TallRider

Starting information:
JIS standard for 1" headset is 27.0mm diameter crown race, 30.0mm cup diameter for inserting into the head tube
ISO standard for 1" headset is 26.4mm diameter crown race, 30.2mm cup diameter

JIS was common on Japanese bikes produced in the 1970s and 1980s. ISO has endured as the main standard for bikes still produced for 1" headset diameters.

Some 1" headsets now only list the crown race diameter. For example, this listing of the Tange Levin CDS headset shows options for 26.4mm (ISO) crown race and 27.0mm (JIS) crown race. I called Jensen (this website listing) and they can't quickly find more information).

I expect that the listed crown race diameters correspond to also having correct ISO and JIS headset cup diameters, but I'm not 100% sure of this. It's possible to shove a 30.2mm headset cup into a head tube designed for 30.0mm (I did it once by accident). This will work, but it's a tight fit and also stretches the head tube so you will have to use 30.2mm (ISO) headset cups in the future.

Does anyone know whether the Tange headset listed as 27.0mm crown race also has JIS-standard 30.0mm headset cups?
Thanks.

AnkleWork

When you asked the sellers and manufacturers, what did they say?

TallRider

I've seen similar listings elsewhere, but I'm guessing Jensen's available info is just what their distributor's catalog (probably QBP) says.
Niagara cycle (out of stock in both sizes) simply lists "EC30" for headset upper and lower cup diameter on their pages for both 26.4mm and 27.0mm crown race versions. Which might add some weight to my worry that they're both the same size, but I'd guess it's simply a lack of information.

I'm hoping some folks in this group will know from experience.

AnkleWork

I wonder what Tange would say (or publish).

TallRider

Thanks! I should have checked that; I just assumed they wouldn't list stuff and just went through distributors.
But here it is. And they list 30.0 cups corresponding to 27.0 crown race, and 30.2 cups corresponding to 26.4 crown race.
Good to know.

TallRider

I received the Tange Levin CDS headsets today. The crown races were 26.4 and 27.0, as listed (I bought one of each) but unfortunately both headsets have 30.2mm (ISO standard) cups.
I called Harris Cyclery (the Massachusetts store where the late Sheldon Brown worked), who also lists the Tange Levin CDS in both sizes. They checked their stock, and the headset with the 27.0mm crown race has 30.2mm (ISO spec) cups.

So: Tange website lists the headset available in full JIS spec, but the 27.0 crown-race version available through the main US distributor (probably QBP) comes with ISO-standard headset cups. Looks like I'm going to eBay.

AnkleWork

I think Tange owes you, but have you measured your headtube? The interference fit may be OK with the 30.2mm cups after all.

TallRider

I could jam 30.2 cups into the head tube. I did it accidentally once on a different bike. It just means I'd be stuck using 30.2mm cups in the future. Not a big downside, given how hard it is to find 30.0mm cups nowadays.

I don't think Tange owes me. They sell various versions and combinations. I'm guessing the U.S. distributor (probably QBP) only carries the 26.4/30.2 and 27.0/30.2 versions of the headset. It would be nice if sellers and distributors made this very clear, instead of just listing the crown race dimension. Kudos to Harris Cyclery for noting this clearly on their website (wish I'd noticed this earlier).

JohnDThompson 

Just get the frame and fork milled to accept ISO head parts. Then you won't be restricted to JIS headsets.

mrv 

howdy - I am having this exact same problem right now today.
I wanted to keep a black headset on my circa 1990 RockHopper. Did NOT realize I was JIS. My LBS could NOT get a low stack, black, 1in threaded headset. So I went to eBay.
Got the headset - TANGE Falcon 250C something or other.
Pressed the upper cone & lower cone in and realized I had a problem when the crown race refused to install.

QUESTION for the frame pros: @JohnDThompson et al: Did I damage my head tube with the 30.2mm ID going in the 30.0mm OD?
- I am thinking "no" based on TANGE's insertion info: Falcon FL250C | TANGE SEIKI

So right now I'm trying to find someone who will mill fork for me. I don't think my regular LBS has that exact cutter on hand. My other irregular bike shop wants $60 and a week and a half to do it. That's $10 per 0.1mm!! (i know i know it's a $539.95 tool......)
Think I'll try a frame builder down in Detroit for help.
Thanks.
-- a very frustrating 0.6mm!! --

JohnDThompson 

Probably just fine.

Andrew R Stewart 

We get this routinely, "it's only XXX. Why so much to do it?". That's when I offer how it can cost less. You do all the break down and reassembly. Hand the shop a bare fork, nothing more or less. I do agree if that's the way the shop was quoting for $60 is on the high side. It suggests that they really are not seeking out the work. Just like any business when the oddity comes around the cost goes up. At Full Moon Vista we would charge less (I forget exactly how much, $30 comes to mind) for a bare fork to be milled down. I do suggest that the shop does the crown race seating after they do the milling, maybe $5 extra. This way they own what they did.

This is one more reason to befriend a good shop in your area. What we do for our selves or good customers can be different then those who we don't have a relationship with. Call this bad business if you wish but it is how much of the world works. BTW MI has some really good builders and one might look at the cost differently then a retail shop does. Andy

Bike Gremlin

Made a list of standard headset dimensions.

At the beginning, there are links to pages explaining what to measure and how, if those instructions are needed.

mrv 

Hi Andy - thank you for replying.
I have a pretty good relationship with LBS1 (which, I'll just refer to as Sweet Bikes, as that's the name of the shop). The owners (husband and wife and sometimes kids) is very accommodating to me. He's let me do tool rentals and supports my vintage habit. This particular repair he could not get this low stack, 1" threaded in black through his regular sources. It's a challenge outlined in this thread and another recent thread. So I went to eBay after he checked. Since he didn't order me the part, I didn't want to use his shop to install, so I was doing it at home.
- too long of a story short:
-- He was not available Saturday at his shop, his fill in help doesn't know a facing tool from a milling tool - so couldn't help me - and he's closed Sunday. So I tried LBS-2, a perfectly fine bike shop also, I'm just friends with Sweet Bikes. LBS-2 required the $60 and week and a half. Even with me standing in their shop with a naked fork in hand. I don't blame them - it's a $500 tool!
Hopefully Sweet Bikes will have tool and I will know Monday - mean while my bike hangs partially dis-assembled.

I fully agree with your comments. My big worry was the cup & cone going in the head tube. Just kvetching on the other stuff.

ciao!

Andrew R Stewart 

Thanks for the fuller story. I really like follow ups and the rest of the story (to borrow from the late Paul Harvey). I hope shop1 will work out. Andy

mrv 

Andrew R Stewart 

As I said in another thread yesterday, this is why one wants a relationship with an accessible LBS. The price is right but far better is the chance for personal growth/experience. Glad it worked out so well. Andy

shmuelyosef

This has gotten to be a worse problem. Just bought a Tange-Levin headset advertised as J.I.S. and while the crown race was indeed 27.0mm, the cups are 30.2mm. It is to be noted that Sheldon says he puts 30.2mm races into 30.0mm head tubes, but my head tube (nice old Miyata 710) measures 29.85mm on both ends, and the races measure exactly 30.20. that's a 0.35mm differential and I'm not comfortable with that.

I will probably end up going to the LBS and have them ream the head...it still has paint remnants on the original milling. I was thinking of having them do a more honest j
ding the rear triangle to 130mm so that I don't have to keep jamming the wheel in! ...combine the pain

Road Fan

I DO like that store!