Author Topic: Alignment Pros - What's Eating My Tires added photos to post 6* (Read 3352 times)

2kwk4u · « **on:** August 07, 2014, 06:44:25 AM »

Long story short:

I put KW V3s on last summer during my home leave. I drove it from St. Louis to Colorado for a few days' road trip with my wife. I moved back to the states in late June and have pressed the car into service as a daily driver (long commute - mostly highway miles) since driving it from St. Louis to the DC area. When I put the coilovers on, I drove it a couple hundred miles before having it corner-weighted and aligned to the following specs (actual):

FRONT Left Right
Camber -2.0* -1.8*
Cross Camber -0.1*
Caster 7.6* 7.7*
Cross Caster -0.1*
Toe 1/32" -1/32"
Total Toe 0"

REAR Left Right
Camber -1.5* -1.6*
Caster ---------------- (no ability)
Toe -0" 0"
Total Toe 0"
Thrust Angle -0.01*

Other suspension mods include:

- GXP Z0K sways front and rear w/ polyurethane bushings
- LVFCB
- Race Backbone
- Probeam
- 6kg/mm springs on all 4 corners (~400 lb/in)

I have a few ideas what might be causing it, but want your input. Initially I thought the suspension might have settled more post corner weight/alignment, but it measures the same with a tape measure (scientific, I know). I have an appointment to get the alignment checked/adjusted tomorrow before I put new tires on. Of course if the alignment is way off what I had set, I'll go back to those settings. If not, then I'm at a loss and wonder if I need to dial out some camber or dial in some toe.

Advice, please?

EDIT: Tried to attach photos, but they're too large. Essentially, the insides of the tires are wearing rapidly - especially up front. No "cupping" evident, though. Can re-post photos tonight if necessary.

POS VETT · « **Reply #1 on:** August 07, 2014, 07:14:53 AM »

The front has substantial negative camber for a street car. Mine is set at about the same value yet front tires wear is, so far, normal. I can't remember what the toes are. While adjusting the alignment, have the technician put a simulated driver weight on the driver seat. In my case, I actually sit still in the driver seat for about half an hour. All my cars have been aligned this way.

2kwk4u · « **Reply #2 on:** August 07, 2014, 07:42:33 AM »

I sat in the driver's seat for corner weighting and alignment originally as well. The consensus on the alignment thread ( http://www.kappaperformance.com/forum/index.php/topic,4395.0.html ) is that kappas can handle a fair amount of neg camber without this degree of uneven tire wear. That being said, I'm not sure if anyone else who was running those settings was daily driving their kappa. Again, I'm putting a lot of highway miles on the car these days. Finally, I honestly don't recall if I ever busted and remounted these tires when I rotated (front/rear only, as they're directional - original Dunlop star specs).

Gentleman Jack · « **Reply #3 on:** August 07, 2014, 11:01:32 AM »

DDM Dave does alignments in his sleep. Perhaps a quick call or email with your specs will provide needed answers?

2kwk4u · « **Reply #4 on:** August 07, 2014, 12:22:36 PM »

Soon as I confirm the specs, I might just...

2kwk4u · « **Reply #5 on:** August 07, 2014, 05:15:51 PM »

Now featuring pictures!

Front Right

Front Right close-up

Front Left

Front Left close-up

Rear Right

Rear Left

Critterman · « **Reply #6 on:** August 07, 2014, 05:26:35 PM »

Easy answer, it is your driving!
Seriously give Dave a call,

he did mine and I am showing now wear. I think my camber is at a -2 front and -1 in the back.

TomatoSoup · « **Reply #7 on:** August 07, 2014, 07:39:19 PM »

Ouch, that's quite an angle on that edge wear. Hmmm.

POS VETT · « **Reply #8 on:** August 07, 2014, 08:44:07 PM »

Take corners faster ...

kwtoxman · « **Reply #9 on:** August 07, 2014, 09:26:17 PM »

If the inside of your tires are wearing faster and you want even wear for your driving habits then you need less negative camber. This change will be at the expense of outright cornering grip.

2kwk4u · « **Reply #10 on:** August 07, 2014, 10:31:37 PM »

Kinda what I figured. Unfortunately, I'm using the car as a daily driver w/ a 45+ mile one-way commute. Highway in the mornings, backroads some afternoons. It's a shame, b/c the thing corners like its on rails, but I'm just putting too many highway miles on it and eating tires in the process. Going to have to back off the camber tomorrow before I put on the new tires... Gonna start with only taking out a half-degree and see how that goes.

Thanks, all, for the input.

2kwk4u · « **Reply #11 on:** August 08, 2014, 02:50:06 PM »

The verdict: negative camber + POSITIVE TOE (toe-out) = worn inside edges.

I had .19* of toe OUT up front and .13* in the rear. These numbers were for "total" toe. The rear left was -.19 and rear right +.06. Left/Right front were -.09 and -.10, respectively. My camber numbers were right about where I left them, so I no longer think my suspension settled any more since corner-weighting and the original alignment. I had them dial me back to very slight toe-IN front and rear and leave the camber as-is. I'll keep an eye on tire wear once I mount up the new tires. Now I gotta decide if I want to do one more race on these star specs before I swap over to Potenza S04's... I gotta burn 'em up somehow! Might just go play drift somewhere instead

Critterman · « **Reply #12 on:** August 08, 2014, 07:23:45 PM »

BMW club is having an Autox this weekend. Sykesville I think. Check their website.

2kwk4u · « **Reply #13 on:** August 08, 2014, 10:18:01 PM »

got a link? You going? BMW club and not Porsche club?

Critterman · « **Reply #14 on:** August 09, 2014, 01:14:50 PM »

Sorry didn't get back to this until now.............
It is tomorrow and closed to the public

CDC is also racing today in Winchester (to late to register) but they are in Fredrick on the 23rd with a test and tune on the 24th. They will be back there in Sept.

Here is the link:

http://www.capitaldrivingclub.com/schedule.php

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