beaten so much I can't read the number on the side of it anymore :(

I laughed, my ribs hurt, thanks.

For whatever reason I can't seem to keep the headset on my bike tight. The only thing I can think is causing it is that my stem is one of the newer 3t ones with just one clamping bolt. Has anyone else had trouble with these stems not having enough clamping force?

I'm sure you know this already, but the usual cause would be not enough spacers above the stem. The top cap needs to bear entirely on a spacer. Some top caps are shaped so that even though it looks like the edges are bearing on a spacer, the inside is actually bearing on the steerer tube.

That's one possibility. The other is that you are using a compression fitting that is loosening up. Carbon paste helps. I have the same stem, 3T ARX-II and have zero issues with it. Pay attention to torque specs on all fittings.

I'm pretty sure the topcap isn't an issue. There's a few mm of stem above the top of the steerer (I know it's better to have a spacer on top of the stem but this is how the bike shop built my bike. If i can't get this issue worked out I may see if using a positive rise stem slammed with a spacer above would help). Part of the issue was the compressor plug pulling up, but I think I've handled that now (is there a recommended torque for that?)

Okay, now that I've got a couple of sets of tubulars, what do I need to carry with me in case of flats? Anything more than a can of Caffeelatex?

There is. Usually printed on the top of it. I use an FSA, and it is. Use carbon paste, it makes a difference.

A spare and a pump.

Cell phone. :)

i'm not sure if there was carbon paste on there originally, but I disassembled it after killington and added some. I'm not sure what brand of compressor plug it is. are you using the FSA one that uses the non standard topcap (FSA Compressor 1-1/8" Black Expander Plug and Top Cap Bikewagon)? Mine has a lip that sits ontop of the steerer similar to the deda one and i'm using a kcnc top cap (which is some stupid lightweight thing, I should probably just use a "normal" topcap but I don't this could be causing the issue). Do you think the fact that I don't have any spacers above the stem may be the source of the issue? I think these 3t stems have a pretty big stack height (maybe the wrong term?) though.

Why don't you post a photo with the top cap off?

to show the amount of gap in between the steerer and the top of the stem? I'm at a work right now but can do so tonight. fwiw i can get it snug but it develops play after a few weeks. I do have a stem that is the same length in a 6 degree rise (currently running a -17 on top of a 5mm spacer because I like the "flat stem" look) so I could run that slammed with a positive rise and the spacer on top which I believe would give me just about the same bar position but then I'd have to buy a new stem for my cross bike and would rather save the $80 or whatever if I don't have to spend it. my only hypothesis is that the stem isn't providing enough clamping force on the stem (you're not supposed to put carbon paste on that interface are you?) so is actually partially relying on the top cap to stay in place, which is not how it's supposed to work (theoretically once you tighten the stem the top cap doesn't do anything).

this is such a dumb problem but is giving me so much anxiety.

+1

Narrow/regular rim (21mm, 21-23mm tire) I'd just ride it home, and I'd try to keep the ride radius under, say, 20 miles. I've ridden a number of flats home, max distance maybe 15 miles. Haven't done it on carbon but I think that the Reynolds I have should hold up, based on my friend/teammate flatting the front tire mid-turn at 30-ish mph and being totally fine.

Wide rim (25-28mm, 23mm tire) I found is unrideable with a flat, at least the front. Call home.

Mikey I would bet you anything you care to name that the issue is the top cap resting on the steerer. What looks like sufficient clearance often isn't. Try throwing a 5mm spacer on top, just for kicks, and see if that helps. If that doesn't work, you know that it's something else. If it does, problem solved.

Mikey, on my most recent bike, I was having an issue with my expander plug slipping. Even with carbon paste, I was having issues. It wasn't until I torqued the hell out of it that it finally stayed put. In the past, I had always torqued them to 5nm - seemed like a good number and was consistent with most bars, stems and seatposts. This time, I had to go to 12nm to get the expander plug to not loosen.

are you suggesting putting a spacer above the stem even though the top of the stem already goes above the top of the steerer? that seems...not safe?

i'll take a picture/measure the gap tonight, but I'm fairly confident that's not it. there's a good 3-5mm between the top of the steerer and the top of the stem (pretty sure it's less than 5mm though as I needed that 5mm spacer). also, if that were the issue wouldn't I not be able to get sufficient pre load on the bearings? I can get the headset tight initially, it's just that after a few weeks, play develops.

i had it at 5nm before and it had slipped just a tad (1-2mm). last night I upped it to 6nm and I think it stayed put (I was able to preload the bearings fine and didn't "feel" it slipping, but then again I didn't disassemble after tightening to double check), I'll check tonight. 12nm scares me, but I least I know I'm still well within the realm of reasonable torques.

It scared me too, but that was where I ended up.

Yes I am, and it is perfectly safe. Threadless headsets are designed to work with a bit of a gap above the steerer, and they are NOT intended to have the stem as the top of the stack. The stem is actually supposed to be in full contact with the steerer, not protruding above it. It's very common for people to install stems with no spacers on top, but that's not actually how they are supposed to be used and it often causes problems. The number of spacers on top is actually doesn't really bear on the security or safety of the headset installation, because the top cap bolt is only used to set the preload. Once you tighten down the stem bolts, that's what holds the assembly together. Which is why I'm suggesting you try putting a spacer on top. There's really no other way to tell if you're getting the headset tight enough. I've also thought I had ample clearance, yet been unable to get the headset tight enough. The worst part is, you can totally feel as though you're really cranking down on that top cap bolt, and the headset will actually feel tight, but once you tighten the stem bolts, there is still slack in the system and it works loose very quickly. Hard to explain what I'm trying to say here, but I've been down this road myself.


Repeated, in bold: the top cap bolt is not what holds your headset in adjustment, it is your stem that holds it in adjustment. Basically, if you find that your headset is loose, and your stem bolts aren't slipping (or your stem itself isn't slipping, which would be pretty crazy), you probably aren't getting it tight enough to begin with. Maybe it's the expander plug and maybe it's inadequate clearance for the top cap, but unless there's something weird going on it's probably one of those two issues preventing you from getting the preload on the bearing cups and races, where it belongs. Throw a 5mm spacer on top and tighten up that expander plug and I bet your problems will go away.

Pics of the new Venge. I'm a Spesh fanboi, so I know I'll be lusting after one of these once they come out. While I generally don't like proprietary stuff, I am intrigued by the design of the hydraulic rim brakes.

http://fcdn.roadbikereview.com/attac...e-img_0275.jpg

http://i.imgur.com/kYXScXL.jpg

http://images.tapatalk-cdn.com/15/06...cab17401c1.jpg

http://i.imgur.com/jcUZFG8.png?1

http://i.imgur.com/pLSWCxM.png?1

^my god that venge is hideous

i understand the bolded, and said basically the same thing in a post above. but i think you're misunderstanding my issue - it's not that I can't get the headset tight. i tightened it last night and it was totally fine for my ride this morning, is still tight now and will probably still be tight for a few weeks, it's that it works lose in 2-3 weeks time (i.e. it was fine from after killington until this past weekend when I noticed some play), which is what leads me to believe it's not the topcap bottoming out and why i'm leaning towards the switching to a positive stem with a spacer on top route. not trying to be totally dismissive of your suggestions, but i'm not totally clueless with regards to how the headset system works.

very hunch-back-ian

the word "spesh" makes me involuntarily recoil.

Ok, I didn't get that you were having it loosen up over a period of weeks. Hmm. But yeah, I got concerned when you were saying that you thought a spacer on top would be unsafe. It absolutely is not.

I think if it's loosening up over time you don't likely have an expander plug issue, either. I would be much more focused on the stem itself, or something else in the headset stack. I don't think the issue is your stem-and-spacer arrangement per se. If switching to a positive stem fixes the issue, it would be because your stem was defective. You could try a different stem in the same orientation. What length are you currently using?

90mm -17 right now. the only reason i think switching to a positive stem may fix things is because it would result in the entire stem "stack" interfacing with the steerer tube as opposed to having a few mm above the steerer, which may be made worse by the fact that the stem has a single-bolt tightening mechanism.