So my friend's comically large 1970s Raleigh Super Grand Prix's fork blade snapped below the fork crown and needs replacing. Unfortunately, it seems impossible to find a fork with a long enough steerer. The bike has a 225mm headtube. The original fork has a 260mm long steerer and has a 27mm crown race. The longest threaded forks I can find are 250mm. Even with a 31mm headset that leaves 6mm short, and thats without the cable hanger for the centerpull brake. I need to do the math but I'm not sure if even a 300mm threadless fork will be enough with the need to make room for the stem.

This is a cheap bike and its not worth spending much money on. Are there any reasonable cost solutions? Unfortunately I already made the mistake of buying a 250mm threaded fork. If cost weren't an object a framebuilder could braze new blades into the existing crown, or we could do a threadless conversion with a 350mm soma fork, but those options are both expensive.

Anyone got any good ideas?

Just, maybe Above what you seem to be willing to spend, ..

You might fake it for the last few inches with a steel tube, stepped, stem raiser, wedged in the top,

then treat it like a threadless fork. >> buy several one goes in the other .. <<

how about 'catch and release' make it someone else's Problem,. sell it cheap, and get a frame with a fork ..

Figure 50-60mm for the stem, and some for the headset, which doesn't have that much stack since there's no locknut and a 300mm fork will be fine if you go threadless. It'll also have enough room for your cable hanger.

You could also buy a steel threadless fork and have it cut and threaded. Figure that will add about $25-35 to the cost, depending on who does the work. You may get the best deal on labor if you let the seller do the work and quote a combined price. (otherwise I do this routinely for $25.00, plus return shipping).

Note that not all threadless forks hace the correct 7/8" ID for your quill stem, so confirm this if you buy planning to thread.

If you can't find a decent fork on your own, call Yellow Jersey in Madison WI, for a quote of either threaded or threadless version. They have a broad inventory of forks and might have a 260mm threaded fork, and/or can cut/thread if that's the route you want to go.

250 mm fork -225 mm headtube -31 mm headset stack height = -6 mm. How do you compensate for that with a stem riser?

Hyperspacer

Also check with local bike shops, as they have access to wholesalers and distributors that might have what you need. It is indeed more difficult now that 27" wheeled bikes are not as common. I often can find unusual things with a well-crafted search, but I zeroed out on this one - the only one I found was "temporarily" out of stock.

as I said :
Frame builder Bernie Mikkelsen in Oakland says grafting on longer steerers is a service offered .

Oh,thats right ,friend . have them go buy another bike . its done ..
Been 44 years of use out of it .. its fatigue life is shorter with such tall people.
leverage .. matters.

the wear and tear metal fatigue is why the other fork Broke.

Forks with such long steerers have always been rarer as the people who ride bikes this large are equally uncommon.

We build forks in advance for our own production and also supply them as replacements since 1 inch threaded forks are not as common... it does get a little spendy once you factor in the build and the finishing and use longer steerers so we can cut and thread them to fit. We also tend to build bicycles for a lot of uncommon people.

I have a fork with a 260mm steerer here but it is worth more than the bike you have.

Local co-ops and shops that salvage and save parts might also be a good option.

Yeah, the local coop has been closed for the holidays. I'll check what they have (including threading dies) on Mon. If they have a die I may consider that route, or I think I'll probably buy a cheap threadless fork, headset, and stem off eBay. It's approaching the value of the bike honestly but I hate to see a good bike (that gets ridden as primary transportation, and otherwise has served very well) die.

You might find a decent replacement fork for $20.00 - $40.00... it will probably be high tensile carbon which is fine for most purposes.

Sometimes you can score a large framed bike on CL on the cheap, they tend to hang around longer. You can just take the fork off of it.

Checked my local coop. I've decided on buying a cheap threadless fork and threading it with their die. Thanks for the help everyone.