Andrew R Stewart 

Please step away from your device and take a breather. You're getting all worked up because one of the most experienced and patient posters here can't read your mind or doesn't know of specific details that really do mater when trying to find solutions long distance.

I, too, was misled by the thread's title and went on to read that the cup was moving within the headtube's end. Not that the bearing was moving within the cup. I am not going to take the time right now to reread the entire thread with this new and very important description. But I will later and might offer more specific thoughts. Andy

Andrew R Stewart 

OK, I reread this thread and easily see why most of us went down the ovalized HT path while thinking the cup was moving within the HT end. I have a few thoughts beyond the lack of best initial description as to were the slop was thought to be at.

First is if the top stack's bearing seating angles are to spec. There's both 36* and 45* angles to the conical seats out there and I have seen them confused. But the slop happening to both the old and the new makes this less the likely issue.

Next might be the lack of the conical centering and pressure split ring that many threadless headsets use, or the wrong one (much like the bearings there are different conical angles for these rings). Again the problem would usually show up both fore/aft and side to side. I will say that bearing slop is far easier to detect the fore/aft slop then the sideways one, given the frame generally being in line with the fore/aft movement.

I am not completely in agreement with the cup always being stiffer radially than the HT is. Or maybe I should be more specific. The back 1/3 to 1/2 of the HT circumference is supported by the top tube's miter and joint. So this portion of the HT won't see much distortion as compared to the front portion of the HT circumference. The front side might be only the HT wall thickness or that and a reinforcing ring, but still lacks the greater 3D structure of the back side with that TT joint. Whether it is the cup or the HT, or some combo of both, that distorts on assembly could be investigated with careful measurements of the before assembly HT OD at recorded points about the top end, cup skirt OD and cup bearing seat ID and the same at different amounts of cup press in. As the cup is pressed further in the uneven stress on it will increase if the HT ID isn't round. By measuring the cups ID one might see this. By measuring at different amounts of cup insertion one might see this deformation progress, helping to confirm the theory. .

I suspect there's some pretty basic thing going on. If the OP can't figure it out I hope they find someone who can sort it out, and we can find out what really was happening. Andy

Kontact 

I would agree that the HT might be ovalized, and this makes the cup distort as well - because this is not a loose ball headset with an upper steel race, but a lightweight aluminum cup that is not necessarily as stiff as a steel HT. So the assumption that the headset upper cup is going to correct the oval is likely inaccurate in the case of a Cane Creek 40.

So the OP might be exactly right that his HT is an oval, and that oval might just be distortion rather than from reaming - since the upper race is both tight and ovalized as well. And both the cup and the HT should be measurably ovalized with calipers.

If the HT is distorted, pressing in a good old fashioned steel headset race may solve the problem. Pop it out and re-measure. If not, a rag and dead blow hammer followed by pressing the steel race again.

79pmooney

I'm pretty sure FB pegged it. I would fill both the front and back with the Loctite so that cup goes nowhere. If it can move it will do it's best to shatter the Loctite. Only in front? Over time and after enough pothole hits, etc, the cup may work itself a little further into the rear section, then slam forward when you do a hard stop.

Use lots of Loctite. So it splays out as you insert the cup. Grease the race ahead of time so any Loctite that finds itself there cannot adhere and will be easy to wipe or chip out. (I don't know what the Loctite is. I'm giving you good advise for epoxy. And assuming you are going to leave the press on until the Loctite sets up.)

Kontact 

You should read the rest of the thread. The cup isn't moving.

grumpus

Does the head tube show signs of reaming and facing at both ends? Possibly before paint. If it doesn't then that's an easy place to start, otherwise I'd be inclined to tap it on the front with a less-damaging impact tool of some sort to see what difference it makes. Although it's more likely that it has previously been dropped on its head and ovalised in the other direction, these small adjustments are reversible. I suppose it might have already been squashed and then stretched back ...

FBinNY 

At the risk of re-offending the OP, and with respect to his VAST 50 builds experience, has he bothered to confirm that the heat tube is ovalized, by the simple expedient of actually measuring it?

IF, it is in fact ovalized, that's easily fixed, by any one with decent hands on experience, and no special tools needed.

grumpus

Post #9 above mentions the difficulty he had trying to measure it accurately.

Kontact 

And it might be unnecessary since the bearing itself shows that the cup distorts into an oval when pressed in. It is hard to imagine another cause - if the HT is already properly prepped. If not, it could be that the HT hasn't been reamed and is undersized, and the alloy cups are ovalizing because they are being squeezed into too small a space.

3alarmer 

.
...any chance of switching to a headset with steel cups, just to see what happens ? Or are those unobtainable for this frame and fork ? Way easier and cheaper than trying to replace or manipulate the headtube round enough to accept the alloy headset that's not working.

FBinNY 

Sorry, I don't buy it. A head tune ovalized so slightly that it can't be measured, yet causing all this grief.

However, I'm not going to argue, and instead suggest that the OP does what Admiral Hopper would have done and properly MEASURE IT. If he can't, then he needs to find someone who can, since we certainly can't do that over the internet. The OP is in Seattle, a city blessed with plenty of highly qualified shops. Offhand I recommend R&E Cycles, but there are others. The correct way to measure, and KNOW what's what is with a Go/NoGo plug gauge like the one here.

Of course the OP and others may prefer to wring their hands and speculate about all kinds of possibilities, and that's their right.

Kontact 

What are you going to do with the information? You've warned the OP off from reaming.


This thread took a really weird course because most misread that the cup was loose. But all this thread really amounts to is "My aluminum cup is distorted when I press it in." Answer: "Do the standard frame prep."

The OP did measure, and said that the difference between width and length was slight. That doesn't indicate a big potential gap, so I don't see why traditional frame prep isn't the correct course. Whether the HT is a bit oval or just a bit small, the cup is being distorted because something is too tight. Ream and face fixes that.


Most of the weirdness in this thread are just because most misunderstood the first post. The cup isn't moving - it is distorted. Do the normal frame prep.

FBinNY 

Sorry, I never did that. In fact, I gave the OP too much credit and assumed that the frame was prepped and whatever might be wrong, happened before he got it.

I still don't know whether it's ever been reamed or not. If not ---- determined by gauge ---- then the tube should be checked for roundness and corrected, if necessary, before reaming.

As for what I'd do with the info if the OP gauges the tube ----absolutely nothing, and let the OP use that info any way he wants.

In any case, I don't post here to be right or wrong, or smarter than you or anyone else. I post to help folks solve a problem. What they choose to do with that info is up to them.

In this case, and at this point, my advice to the OP is to let someone do the necessary measurement, then take their advice.

bboy314

I doubt a Salsa frame came with the head tube reamed and faced from the factory. If I were the OP that’s the first thing I would’ve done.