I have had a 'Deore' equipped mountain bike for 3-4 months now. However, there is grinding noise from the area of the cranks and I suspect the bottom bracket.
On a local MTB forum I heard that Deore BB's last exactly that long. So I am worried about replacing the part with an exact duplicate (for fear of short service life).
Do more expensive Shimano groupsets use the exact same BB or is it different for each? Do they last longer? Is it normal for a Deore BB to fail after such a short time?