hazben1

FSA Mega-Exo 8160 BB has a little bit of play. It is 1-1.5 years old and had pretty decent use. How much play is acceptable in a BB? Also if the answer is none how fast do I need to fix it? I did check the cartridge and it is screwed tight into the frame. Also checked the right crank arm where it screws onto the shaft and that is also in there tight. So I am guessing it is probably bearing wear?

fietsbob

Loose ball BBs can be adjusted , cartridge BB IF radial bearing they are what they are , side loading them causes Binding

Angular contact cartridge bearings ar rare in sealed Bearing Units , but they can be preloaded a bit like loose Ball BB's

when a Mechanic is trying to speak of Bearing play the ' run out ' term is used and a Number measured usually in decimal fractions.

nfmisso

My rule is non detectable by feel. Your are just wearing out the bearings, which you are going to replace anyway. Based on: https://www.stilen.com/bike_stuff/Meg...l_040820-1.pdf there does not appear to be anything else that will be affected. Bearings are inexpensive, so I would replace them.

FBinNY 

First diagnose to confirm that you're feeling bearing play and not something else.

Place your cranks horizontal with one near the chainstay. Wiggle the other one in and out (in the direction that it's not supposed to move) and see or feel for movement of the one near the stay using the stay as a frame of reference. If the two crank arms move together, it's either bearing play of the bb unit is loose in the shell (easily observed).

Ideal is zero play and a slight preload. Some vestigial play (you think you feel it, but aren't dead sure) is fine, but obvious play, ie crank can wiggle about 1/16" at the tip should be corrected. Some BBs are adjustable, some aren't, and the method of adjustment varies with the type of BB.

Without knowing details I can't give you a specific answer for your bike, but hopefully this will help you decide whether you have a problem or not, and start you looking at how to fix if necessary.

hueyhoolihan

OP, if the FSA crank is like some that i have seen, discrepancies in frame's BB shells are dealt with by use of a wavy washer, essentially a spring, like some Campy cranks. so most cranks could be considered laterally sprung. as the washer wears, it becomes less springy, finally resulting in a sloppy fit. if so, this may be what you are experiencing.

i wouldn't run it that way. i would disassemble and try a new wavy washer, if indeed the FSA crank that you have uses one. then i would try new bearings.

here's the type of wavy washer for use with an FSA crank i am referring to: https://www.amazon.com/FSA-MegaExo-Li.../dp/B001GSSIUE

what i think can happen is this...

initially the spindle is a loose fit with the inside race of the BB bearings. after all, we can usually shove them in by hand. in addition to that lateral resistance there is the wavy washer. in most instances the two conspire to hide the laterally sprung nature of the design. with wear, the loose fit becomes looser and the wavy washer weakens, when that happens, both conspire to now reveal that the frame's BB shell is in fact too wide for the crank. the fix, as mentioned, may be a new wavy washer and new bearings.

hazben1

Put the crank arm close to the chain stay as suggested and indeed there is some play. Probably not a whole 1/16th" but, not far off. The cartridge is threaded tight into the frame and the cartridge is not moving when I check for play in the BB. So I guess it looks as though I will be in the market for a new cartridge. Where would the most reasonable place to purchase a Mega Exo 8160 cartridge?

hazben1

I do indeed have one of the springy washes installed with the cartridge. I will probably go ahead and order a new cartridge and replace the springy washer at the same time.

FBinNY 

Sorry, I don't make any specific product or source recommendations, but before you buy, consider this.

There are only two issues with bearing play in a BB. 1- when it's bad enough it makes FD trim adjustments nearly impossible, since the ring moves sideways as you ride. 2- sloppy bearings wear faster.

So, since there's no real consequence to using your non-adjustable BB until it makes FD trim impossible, you have nothing to lose by continuing to use this as long as you can.