Bottom Bracket Washers Help...???

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8/28/2016 12:50 PM
Edited Date/Time: 8/28/2016 1:06 PM

Really confused when it comes to installing your cranks and bottom bracket.

What is the main purpose for using the little washers in a BB set...??? Is it...

A. For prevention of chain stay and crank arm from hitting each other.

B. For an 'even' adjustment of crank arm width across your BB spindle.

C. For proper Chain Line Alignment.

D. All of the above

If its all of the above...

1. How many washers are you supposed to use/have on hand...?

Because it seems like different brand BB sets seem to carry varying amounts of washers. (2 - 6 depending on manufacturer) So...Do I just choose a BB set that has a lot of washers (3-4+)...??? Obviously...its better to have more just in case.

2. Are you supposed to use enough washers just so you 'BARELY' get enough crank arm and chain stay clearance...? it possible to 'ADD MORE' washers and play around with the width of the cranks on the spindle for personal riding comfort/preference...?

3. How do you adjust the amount of washers for Chain Line Alignment...??? want your Drive sprocket and rear hub sprocket to be as perfectly aligned as you can get for proper chain performance/reliability.

4. How do you make sure that your crank arms are 'EVEN' on both sides of the BB spindle when adjusting the amount of washers...? don't want one crank/side to be slightly further from your BB ('center line of gravity')....and potentially throwing your center of gravity off slightly to one side.

Therefore...Are you supposed to use washers on 'BOTH' sides (I.E. Drive Side and Non-Drive Side) in order to make the cranks sit even on the spindle...?

Or...Are the washers supposed to go on 'ONE' side of your bottom bracket only (I.E. Non-Drive Side) in order to 'MAKE UP' for the sprocket and sprocket spacer on the drive side...?

Sorry for the noobie questions. I need some major help before choosing/installing a BB set and cranks.


8/28/2016 3:00 PM

You usually get 2 cone spacers, a narrow one and a wide one. The wide one goes on the non drive side and chances are you won't need any others. Then you have the tube spacer which goes between the bearings, sometimes you need to add a thin spacer or two to get it the correct length (if it's too short, you'll put lateral force on the bearings, they'll stiffen up, and won't last as long). Then on the drive side you should only need a thin spacer or 2, to adjust the chain line. Although, that depends on your frame. If it has wide tyre clearance, you might need the thin cone spacer to get sprocket and crank arm clearance. It'll probably mess up your chain line, but it's either that or you won't get sprocket clearance.
You just have to put it together and see what you need, then adjust as necessary