You're inside edge only looks slightly better, indicating this is mostly caused by insufficient tire pressure. Excessive camber tends to wear the tire "conically."I just installed a new set of 20' tires. Below are the specs I got the last time (got min toe 0.04 as the machine indicated this as min ). Generally, handling and wear in the back was good (even). The front was wearing more on the outer edge. What should I correct now? 40-50% mileage currently is towing (heavy rear axle), but I am not sure, if there should be anything to correct for this. Thanks!
BMW's recommended tire pressures are not those for optimal tire wear. Other considerations are ride quality and the ability of the tire to maintain adhesion to the road when encountering pavement discontinuities. Also, run-flat-tires tend to wear as if under-inflated. That's because the sidewalls can't stretch as much in the circumferential direction as on a non-run-flat radial tire.
Adjusting front camber on BMW's requires replacing the upper control arm or knuckle (on cars with struts), or installing a "camber kit." BMW sells the upper arms and knuckles with standard camber, and also plus or minus one-half degree.
Towing and carrying a lot of weight in the cargo area actually reduces the weight on the front axle.
Frau Putzer's G01 X3 has non-run-flat tires. The recommended pressures are 32 PSI front and 35 PSI rear. At 36 PSI front (measured cold in the early morning) the tires were still wearing as if slightly under-inflated. The rear tires at 39 PSI were wearing as if slightly over-inflated. With tire rotation, they're wearing almost perfectly (average wear of the two middle circumferential channels are equal to the average wear of the two side circumferential channels).
BMW SUV's tend to wear the outsides of the tires more. This is due to a higher center of mass (causing more body roll and concentrating weight on the outer tires in a turn), taller tire sidewalls, and less rear negative camber spec's. BMW passenger cars tend to wear the insides of the tires more. Frau Putzer's X3's tires' outer channels are wearing faster than the inner circumferential channels. Because of the over-inflation, the edges of tires are fine, though.
I bet you had to pull the steering wheel to the left constantly before the alignment. Even then, your total toe-in in the front was just 0.06 (degrees?) or 0.03 (degrees?) per front wheel.
If you have a square set-up, rotating the tires would help greatly. It averages out any uneven wear over all four tires.
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