Need help, who knows this Time Trial headset?

Remko · #1 03-30-2016, 12:33 PM

I urgently need your help and I hope someone can point me in the right direction. I'm working on a time trial bike and welded handle bars straight on my fork. This means that I don't need a stem but I will need an headset off course. I'm looking for a headset like on the below mentioned pictures (that is not my bike).

1. Does anybody know how you call thise kind of headsets?
2. Do you know where I can buy it?
3. Any comment is welcome!

Thanks in advance for your help!

Headset.jpg

Mark McM · #2 03-30-2016, 12:54 PM

That is obviously a very customized setup. I don't think the bearing in the head tube on this bike is a standard headset bearing. Looking at the slotted nut/split pin, it looks to me like it could be a car/trailer wheel hub bearing that has been retrofitted to be a headset bearing.

As I understand it, your fork does not yet have a headset bearing? Does your fork have a standard steerer tube? If so, why not cut it short enough so that the top cap presses directly on the top race (no stem or spacers on the steerer)?

Black Dog · #3 03-30-2016, 01:06 PM

Do what Mark said. That is the way that most of those set ups are done.

Remko · #4 03-30-2016, 02:30 PM

Quote:

Originally Posted by Mark McM

That is obviously a very customized setup. I don't think the bearing in the head tube on this bike is a standard headset bearing. Looking at the slotted nut/split pin, it looks to me like it could be a car/trailer wheel hub bearing that has been retrofitted to be a headset bearing.

As I understand it, your fork does not yet have a headset bearing? Does your fork have a standard steerer tube? If so, why not cut it short enough so that the top cap presses directly on the top race (no stem or spacers on the steerer)?

Thanks, but then you still need to have the bearing on the top end lock the fork (threaded) at the top, am i right? I would like to skip that to get a flat surface like on the picture.

ultraman6970 · #5 03-30-2016, 05:23 PM

IMO, the only person who might know could be potato, always wondered how they fixed the fork to the frame in frames like that.

bikinchris · #6 03-30-2016, 05:31 PM

It's not just the headset that is special, but the fork too. I really don't see any advantage to that design. There is a lot of hardware inside that head tube.

Tandem Rider · #7 03-30-2016, 09:38 PM

The upper looks to me like a small version of a normal industrial bearing. There should be a machined "seat" on the inside of the headtube to receive the outer race, this will be a press fit. The inner race is slotted and it grips the steerer when the "nut is tightened down, similar to the way a collet grips a mill, more importantly, this also adjusts the preload on the bearing. It is locked into place by either a cotter key through holes or bending "ears" up against the nut flats.

It should be available at any largish bearing supply. Might be metric, you will have to have exact measurements to get a replacement, probably special order.

Mark McM · #8 03-31-2016, 09:49 AM

As Tandem Rider has alluded, the heat tube on that bike has been modified by adding a top bearing seat internal to the head tube (probably by brazing it in place), and the steerer on the fork must also have been modified to mate with the industrial bearing. That's an awfully large amount of work to hide the top bearing.

The frame in the picture dates back to before threadless steerers and headsets, so the builder must have deemed that the work that was done was preferable to having a threaded top race and lock nut above the head tube. A threadless headset top race and top cap will be lower profile and cleaner looking than a threaded headset, so I'd recommend finding a threadless headset with a smallish sized top bearing, and then painting it match the frame to make it as unobtrusive as possible.

ultraman6970 · #9 03-31-2016, 04:36 PM

I have an idea that well could work. There is like a center quill bolt that is used in BMX bikes to hold the fork and headset in place, wonder if you can use that. And add a top headset bearing and cup, that piece im taking can help you to keep everything in place.

ps: darn cant find it... imagine a long quill center bolt that uses a rounded piece at the bottom that is stuck in the bottom (from the outside) of the fork, is used to replace the expander.

pavel · #10 03-31-2016, 04:55 PM

this is a Takhion TT bike made in Ukraine in the 1980s. Not many like it floating around...

dustyrider · #11 03-31-2016, 05:05 PM

I wouldn't cut the bike's head tube. Unless it were absolutely nessecary. Don't see anything wrong with just running with out the stem. I suppose the top cup of the headset could be in your face when completely tucked...but cutting a bike seems excessive.

Tandem Rider · #12 03-31-2016, 05:57 PM

The fork steerer will be too short for any version of a conventional upper headset. The original steerer likely was also machined to accommodate the inside diameter of the upper bearing, reaming the inside of the steerer would probably make the walls too thin. It looks like a conventional lower 1/2 of a headset will be required, LBS should be able to measure it and set you up with correct diameters.
Rather than monkeying around with expensive workarounds, no matter how much fun that can be, just pay a visit to the local bearing supply house with f/f in hand, let them take measurements. You will probably have a bearing in hand in less than a week. I would get the lower installed before going to the bearing supplier.

ultraman6970 · #13 03-31-2016, 06:07 PM

Yes, the one in the pictures is a tachyon, russian made and stuff.

OP do you have a picture of the actual bike?? fork, front tube and stuff??

Ed-B · #14 03-31-2016, 06:53 PM

This looks like a lot of effort for a very small benefit.

Why wouldn't you just run a conventional headset and plug the opening at the top of the fork?

I really don't think that the bike is much more aerodynamic with that internal arrangement. What did it save - 30mm of stack? Would you really put your body/face that low over the frame when you're riding the bike?

ultraman6970 · #15 03-31-2016, 06:58 PM

Saw another picture at the web of this nut system thing and I think this is how that worked.

There must be something inside of the or around the steering tube, then they used like a large pin just like the piece I was talking about before, a large pin put from the bottom of the fork and up, then like a wedge with maybe a central bearing or something that press down using that nut and safety pin system, helping it to be centered at the same time.

The Bottom cup and race can be any headsed.

Either way pictures of what you have could help a lot.

Ed-B remember this is when eveyrbody was experimenting, the idea was more a psychological thing than actually save a few watts as is today. Darn cool bike tho.