Seems to me a careful read of the insurance policy is in order. In any case I think a deductible would apply, so filing a claim for a tire or wheel might or might not make make sense, depending. The dealer-offered policy has no deductible. In my 40+ years of driving, I've had my share of damaged tires and rims from New England potholes, etc. I may not get my money's worth out of it but I'm inclined to go with it. If I were living in Florida or another state with decent roads, I might reconsider. YMMV
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2013 x35i (Space Gray, MSport, CW/CWII, DHP, Premium, Premium Sound, Technology, BMW-Apps)
Retired: '09 C300 4Matic, '09 GTI, '06 750i, '05 C55, '04 R32, '03 M5, '02 GTI, '01 M5, '00 M-Coupe, '00 540i/6, '99 M3 Coupe, '98 M3 Coupe, '96 328i,... '86 4000 CS Quattro... too many to list.