Originally Posted by
due ruote
Cool. I've done basically the same thing but without the coupling nuts - those look like a good addition.
Fine print: what is the "correct" placement for any alignment tool in the dropouts? In the center? All the way back? I imagine the most important thing is to have both sides the same, but does the rest matter?
What I read about placement of the tool is that it should be in the same place as the axle when it is aligned properly. In other words, if they're vertical dropouts, you should fully seat the tool in the dropouts, just like the axle would be if you were using the wheel.
If they're horizontal dropouts, you should first get the alignment of the wheel right - adjust wheel alignment with the little adjuster screws - and then seat the tool fully into the dropouts, just like the wheel. That's what I did ... this makes sense to me.
Originally Posted by
eschlwc
can something like this also be used to adjust the spacing or the alignment of the stays? on one bike, my stays are 3mm off center, and i'm averse to using the 2x4 (wood plank/leverage) method to move both of them over this small amount.
The tool can definitely be used to spread the dropouts and they spread very easily with it. Simply start with the coupling nut totally threaded onto the bolts, and the ends of the bolts touching in the center (you'd set the dropout clamping bolts accordingly). Then evenly rotate the coupling bolts so they press together, spreading the dropouts. (hope that makes sense). I think my coupling bolts were nearly 1 1/2 inch long, so even keeping a good deal of them threaded onto the bolt, you can get a good inch/25mm out of each for a total of 50 mm of spread.
This is the first time I've spread dropouts and this is what I learned: the stays on my bike seemed to spread differently when I used this tool to spread them. The drive side seemed stiffer than the non-drive side. So, my impression with my frame is that if I used a tool like this to spread the dropouts, they wouldn't spread evenly. I didn't actually test that though. I did very easily use it to spread the dropouts out to 140mm+, but they sprang right back when the pressure was released. I have no idea how much I would need to spread them.
My issue was that I wanted to spread the drive side more than the non drive side because the frame started off a little (~2mm) off alignment when measured with the string method (one side was ~3.3 cm from the seat tube, the other about 3.1 or so)
I used the "vice" method rather than the Sheldon Brown 2X4 method, just because it was easy for me to do it that way with my bench vice ready to go. Plus, in the vice, you can just leave the frame alignment strings in place and can very quickly and easily just check the frame alignment on both sides of the seat tube while you're spreading one side or the other. I just clamped the vice solidly on it's rotating baseplate, secured the bottom bracket very securely using hard oak boards to protect it, and pushed against the drive side, holding both the seat and chain stays to even the pressure. If I wanted to spread a little on the non-drive side, I just pulled.
Those things are strong though and it was fairly tough to get the total of 4 mm I was looking for. I think next time (if ever), I'll use the SB 2X4 method because I think it would be easier, but I can see how it will be a little bit of a hassle to spread the frame, set it somewhere to measure spread and alignment, re-set up for spreading, etc.