Contact and Rear Toe Adjustment

[HaB racing]

Hey guys,

A few races back I had a guy make wheel to wheel contact with my left rear tire (his front right). After that weekend a inspected the left rear suspension and looked for any obvious damage, other than wheel scuff marks. I didn't see anything. I finally got around to checking my alignment yesterday and that wheel will not adjust to anything less than 5mm of toe-in. I'm assuming that I have a bent trailing arm but can't find much info on a M car bending a trailing arm. Spec E46 guys bend them often. I haven't done any tear down to really dig into the issue yet. Have any of you seen this issue on a E46 M car? Those trailing arms are expensive and hate to replace it without it correcting the issue. At the end of the day I need to tear into it but thought I'd check with you guys for any experience.

EDIT (for more info): I have ground control lower control arms so that weak point was addressed. RTAB are powerflex and were installed by the previous owner prior to me turning it into a race car. Maybe it's time for monoballs. I just looked over the entire rear suspension again and the upper control arm is showing no obvious issue. The trailing arm bracket that attaches to the chassis could be bent slightly, tough to tell but it looks the bolt holes aren't allowing the additional range needed for the toe adjustment. Wondering if the bracket and monoballs could be a start.


Brad

[BBRTuning]

The local race alignment shop here does tons of E46 M3s and says this is somewhat common (especially from Buttonwillow, a known wheel-bending track). Apparently my left rear is bent just enough that I had a similar issue when trying to run a bit more rear camber and was unable to get the toe back in check with adjustment maxed out.

Either way, I’d definitely recommend going monoball. I’ve had Turner monoball units for 4 years now and probably 30-35 track days and they’re still tight. IMO polyurethane doesn’t belong in cars, especially in race cars, and especially on components that are designed to articulate. Among its many faults it will deform over time and not return to its original shape; it’s possible this is at least part of the issue.

[HaB racing]

The local race alignment shop here does tons of E46 M3s and says this is somewhat common (especially from Buttonwillow, a known wheel-bending track). Apparently my left rear is bent just enough that I had a similar issue when trying to run a bit more rear camber and was unable to get the toe back in check with adjustment maxed out.

Either way, I’d definitely recommend going monoball. I’ve had Turner monoball units for 4 years now and probably 30-35 track days and they’re still tight. IMO polyurethane doesn’t belong in cars, especially in race cars, and especially on components that are designed to articulate. Among its many faults it will deform over time and not return to its original shape; it’s possible this is at least part of the issue.

Thanks for the response. Monoball RTABs were on my winter upgrade list for sure. Guess my hand is forced a little early. Thinking of going with Condo or Synco designs but need to do some more homework. Hopefully a RTAB change gets me the adjustment range back.

[Apex_80]

Thanks for the response. Monoball RTABs were on my winter upgrade list for sure. Guess my hand is forced a little early. Thinking of going with Condo or Synco designs but need to do some more homework. Hopefully a RTAB change gets me the adjustment range back.

FWIW I have the syncro and love them. Installed for 2+ years now and no noises and still as solid as they started.