Join Date: Jan 2005
Location: North DFW Metroplex
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Trek T900 BB/Crank 'click/thump'
Have a 2010 Trek T900 tandem bought off of CL a few weeks ago. In very good shape....although, it's just developed a 'click' or 'thump' at the top of each stroke (meaning at the top of both right and left crank rotatation). Not a bad thump/click, just noticeable though. This is concerning the front crankset/BB, but the stoker can feel it. If I ride the bike alone, it still does it.
So, with some searches here.....I see it's BB or crank issue most likely. Twisted the front crank arms every way possible, and it doesn't appear to be the BB (no apparent movement). However, when I move the crank arms side to side, like trying to push them out of either side of the BB, there is a <1mm lateral movement and corresponding click/thump.....hard to tell if this the same issue (but likely is).
Can't tell a manufacturer on the BB. Crankset is Trutativ (don't know specific model from their website, probably a lower end option).
Attached a pic. It's exactly like this, except that the BB tool locations are top, not on the bottom.
Have an extensive set of tools, (like car mechanic would, as I've rebuilt cars/motors, and lots of bike related stuff) but nothing BB/crankset specific. No aversion to purchasing the right stuff to DIY.
Any ideas or notes of what I'm going to need and what to look for once I have the tool(s)? Attached a pic of the stock bike...can send more detail if needed.
I also looked at Sheldon Brown's page on BB and Crankset pages.....but still a bit confused.