If you have a 4-foot level and a dial caliper, you can get a more accurate measurement using the same technique as the string method. I recently did this to my Trek 616, my long-suff'ring all-rounder. It never had ridden right since it'd been in a crash with me a year and a half ago. I'd thought that I'd re-aligned it fairly well, but... not really. SO I wrapped a piece of tape around the head tube as a reference point and another one around the seat tube so I could get repeatable measurements. I then clamped the level to the head tube and the dropout, measured the distance between the seat tube and the level, then flopped the arrangement and repeated the procedure. Turns out I'd been off by a little over 5mm!!

So Ai sat down with pencil and paper and committed arithmetic for a while, came up with how far each side had to move to center the rear triangle and maintain my 132.5mm spacing, and went to work with a piece of plywood (on the seat tube, to spread the load) and a 4' length of handrailing. The actual coldsetting only took about 5 minutes.

So now the frame is aligned perfectly side-to-side, within a millimeter. The difference is startling. Before, I had a shimmy that would start up at about 15 mph; and riding no-handed required me to shift my whole self off to the left a good little bit. Now I can stay centered on the saddle and run downhill no-handed without any shimmy at all. I run out of courage before the bike gets unstable.

If you don't have a long level or other solid straightedge, I might possibly use a fluorescent tube and duct tape. They are the most common really straight thing around, with tolerances of something like .0001 per foot. *I* might do this, but probably wouldn't: Mercury vapor is A Very Bad Thing. You shouldn't even think about it.

You can get good results with the string method; but you've got to be able to get the string really, really tight, and it takes some care and thought to do this without pulling the dropouts in or out.

Hazzak, what is the make and model of the bike? It doesn't look to be of dreadful quality in your photo. Got any more pics?