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Headset-fork compatability(12 posts)

Headset-fork compatabilityrobk
Oct 5, 2002 2:08 PM
I am putting together a new bike and purchased a Syncros 1" threadless headset and an Easton EC-70 fork with an aluminum steerer. I took them and my frame to my LBS to have the headset installed and found that the lower section of the steerer tube above the crown is 26.2 mm, too large to fit into the headset! Is anyone familiar with this fork and other quality headsets that will work with it? Easton doesn't tell you that their fork won't work with some headsets and doesn't provide a list of compatible ones.

Thanks for your help.
odd-ball headset??C-40
Oct 6, 2002 6:03 AM
See this website for headset info:

http://www.sheldonbrown.com/gloss_h.html#headset

The standard crown race inner diameter is 26.4mm, not 26.2mm. The steering tube above the crown should be about 26.45 to 26.50mm diameter to provide an interference fit with the crown race.

If your crown race diameter is less than 26.4mm (1.0394 inch) then it was made wrong, or you've got an obsolete size.

Any standard 1" headset should fit your fork.
CuriousKerry
Oct 6, 2002 4:45 PM
Could it be that the crown race seat diameter is 27.0 (Japanese standard) and the steerer tube is expecting that larger diameter. The two standards for crown race seat diameter are 26.4 (Euro) and 27.0. A 26.4 crown race should "just" fit over your steerer tube, though slight variations could make this a close fit. A 1&1/8 steerer would be much larger, so your predicament is curious. Check the crown race seat diameter - I'm guessing is 27.0.
Curiousrobk
Oct 6, 2002 5:43 PM
Thanks for your reply. I guess I wasn't clear on what the situation is since the mechanic at the LBS was doing the install and not me. The crown race seated on the steerer tube without a problem and the lower cup assembly fit on the frame as well, but when he tried to fit the whole setup together he couldn't get the fork up far enough to make the crown race meet the bottom of the seating boot of the lower cup. It's like the widened lower section of the steerer tube wouldn't go into the lower cup assembly. So the problem was not an incompatability of fork steerer with crown race but with the cup/boot assembly. Any new thoughts?
Oddthe other Tim
Oct 6, 2002 9:28 PM
Hmmm ... is it possible that the mechanic put cups in the wrong ends of the head tube? The upper cup would not need to clear the 26.4mm diameter of the steerer tube at the crown. If you can insert the fork all the way up-side-down, that would be a pretty good clue.
Oddrobk
Oct 7, 2002 8:15 AM
I don't really think so. It's pretty obvious from the design of the headset which end is up, besides, the crown race will only fit into the lower cup and boot. I'm going to call Easton and Syncros and see if they know of any compatability problems.

From looking at the headset and fork and fooling around with it myself, it appears that the sleeve or upper portion of the lower cup, the part that goes into the lower part of the headtube, is of a slightly smaller diameter than the crown race. This is the part that won't match-up with the fork diameter. If you turn this upside down the "Syncros" logo would also be upside down, suggesting that it doesn't go that way.
length of 26.4mm diameter...C-40
Oct 7, 2002 8:15 AM
If the length of the 26.4mm diameter is too long and intereferes with the lower cup, it could be filed down. There's no reason for this enlarged area to be any longer than the thickness of the crown race.
length of 26.4mm diameter...robk
Oct 7, 2002 8:17 AM
You may have something here C-40. Do you know of people who have had to do this to get a headset properly seated?
length of 26.4mm diameter...C-40
Oct 7, 2002 2:09 PM
Never had to do this personally, but I've noticed that some forks do have a very long length of 26.4mm diameter, when only about 1/4 inch is enough to do the job.
Please post a follow-up when you find the solution (nm)TFerguson
Oct 7, 2002 5:55 AM
Please post a follow-up when you find the solution (nm)robk
Oct 8, 2002 5:50 PM
I'm not sure I found the "solution" but here's how I'm going to resolve the issue. Our friend C-40 was right in identifying the offending feature as being the unnecessarily long 26.4 mm section of steerer tube above the crown. Apparently, not all headsets have such extremely close tolerances between the lower cup sleeve and the steerer tube as is found in the Syncros headset. I found a LBS with a Ritchey Scuzzy Logic Pro 1 in. headset and tried it on for size. The crown race and lower cup slipped over my fork steerer tube and seated without the need of a headset tool! Of course, the quality disparity between the Ritchey and Syncros headset models was, in my opinion, very clear, the Syncros an obviously superior headset. Unfortunately,I am unwilling to file down the oversized section of steerer tube to accomodate the narrow diameter of the Syncros headset, since I don't have the tools or the skill to do what I think would be a satisfactory job. So I am left to unload my headset on ebay and find an alternative headset with a wider lower cup sleeve. I'm thinking about a Cane Creek, any other thoughts? The moral of the story is, be aware that not all headsets and forks are equal, regardless of their description as 1 in. or otherwise. Caveat emptor!
One more thing to considerKerry Irons
Oct 9, 2002 5:14 PM
I hate to bring this up, but is is possible that your head tube is ovalized? If so, it would distort the lower HS cup and cause the problem you are experiencing. Also, if you decide to fix this with a file, don't work on the steerer tube, enlarge the "hole" in the lower HS cup. Easier to do, and no risk of losing strength or functionality. Seems like the easiest fix.