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Headset comes loose after ~ 30 mins on roughish terrain

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Headset comes loose after ~ 30 mins on roughish terrain
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flag Steventux
Posted: Aug 20, 2018 at 13:50 Quote
I've had a few attempts at solving this with shims and various locking compounds between the stem and steerer...

The shims definitely help, getting the bearings tighter into the frame made a big difference and it only cost a can of beer.
Also a new star nut installed FWIW.

After a few runs down some BPW trails I could feel a light amount of play, defo less than before.

So the stem is slipping and I have a replacement, https://www.dmrbikes.com/Catalogue/Components/Stems/Defy50 as it's the same reach dimensions as the RaceFace Atlas. The steerer bolt torque settings look worryingly low though.
6nm compared to 13.6nm on the RF stem...

I've also thought about honing the inside of the RF stem as it's a very smooth surface, some very light crosshatched abrasions might give it more bite.

I'll update what is possibly the dullest thread on PB when I get a win.
flag lewiscraik
O+ FL
Posted: Aug 21, 2018 at 9:15 Quote
I am having similar frustrations with a 3 month old Hope headset on my Orange Four. Especially frustrating as the cheap headset on my other bike has lasted years.
flag Slizger
O+
Posted: Aug 26, 2018 at 11:19 Quote
Carbon YTs have a problem with ovalized headtubes. They have told my customers to simply fit a larger bearing in there and see if that fixes it.
flag lepak1corner
Posted: Aug 27, 2018 at 0:59 Quote
Slizger wrote:
Carbon YTs have a problem with ovalized headtubes. They have told my customers to simply fit a larger bearing in there and see if that fixes it.

Carbon YTs uses integrated headset cups? That's lazy.
flag lepak1corner
Posted: Aug 27, 2018 at 1:00 Quote
lewiscraik wrote:
I am having similar frustrations with a 3 month old Hope headset on my Orange Four. Especially frustrating as the cheap headset on my other bike has lasted years.

Cane Creek is my trusted headset brand. No creaks and freeplay.
flag Steventux
Posted: Sep 2, 2018 at 11:33 Quote
New stem fitted and after a 4 hour ride today the headset rattle was evident but took a while longer to occur than usual.
I did crash and turn my bars though so the science all goes to sh*t there.
I've been over the integrated headset cups with a digital vernier gauge, they aren't oval.
The aluminium shims have helped, so I think the OD of the bearings is an issue, finding slightly fatter bearings would be ideal. Anyone know if it's possible to order oversized bearings?

I'd say the new stem was a success up to the point where I crashed so mebbe I need to go again and see what happens.
flag BarneyStinson
Posted: Sep 6, 2018 at 6:16 Quote
If you’re using spacers and the headset stack is tightened down, the chamfers on the bearings should hold everything in place.

OP - I had the same problem as you on my 2017 Jeffsy. When I dismantled everything it turned out that the crown race had been installed upside down. This meant that I could tighten it in the workshop (by *really* tightening the top cap) but it loosened as soon as I rode it.
flag Steventux
Posted: Sep 11, 2018 at 1:33 Quote
TL;DR New stem (and possibly bearing collar shims) seems to have solved the problem. Rode for a day without any issues on trails I've experienced the problem with before.

Looking at the RaceFace Atlas stem I replaced one thing looks a bit iffy, when I tighten the upper pinch bolt it clamps tight to the lip under the top cap (the star nut bolt cap). I wonder if the interference was enough to stop the top bolt clamping the fork properly as the top cap was in the way?
Also I noticed that the step seemed to pinch up to a smaller gap than when I first bought the bike (never been over torqued and bolts replaced for good measure). So perhaps the stem got deformed somehow? I have measured the fork steerer and it's not ovalised either.

The DMR stem is quite different in how it clamps the steerer as it bites much lower down, anyway it works and was a cheapish fix.
flag Steventux
Posted: Sep 23, 2018 at 3:47 Quote
Spoke too soon, after a couple of rides the new stem seemed to slip, the rattle was back.
So I reset/re-tightened mid ride and went out again only for the headset to start rattling after a few steepish bumpy runs.
When I got home I took it all apart and inspected everything.
Bearings had no real play (they'd been repacked with grease 2 rides ago), they were tight in the frame thanks to the beercan shims, I couldn't see anything wrong...
... except for the some strange marks on the steerer tube, like the bearing had been in contact with it.
It looks like the compression ring for the top bearing which is split so it can compress properly had been installed by some utter fool with the split facing rearwards. I think the fork steerer was squashing through the split and moving slightly.
I installed the compression ring with the split 90 degrees off to one side and rode again this weekend.
There's been no movement not even a hint of a rattle.

I think the compression ring, which is a feeble piece of plastic may have been the culprit, it's probably quite worn, maybe it's been works over a bit now so a replacement is on the way.
I hope this helps someone in future as this has taken me about 8 months to solve and cost a few quid for a new stem, assembly paste etc. A compression ring costs about the same as a beer.
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