Converting 27" quil stem to 700c disc; Are there any forks available?
 

I would like to convert an old 27" bike to use 700c wheels and disc brakes. I've got the rear sorted but I am not sure if I can get a replacement fork that has disc mount and will fit in the steer tube of the frame which currently uses a standard quill stem and threaded steerer. Does anyone know of a fork that can be used for this? Will it require a change in headset?

More to it than that.
"axle to crown" length, fork offset or rake.
might look at Somafab
might have to go custom which will totally upset the economy.

Perhaps it would be easier to weld a disc mount to the fork? I think it is hi-ten steel.

1 inch quill like a Schwinn, or 1 inch quill like a French, or a 1 inch quill like a JIS? Or 1 & ⅛ quill, like on mountain bikes? Or 1&¼ quill like on 90's Treks & Gary Fishers? Which one it is will determine the chances of success.

Your current fork will need a tab welded on. The Amazon kits are garbage. Besides your fork was never designed for the load a disc would impart. The left blade would need to be replaced.

A custom fork would be easiest. A frame builder could build one. The local shop (to me) will do it for about $800

I would not. There might be a weldable bracket that provided extra support above the caliper but really questionable in utility as previously noted.

Get thee to Google...

https://www.mainstreetbicycleco.com/parts-1/1-threadless-steerer-disc-fork

not a super good idea. forks for your bike were not designed for stress that disk puts on them, nor were dropouts and quick releases

there is a reason why disk has gone to thru axle

in general the disc part sounds like putting lipstick on a pig

also if you get modern dual pivot brakes you can get super good braking like tektro https://velo-orange.com/collections/...g-reach-brakes

You mean the "geometry?" Because aside from high inflation, unemployment rates are still pretty low, and I don't see a single custom bike fork really throwing the economy too much out of whack.

I think you missed the subtle joke. It's your personal economy that would take a hit.

Well, at $800 bucks a pop, that would definitely be true.

the implication of a 1020 steel frame and fork (as mentioned a few posts later) being upgraded to disc as the economically viable way to attempt to retrofit is a question, if the geometry is equal. No idea what it is, but to get the handling the same may overturn the rational basis.
I'm sure a suitable fork could be fabricated, is it justifiable for the economy of the project? Doubtful.

I don't know. I have a low trust of Chinese stuff on AliExpress. That said, we have some medical supplies in our office that are ok, small clamps, forceps, etc. I have long thought that some Taiwanese company should make and sell a decent basic 1" fork series. Not a huge demand but judging by current fork prices on eBay who knows. Hard to spend big bucks on used forks and then still have to strip and paint or powder coat.

Somafab- 1" threadless - disc capable fork

https://www.somafabshop.com/shop/pro...=4&search=Fork

A threadless 1" headset and stem, cap will be needed, things add up. I think that would be the cheapest way to go.

forgot, will require a thru axle hub, but rim brake to disc will require that anyway.
just make sure the disc lines up with the caliper opening ...

Theres some more info on amazon.

https://www.amazon.com/MYFFF-25-4mm-...88&sr=8-2&th=1

That appears to be the same fork as the AliExpress but for higher dollars. Also, the MYFFF 'brand' appears to be a generic importer of many goods. Clicking on their link shows xyz goods of all sorts. This is interesting, you can go direct for 75 or pay an importer 300. With that big a variance, seems to me there is still room for a company like Velo Orange or some other retrogrouch vendor to have a line of good Taiwanese built forks. Rivendell sold a fork for some time in their quest to rid bikes of carbon forks, "Carbonomas" they called it. But there were no variants for brakes, rake, etc.

The bike is an '86 schwinn world sport, chromoly main tubes, hi-ten fork, 27" wheels. I would like to use it for a cargo bike conversion using a 700c xtracycle free radical extension because I think the frame would be reasonably heavy duty for cargo bike service. The free radical extension has the necessary tab for the rear disc.

I think you would save a bunch of cash and potentially have a better bike if you found a high end 90's mountain bike with a 1 1/8" threaded fork and replace it with a 700c disk fork. As a Big Dummy with live cargo rider I would suggest finding something with a low stand over. Mines a bit big for me and I wouldn't be able haul my kid without the $300 kickstand...

Yeah, knowing the A-C measurement you're looking for is key. Seems that 1" threadless disc brake forks aren't hard to find, such as this one.

For lots of fork-age, this listing will give you plenty to think about: https://bikepacking.com/index/forks-...e-cage-mounts/

The world sport is a step through frame which is another reason why I am considering it. Debating whether to just leave the front wheel alone just go with the disc on the rear.

Crust Bicycles have 1inch threaded forks that take disc brakes. I haven't used one so can't vouch for them but they look nice.

https://crustbikes.com/collections/f...romanceur-fork

2 (offensive to some) old time comments:

"Silk stockings on a rooster".... and "You can't make a silk purse out of a sow's ear".

Being able to stop successfully while keeping a bike under control is far more important than making it go. The operant word is CONTROL! There's more to what you are looking to do than just changing forks.

Dual pivot brakes can have ginormous stopping power with good control.

BTW, Hi-ten steel means nothing! It's not an industry recognized standard or specification. It says nothing about the strength or the alloy or chemical composition. The term goes back to the late 1800's when "High Tensile" steel was an advertising term. Most structural steels back then were plain low alloy carbon steels. There was never any indication as to the strength or fatigue resistance.

Good luck with your venture.....

Hey watch this.... Hold my beer...

verktyg :50:

Oh this looks promising. It is expensive but negates the need replace the headset and cut the steer tube. However it causes another problem, the trekking wheel I would use is a quick release and this fork appears to be a through axel. I wonder if it is possible to convert a quick release hub into a through axel?

Economy's bent!

Doubtful. You will be on your own.