I recently cold set my steel frame from 126 to 130 mm. I looked up some DIY dropout alignment tools that had been posted on various forums, and looked at the "real" tool sold by Park and others. I didn't have ready access to the real tool and didn't really feel like spending the money anyway, so I went with my own version of a DIY tool using hardware available just about anywhere, any time. It's pretty much the same in function to the other DIY and real tools.

I've attached photos of the materials I used and how it worked. I think that the differences between what I used and what I've seen used are:

I used 3/8" threaded carriage bolts because it had full-length threading and was easy to find. Most of the other bolts I found had threading that was too short, and I didn't feel like messing with threaded rod which only came in something like 3 foot lengths. I used 7 or 8" carriage bolts thinking I'd need the leverage, but I think 5" would work fine

I used fairly long "coupling nuts" to act as the alignment surface. The long threading allowed them to adjust toward each other and still stay solidly threaded on the bolts. Regular nuts would serve a similar purpose, but would be less adjustable toward and away from each other.

The only other variable is the flat washers. I just bought a few sizes, and used the largest ones that would fit flat against the dropouts to maximize the force/leverage that would keep them aligned perpendicular to the bolts.

The steps are the same as used for every DIY tool and in the Park tool instructions.

Center the rods - I threaded the coupling nuts totally on the bolts, and left a 1/2 " or so gap to begin with.

Secure the rods very tightly to the dropouts.


Adjust the coupling nuts toward each other until they almost touch.

(the extra nuts were intended to lock the coupling nuts in place. They're not really needed.)

Use the leverage of the extended bolts to move each side into alignment with the other. Follow the instructions on the Park Tool website for their tool if you're unsure how to do this. I found it totally intuitive and simple.

Use the facets of the coupling nuts to decide which way to move the dropouts. You can feel how well each facet on the coupling nuts arealigned. I think you can easily feel 1mm or less, which is a specification I read for adequate alignment.


This was pretty easy. The dropouts were very easy to align, and the 3/8" threaded bolts were more than adequate in strength to do it

Cool: that's pretty much how the real ones work.

I love it when some one adds something useful, this will be put in my brain locker for use later. Thanks. Now we just need a cheap frame table.

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?

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.

No.

... but after you pull one stay inward and the other outward, you can use this tool to make sure your dropouts are parallel. Having non-parallel dropouts increases your chances of breaking an axle.

The threaded rods remind me of the lock carrier hangers we made for working on VW/Audi cars with longitudinal engines. The entire headlight-radiator-grille assembly can be pulled forward about 5 inches to facilitate timing belt changes and other front-of-engine work, and 8mm threaded rods are a great alternative to the official hard-to-get Audi tool.

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.

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.

Or snapping a dropout, but they, or any dropout aligning tool will not push the stays into proper alignment.