Okay...I found a late-90's (1999?) Specialized Hardrock without a fork at my bike co-op....and I have a threadless fork to put on the bike, but the headset that is on it is threaded...

Does anyone know what size threadless headset I need to get for the bike in order to install the new fork?....

The bike is still at the co-op workshop right now...otherwise I could just check myself. I'd like to go ahead and buy one before I go back there on saturday to finish it up.....

can anyone help me out with this???

There are 2 sizes, 1 inch and 1 1/8.
I would say most threaded forks would be 1 inch, threadless 1 1/8.
Which may just add to the confusion.....
Late 90's I'd say probably 1 1/8, unless a low end bike.
I know little about Specialized.
Take some calipers with you and measure?
Can you call the shop and get the serial #?, then you could date the bike and look at website specs.
All I can think of....

I can't say there isn't a threaded 1 1/8, but it would seem unusual.
My guess, the bikes older, and has a 1 inch headset.

If the bike is a '99, it will need a 1 1/8" headset. I agree with Jeff Williams, the more common size for threaded forks/headsets is 1", but there are threaded 1 1/8" out there, and by '99 this is what this bike would have. During this time, MTB's such as the Hardrock were sometimes offered in two models, either with a rigid fork or a suspension fork, but the frame was usually the same for either model, therefore the 1 1/8" fork/headset size on these bikes.

Your choices are limited to the fork you're installing. The fork size must match the head tube on the frame. Don't guess at this, measure and be sure.

I'm going to have to disagree about the 1 1/8" threaded steerers. They were very common throughout the '90s.

okay...i checked on it and it seems that the headset that came with it should be 1 1/8"

so do I just need to get a 1 1/8 threadless headset??

I think the fork is only 1" though...so should i go through the trouble to get a shim for it? or should I just look for another fork?

A 1 1/8" threadless headset should be all you need (other then a stem). On the fork, measure it. Or take it with you when you buy the headset. If it is a 1", I'd get a new fork since shimming and adapting a 1" to a 1 1/8" can be done but it requires a lot of futzing that you might not want to do.

yeah i kinda figured it would be more work than it's worth....

the fork is at the co-op lower end suntour so it's not like I bought it or anything...we're allowed ton swap whatever parts (as long as we do volunteer work too).. and I might be able to find another bike with a 1 1/8" fork that I can cannibalize there....actually I already have my eye on one...i just need to make sure it's a 1 1/8"

I think I'd try and find a 1 1/8" threaded, rigid fork and stem at the co-op, use the 1 1/8" threaded headset that's already on the bike, and you're good to go. I'm pretty sure that's what would have come on that model Hardrock to begin with-

I feel kinda stupid saying I 1/8 inch threaded are rare....there is one on my fork wall.
Came off a Diamondback mtb. So ya, they exist..right under your nose!
I'd send it but i'm in Canada, and really -it's not a super nice fork.
Look at any AL frame mtb's -older with Rigid forks. The larger AL tubing\headtube are more likely to be 1 1/8 inch. 1 inch I relate to steel frames.

well I found out it's a 2000 hardrock, and it came with either front suspension or rigid fork...

since I live in WV and we have some pretty intense trails right around my house I would really rather go with front suspension....

that and i'm just really not a fan of rigid forks...

get a threadless shock off ebay, and a headset and your off. just check on the stem lenght and make sure its long enough. you get get a rock shox judy for pretty cheap off ebay.