chico1st

I know you can coldset a frame just by pulling on the chain stays with your hands but is this a bad idea?

I may want to respace a frame and long story i wont have a 2x4 or anything like that. At some later point i would check the alignment and use a 2x4 but can I just manhandle the frame for the time being?

well biked

You need a lever (such as a two dollar 2 x 4), a piece of string several feet long, and a ruler. And Sheldon's instructions. With those simple items, you can cold set a steel frame and insure that the rear triangle is aligned when you're done. Whether you need to align the dropouts afterwards is another issue. Sheldon adrresses this in his instructions. The keys are that you check the rear triangle alignment before you start (using the string and ruler), bend each side of the triangle, individually, the needed amount. Use the string and ruler to check alignment, and when you have the desired dropout spacing and the frame is aligned, you're done. Again, dropout alignment is an issue, read Sheldon's instructions on this. In most cases, it's not necessary.

well biked

P.S. When you say "man handle" do you mean just flex the stays apart and force the hub in? If so, then yes. Cold setting is actually permanently bending the tubes, not just flexing them apart.

chico1st

lol i mean permanently bending the tubes... i know its possible because i did it to my fork but wasnt sure if it was a good idea.

tjspiel

If you grab both sides of the triangle to spread them the chances of them getting spread an equal and appropriate amount isn't that high. A 2 X 4 let's you move one side at a time carefully until you get the distance right. Then you switch to the other side.

garage sale GT

I have done it. It worked. If the wheel is misaligned in the frame then you can go back and use the 2X4 and string.

You gotta figure the frame tubes on the right and left are about the same. If you are holding the frame only by the dropouts and pulling them apart, then the forces on the dropouts will automatically be equal and opposite. In fact, they can't not be equal and opposite unless something else is touching or pushing on the frame.

The extra forming which is sometimes applied to the right chainstay may screw up the picture, though, because cold working (bending) metal tends to harden it, and the slightly different shape will alter the way it reacts to the load you put on it. So it won't bend the same as the other side even though the force is equal, and it will spring back more.

I suppose it's possible one side of the rear triangle is more heat-softened than the other if the bike was brazed by hand. In that case, it won't spring back as much.

I did find I had to bend the dropouts back in with a wrench to get them to grip the hub tight enough to keep it from moving i.e. to make them bear squarely on the ends of the hub.

well biked

It only takes a few minutes, there's no need to take short cuts or worry yourself with wondering whether one side of the rear triangle will bend more than the other (which it probably will). Again, the tools are a string, a ruler, and a 2 x 4. These are not exactly expensive or hard to find items. Sheldon's article on cold setting is very easy to follow.

Retro Grouch 

It's been awhile but I've done it a couple of times. I used a 4' straight edge from the head tube to the drop out to check the alignment afterward but it didn't require any fine tuneing.

I've never done it on a real good quality frame. I'm thinking they might take more strength than I can provide with just my hands.

ultraman6970

I asume u have a steel frame, if you are going from 126 to 130 mms better just leave the bike as it is, it will work fine forever.

LesterOfPuppets

My frame seemed to have cold set itself after 10 years or so of having a 130 rear wheel jammed in there.

chico1st

that makes sense, from a materials science point of view... especially with all the vibrations from cycling