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I'm wondering if anyone can tell me what size bottom bracket would have originally come with the 2015 Trek CrossRip Elite?

Their bike archive doesn't have any BB detail.

I did find these two StackExchange posts, and both point to a 68mm BB, with the latter more specifically identifying 68mmx110mm. That'll probably do, but I wanted to see if anyone had exact information about my bike before proceeding.

Thanks!

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There are two measurements you need: shell width and axle length.

Shell width is very easily determined - you can just measure it. The standard for road bikes with threaded bottom bracket shells is 68mm but some gravel bikes use 73 so it's worth checking.

The axle length can also be measured but you need to at least pull the cranks off to do so.

Different model cranks require different axle lengths to get the correct chainline. Shimano publishes detailed specifications going back to 2005 that will tell you what BB you need for any of their square taper cranks, but as you have an FSA crank that does not help. FSA does publish some documentation if you dig for it a bit. The manual for the current version of the Vero crank is here. It gives a FSA BB part number, the notes say '110.5 for Chainline 44' - i.e. 110.5mm axle for 44mm chainline - which is correct for a road double drivetrain.

Looks like you are correct and a 68x110 BB will be fine.

  • Thanks for all the details. That link to the Vero crank manual doesn't work, it looks like a PDF download link. Would you be able to link me to the site where the PDF came from? I'm searching around for it, but only finding forum posts or Vero cranks for sale. – Chris Woodruff Sep 12 at 15:50
  • Ok thanks. That looks like the Vero Pro, whereas mine is the Vero Compact (not listed in their library, so I reached out to support to see if they have it). – Chris Woodruff Sep 12 at 18:17
  • There is slightly more to this story, for context - I took my bike to REI for front derailleur issues that I didn't have time to diagnose. They chalked it up to a BB / crankset mismatch, and installed a shorter BB AND replaced my front shift lever for an exorbitant fee. I'm fundamentally skeptical of their diagnosis (I think it was more likely something small, like needing an inline barrel adjuster on the front derailleur housing), but I don't have the original BB to test, so I'm trying to track one down. – Chris Woodruff Sep 12 at 18:19
  • @ChrisWoodruff crank/Bb mismatch seems unlikely, this is not the kind of thing that Trek messes up. – Argenti Apparatus Sep 12 at 19:06

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