Threads size on Schwinn fork

[user 26311]

Does anyone know for sure what the thread size/pitch is on the top of the made in Chicago Schwinn forks?

 

[musclebikemadman]

Does anyone know for sure what the thread size/pitch is on the top of the made in Chicago Schwinn forks?

I believe most were 24TPI but not 100% positive

 

[user 26311]

Thanks musclebikem, I believe that’s correct too. I was planning on ordering a die so I could thread the steering tube of a fork from a girls bike down far enough to use it on a boys bike. But at $70.00 dollars for the cheapest one I can find (except the ones from China that are on Evil-Bay) I need to be sure that’s the right thread.

 

[musclebikemadman]

Thanks musclebikem, I believe that’s correct too. I was planning on ordering a die so I could thread the steering tube of a fork from a girls bike down far enough to use it on a boys bike. But at $70.00 dollars for the cheapest one I can find (except the ones from China that are on Evil-Bay) I need to be sure that’s the right thread.

I should buy a real nice one and rent it out haha

 

[user 26311]

There is that!

 

[rickpaulos]

I had my lbs do one a few years ago. $10. I had to teach the shop kid how to do it. I have tools to rival an average bike shop but some just don't pay off.

 

[user 26311]

I had my lbs do one a few years ago. $10. I had to teach the shop kid how to do it. I have tools to rival an average bike shop but some just don't pay off.

That’s cheap enough! I just don’t like have someone else work on my stuff when I can do it myself. I’ve been this way ever since my Air Force days when we’d take our truck to the motor pool to have something fixed, then when it came back I would have to not only straighten out the original issue but also correct whatever they did to it…..

 

[us56456712]

Thanks musclebikem, I believe that’s correct too. I was planning on ordering a die so I could thread the steering tube of a fork from a girls bike down far enough to use it on a boys bike. But at $70.00 dollars for the cheapest one I can find (except the ones from China that are on Evil-Bay) I need to be sure that’s the right thread.

The China ones are fine. Get the 1 1/8 at the same time to save shipping. Grind a flat spot in the die so you can put it in a vice and use a breaker bar to turn the fork. Ive done many thread jobs with my China one over the last 6 years. I keep them wrapped in an oil soaked rag.

 

[user 26311]

Thanks! I’m going to order them so I will have them for future projects!

 

[toomanystings]

The China ones are fine. Get the 1 1/8 at the same time to save shipping. Grind a flat spot in the die so you can put it in a vice and use a breaker bar to turn the fork. Ive done many thread jobs with my China one over the last 6 years. I keep them wrapped in an oil soaked rag.

hoping this one will work as I just bought it, also what is the 1 1/8 used for an can you post a pic of how you flattened your die? Trying to cut down a fair lady for for a 70 rat rod stingray I bought at the swap meet a few weeks back.


https://www.ebay.com/itm/185145040888

 

[rickpaulos]

"what is the 1 1/8 used for"

Some mountain bikes use 1 1/8" threaded forks. Many use 1 1/8" threadless so no die needed for those.
A few mountain bikes used larger threaded sizes. 1 3/16, 1 1/4, 1 3/8, etc. Pretty rare unless you have a pre/early-trek Gary Fisher or an English tandem. Many current mountain bikes use tapered forks, 1 1/8 at the top and bigger at the bottom.

 

[toomanystings]

"what is the 1 1/8 used for"

Some mountain bikes use 1 1/8" threaded forks. Many use 1 1/8" threadless so no die needed for those.
A few mountain bikes used larger threaded sizes. 1 3/16, 1 1/4, 1 3/8, etc. Pretty rare unless you have a pre-trek Gary Fisher or an English tandem. Many current mountain bikes use tapered forks, 1 1/8 at the top and bigger at the bottom.

I legit only mess with schwinn sting rays so I think I should be good.

 

[us56456712]

hoping this one will work as I just bought it, also what is the 1 1/8 used for an can you post a pic of how you flattened your die? Trying to cut down a fair lady for for a 70 rat rod stingray I bought at the swap meet a few weeks back.


https://www.ebay.com/itm/185145040888

I used a grinder on one side. It won’t spin in the vice this way.

 

[toomanystings]

What does everyone use to drill out the girls forks? I measured 53/64.

 

[rickpaulos]

No no no. No drilling. Get the correct size stem. They are nicknamed .833 stems. Some are stamped 21.1 mm. No one drills out forks. That would just make them much weaker where they are most likely to break.

In the 1960s several of the USA bike companies agreed to use thicker walls on the fork steerers to counter plain carbon steel forks breaking. BMA/6 (Bicycle Manufacturers of America) tried to police themselves before CPSC, EPA and OSHA were created. The .833 forks were used for 10 to 20 years depending on each company and models. Standard stems are 7/8" that fit in a 1" steerer with a 1/16" thick wall. The .833 stems fit in a 1 inch fork with 1/16 + 1/32 = 3/32 wall thickness. 13/16 is the .833 id.

I've seen too many aluminum stems filed down to fit. (ditto for french bikes that use a 25 millimeter steerer). Not a good idea.

They still make new stems in .833 and there are plenty of used .833 stems around. Schwinn and Wald were the biggest makers in the 1960s/1970s of .833 stems but there were others.

The top nut on the headset was also made in a .833 size. A smaller opening to match the skinnier stem. I've seen .833 stems in standard forks and that kinda works. They tend to sit crooked and not hold as tight. One tell-tale sign is a big gap around the stem where it goes into the headset & fork.

if you want that in metric:
standard 1" forks are 22.2 mm id
french forks are 22 mm id
.833 forks are 21.15 mm id

 

[horsefarmer]

Put a .833 allloy stem in my Monark (standard stem). Fit was loose, so I added a aluminum pop can shim...