Major play in bottom bracket (pics+video), what's broken?
This is what I've got:
Crankset: FSA VDrive Hollow-Forged Aluminum arms, 24/32/42T,*(15 ~17:170mm* 19~21:175mm)
Bottom Bracket: FSA MegaEXO external bearing 73mm
I've got major side-to-side play in the bottom bracket as shown in the picture and videos below:
What exactly have I broken, and what do i need to do/replace to fix it?
What would have caused this, and what should I be doing or not doing to prevent this?
Assuming you have the correct width of bottom bracket, you need spacers. See the instructions here:
“Nothing compares to the simple pleasure of riding a \mountain or fat/ bike.” ~ John F. Kennedy
How far is the spline into the crank arm ? Is the spline bottomed out against the adjusting nut? May not help but this is right from FSA 's website :
CRANKSETS: MEGAEXO CRANKSET SIDE TO SIDE PLAY
I have play in my MegaExo crankset, it moves side to side similar to the handles in a foos ball table. What can I do?
The answer to this question depends on the model of crankset you have. But first check the instructions and make sure the small parts listed in the illustrations are assembled in the correct order on your bicycle. Replace any broken or worn o-rings, rubber washers, and bearing covers. Then make sure your crankbolt has been tightened with a calibrated torque wrench to the proper specification. If there is still side-to-side play, this may indicate a frame incompatibility or much more serious issue and having the bike be inspected by a qualified bike mechanic is in order.
Is this a new crank that you just installed, or one that suddenly just developed this play?
Thanks for the feedback guys.
The bike/crank are a little over a year old, I couldn't say how many miles, over a hundred? This is what I'm riding.
I managed to resolve the issue by tightening the dust cap as shown in this video:
FSA Mega EXO BB-7000 lateral movement, now repaired - YouTube
However I've still got some nasty friction/noise coming from the crank and rear derailleur. This whole issue was discovered when trying to adjust the derailleurs on the bike - I've got some nasty noise/friction, and some bad chain jumping when shifting to the smallest chainring on the front, and bad hesitation when shifting from the middle chain ring to the largest one. The small adjustments I've made to the front and rear derailleurs haven't made any difference. Not sure if it's the chain rubbing on the rear derailleur (which took a nasty hit several months back and has been giving me trouble since), or if it's from this bottom bracket, or both (what I think is most likely).
Stay tuned and I'll try and get a video of what's going on later today after work.
If it is the bottom bracket, is this something I'm better off replacing entirely (looks like I can get the entire bottom bracket for $39 shipped on Amazon in 2 days) or rebuilding? Also, if I am better off replacing the entire unit, should I stick with what I'm running, or replace it with something better (and what would you recommend)?
That's not a dust cap, that's the bearing pre-load adjustment. There's usually a torque value printed on it, something like 6-13 in-lbs, to achieve the proper adjustment. You adjust that with the pinch bolts loose and then tighten the pinch bolts (to a higher torque value) to hold the crank arm in the right spot.
If your crank arm moved that much I suspect the pinch bolts weren't tight enough and the pre-load adjustment bolt worked it's way out over time.
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