Headset - is this as bad as I think?

[ootini]

So you may remember my technically incompetent post about a clunk in the fork. Well, taking on board the advice provided here and watching a YouTube video or so, i set about sorting it.
Loosened the stem a half turn each side, tightened the top cap bolt, but it didn't tighten properly. I use an SP connect phone mount system which, on the Arkose, includes the SPconnect top cap mount. Like this :https://bikesale.com/spconnecttopcapmic ... opcap.aspx

Each time it started to tighten in the starnut it felt a bit grindy, then it just fell to pieces. The plastic "mount" completely came away from the "topcap" piece below, which was now conical, not flat with the bolt making it's way through the cap, with curled pieces of plastic and, what I value very to be poor show aluminium, dropping on top of the starnut.
I'm assuming if this had happened mid-ride, the stem and fork could have separated resulting in something rather unpleasant happening?

I'll try to post pictures. Bear with... The pictures show the underside of the plastic mount, where it came away from the Aluminium base.

[ScotRoutes]

I'm assuming if this had happened mid-ride, the stem and fork could have separated resulting in something rather unpleasant happening?

In theory the topcap is irrelevant once the stem bolts have been tightened up. It shouldn't be taking any load whatsoever, it's only there to pre-load the headset bearings.

[ootini]

I'm assuming if this had happened mid-ride, the stem and fork could have separated resulting in something rather unpleasant happening?

In theory the topcap is irrelevant once the stem bolts have been tightened up. It shouldn't be taking any load whatsoever, it's only there to pre-load the headset bearings.

Fair enough. I'm still mega f###ed off as it means my £40 phone cases and mounts on the other bikes are now almost useless.

[ScotRoutes]

I've always assumed with those topcaps that the bearings should be pre-loaded with a standard one, stem bolts tightened and then the standard topcap removed and replaced with the fancy one. I've certainly seen that in the instructions of some models.

[RobLyon]

Are the spacers/stem definitely a few mm higher than the fork steerer?

[ootini]

I've always assumed with those topcaps that the bearings should be pre-loaded with a standard one, stem bolts tightened and then the standard topcap removed and replaced with the fancy one. I've certainly seen that in the instructions of some models.

Bugger. I'll check

[stevenshand]

I've always assumed with those topcaps that the bearings should be pre-loaded with a standard one, stem bolts tightened and then the standard topcap removed and replaced with the fancy one. I've certainly seen that in the instructions of some models.

^^^ Listen to that man up there ^^^

[ootini]

Nein. Just checked the instructions. No mention of preloadijng on a "real" topcap. Either way, it is what it is.

[ootini]

At least my forks don't clunk anymore.

[rudedog]

The link youve posted seems to be for a different mount than the broken one in your pictures?

For the one you've linked, you can get that for 8 quid on Amazon.

[ootini]

I don't think its a different mount. They only do two, afaia, this and a hinged version. I think it's the 3d model visual of the one I've taken a picture of, but happy to be corrected. Mine came as part of a pack for about £40 including a couple of other mounts, as I wasn't sure which I'd need at the time.

I think I'll just learn from my mistake and pony up for a new one, I just wish the instruction's had suggested the preloading on a "real" top cap.

[sean_iow]

Nein. Just checked the instructions. No mention of preloadijng on a "real" topcap. Either way, it is what it is.

When everything is brand new the force required to pre-load the bearings is so low that it would probably be ok, but once there is wear and you're cranking it down to try and get rid of the play it's too much load.

I always use an old chunky topcap and steel bolt to set mine - hope topcaps have an ally bolt that snaps if tightened too much. I now have a standard ally topcap and steel bolt as I had a custom one printed.

As has been said, the bolt is redundant once the stem is tightened. On the HT550 I lost a bolt from the front callper, I used the one from the topcap to replace it as it was the only bolt on the bike long enough and rode the last 300 miles with no topcap with no ill effects.

[sean_iow]

preloading on a "real" top cap.

Do you have a normal one? If not I've got a spare I can send you as they come with some headsets and I never throw anything away, as a trip into my loft today confirmed

[ootini]

preloading on a "real" top cap.

Do you have a normal one? If not I've got a spare I can send you as they come with some headsets and I never throw anything away, as a trip into my loft today confirmed

I do. Thanks. I kept the original pinnacle jobbie when I fitted the mount. Much appreciated though.

[ootini]

The link youve posted seems to be for a different mount than the broken one in your pictures?

For the one you've linked, you can get that for 8 quid on Amazon.

You were correct. I bought the £8 amazon replacement, which arrived today.
It appears that the mount I had, the one that came as part of the bike bundle, is thin alloy and plastic in construction. The one I replaced it with, and linked to is a single solid aluminium machined piece, much stronger and id imagine I could, although I didn't, use it to preloaded the bearings. It's also a much lower profile unit, so I've had to chuck a spacer on to avoid the phone fouling the stem bolts when fitted.

For reference neither Mount's instructions for fitting mention anything about preloading and setting the stem using a "real" topcap. I guess they assume the people fitting them would already know this through experience. You live n learn.