The front end of my Gen 2 SC has started “sticking” (not sure how else to describe it). Took it apart and if I loosen off the Steering axle then it has normal play again, but when I retighten to 2nm then it sticks again when turning. Is this a sign that the bearings need to be replaced?
If they need to be replaced I see the part numbers in the service manual although the lower bearing seems to be harder to find. And now my dumb question - how do I remove the current bearings…? I assume just push the top one out, but not sure if there is a trick for the lower one.
Thanks
How do the bearings feel?
I could not tell you - no idea what would be good vs bad, and at this point they are still attached to the bike
The “sticking” headset bearing issue is fairly common with the 2nd gen SC.
The bearings are a weak point as they are undersized for the kind of load they have to sustain and IMO sort of a poor design.
Luckily they are not overly expensive, readily available and swapping them is a pretty straightforward job.
Remove front tire, remove stem cap, remove steerer axle retaining bolt (hex m4) down inside the fork, loosen stem pinch bolt (hex m4), remove steerer axle (hex m8?) and pull it out.
Now you ideally have someone holding the front end while you pull it away from the frame to get access to the bearings.
Pry out upper headset bearing. Remove lower bearing from fork, clean everything, grease everything, put fresh lower bearing on fork, put fresh upper bearing in frame, put front end/fork back in place, stick steerer axle back in place and fasten to 2nm (!). Test if fork rotates smoothly without play.
Hold axle in place (make sure it won’t turn, as you put axle retaining bolt back in and tighten to 6nm. (Put some blue loctite on retaining bolt!)
Press down stem firmly and tighten pinch bolt to 5.2nm, put stem cover and front tire back on.
Upper bearing:
Enduro Bearings ACB Mini 276442 BO ACB series
Lower bearing:
CANE CREEK ZN40 1IN ST 581410
Stick your finger inside the bearing and turn the inner race.
You can feel if the bearings are bad.
Thanks so much for the insights. I already have everything apart just wasn’t sure about how to go about removing the bearings themselves. For the lower it looks like I should just pull it off but it was pretty stuck so wasn’t sure if there was a trick to it. For the upper you mention pry it out, but I was originally thinking I would push it out from the bottom. Open to inputs on the best way to remove them both!
They should just come off very easily with your fingers.
Hmm…okay, will give it another try this evening
Since you already have dismantled everything it’s an no brainer to swap new bearings in!
Even if they appear fine with no load, they are bad from what you described.
Insert the axle from below and pop out the upper bearing. It really shouldn’t fight too much. Probably just stuck in by old grease.
The lower one might need a little persuasion to come off the fork, but shouldn’t pose a problem either.
Make sure to clean the surfaces really good and put a layer of grease on them before putting in the fresh bearings.
Thanks again - super helpful
Got the bearings out, the lower came apart when I removed it so guessing that was likely not a good sign. Thanks again for the help.
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Are you saying that the lower bearing fell apart?
Did the individual bearings come loose?
Would you expect to replace the top bearing? It is the lower bearing that sees the axial load, that leads to brinnelling failure. While riding, the upper bearing sees very little axial load.
Salmon
I figure I might as well replace both at this point since I’ve got the bike apart.
This was the lower bearing.
I have the gen 2 SC and changed my bearings in the headset last week. Before changing it felt a little “twitchy”. Since swapping bearings it feels much more secure.
I had to take the entire front end apart and disconnect the electronic shifting. It took me about 2 hours to do. I just went through my local shop to get them to order the bearings for me.
