Hello again! Man, it's been a L O N G while since I've posted up here....
Anyway, my most recent problem began yesterday. I was installing the new shimano XTR BB and cranks on my Giant NRS carbon. The cups went in smoothly, no over-torquing issues at all, it seemed. However, as soon as the cranks went in I noticed a rather big issue.
The cranks will not 'free wheel' when pedaled in reverse, and seem to drag when pedaled forward.
You know when you have your bike up on your "ultimate bike stand" and you toss the crank arm backwards and it'll usually do 4-5 revolutions before it stops... mine stops instantly. Also the same applies when tossed forward, but when chained up to the rear wheel it does a few revolutions (I suspect the mass of the tire is carrying it around).
Basically there appears to be much more drag than there should be. The cranks and BB were NEW.
Upon close inspection of the BB I've found that the right hand side of the plastic sleeve that travels across the BB shell is not perfectly round, it's oval. It appears to have been manufactured this way because I don't see any creases that would indicate it got crushed on installation and is now out of spec. The ovaling is very slight, and I think contacts the crank arm cross member in two spots (as any oval would contact a circle in two spots..). Plus the outboard bearings never really spun like a conventional BB bearing when I 'finger tested' them before installation.
Did I just get a bad BB out of the box?
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