Schwinn Frame and Fork Geometry Question

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Jeffrey Edwrads

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Greetings all, I am new to this forum, but look forward to being part of many discussions moving forward.

So I am building what I believe to be a 1957 manufactured Tornado as a klunker. I have an opportunity to get some forks that are from an 80's era Schwinn beach cruiser. I am wondering about the compatibility rake wise. (I bought the frame without forks)

The serial number on the frame indicates that it was manufactured in January of 1957, but it is also a serial number that was used more than once so I am not positive that was the date of manufacture. I am fairly confident that the forks are from the 80s.

Short of measuring the frame geometry myself, I am not really able to figure out trail and such, so my question is if anybody knows if the head tube angle of the beach cruisers built in the 80s is significantly different than the head tube angle of the ones built in the 50s. Just from looking, it is hard to tell if the angles created by the springer forks on those older bikes are the same as the angles created by the straight forks with BMX style dropouts welded on the front of the forks.

I attached photos of the bike as it is currently built with some cheap, beach cruiser forks, as well as the fork I am going to get tonight.

Thanks for any info you have.
 

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Hi. Sorry i hadn't seen this thread earlier. I cannot give you any exact figures as far as specs go in regards to a '57 Tornado headtube angle versus that of an 80s Giant-built canti-frame, but i've spent time with bike bikes, and the geometry is pretty danged similar, overall. Not identical, but similar.

A lot of folks, especially klunker guys, run the straight-leg fork from the 80s Schwinns, or similar. And, the results are good. Different forks of this style might have different axle-to-crown (atc) measurements, and that will affect HTA as well as other peripheral geometry specs, but most folks who are looking for a more "sporty" ride will agree that any of these bmx-style forks improve the ride characteristics for dirty work. In my view, the way that the straight forks speed up the handling is awesome all on its own.... The raked-out cruiser forks, like the ones in your "before" pic, are comfy, but not as responsive on the trail.

Just my $.02; at any rate, relax. You're running a set-up in terms of frame/fork that has been working for lots of ppl for a long time. (The stem/bars will also impact steering geometry; I'd suggest a bit of trial and error as far as that goes....see what works for you.)
 
Thanks for the response. I know I am over thinking it, but it is about 105 degrees here right now so it is more pleasant to get theoretical and type about bikes than go do the work in my shed right now. (-;

Unfortunately the steer tube on the forks is just a few threads too short. Using a classic Tioga headset I can't get a locking not on it. My buddies with a shop say we can "stretch" it by cutting it and adding a bit a plug welding it.
 
Jeffrey Edwrads said:
Thanks for the response. I know I am over thinking it, but it is about 105 degrees here right now so it is more pleasant to get theoretical and type about bikes than go do the work in my shed right now. (-;
Click to expand...
:21: :thumbsup:
Jeffrey Edwrads said:
Unfortunately the steer tube on the forks is just a few threads too short. Using a classic Tioga headset I can't get a locking not on it. My buddies with a shop say we can "stretch" it by cutting it and adding a bit a plug welding it.
Click to expand...
Yes, that can be done, and often is, but if it is only a small amount too short, you might be able to trim a little off the frame headtube top and bottom to make up the difference, a far easier proposition than stretching the fork steerer...

Either way works well, just make sure that if you do stretch the fork, to add a sleeve inside to support the weld, but make sure it is far enough down to not interfere with the stem when inserted, it is also a good idea to clamp it in a piece of angle iron while welding to ensure it remains straight and true, one last tip is to make sure you keep the lock washer relief cut at the back, simple but easy mistake to make... Been there, done that, looks silly... :blackeye:

Luke.
 
Now that I look at it again, I think that the "trim a little off the frame headtube" option would work. Would you use a facing tool to do that?

To be honest, I would ideally like to be able to use this fork without altering either the frame or the fork. I am looking into using a quill adapter and then using a treadless stem but I am not sure that will actually solve the problem. I still have some work to do.

I love the cranks and bottom bracket I just installed, but I am not crazy about the chain line and I am not sure if it is a problem and if so, how big a problem it is. I am looking at some hubs from a 1995 anniversary edition of the Black Phantom to replace the crappy coaster hub I am running now, so I am not going to worry too much about the chain line until I build the wheel that I am actually going to be running.
 
I have a 59 Schwinn Corvette, different frame than yours. It doesn't work for trail riding with the standard 6.5 inch crank, the BB is too low. I bent pedals. I can just fit my foot through the bottom of the pedal and the ground with little to spare. From looking at photos on the net the Tornado frame appears to have the same pedal problem. I have used cranks from 20 inch bikes on these old frames and it is much better as far as pedal strikes go but it is odd pedaling. I don't mind the short cranks and use a 5.5 inch crank on one of my 1940s CWC Klunkers. My 1940s Columbia Klunker is OK with 6.5 inch cranks. I would check it out to see about clearance before I installed a crank.
 
This will not be a true klunker in the sense that it would ever see any trail riding. This is being built as a BMX style beach cruiser in the klunker style for rides around town. I can't afford the BMX frames that these Schwinn frames inspired, so I am building this bike. It will mostly go to the pub and be used for actual beach cruising when I get down to Port Aransas. So far I am not having issues with 175mm crank arms (6.88976") but I have not ridden it much. Thanks for the tip though, I will keep it in mind. Crupi actually has some short crank arms on close out that I had not considered even though I have a Crupi BB that would work great with those cranks.
 
As far as your fork problem is concerned, if you get a Schwinn delux headset, the top cup is replaced by a race with a reduced male end that fits into the head tube, replacing the cups. Here's some pics of one I have.
20160802_140402.jpg
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Installed rhey look like this minus the mount for the front rack on this 63 Racer.
20160802_141157.jpg
 
I was gonna suggest the Deluxe headset, too... if it's close to long enough, that 'set just MIGHT do the trick.... and easier/less invasive than extending the steerer or chopping the headtube.

Sounds like you're building more of a strandie than a klunker. How do you intend to gear it?
 
Thanks for the tip guys. I put the old race back in and found a piece that works with it. Still not perfect. No room for a lock nut, but it looks better and will ride for now.

I suppose this is more of a strandie than a klunker. I did not know either of these words a month ago. All I knew is I wanted a Cook Bros. 26" and couldn't afford one so now I have this.
 

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She still needs some work, but we are getting there. I might end up stretching the fork after all. I am also having some issues with the chain line. The Euro conversion works great and the BB I have in it spins like a dream, but the spindle might be too long. Oh well, more fun to be had I suppose.
 

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It looks pretty good with that set up. You've added an inch or so of height to the front from the original forks, so that may give a little clearance on the pedals and angle the head tube slightly more than it was new. If the fork seem like a lot of work, why not get a new one? I think that style is about 20 bucks or so new.

http://www.niagaracycle.com/categor...rk-threaded-length-95mm-1-od-chrome-non-canti
 

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