Bottom bracket

[RecordAceFromNew]

Well bike is provisionally booked in for a check of the bb tomorrow but in the mean time i've removed and cleaned the cleats and added a dab of grease to the threads. Next i'm going to swop over the peddles to another pair i've been meaning to use for a while. Then, i'm giving it one last shot on a local hill to see if it is actually the bb (which i still suspect it is) then at least i've removed some other possibilities from the equasion.

It is the BB if you could feel the grind when you spin the chainset by holding the crank arm (i.e. not the pedal) when the chain is off the chainrings).

If your month old BB is shot and if you never abused it, and your chainset is sound, then the cause is likely an installation, preparation or manufacturing problem. All of which I would expect the shop to fix it for free.

 

[compo]

I don't get it with all these modern format BBs. All you hear are people moaning about short lifespan and repeated problems/high price. The Shimano tapered axle cartridge BB (like UN54/55) appears to be the pinnacle in relation to price, ease of installation, reliability and life span. So why have all the manufacturers moved away from a proven concept? The cynic in me suggests they weren't making enough money from selling such super reliable gear!

When was the last time you heard of someone being disappointed with a UN55?

You hit the nail on the head. They were lasting too long and sales have to be maintained. Damn clever these Japanese. My bike is a little over a year old and the free hub is obsolete already and pretty well unobtainable. I either have to have a new wheel or a have my rim laced onto a new hub.

 

[accountantpete]

If the bearings are shot then as RAFN says - it is an installation problem.

Either the preload has been over-tightened (ie the bit that screws into the end of the axle on the non-drive side) or the spacers have been wrongly installed.