E9X What can cause toe to change at high speeds?

[KClemente]

Been having this issue for a couple weeks now and the rundown is; at 60-80 mph it feels as if one or both of my front wheels all of a sudden have outwards toe because steering gets real light and very very twitchy. Also the fact that the steering wheel vibrates pretty badly. But anything over 85 (only tested it to 100mph) the steering feels normal and vibration has reduced.

I aligned my car with my friend using their hunter machine and front is within spec (0.15 degree toe) though I am running -1.6 degrees of camber which shouldn't have anything to do with things. Car tracks straight nonetheless

So far I have replaced the outer tie rods, replaced the front tires, put on M3 thrust (upper) control arms BUT left my stock lower control arms on. Everything is preloaded and torqued to spec.

I highly doubt its to do with the wheel balance or anything of that sort because it still did it with my last pair of tires.

My guess is that a possibly blown lower control arm moves out of its designed axis and allows for toe out at higher speeds. Note that I am not able to shake either wheel on any of its axis'. Everything's tight and doesn't have any play.

 

[Cruizinmax]

Not a lot of suggestions here but does your car have active steering?

 

[KClemente]

Not a lot of suggestions here but does your car have active steering?

I wish it did haha. Just replaced the passenger lower control arm and the problem still persists. None of the wheels have any sort of play whatsoever when they're lifted off the ground so I doubt its anything to do with the arms. 75 mph is the danger zone and steering gets very very light and twitchy but I can easily cruise at 100+ with tight steering.

 

[derekgates]

Have you inspected the rear toe arms? I had incredible issues with the rear of my 335is under load; the rear toe changed wildly and made for a dangerous situation. It is possible yours are worn further than mine were?

 

[KClemente]

Have you inspected the rear toe arms? I had incredible issues with the rear of my 335is under load; the rear toe changed wildly and made for a dangerous situation. It is possible yours are worn further than mine were?

Yeah so the last tire shop that claimed to have balanced my front's actually didn't end up balancing them.. I balanced them myself this time and it solved my issue.

I had about 1.25oz worth of old weights so I took those off and the machine told me I just needed 0.5 oz on the inner barrel. Problem solved lol

 

[fmorelli]

@barry@3DM any input?

Filippo