I bought an 1 1/8" Crust Clydesdale fork, but don't have a frame
 

I got a good deal on it, and have always wanted a little lite truck style cargo bike. However, I didn't expect the easter egg hunt that would accompany the purchase in trying to find a compatible frame.

It seems like the broad swath of vintage hardtail mountain bike frames came with 1" steerers. In my amateur research digging up old catalogs, it appears that by the time -- say, Specialized -- started using 1 1/8" steerers they were also using suspension forks. Regarding that, I have a hard time parsing this part of the Crust product page:

Can anyone help me wrap my head around what I should be looking for? It feels as though buying the 1 1/8" size fork severely limited my options for hardtail MTB conversion candidates. Should I be avoiding vintage suspension MTBs in the first place, or is not that big of a deal? I find bike geometry difficult to understand, haha.

I bought a high end mountain bike in 1995 and put a rigid fork on it (1 1/8"). It is a little quick handling, but not in a bad way because my fork is probably shorter than the suspension fork it was designed to accept.

Trek, Giant, Diamond Back and many, many others made mid-to-high end rigid fork MTBs with 1 1/8" steerers from at least 1992 on. Boulder, ATX 770, Trek 930, DB Ascent, etc. They are out there. 1" kept going for a big with lower models for longer - Trek 830, Giant Iguana, etc.

The 1-1/8 age started in the early 90s. Far more bikes from then and forward came with 1-1/8 than 1". There was a span of time (c. 1991 - 1995) where 1-1/8" threaded steerers were the norm. Up until the late 90s, many bikes were available with either suspension or rigid fork, and the suspension forks were all short travel so generally speaking, a rigid fork wouldn't be a terrible fit.

Note the comment from the vendor you posted specifically referenced a long-travel freeride or DH bike (a 'Big Hit') not a run-of-the-mill hardtail with a 50 or 75mm travel fork.

I had a 1992 Trek 7000, a bonded aluminum frame hardtail with a 1-1/8" threaded fork. A similar frame with a change of headset should be compatible with your fork. I hope the original owner didn't cut the steerer too short for you.
BTW, what you did seems similar to renting a Tuxedo and then looking for a woman to marry. :love:

When I read that I burst out laughing. Great line

1 1/8" MTB frames should be super easy to find, it doesn't matter if they were threaded or threadless when new if replacing the fork.

1" had a short life time for MTB frames (as long as you not looking at BSO or entry level bikes), although far longer than 1 1/8" threaded, which was last seen in 1995, 1994 was the last year for all but a few holdouts, look at you Marin, almost anything older than 1993 should be 1 1/8", a few exceptions from experience are Bontrager and Univega (Steel, not Alu), sure there will be a few more, but these are not the norm.

400mm axle-crown seems pretty typical of a suspension-corrected rigid fork, no? You might be off by a few mm but that won't affect the head angle too much. Plenty of 1 1/8" frames around on the used market - I would say the majority.

The axle-crown measurement on the Soma suspension corrected fork for 26 inch MTB's with 80 mm suspension fork travel is 440 mm. If I understand correctly, the 40 mm difference in axle-crown distance will steepen headtube angle by 4 degrees according to Crust. That's significant. Steepening the head tube angle will quicken the steering. I'm not sure you'd want that when you plan to carry significant weight on the fork mounted rack.

https://www.modernbike.com/soma-curv...-1-1-8---black

Good info. Happy to stand corrected.

That 440mm A-C measurement probably shrinks to 400mm with the rider on the bike as 50% static compression is typical. So a rigid fork with a 400mm A-C should be correct.

The Soma fork I referenced is rigid. It does not collapse to 400mm. It is designed to replace a suspension fork with 80 mm of travel and not alter the bike's front end geometry. Are you saying Soma is wrong? Help me to understand.

Okay, this broadly confirms what I had suspected. Now, here's the question: As I search for a project bike (or just a frame), is there an easy way to tell at-a-glance if the bike has that 1 1/8" headtube compatibility? Current, I'll check the pic and see if it has a quill stem or not. If not, move on. Is that ill-advised? Am I missing something?

(Side gripe: What is *with* bike sellers on CL/Facebook and not noting *any* kind of size info? It's absurd to me how often I'll have to ask for a seat tube measurement.)

Tons of 1 1/8" bikes had quill stems. That's what people are referring to as "threaded". Threaded steerers and headsets with quill stems.

So youve been missing a bunch of candidates.

Bummer! But this new knowledge just means I'll have an easier time finding a nice base bike for my project.

Is there a go-to way to determine the difference in headtubes? Asking sellers to "let me know the steerer size" just causes confusion. Should I just be meeting and measuring myself?

Better question: What's the OD of quill stems that went in these 90s 1 1/8" quills?

Thanks for your help on this, sincerely.

What? Most folks try to get their sag in the 20-30% range, IME.

I think you can kind of tell by looking, and then use catalog websites to confirm. Or ask here. But the oversized head tubes were proudly listed in catalogs at the time.

Look at pictures of both kinds and get a feel for the fatness of the quill and the headset.

So I found a 1991 (maybe 92) M2 Stumpy in museum piece quality -- purple! -- and I'm stoked to grab it, but it's a bit of a schlep to travel for it.

AFAIK, all of the suspension fork models are 1 1/8" without fail. Safe to say the same goes for the rigid fork M2? I'd post the link but I can't yet due to my forum post count. It's on page 4 of the 1991 Specialized catalogue on Retrobike. Looks just like it, too, like it hung in a storage unit for 30 years.

I would say that is not 1 1/8". Specialized was one of the hold outs. By the '95 catalog it says "1 1/8" Aheadset", but not before.

Got it in one -- unfortunately. The seller measured for me and the stem is 22.2. Hard to let this one go, but I can only handle one bike project at a time.

Hi,
Do you have a bike co-op or similar near you? These folks can be very helpful in suggesting a frame for you at a reasonable price. Personally, I’d go with a mid level frame from a reputable company. Just make sure it fits you before the modification. If they will answer your questions, Craig’s List sellers are OK, but I’d stay away from ebay or Facebook.
Cheers & good luck,
Van

johnexcept - where are you located and what size frame are you looking for? I have a couple 90s mtb frames that may fit the bill, located in New England. Others may also be able to help source something with this info.

Okay, here's a fun twist to the story. The seller hit the stem with calipers, measures 7/8". Bummer, right? Well, on a lark I ask him to measure the headtube OD and it's 1 1/2". What do you reckon the odds are that the bike has a 38mm headtube OD, 34mm ID, but a 1" headset (somehow)?

Very kind of you, but I'm on the wrong coast! If this minor obsession with an M2 Stumpy for sale goes south, I'll be going the route of finding a passable frame at a LBS.

Hi,
How about a little more info on your location? There are co-ops, bike kitchens or coalitions all over the west even in some small towns. Portland, OR has 1/2 dozen.
Cheers,
Van

More likely the headtube walls are really thick.