BobbyB had a similiar problem to you. If you look at the bottom of page 152 he mentions the problem. The conversation continues on page 153, 162, 163, and 164. Not sure if it continues past page 164.
Dalton wrote: ↑Sat Oct 14, 2023 1:41 pmHi Bobby, this has happened to me twice already. The problem i think is that the owners manual calls for loctite on the top cap bolt threads and imo that is a mistake. When you go to loosen it the loctite does not break free and then the whole thing just threads out and the bottom piece falls into the frame! Its very annoying and I think if you make sure to use no loctite then all should be good. The issue is then you should be checking the topcap on a regular basis to make sure it is not coming loose and your preload is set properly. Not the best design to be honest but hopefully it works ok if you omit the loctite. Good luck! Putting back together the delta compression plug after its come apart is sort of like a jigsaw puzzle.....not very fun.BobbyB wrote: ↑Sat Oct 14, 2023 7:53 amThanks for the info again. Just to clarify, this was a different shop I took the bike to, a local shop Vs the online retailer where I got the bike from. This was a new expander plug (as my original one also had the Conceal bolt stuck on it) installed by the local shop, and after the steerer was cut (30mm taken off). So for this to happen again is odd. The new plug does have the little bands that help keep it together, and I think the cap may be stuck again but will need to confirm.johnpuga1982 wrote: ↑Sat Oct 14, 2023 12:44 am
My recommendation, buy a new expander plug, install it, and be done with that bike shop. If the new expander plug does not adhear to Cannondale's torque specifications there may be something wrong with the carbon steerer. Again, due to the initial installation of the expander plug.
New expander plug: https://www.cannondalespares.com/Cannon ... il/3-49447
New top cap and compression bolt: https://www.cannondalespares.com/Cannon ... il/3-49440
You could be right, maybe the steerer is out of tolerance and the recommended 4Nm doesn't hold the plug in place, or the inside of the steerer isn't the right shape and the plug can't grip it enough. But the plug goes into the steerer ok so can't be that far off. I'll try go back to them next week to try figure out what's going on.
I use grease on all my bolts. These bikes are basically race cars that need to be maintained on a regular basis. I find loctite too much of a hassle for something that needs to be checked periodically. The grease acts as an anti-seize on the bolts.hannawald wrote: ↑Mon Mar 25, 2024 9:42 amSo you would grease the top cap threads. Should I also grease expander plug bolt? anything else? Your advice is to put grease on Momo stem bolts as well? I only use loctite or anti seize on these bolts... so grease? What about carbon paste inside the steerer?
BobbyB talks about his experience with two different top caps.hannawald wrote: ↑Mon Mar 25, 2024 9:42 amActually I have 2 top caps, one came with the frameset and one with Momo bars. I might try the 2nd one. My expander is the black one. I can see there is black one (K35063) and silver one (K35051). It seems the black one is the newer one as it has the higher number in product code?
BobbyB wrote: ↑Sat Oct 14, 2023 9:09 pmThanks all for the info and experiences. Good (well, not good ) to hear I'm not the only one who has had this issue. A few things worth mentioning:
- my first conceal top cap didn't have any locktite on it. I don't think the current one has any either, but can't be sure yet.
- haven't got the current Conceal bolt off yet. The first one I couldn't get off. It was incredibly difficult to grip the expander plug screw/bolt as it's quite narrow and has a smooth finish. I ended up damaging and scraping the expanded bolt in my attempts to free the Conceal top cap bolt.
- as a few of you described, if I keep unscrewing the Conceal top cap bolt then the expander plug will come apart and fall down into the steerer. It's then quite fiddly to put back together! (On my first expander plug I snapped the little rubber bands which made it even harder to put back together!).
- headset preload on my bike is good and the stem bolts are torqued correctly so nothing should change and the top cap bolt is largely cosmetic for the time being.
- when my bike arrived it had the system top cap on it for some reason. I used an allen (hex) key to undo it and it slightly rounded it out - what are you meant to use with this? If it is a hex key it's either a very soft metal or it's been poorly coated and it's just paint that's coming off.
I might contact Cannondale about this issue and see what they say. To me it seems a poor design thats easy to have issues with.
Just a few reference points to help solve your issue or give insight about what may be going on.BobbyB wrote: ↑Tue Oct 17, 2023 9:46 pmUpdate on the issue I had with the expander plug and conceal top cap bolt. I took a look at it the other day again and decided to slightly tighten the expander plug using a 4mm Allen torque wrench. It was just under 4Nm and as I got to 4 (or went slightly beyond) there was a little crack noise, which was the top cap bolt freeing up from the expander plug. I've since put some anti-seize on the threads and lightly tightened (2-3 Nm) the top cap bolt back up so it's working ok now.
I had reached out to Cannondale before this and they were really helpful, replying within a couple of hours. I thought I'd share some of their advice in case it's helpful to others.
They said that this hasn't been brought up as an issue to them before so they didn't think it was widespread. They recommend cutting the steerer flush with the top of the stem for the best fit. 4Nm should be enough to hold the expander plug tightly in place, and the top cap should tighten on smoothly just enough to remove any play in the headset. They recommend adding grease to the expander bolt threads to avoid them becoming stuck (so not Loctite as the manual shows).
They also suggested using some micro spacers (https://shop.fullspeedahead.com/en/prod ... cro-spacer) under the bearing cap to fine tune, which may help with getting the right preload. On this point, my bike came with one of these micro spacers installed under the bearing cap. I had quite a large gap between the bearing cap and the frame which was a little annoying. I told the shop about this when they were doing some work on the bike for me and they removed the micro spacer. Here are the before and afters:
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Much better! Only a tiny gap now which isn't visible unless you're at eye level with it and very close. The shop did say to keep an eye on the paint to make sure it isn't being worn away but I think it should be fine.
And still a total pain, removing this stupid sticker! It's stuck pretty good:
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