To Face or Not to Face?
 

I've been working on a project which has been stalled by a headset stack height issue. The problem is that the Dura Ace 7400 headset I very much would like to use has a taller stack height than I expected. The headset does barely fit, but there are only perhaps 2mm (a couple threads) showing before I screw on the top locknut. The original fork is an aluminum Tange Fusion fork. I'd prefer to stick with the existing fork (mainly just to keep everything original), though I don't know if I'd have any luck finding a matching fork with a longer steerer tube.

So, I was in the LBS asking their opinion, and it was suggested that one possible solution would be to give the headtube a heavy facing--just enough to expose a few more threads for the headset. How much exposed threading is sufficient? (I'm guessing I will only need another 2-3mm, plus the 2mm or so I already have.) This seems like it may be the cheapest option and also allow me to use both the DA 7400 headset and the original fork.

What do you think? Please stop me if this is a bad idea!

Should work, looks like you've got enough headtube & lug there to play with. What I would do is mark a line around the lugs to where I want to remove to, very carefully take a large file to it and get within a MM or so, and then face to the line.

One thing to consider is if you can get the additional "height" you need from just taking away from the top lug, do that; removing material from the lower lug will (very slightly) alter your bike's geometry.

^ Agree with mudboy on the top lug only. It would definitely be the cheaper solution. However, you're not likely to gain more than one or two thread revolutions this way. Is the steerer tube steel? If so, you can have a frame builder either replace the steerer tube or braze on an addition, and then rethread the whole thing. However, this will cost significantly more.

Alternatively (and this might just be crazy talk), I wonder whether using smaller loose balls on the upper race would gain you one additional thread by reducing the adjustable cup height, without affecting headset function?

Sutherland's says you should have at least 3 complete threads for the locknut to engage, if you can gain that just by some "heavy" facing, I'd go for it, but would not try anything but a real head tube mill (not a file) if you expect things to stay parallel and aligned. The DA already has smaller balls than typical (which is why its SH is lower than most) and I would not substitute even smaller balls since the radius (ai) of the races/cups is designed for the contact of those balls.

Re the below: the DA7600 is the shortest stack of all the Shimmy HSets, the Exage R500 then the Sante is next (good luck finding one), Deore M730 also short but not sure if that's 1" or 1.125"

I'm in a similar situation, and am considering a similar solution to the op's.

The steer tube replacement idea is one thing I am seriously considering; having the tube replaced with a threadless one. Has anyone tried this? About what does is cost? Will I have to completely repaint my fork? I'm considering this for my Colnago.

Bernie Mikkelsen (Alameda, CA) did it for 2 of my forks, one went from threaded to threadless and his work is perfect...he was charging about $65, but I heard his price has gone up. Ideal guy for gaucho777 since he's in Berkeley, but those of you outside the SF Bayarea will have to find a local framebuilder who does as good a job as Bernie (or ship it to him).

Thanks everyone for the advice.

Excellent advice!

Hmm, that’s interesting since I seem to recall the ball bearings were quite large, larger than I’ve seen used in a headset before. I'll have to open it up when I get home. I bought the headset used. I wonder if it has the wrong size balls. Do you know what is the correct size bearing for the DA 7400 headset?

But that would be the easy way out! ;) Almost everything else on the bike will be DA 740X, so I'd very much like to use the headset if I can.

Great to know! Thanks.

Let me see if I have this right. The OP wants to install a component that does not fit properly. To make it fit, he, or she, intends to irreversibly alter a frame set. And someone here suggested this is good advice.

I wouldn't and I didn't. I have this problem, with two bikes, at the moment and I went with component modification, as opposed to damaging a frame set. But that is just me.

I agree with Randy. Can't you just grind down the top of the adjustable cup?

Thanks for your input, which I do respect. Normally I am opposed to making any irreversible modifications to a frame. In this case, the frame has been used and abused for a long time and wouldn't necessarily be considered a collector's bike (though it does has sentimental value to me). Taking an extra mm or so off the top of the head tube does not seem to me such a horrible offense. If I said I inadvertently faced the frame more than I intended, I don't think anyone would be screaming "Drew!"

Btw, when you say "component modification" do you mean that you altered the headset to reduce its stack height (which was really my first hope; my question to the LBS was in fact "Is there anything I can do to this headset to reduce its stack height?"), or simply went with an alternate headset?

Sounds like you already knew what you wanted to do.... why did you bother to ask?

Honestly, I still haven't made up my mind. Sure, I am leaning toward the facing option since it will allow likely allow me to use the headset and/or not require the purchase of a new fork with longer steerer. I did spend a couple hours looking into new forks yesterday. I asked because I wanted people's opinions, and thought someone might say "No, facing's not necessary, all you have to do is X, Y, or Z and the you'll gain the extra 1-2mm."

And, to boot, before I do anything, my first step is now to see if the ball bearings I have are too large.

+1

While the OP's plan may well work, it strikes me as odd that he'd modify his frame out of a desire to run the original fork and a non-original headset. Everyone's got their own priorities, but why would the originality of the fork mean more than the preservation of the frame, but less than the use of a non-original headset? I know ya said the frame's been thru some abuse already, but i'd just get a different fork or run a different headset...

-rob

from Sutherlands: the 7400 uses 22 balls, 3/16"D but the 7600 (and the others with shorter SH) uses 25 balls, 5/32"D and the gain (or loss) in SH is around 3mm...the 7600 has SH of 31mm, your 7400 is 36.7mm and the Sante is 33.4mm and just for the record, the Ultegra 600, HP6400 is 33.8mm, and the 105 HP1055 is 33.3. I wouldn't balk at removing just a mm or so from the HT, and it sounds like this is all you really need, but more than that would stop me. YRMV, but you're always better off if you can achieve desired results without milling.

After looking at gaucho's frame I'd say face the headtube 1-2mm, no problem, to make a desired set of components work.

^Thank you! I'm heading over to the LBS to pick up some ball bearings now.

Cost is also an issue.

Again, I don't yet have any plans or intentions, except try smaller ball bearings. All I said in my original post was here's a suggestion from a LBS which seems like it might work, what do you think?

FWIW, I also have a call in to Mikkelson Frames to inquire about a steerer tube replacement.

Now, I could always just say to hell with the curmudgeons (and I consider myself one), go ahead and face the HT, then say all it needed was smaller ball bearings. Only me, the LBS, and the bike gods would know. :innocent:

Btw, I HATE Drew, but facing one thread's worth of height off the HT does not offend my sensibilities--though I do still respect everyone's difference of opinion.

1. Cutting the bottom of the head tube has almost no bearing on geometry. Think of it this way....framesets dont come with headsets yet each headset has a different stack height that could in theory alter the geometry. Seriously.....cutting 1 or 2 mm from the bottom of the head tube changes geometry no more than changing headset or running a 23c tire on the front in conjunction with a 25c on the back. Sometimes its best not to look to deep into things.

2. The 7400 headset has a recessed washer. Use that washer and nothing else.

3. If your going to cut the frame do both ends an equal amount and the amount you cut will be dpendant on the the lug. I wouldnt cut to much of the lug away....cutting both ends will make the head lugs symmetrical.

4.

I decided to go with the original(???) head set, because I like the looks and it was in great shape, but the steering stem was too short to allow for this set-up...
http://bikeforums.net/attachment.php...hmentid=185118


The center pull brakes caused two problems. The bracket was too thick, increasing stack height and, the leverage applied through using the brakes would loosen the lock nut off in short order.

I am going with Universal 68 side pulls, and I swapped out the brake bracket for the thinnest spacer washer I could find in my stash. Then, I got rid of the cages/balls and went with smaller ball bearings, but more of them. The result looks like it should be OK and the Bottecchia sits, waiting for some decently dry roads to test the bike, and the modification, on. My guess is that the fix will be just fine since I have a decent thread count now.

I can still, if I wish, grind off some of the bottom of the lower cone, gaining another mm, with luck. But I doubt that I will have to.

Hope this is a help and that my fix worked. Don't even ask about the Bottecchia Special that I am also interested in restoring.

my steerer is 10mm too long. if only it were possible to give you half of it.

By way of an update, I am pleased to report that my DA 7400 headset is now installed, and nothing more than a standard/light facing was done to the frame. After the original post & feedback, I got some quotes for new fork as well as a steerer tube extension, and then weighed my options for another week or so, before I ultimately brought the frame in to the LBS for their advice. Beyond the light facing, the LBS replaced the stock, recessed, notched washer with a nearly identical, though very slightly thinner washer. Further, I apparently did not set the rear edge of the bottom cup completely flush against the head tube, which they corrected. I could have even gained another mm or so by removing the plastic seals if absolutely necessary, but the light/normal facing, resetting of the bottom cup, and different washer all combined to do the trick.

A question for miamijim (if you are out there): In your reply above, you advised not to use anything but the stock DA washer. The new washer is basically identical to the stock washer when viewed on top of each other--the new washer being about a mm thinner when viewed from the side--and it fits perfectly into the DA headset. Is there any reason I should be concerned about the new washer if it's a perfect, albeit slightly thinner, match?

I wouldn't answer for Jim, but I'll guess that his intention was that you use only a washer that would fit in the recess, not any other that would not fit in the recess and no additional washer(s)...all to minimize the stack height. Glad to hear it's all worked out and you're back on the road.