captain
8
Rep
753
Posts

 
Drives: 2009 BMW 135i
Join Date: May 2010
Location: Florida

iTrader: (0)

In addition to ^, you almost certainly increased the MOI of the wheel. Even if we assume the total weight and diameter or the wheel/tire combo stayed the same, the weight of the wheel's barrel (i.e. the heviest part of the wheel) was moved 1/2 inch further from the center of rotation.
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
Forum Jump


All times are GMT -5. The time now is 10:52 PM.




1addicts
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
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