03-04-2014, 10:55 PM
On my Treks the bottom bracket size is stamped on the frame. Flip the bike over & look. Here's a pic, showing 122.5 UA53. I like Tange BBs rather than shimano.
![[Image: BBMarkings2.jpg]](http://i236.photobucket.com/albums/ff106/unclejef/Bikes/Trek%202%200/BBMarkings2.jpg)
4 7/8" would be a 123.8mm
Here is a good rule to follow. If the rear cogs look worn, you replace the chain AND the rear gears at the same time. If the chain is stretched too much the same applies, you replace both.
Your pedals look fine, but if you need new ones I recommend Wellgo LU-313 which are marketed under a bunch of names. You need a 9/16" pedal. Even Walmart has a version for $20 a set.
Is there play in the headset?
![[Image: BBMarkings2.jpg]](http://s236.photobucket.com/user/unclejef/media/Bikes/Trek%202%200/BBMarkings2.jpg.html)
4 7/8" would be a 123.8mm
Here is a good rule to follow. If the rear cogs look worn, you replace the chain AND the rear gears at the same time. If the chain is stretched too much the same applies, you replace both.
Your pedals look fine, but if you need new ones I recommend Wellgo LU-313 which are marketed under a bunch of names. You need a 9/16" pedal. Even Walmart has a version for $20 a set.
Is there play in the headset?
![[-]](https://forums.bikeride.com/images/flatty/collapse.png "[-]")
