Am I correct in believing that a majority of vintage threaded headsets have locknuts that are 32mm across the flats? (I'm just talking road bikes here.) I realize that there are all sorts of exceptions--the weird Shimano 600 aluminum nut, the various headsets where the locknut is engaged with a pin spanner, and so on--but 32 is fairly standard, yes? That's what's on all my own non-French bikes, but maybe I'm an outlier.

That would be useful to know before I get too involved in a (possibly Quixotic) project to make a prototype of a lightweight pedal/headset wrench for touring use. I lugged a heavy steel pedal wrench from California to Florida earlier this year, along with a huge pair of channellocks that I had to buy when my headset worked loose. I have an idea for a very lightweight tool that will do the work of both, but I want to get the sizing right.

Jon, yes, 32mm seems to be standard for the headset locknut. Interesting idea for a tool, but will it be different than the Park HCW-6?

I actually just came across a locknut that was bigger than 32mm, though I have so many projects going I can't remember what it was. I'll have a look and come back.

I realize you might have a terrific design idea but I've done a lot of riding and have never had a headset come loose, so am doubting the necessity for such a tool.

Simpsons did it...

This is on my Miyata 210. Also an odd, threaded, notched spacer in there.


Untitled by Joshua Paschall, on Flickr


Untitled by Joshua Paschall, on Flickr

Well, functionally similar but half the weight. And brightly colored. Everyone likes bright colors, right?

Yeah, it's only happened to me a few times, but it was a big nuisance when it happened on my recent tour. If this sucker works I'm definitely bringing it on my next long tour, just in case. Having it with me will probably guarantee that I never need to use it.

Going to make it out of alloy like AN hose coupler wrenches? Would be nice not to mar the top nuts like happens so often.

Strange, because the Japanese were usually so rational. Then again, my Miyata 610 had the only 26.7mm seatpost I've ever seen. Not just an out-of-tolerance post, either--it was actually stamped "26.7" on the side.

I may be mis-under-remembering but I think I've got a 37mm in the basement. Now I have to check.

32mm is definitely the most common but I've come across lots of other sizes. Department store bicycles with 21,15mm stems sometimes used used a locknut with 30mm flats. At the other end of the spectrum, Fisher's Evolution headsets required a 40mm headset wrench

This jogged my memory of tool that I own, but have yet to use on the road... the Park RW1 tool.
This is a short combination wrench that has a 32mm headset wrench at one end and a 15mm wrench at the other end. It's about the thickness of the average pedal or headset wrench... roughly 0.1 inch.
The wrench is a bit under 6 inches long, and has two holes to permit mounting on water bottle bosses (presumably mounted under an existing cage, as a "just in case" tool)
My cheap scale says that it weighs 100 grams.

a quick search doesn't pull up much on the web.
Nothing on Park's web site, but there is a finished auction on ebay UK:
Vintage Park Tools RW1 32mm 15mm Wrench Spanner Headset Pedal Cycle Bike | eBay

So.. I'd say that it should be easier to find a used RW1 than to prototype your own.
Or make me an offer for mine?? It doesn't seem to be getting much use.


Steve in Peoria

I remember these. There was more than one version, to accommodate various headset sizes. I also recall versions with a single long mounting slot, as opposed to two mounting holes.

Our tandem's headset locknut measures 36.4mm. Fortunately it does not require a thin wrench. My Raleigh Gran Sport's measures 31.5, so I guess it is a nominal 32. Most others measured about 32.

[QUOTE=jpaschall;19969022]This is on my Miyata 210. Also an odd, threaded, notched spacer in there.

Hi Josh : Have you found a tool to use to remove the threaded spacer? I am trying to figure out what to do with this on my 210. My headset feels OK, but I would like to take it apart just to check it. But also need to get it apart and back together.

[QUOTE=IslandTimePE;19971953]Thankfully mine was not tightened down super tight and I was able to get it with a channel lock. I’m interested to hear what others have to say about this though. I’m not really sure what purpose it serves, either.

[QUOTE=jpaschall;19971958]I believe you can remove the notched spacer with the small end of this Hozan lockring wrench:

https://www.ebay.com/i/162030762774?chn=ps&dispItem=1

I would think its another layer of security for the whole thing to keep it tight over the long haul, maybe overkill but on a long loaded tour it might be one more thing that doesn't come loose which of course would be a good thing.


[QUOTE=jpaschall;19971958]

I remove and reinstall those Japanese notched lockrings using a thick screwdriver as a punch.


As with turning a hex locknut with an adjustable or open-end wrench, one can get the nut tighter by repositioning the tightening tool while repeatedly tightening the nut to the same reduced level of torque, since the differing wrench position (or different notch) will distort the locknut's roundness which assists with achieving a sufficiently-tensioned nut but with less force required. This works on these notched lockrings and works well with alloy locknuts for the same reason, that you have limited force to work with. And on bikes with keyed washers or keyed reflector brackets, there is much less chance of shearing the key or moving the reflector off center (easily retained with one hand while turning the wrench with the other. Lubing threads and nut/washer faces makes things even easier.

Apparently there was a headset made with a 31mm nut. I know because I have a wrench of that size. You can have it if you find you need it, which is unlikely.

Yes, that's the idea. I bought one of these to start with:

https://www.ebay.com/itm/AN-Hex-Wren...YAAOSwt5hYd57r

The one I received has a slightly different style handle from the one in the picture. It seems to be made from T6 aluminum--probably 6061--and is made from 9mm stock, which is thicker than I would have expected (never having held an AN wrench in my hand before). It's light--I have no good way to weigh it, but it's clearly lighter than a Park cone wrench.

A -12 AN wrench (I don't know what the dash signifies, but it's what they're called) is nominally 1 1/4", and that's very close to 32 mm. At the price I paid the quality control likely is not great. My particular wrench measures 31.8mm, according to my non-digital-and-perhaps-less-than-super-accurate calipers. By comparison, the 32mm end of my Park HCW-15 headset wrench measures 32.1 mm.

But as others have noted, 32mm locknuts are actually all over the place. The AN wrench fits well on the nut on my Miyata 1000, is a tight fit on the Stronglight nut on my PX-10, a very tight fit on the Campagnolo nut on my Raleigh, and doesn't fit at all on the Tange nut on my Lotus, the unbranded nut on my low-end Univega, or the nut on my 1967 Dawes (which looks like a 32 but may actually be some crazy whitworth size for all I know).

If I remember right, threaded headset locknuts should be tightened down to something like 200 in-lb. The maximum rated torque for a -12 AN fitting is 550 in-lb, so tightening a headset locknut presumably shouldn't overstress the wrench (although again, it's a cheap wrench and who knows what it will actually take to break it).

Bottom line, I guess I'm going to add this to my long-distance-touring tool kit. I had thought it would take a little machining to get the jaws to fit, but it happens to fit the nut on my preferred touring bike right out of the box. I wouldn't use it as a shop tool--the aluminum wouldn't hold up for long--but for occasional use on a tour I think it will do fine.

I had thought about making a machined insert that will fit into the jaws to reduce them to fit a 15mm pedal fitting, but now I'm thinking that's a waste of effort. It seems more sensible just to make sure that the pedals one uses on a tour have allen wrench fittings on the back, since you'll already have a folding allen wrench set. For some reason I didn't do that last time, and ended up hauling a steel 15mm pedal wrench all the way across the country. How many calories do you suppose that took?

I carry these just so headsets and pedals will never come loose. Not sure who made the wrench, but it was inexpensive and does the trick.

Thats funny, my 93 Miyata 512 has a 26.2 seat post. Not sure what the steerer is, but Im waiting until i can get another pair of micrometers before I take anything apart on that bike.

Yes, there's nothing like carrying a tool so you won't need it.

I used to have one of those, too. I can't remember who made it, either. I say "used to," because in my innocence I used it as a shop wrench and quickly wore out the pedal wrench part--I think it was made out of regular mild steel, maybe 1/8" thick? It rounded off pretty quickly. At that point I got discouraged and lost it or gave it away.