Bicycle Mechanics - J.I.S. headset quandry

I decided to overhaul my old bridgestone 400 which I use as an around-town/commuter. I stripped it down and had the frame powder coated. The headset was shot so I went to buy a new one. Doing a little research online I learned that my bike had the J.I.S. sized headset, which requires a 27.0mm crown race I.D. The local bike shop only sold one, an inexpensive Tange Passage headset, so I bought it, and had a friend with the proper press install the cups. This seems about the level of headset that the bike came with when it was new, and for my purposes, should be fine.

This is where my headset woes began. No amount of adjusting could really get rid of all of the binding. I had followed some advice and opted to use loose bearings rather than the bearing retainers that came with the headset. In theory, more loose bearings should be smoother than the bearing retainers, or at least this is what I gather. Anyway, I started reading around more and learned that J.I.S. measurements specify not only a 27.0mm crown race, but also a 30.0 mm internal diameter on the head tubes. THe more common, modern ISO headset dimensions are 26.4mm crown race and 30.2mm cup ID. Looking at my Tange Passage headset box, I discovered that this unit has a 27.0mm crown race (which I needed) and a **30.2 mm** diameter cup.

Now this explains why it was hard to press the fixed cups into my headtube. My bike was probably the JIS measurements, rather than the ISO size. Why on earth would Tange sell a headset that combines a JIS crown race with an ISO headtube diameter? In any event, my questions are: 1) is it likely that I screwed up my freshly painted frame's headtube by pressing in the slightly larger cups? THey are both made of steel. 2) Could this explain why I'm having trouble adjusting the headset, or is that more likely a facing issue? 3) Should I remove the headset and re-face the headtubes and ream them out to the proper ID for a 30.2 ISO headset, and then either re-install the Tange unit or get another ISO one? Any thoughts would be appreciated. thanks!

Tange has both sizes, they sell iso and Jis from what i have seen, the differences are so minimal that u can get away sometimes putting one or the other one.

U mentioned a problem, What is the problem u are having?

For the record tange makes crownraces for iso or jis if you have those problems mixing frames and forks in different standards that match specific headsets.

the problem is that I can't get the headset adjusted so that a) it doesn't bind at about 9 o'clock and 3 o'clock, or b) it isn't too loose.

the problem is that I can't get the headset adjusted so that a) it doesn't bind at about 9 o'clock and 3 o'clock, or b) it isn't too loose.

You need to have the head tube and fork crown race re-milled -- I suspect there's powder coating on the faces throwing off the alignment. You LBS should be able to do this as well as install your headset.

I had the same bike and when the OEM Tange headset went south I had the fork crown milled to 26.4 mm (ISO) diameter and installed an Ultegra headset.

I expect JohnD is correct and that the headset faces are distorted with the powdercoat. Have them faced and have the cups pressed in correctly..

You can buy headsets that mix JIScrown races with ISO cups and vice versa. This allows for mixing and matching without milling or reaming.
http://www.unitedbicyclesupply.com/index.cgi?id=749172023320&c=Components&sc=Headsets&tc=Threaded
Nothing wrong with Tange headsets either, in my opinion.

thanks for all your advice. I think that I'll take the headset out and have the surfaces properly milled. they looked sufficiently clean from paint so I omitted this step but perhaps there was a little something on there getting in the way. But since I'll be sticking the 30.2mm cup back into the slightly smaller headtube should I also have the shop ream it out to the proper diameter. Or is that not an issue because the larger cup has already been crammed in there?

thanks for all your advice. I think that I'll take the headset out and have the surfaces properly milled. they looked sufficiently clean from paint so I omitted this step but perhaps there was a little something on there getting in the way. But since I'll be sticking the 30.2mm cup back into the slightly smaller headtube should I also have the shop ream it out to the proper diameter. Or is that not an issue because the larger cup has already been crammed in there?

I'd have them ream it since reaming and facing are often done in the same operation, at least with the tool I have.

I removed the headset and faced/reamed the headtube to accept a 30.2 mm OD cup. I also got a new tange levin headset and pressed the cups in. But now for some reason the 27mm crown race fits on the steerer pretty easily, and it has a little bit of wiggle in it. I'm positive that the original unit that was on the bike had a 27mm crown race, as I measured it with my calipers. It looks to me like the ridges that the race sits on are worn out--does this happen? The surface that the crown race sits on measures 27mm OD, which would explain why I can get the race on by hand--there is no interference. Is it common for this surface to wear out? or am I going crazy and I actually have a bike that takes a 26.4mm crown race despite what the specs say, and what the old headset seems to be. If it is worn down so that I can slide the 27mm piece on, can I just go down to a 26.4 mm race. As this is the second headset I've purchased, I'd rather not buy a whole new unit.

But now for some reason the 27mm crown race fits on the steerer pretty easily, and it has a little bit of wiggle in it.

Using a hammer and a sharp pointed punch, you can dimple all the way around the sleeve the crown race presses onto. Should solve the problem of the wiggle.

hi, could you explain what you mean by dimple? I've got a punch...this is sounding good to me, but I don't want to screw things up further. thanks!

I removed the headset and faced/reamed the headtube to accept a 30.2 mm OD cup. I also got a new tange levin headset and pressed the cups in. But now for some reason the 27mm crown race fits on the steerer pretty easily, and it has a little bit of wiggle in it. I'm positive that the original unit that was on the bike had a 27mm crown race, as I measured it with my calipers. It looks to me like the ridges that the race sits on are worn out--does this happen? The surface that the crown race sits on measures 27mm OD, which would explain why I can get the race on by hand--there is no interference. Is it common for this surface to wear out? or am I going crazy and I actually have a bike that takes a 26.4mm crown race despite what the specs say, and what the old headset seems to be. If it is worn down so that I can slide the 27mm piece on, can I just go down to a 26.4 mm race. As this is the second headset I've purchased, I'd rather not buy a whole new unit.
I'd just mill it down to ISO 26.4mm. The presence of ridges on the the steer tube suggests to me that the race seat was milled undersize for JIS 27.0mm and was then knurled to build it up and hold the race. You could try re-knurling it, but IMO knurling is a cobble-job in the first place and re-knurling a step beyond that even. Milling it to the proper ISO dimensions should solve your problems.

johnd-- its funny you should say that because the guys at the lbs said exactly the same thing today when I took it by to get their opinion. i figured that i should just mill it down and go with the 26.4 crown race, which is what they are going to do. the other option was trying to use locktight but i figured why not just resize it in case i ever need to put another headset on (doubtful), but more importantly having them mill it will clean off the powder coat from the surface that the race sits on. so another 20 bucks or so later and i'll be in business. this project is getting expensive...