Hi all, rear triangle on 1936 Snyder fastback klunker is a little out alignment. Using string method, driveside is 35mm from seat tube, nondrive is 30mm. Non issue with ballon cruiser tires but likely mtb knobbies will rub on nondrive. Cold setting with long wood lever unsuccessful. Rear flexs and just springs back. Even with maximum exertion, using knees arms, bending bouncing, throwing full weight, kneeling on the wood lever I cannot bend the rear frame far enough beyond to set it. Any suggestions? Thx!
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Cold setting steel frame
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I've never had any success doing it that way either , what has worked for me is turning the frame upside down from your picture , put wood blocking up by the neck and just in front of the seatube , have someone stand on the front section of the frame while you put your foot on the dropout , lift your other foot off the ground and start bouncing slowly on the drop out , check it and keep increasing the force of your bouncing until you get it where you want , I'm 225 lbs and I have to put a good bit of bouncing to get it right , if you go too far just flip it over and repeat the process
Andrew Gorman
Cruisin' on my Bluebird
Just make sure to mount the frame solidly- a tree, a fencepost, a heavy workbench:
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That's actually not that bad at all, but if it were mine I'd probably fix it. How sure are you about the symmetry where your strings are coming out of the rear forks? I've been known to use the dropout holes. How is your rear spacing right now? Are you sure which side(s) need to move?
I have always been able to bend things with Sheldon's methods, but since this part isn't going easy, the one suggestion I would have is check EVERYTHING, so you don't find out there are other problems that are affecting your measurement and have to redo it. He didn't really address stuff like twist in the front or rear triangles. He probably thought it was too complicated for the average person, but we CABERs are not average people... For what it's worth, most of these old frames are really clobbered, but yours from what I can see of it looks very nice.
Working on frames with no frame tools is a PITA. I would start by taking a straightedge to the BB shell on both sides (a piece of straight angle iron or better yet a long carpenter's level would work good), and check that the seattube goes straight up and the bottom tube goes straight forward. If the bottom bracket is square to everything, but off center write down how far off. Everything about frame alignment should start from the bottom bracket (so I'm told), but if it is off center either on purpose or by accident, the seat tube may have to stand in. You'll need to know how far the bottom bracket is off center so it doesn't screw up any other checks.
To check the front triangle for twist, rig up the frame somehow so you can get the seat tube perfectly vertical from the side (checked with a spirit level) and then check at the headtube side with the level. I guess its obvious they should match. If it's way off an angle gauge might prove useful. If it's not straight, getting the frame tied down securely at the bottom bracket and seattube to prepare for a bend without doing more damage might require building stuff. A piece of pipe through the headtube works for a lever, but be sure to have old scrap bearing cups in there so you don't stretch the headtube out of round. Sheldon said somewhere that the end the lever comes out of moves more, and it turns out he is right, so it is important to plan so you are pulling on the most wrong end of the headtube.
If the rear triangle is twisted, you can see pretty easy with a bare wheel bolted in. If you put the axle in the bottom of the slots, and the edge of the rim is closer to a seatstay than it is to a chainstay, that is the classic symptom. The wheel is tilted because one rear fork is up higher than the other. Of course that assumes the stays are all straight. You might have to rig up something to prove the stays are straight if you see a problem. If the wheel is off center equally on both, the stays might be a different length, or is might just be bent to one side like the original issue you found.
Keep in mind that when you measure from both sides of something, you only have to move half that far to correct it. Good luck and keep us posted.
I have always been able to bend things with Sheldon's methods, but since this part isn't going easy, the one suggestion I would have is check EVERYTHING, so you don't find out there are other problems that are affecting your measurement and have to redo it. He didn't really address stuff like twist in the front or rear triangles. He probably thought it was too complicated for the average person, but we CABERs are not average people... For what it's worth, most of these old frames are really clobbered, but yours from what I can see of it looks very nice.
Working on frames with no frame tools is a PITA. I would start by taking a straightedge to the BB shell on both sides (a piece of straight angle iron or better yet a long carpenter's level would work good), and check that the seattube goes straight up and the bottom tube goes straight forward. If the bottom bracket is square to everything, but off center write down how far off. Everything about frame alignment should start from the bottom bracket (so I'm told), but if it is off center either on purpose or by accident, the seat tube may have to stand in. You'll need to know how far the bottom bracket is off center so it doesn't screw up any other checks.
To check the front triangle for twist, rig up the frame somehow so you can get the seat tube perfectly vertical from the side (checked with a spirit level) and then check at the headtube side with the level. I guess its obvious they should match. If it's way off an angle gauge might prove useful. If it's not straight, getting the frame tied down securely at the bottom bracket and seattube to prepare for a bend without doing more damage might require building stuff. A piece of pipe through the headtube works for a lever, but be sure to have old scrap bearing cups in there so you don't stretch the headtube out of round. Sheldon said somewhere that the end the lever comes out of moves more, and it turns out he is right, so it is important to plan so you are pulling on the most wrong end of the headtube.
If the rear triangle is twisted, you can see pretty easy with a bare wheel bolted in. If you put the axle in the bottom of the slots, and the edge of the rim is closer to a seatstay than it is to a chainstay, that is the classic symptom. The wheel is tilted because one rear fork is up higher than the other. Of course that assumes the stays are all straight. You might have to rig up something to prove the stays are straight if you see a problem. If the wheel is off center equally on both, the stays might be a different length, or is might just be bent to one side like the original issue you found.
Keep in mind that when you measure from both sides of something, you only have to move half that far to correct it. Good luck and keep us posted.
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GTs58
I'm the Wiz, and nobody beats me!
The longer the lever the more force you can easily apply. I can't see how you did it, but it looks like you have the pedal on the ground? I spread a rear fork end from 4 5/16" to 5 1/8" on a Schween with a good 7' 2x4. The frame was completely stripped and I just layed it in the yard and started with some easy bouncing on the 2x4 and kept adding more pressure with about 5 tries until I found out what it was going to actually take to set the dang thing. .................. Longer lever..............
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SirMike1983
Riding a '38 Autocycle Deluxe
When you measure, do it down the full length of the string. You not only want to know how much the end of the triangle is off, but you want to know where it is going off track. Then you can target your bend to correct the spot in the leg where it is deviating.
The Park FFS-1 can help set rear triangles. It's still being made and sold. If you are going to be doing this more than once, I'd invest in the FFS-1 because it gives you better feel and more control than the board. The other thing is that the FFS-1 has a set pad and a padded hook so you can target where you want to bend along the leg of the triangle.
The Park FFS-1 can help set rear triangles. It's still being made and sold. If you are going to be doing this more than once, I'd invest in the FFS-1 because it gives you better feel and more control than the board. The other thing is that the FFS-1 has a set pad and a padded hook so you can target where you want to bend along the leg of the triangle.
Thanks all for technical and technique insight! 
More on the frame here :
Thread 'Identify prewar frame' https://thecabe.com/forum/threads/identify-prewar-frame.195975/
Yup, a few things going on with the rear triangle, twisted, dropouts splayed and laterally bent, axle sits uneven, uneven distance between chainstays, and probly more. Visually, alignment issues very obvious. Functionally, bike rides fine. I'll try fix it sooner or later. But first I'm going to ride it more before tear down.
More on the frame here :
Thread 'Identify prewar frame' https://thecabe.com/forum/threads/identify-prewar-frame.195975/
Yup, a few things going on with the rear triangle, twisted, dropouts splayed and laterally bent, axle sits uneven, uneven distance between chainstays, and probly more. Visually, alignment issues very obvious. Functionally, bike rides fine. I'll try fix it sooner or later. But first I'm going to ride it more before tear down.
I just remembered, the BB is offset, pics here:
Post in thread 'Identify prewar frame' https://thecabe.com/forum/threads/identify-prewar-frame.195975/post-1374594
Ok. I threw on a Kenda Nevega 2.1 and it clears! I was worried nondrive might rub chainstay.try it first