An Odd one Dec. 24th, 14:15 hrs.
Some pics would really help with this one. Hard to describe uneven tire wear. PICS !!
I've used TKC's on two of my bikes (not BMW's) ... never have had the radical uneven wear you describe. The rears do wear fast on pavement, the fronts last 3 times as long.
The one in pic below is from my DR650 (about 390 lbs. fully fueled and loaded) About 1500 miles on this tire. It's wearing quite well, about 800 miles tarmac, 700 miles dirt. Wearing perfectly! (PS: I never balance my wheels)
TKC80 front at 1500 miles. (90/90-21)
I've seen TKC fronts wear badly on a RTW R100GS (and other bikes) ... Some of the R100's were ridden on almost ALL paved roads ... so center wear was quite pronounced but wear was fairly even, save the unworn knobs on the side of the tire, which were still in fair shape.
Really the WRONG tire for paved roads ... and can be dangerous on wet, greasy roads, especially if over inflated.
(I've seen a couple R1150GS riders GO DOWN running TKC's in wet. Not good)
Tire pressures are important and a wobbly wheel could also cause funny wear patterns. But you should feel this when riding if out of alignment or wobbling at various speeds.
Maybe try a nice 50/50 tire if riding at least 50% tarmac? (Heidenau, Shinko,
Kenda, Mefo et al)