CK Gripnut (inset) installation woes

[polyhistoric]

So... I pulled my fork (Enve CX tapered) out to check for cracks in the steerer tube. King Gripnut assembly was tight, but a tap on top with the rubber mallet got it all out.

All is good with the fork, went to reinstall and can't get the gripnut back on. Either (1) the rubber compression ring simply won't fit over the steerer tube or (2) the rubber compression ring pops out from around the top of the gripnut cap assembly.

Copious amounts of grease did not help the rubber compression ring slide over. Lots of pressure and twisting were of no avail either.

Hive mind... what gives? Never had this issue before with other King HS.

[CiclistiCliff]

Loosen the compression plug

[Blown Reek]

This happened to me on one of my bikes. Being a competent mechanic, I couldn't get it to get back on for the life of me. So, I ordered a new one from King, and it went on no problem. I think the issue has to do with the o-ring not seating back in the groove in which it's designed to sit. And the compression plug had nothing to do with it, at least in my case.

[arik]

If you search the internet you will see a lot of folks having issues with the CK inset griplock headsets. I have the inset 7 and it is way more annoying than any headset I've ever used to install and keep tight. These inset headsets do not seem to match the standard of their other products.

[Mark McM]

I've only used the Gripnut headset on metal (steel and titanium) steerers, not on carbon. I have found that the o-ring can be a tight fit, but I always managed to slide it on.

Since the headset was installed before, presumably the o-ring was able to fit at some point. Some types of oils/greases can cause rubber to expand, so maybe your o-ring is fatter than it used to be. Have you tried using a new o-ring? You also might try deburring/chamfering the top edge of the steerer.

[polyhistoric]

Thanks all - carbon steerer, smooth as a baby behind (no burrs, edges, etc.). Tried install with expander plug in and out. The rubber o-ring won't compress - rather than pushing IN to the groove in the gripnut, it is coming out of the top and deforming. Tried with various types of grease/lube and using a fingernail or other small flat edge to push it in to no avail.... we'll see if CK technical supports responds to my email.

[Mark McM]

Originally Posted by polyhistoric

Thanks all - carbon steerer, smooth as a baby behind (no burrs, edges, etc.). Tried install with expander plug in and out. The rubber o-ring won't compress - rather than pushing IN to the groove in the gripnut, it is coming out of the top and deforming. Tried with various types of grease/lube and using a fingernail or other small flat edge to push it in to no avail.... we'll see if CK technical supports responds to my email.

I'm still guessing that the o-ring has expanded. Normally, the o-ring sits deeply into its groove (and the o-ring rubber is fairly stiff), so it really can't pop out when the installing the gripnut. If it is popping out, that suggests to me that the o-ring has expanded to a too large diameter to fully sit in the groove, and is getting bunched up. Or, another possibility is that the o-ring has shrunk, and it no longer seats all the way into the groove. Have you tried pulling the o-ring out, to see if it's (still) correctly sized?

[polyhistoric]

Solution - per CK Tech. The o-ring can get squashed between race and split ring making it hard to push the whole assembly on the steerer.

Disassemble the whole shebang and install one bit at a time: race, split ring, o-ring, top cap, spacers, stem and top cap and torque to spec.