Another of those "what have I done wrong?" jobs....

[Brandane]

I decided to take the 1.7kg suspension fork off my Trek MTB for the summer (??!!) and replace it with my 0.8kg carbon fork. A job I have done many times in the past. So I was surprised to find movement when applying the front brake, as if the cap bolt was loose.

Dropped the fork out a bit to make sure the lower bearing was seated correctly. It was. Still movement.

Noticed some slack in the wheel axle. Took it apart, cleaned bearings, races, re-greased and put it back together. Still the same.

Scratched head some more. Light bulb moment, maybe it's the brake disc that's loose. Tried moving it by hand, seemed ok.. But took wheel off, slackened the lock ring, greased the threads and re-tightened it. Success!!

A 15 minute job turned into an hour and a half. But at least it's done, and I have serviced the front axle at the same time.

 

[fritz katzenjammer]

Check the caliper mounting bolts as well, another thing that if it works loose can cause all kinds of weird noises and problems.

Checking disc brake system fasteners has become a standard part of my service routine, even on new bikes.

Covid has been good for a lot of strange defects in assembly on new bikes. With both components and labour being in short supply at the factories you had a lot of substitute parts being installed by new employees leading to so interesting finds when you unpacked each new bike. Additionally some products were moved to different factories in areas which were not so heavily disrupted by “ the bug” in order to keep product moving. It seems to have settled down now, but it was real fun building new bikes for a while.

 

[figbat]

You can isolate front end knock location by turning the front wheel through 90° when trying the to-fro test. This takes the brake out of the equation.

 

[Brandane]

You can isolate front end knock location by turning the front wheel through 90° when trying the to-fro test. This takes the brake out of the equation.

Why didn't you tell me this yesterday? 😅

 

[fossyant]

I've done the missing, or not quite enough spacers on a cassette a couple of times. 1mm is quite a bit it seams.

 

[ColinJ]

I've done the missing, or not quite enough spacers on a cassette a couple of times. 1mm is quite a bit it seams.

Yes! Last year... (1.85 mm though, in this case)

I had that recently on the 1 x 11 bike that I keep in Devon. I had tightened the lockring as much as I reasonably could but the cassette still creaked. Then I discovered that an 11-speed MTB cassette (such as the 11-42 on the bike) needs a 1.85 mm spacer on an 11-speed road freehub (such as on my wheel).

I fitted a spacer, refitted the cassette, tightened the lockring and...



... the creak was gone!

 

[C R]

You can isolate front end knock location by turning the front wheel through 90° when trying the to-fro test. This takes the brake out of the equation.

I guess that you could get knock from the axle that way, if the bearings were dodgy or poorly adjusted.