Hi. Bought my 2018 bike a few months ago with 4000 miles. Now 7000 and needs new rear tyre. When I took the wheel off both bearings were very notchy when rotating with fingers. I will replace them but am really surprised at this mileage. Recently checked those on my st1300 at 50000 and smooth as silk. The rest of the assembly looked well greased and in excellent condition. Is there anything I should be checking that might cause this premature wear? Don't know the prior history but bike in pristine condition so assume not abused. Thanks for any advice.