Biking_Lawyer

I hope this is an easy one. I purchased a brand new 1 inch threadless 650 cc fork from chuckbikes before it closed for use on a recumbent bike I am building. I ordered a 1 inch Ritchey logic threadless headset to use with it, but the crown race is too big i.e. its diameter is wider than the steerer seat on the fork and I cannot get a tight fit.

I took the fork to a LBS yesterday and the teenage mechanic told me that they do not make parts for this size of fork anymore.

Obviously, the kid was a moron. I am assuming there is some other standardized headset size for a 1 inch threadless fork. If so, what is it and where can I get one?

Alternatively, I do have a crown race from an old headset that fits on the fork. Can I use this, or will I have problems due to the size discrepency with the lower bearings? It seems to seat alrright with the little plastic ring once the preload is adjusted.


Thanks.

HillRider

1" threaded headsets (and forks/frames) come in two different sizes, JIS and ISO. The JIS crown race is 27.0 mm ID and the ISO is 26.4 mm so apparently you have a JIS race and an ISO fork

ISO is now almost universal but JIS was used on older Japanese bikes. It's JIS that is now the rare bird, not ISO.

I presume your fork takes the ISO size race and the headset you got is JIS so you will have to return the headset and get the correct configuration. As a rule, crown races are specific to a given model headset. They are not a universal item.

Dan Burkhart 

Yes but, he said his headset was threadless. As far as I know, they only come in ISO.

mrrabbit 

What HillRider says is pretty much true...however...

1. You'll find generic steel headsets to have a lot of interchangeability in parts including races.
2. The same applies to very cheap no-name or unrecognizable Taiwan name generic alloy headsets.

If what you want is a quality or high-end headset - gonna be more of a challenge.

=8-)

Biking_Lawyer

I am just trying to get the bike functional. I thought the problem would that the fork would be an off-size, as you can buy Ritchey headsets everywhere (It also would have been nice for them to tell me what size the crown race was BEFORE I purchased it).

I'm fine with using the existing crown race with the remainder of the new headset if that will work. I was just worried there would be some compatibility problems or that the plastic ring thingy (sorry, I dont know the proper name for it) that came with the new headset would crack on the smaller race.

Dan Burkhart 

How much too big is the crown race? is there detectable play when fully in place, or is it just that there is no interference fit and you can slide it on by hand? If it is the former,an assembly compound like Loctite 680 will work to hold it in place.
There should be no ISO/JIS issues with a threadless headset and fork, as, like I said before, they are all ISO. Sounds like poor quality control on the part of the fork manufacturer. They may have undersized the mounting seat. Easy enough to check with a digital caliper or micrometer.

HillRider

Point taken. I don't know why I read "threaded" in the OP. Right, all threadless 1" headsets are ISO.

Gonzo Bob

Actually, there are a couple of JIS threadless headsets. Someone here was searching for one a couple of months ago and found one - I think it was a Ritchey Logic, too. https://www.bikeforums.net/showthread...jis+threadless

EDIT: To OP - sounds like your original headset was ISO but the new one is JIS. Note that the cup diameter for JIS is 30.0mm while ISO is 30.2mm. This means there is a small chance that JIS cups in an ISO headtube may be too loose which could result in headtube damage over the years. I recommend determining the size you need and getting that.

Dan Burkhart 

Well, Shazam, ya really do learn something every day. Thanks for that.

HillRider

Me too. I guess these are for riders converting older JIS threaded headsets and forks to threadless. I expect the required headset is "mixed" using JIS cups and an ISO crownrace since I can't believe anyone made a JIS size threadless fork.

Wordbiker

Bear in mind that since the standards are so close in size, one may be able to either face the crown race seat down, or knurl it to accept the larger standard. The shortcoming is in the shop's knowledge or lack of the appropriate tools, not the parts.