NC35 Steering head bearings

[manicguitarist]

Is there a design flaw in the locking mechanism on the steering head bearings?
Mine were loose - took it back to the dealer (still under warranty) - got them retightened...came loose again.

Had a look-see myself today (with the help of the Haynes-book-of-lies) - and the issue is, well - the procedure is to adjust the bottom nut till the bearings are at the correct tension, then hand tighten the locking nut and then tighten the locking nut further until the locking washer (a washer between the two nuts - it has lugs that are bent up and down into the cut-aways of the two nuts) has a tab aligned with the locking nut - and bend the tab into place. This will stop the damn thing coming undone.

However, this *doesn't* work - if you when, hand tightened it is exactly aligned so you can bend a tab up now...there isn't enough "squish" in the locking washer to rotate the locking nut another 90 degrees to align with the next tab....

What I did today was fashion an extra washer between the two nuts (above the locking-tab-washer) so that the locking nut was in a slightly different location - and could be tightened properly before the locking tab got put into place.

Anyone else come across this?
Or even understand what I mean.

[Drunkn Munky]

Nope done countless head races and never had this problem, what bearings you using

[manicguitarist]

Nope done countless head races and never had this problem, what bearings you using

Not sure. The bearings were new when I got the bike a few weeks ago.

Not sure that the type of bearings would make a difference here?

Essentially - if, when you hand tighten the locking nut it is already aligned with the tabs on the locking washer - it can only ever be hand tight. I guess a 1 in 180 chance (I reckon 2 degrees out is the max - so 2 in 360 degrees) of it happening.

Seems ok now though...obviously this is now a good reason (not excuse reason ) for taking the bike for a blast.

[Drunkn Munky]

Theres tapered and ball race bearings both are tigthened differently and I seem to remember the need for a extra spacer if using tapered although I can't remember if thats for nc30 or 35.

[arsey30]

Sounds like the lock nut has been over tightened and flattened the lock tab, so the lock nut cannot be further tightened to line up.
Either fit a new tab or bend the old one so that it has some spring in it.
If original bearing, torque adjuster nut to 25nm fit tab, screw lock nut down until it touches the tab the turn to the next groove. That will be well less than 90deg, as although the adjuster has 4 grooves at 90deg, the lock nut has 8 spaced at 45deg.
Taper roller bearing will only need to nipped up to remove slack but free to turn

[manicguitarist]

On mine both the lock nut and adjuster only have 4 grooves each...

[arsey30]

Never seen that before, mine had 8 [so did nc30] and the parts book shows 8.

The lock nut should only be hand tight, the top toke clamps it in place and stops it moving.

[manicguitarist]

Hmmm...I guess that a previous owner or a garage has lost one at some point...

Where could I get a correct replacement?

[arsey30]

Both NC30 and 35 are locked in the same way, finger tighten the lock nut so it contacts the tab then hand tighten the lock nut within 90degs to line up the grooves

If you fit a new lock tab there will be sufficient give in it to allow you to tighten the lock nut hand tight to align the grooves.
In practice it will be anywhere between 1 and 90deg.
It would be almost impossible to fully tighten the lock nut and the grooves to line up.