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Hi
Bit of an odd one as I have fitted many headsets before with no problem
The bike is an orbea rallon 650b which I fitted with new top and bottom cups and bearings.
Forks are manitou. I pushed the sfn in around 10mm down into the steerer. Have two 12 spacers below the stem And around 12mm above.
The top spacers leave around 3mm above steerer tube.
Now when I install it all no problem no play at all. After a days riding there is play and I can rotate the spacers
All I can think of is either the stem is creeping up the steerer tube or the sfn is?
Any thoughts
Cheers
Kwack
Are they metal spacers ? I had some plastic / carbon spacers once, they were rubbish and broke. Took me ages to spot as the crack was tiny and only moved under load.
If not the spacers it must be the SFN.
If not the spacers it must be the SFN.
Surely, the star nut doesn't actually do very much work once everything is clamped into position. I've never tried it, but my belief is that once you clamp up the stem, you could effectively unscrew the top bolt and everything should still stay put.
My bet would also be on spacers as the rest of the headset stack should be pretty uncompressible.
Is the stem loosing it's grip on the steerer? Try removing the stem bolts, clean & grease them & then torque up.
How tight did you do up top bolt on fitting? That is the key bit to draw the fork up and eliminate play, but not over tight that the bearings will bind or crush. Once done the stem bolts take over to hold it all in place.
When doing up, brake on front and rock the bike feeling with fingers around the top and bottom headset for any play in the steerer.
As far as I can see, either the stem is slipping on the steerer or the steerer is working loose from the crown. If the latter, then you need to bin the forks or you will die.
Re-grease the stem clamp bolts and try again. Some stems have differing grip it seems too so the sfn can be subject to load. Try a cheap bung instead of the sfn if it continues.
Did you put both bearings in the right way up? That can cause what you describe.. although Im assuming you've taken it apart again!
All good advice. I will check again. I do have one plastic carbon spacer in there so reckon that would be a good start.
After that if still doing it will pull the headset apart and refit..
If it is the sfn slipping up what's the best way to pull it out? Or is or better just to knock it down further and fit another on top?
Cheers some good tips here
Kwack
SFN slipping shouldnt be relevant, it/top cap could theoretically be removed entirely once the bearings have been properly preloaded, stem possition determined and the stem fixed. Is the underneath of the top cap just touching the steerer's top? (meaning that the bearings arent actually properly preloaded even though they would appear to be.) A further top spacer would test this
The star nut doesn’t actually do very much work once everything is clamped into position
This. Clean up the camping surfaces and grease the stem bolts.
I too would say the issue is the stem - THAT should be holding the thing tight together once it is all done up. The top cap and SFN only hold things preloaded until you get the stem done up.
Had this exact problem on my new bike, it was the stem not clamping tightly enough. Would work up the steerer over about 20 miles enough to create a slight wobble in the headset. It was tight enough to ride around on, go off jumps etc without budging but I found out it wasn't holding perfectly when I loaded the bike on an uplift trailer and the bars twisted slightly from doing up the straps. Strange as I could put the front wheel between my legs and haul on the bars without it budging. A new Hope stem sorted it.
a bit of carbon fibre grip paste on the steerer can't hurt either, works as well on metal to metal contact.
Some top caps are profiled so that they sit quite deeply into the top spacer. Could it be filling that top 3mm and touching on the top of the steerer?
It would feel like you’re torquing it right down but it’s not really putting enough load on the bearings.
Edit: jamiep said it first!
Could it be filling that top 3mm and touching on the top of the steerer
It would never be tight in that case
I’ve seen it, “a friend” has done it. 🙂
It does feel tight at first in the workshop, but then appears to loosen on the trail.
a bit of carbon fibre grip paste on the steerer can’t hurt either, works as well on metal to metal contact.
As far as I understand it, this is generally not recommended as it can seep down and get into the headset bearings causing accelerated wear. There was a thread discussing this point a few months back.
A tiny bit of carbon paste isn't going to end up in the bearings, but might make the difference for a stem that isn't gripping well.
As far as I understand it, this is generally not recommended as it can seep down and get into the headset bearings causing accelerated wear.
In theory it might but it would have to seep past the seal on the bearing top cap and the bearing itself. My experience is that in practice this doesn't happen
Had this on my Hightower. Solved by tightening the stem bolts up a good bit tighter than the recommended torque. Race Face stem
Right so replaced the plastic carbon spacer
Greased bolts and fitted and torque up the stem to more than required
Let's see what happens at next ride out.
If that doesn't work will try a bigger spacer under the top cap to try that theory
Cheers
Kwack