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Please help with cracking noise when front tire hits the ground - video link

3K views 11 replies 10 participants last post by  EatsDirt 
#1 ·
Please see the video link for a demo.

There's a cracking sound when the wheel hits the ground. I've taken apart, cleaned and re-greased the headset. The headset bearings are in good condition and the headset cups are solid. The crown race is tight on the fork stem. I've tried a different front wheel to eliminate the hub as the culprit. If I lockout the fork, it takes a bit more banging of the front wheel to get the cracking sound. Could it be something banging around in the fork?

 
#2 ·
Is the preload on the headset properly torqued? With both wheels on the ground and front brake applied, rock the bike and look for movement, particularly on top of the headset below the stem.

Could be something wonky inside the fork.

More likely, the CSU is creaking. Flip the bike upside down and put some lubricant where the steerer is pressed into the upper crown. If the sounds goes away or gets quieter, there's your answer.
 
#9 ·
Crown Steerer most likely, as others have said. I'm not sure loctite is the best when it's structurally compromised. It seems to have worked for some, but I have to wonder if it's really wise.
 
#10 ·
Is the front brake caliper tightened?

The sound hints that it's something that only has very little room to rattle, and the pitch makes it hints that it's relatively hard (like metal) with a certain amount of mass behind it.

Brakes should work fine even with them loose (with surprisingly tolerable brake rub) and there's a possibility that they were for forgotten due to distractions, loosened with intention of minimizing brake rub. Nothing obvious to point to it as the problem unless you do a full check, as brakes tend to be set-and-forget until there's an issue with braking power.
 
#12 ·
Perhaps try these to help narrow it down or confirm CSU:

Grease axle, make sure it's tight.

Hold front wheel between legs and twist (indicates possibly stanchion)

Put front wheel head on against solid wall and load pedals... or just bounce it off.

Turn bars to 90 each way, perhaps up against wall and rock back and forth, checking for play/knock in HS.
 
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