SWB0 1948 Triumph

[twojs.bike]

Plan A. Build a jig similar to what wildcat described.

Plan B. Get a little ratty and use this red fork. From a Schwinn Varsity but is a dimensional match.

 

[curtisfox]

Put it on some wood blocks and use a bottle jack, long 2x4 under a door opening, press it back straight. The head tube on the Schwinn looks shorter.......Curt

 

[bleedingfingers]

Put it in a vise heat it with a torch and bend it back .
Or take it to a bike shop there is probably a Park tool to fix that exact problem .

 

[twojs.bike]

Game on!

I built a jig for straightening forks. It didn’t work.

Then I slipped a 1inch pipe over the steerer tube and propped the pipe up on the bottom of my workbench. Stepped on the pipe to bend.

Example photo

The steerer tube bent very easy. It appears it is actually two tubes somehow softly welded together. ??? Beats me, but there is almost a joint that bends.

I actually overshot it and had to make a correction.

Crude measurement

I installed the fork and the problem seems to be gone. Although I don’t think this bike would survive any sweet jumps!

 

[twojs.bike]

Zoomed in you can see what I mean by soft joint.

 

[SkyknightJohn]

that's a little worrisome.

 

[Wildcat]

That one's good for photos. I would try to get a good fork. The problem is if it develops a crack you won't see it because it's hidden in the head tube. Bent forks are known to develop cracks, usually in the crown. Then it fails, usually at the worst possible moment.

 

[twojs.bike]

Maybe soft spot isn’t a good description. The soft part might have been my imagination. Curious spot might be better.

I am wondering it the curious spot could have been caused by this stem being over tightened. Not sure what to call this. Split Quill Stem??

 

[twojs.bike]

Making progress.

I spent a ton of time on the wheels. One thing that screwed me up was these axle tensioners. (Or whatever they’re called). I added spacers to my hubs to match the 113 mm O.L.D. I didn’t take into account the 4mm these things add and had to remove some spacers.

I used this tool that @ingola told me about to press in the cotter pins. Pressing the cotters in and out is far better than beating them with a hammer.

I would love to get this seat reupholstered with leather. I did wipe it down with boiled linseed oil. Not sure if that was a good idea, but it soaked it right up.

 

[Bike from the Dead]

that's a little worrisome.

That one's good for photos. I would try to get a good fork. The problem is if it develops a crack you won't see it because it's hidden in the head tube. Bent forks are known to develop cracks, usually in the crown. Then it fails, usually at the worst possible moment.

Speaking from experience, the fork is one of THE MOST STRESSED parts on a bike. If a damaged fork isn't repaired properly, it can be disastrous.

This isn't my first time bringing it up, but I had a fork snap in half on a test ride due to a faulty steerer tube repair. I wasn't going too fast thankfully, but I scraped my hands, fingers and knees terribly, messed up my arms for a month or 2, and was generally sore from a fall at relatively slow speed. I was lucky I fell arms-first, since I didn't have a helmet at the time.

If you have another undamaged fork you can use, I'd strongly recommend using it. Otherwise you better hope the repairs you made to your fork hold up, because if that fork breaks while you're riding, you're going to be in a lot of pain.

 

[MattiThundrrr]

I used this tool that @ingola told me about to press in the cotter pins. Pressing the cotters in and out is far better than beating them with a hammer

That's super awesome, love to see that knowledge getting passed around. Now, someone can learn from you.
@Bike from the Dead thanks for sharing your experience too. I remembered your story, it got me wearing my helmet more

 

[twojs.bike]

@Bike from the Dead is there a link to your story? I’m curious what the back story was with the fork. Goes without saying you all have me worried. All I did was bend the tube back a few mm. However, I don’t hang bikes on walls. I want this bike to be rideable and find a new home.

 

[Bike from the Dead]

@Bike from the Dead is there a link to your story? I’m curious what the back story was with the fork. Goes without saying you all have me worried. All I did was bend the tube back a few mm. However, I don’t hang bikes on walls. I want this bike to be rideable and find a new home.

Here's the build thread for that bike. You'll have to do a little digging to get the exact details, but long story short: the original steerer tube on that fork was trash, but a buddy of mine cut and welded a new steerer tube for it. What most likely caused mine to fail was not having a sleeve to join the 2 tubes (though I recall that there was already an original sleeve at the base of the fork that would've prevented that anyway,) and an improper weld-job. The fork snapped right where the weld was on my 2nd test ride right after assembly.

So, not the same situation as your fork, but I'd still want to err on the side of caution either way. That steerer tube not only has to support the weight of the rider and the bike itself, it has to put up with whatever bumps in the road the tires don't soak up, and it has to do all that while steering. Like I said, it's one of the most stressed parts of any bike, and any imperfections could be problematic to say the least.

 

[SkyknightJohn]

I’ll add a little thought: metal has an Ultimate strength, the point it breaks, and a Yield strength, the point it bends instead of returning, springing back to its original position. Once the yield strength has been passed, i.e. the tube bent, that spot has lost its stiffness/strength. (there are heat processes that can re-strengthen, think knife forging, but…)

We get away with minor cold-setting of stays pretty regularly, likely due to the direction of the bend vs. stress load direction, and triangulation. As noted, the steerer takes a lot of stress, along the direction it has already bent. And failure there can be worse than, say, a chain stay.

How hard will you ride it? What are your risk tolerances? How easy is it to reinforce or replace?

 

[Bike from the Dead]

@Bike from the Dead thanks for sharing your experience too. I remembered your story, it got me wearing my helmet more

You're welcome. That experience made me get a helmet! I'd still like to get a pair of riding gloves and some pads too, since that's what I really needed at the time.

 

[twojs.bike]

My intention is to build a 100% mechanically sound bike. Whoever winds up the lucky owner should feel free to ride it like it’s 1948.

You all have convinced me. The fork needs to be replaced.

I have this red Schwinn Varsity fork. I believe I can get the rod brakes attached to these. Hopefully I can figure out a headset.

View attachment 258388

 

[twojs.bike]

Good news: the whacky headset has standard threading, so I can re-use it on a new fork.

Bad news: the red fork steerer tube is 5mm to too short.

Bad news 2: the stem diameter is oddly large at 22.2mm. It doesn’t fit in the majority of the forks I have laying around.

So, I’m in the market for a fork.
175mm steerer tube
Crown to axle 385mm
22.2 min ID

It’s the ID that is going to be a challenge to find.

 

[ingola]

Good news: the whacky headset has standard threading, so I can re-use it on a new fork.

Bad news: the red fork steerer tube is 5mm to too short.

Bad news 2: the stem diameter is oddly large at 22.2mm. It doesn’t fit in the majority of the forks I have laying around.

So, I’m in the market for a fork.
175mm steerer tube
Crown to axle 385mm
22.2 min ID

It’s the ID that is going to be a challenge to find.

Find a Raleigh fork or anything off a Raleigh made huffy or such. Accomodateing the 28 inch wheel mybe the hard part.

 

[twojs.bike]

There are a few Raleigh forks on eBay that look good. However I think the Raleigh forks have unique threading. So I would have to figure out a headset too. I think (hope) I can mix and match a Raleigh headset with the non-removable cups on the triumph.

This has been the most challenging bike I have ever attempted.

 

[twojs.bike]

Just bought this. I may have to trim the steerer tube. It has a crown race and headset that I believe will be compatible. Fingers crossed!!