Uneven dropouts
 

Hi all,
​​​​​​ I'm working on a '78 low end Schwinn. Trying to get it working well enough to give away. Having spent far too much time already, here I remain. The rear wheel, while centered between the chainstays will not center between the seat stays. It's always off toward the nds. I've done everything I can think of to do and it doesn't change. So I'm thinking perhaps they are out of level. And I can't find anything online that speaks to the issue of correcting this. What say you?

Probably a better question for the frambuilders sub-forum. There are simple little things you can do with string to see if things are the same distance from one point to another. If you can get the frame vertical and know it's vertical then a measurement taken on something going straight across the drops should be horizontal. If the seat tube and top tube are the same diameter, that should be easy to get the frame sitting vertical with a carpenters level.

Here's another place you might get some ideas..... https://www.sheldonbrown.com/steel-frame-repair.html

If you put the wheel in the wrong way around is the problem still there or does it move to the other side?

Once you've proved it's the frame and not the wheel the fix is just to file the top of one of the dropouts a bit to rotate the wheel. You only need to remove a very small amount of material as the wheel multiplies the error by about 5.

I did exactly this on a Dahon fork. If the wheel mounted on reverse exhibits the same problem, it's a frame issue.

I haven't tried that, though I did re- dish it. I don't understand how the wheel could cause this issue. I will try it nonetheless. Thanks
Edit: Same problem turned around. I guess I'll work on levelling it. And get out the file.

Why do I file the top, rather than the bottom?

...I have a Spanish built Zeus Competition that was made with this flaw in the frame. Before you start filing (assuming it is the frame, and one of the seat stays is off from the other), try the wheel in different spots along the dropouts. I managed to find one location where the wheel would center, so that's where it sits now when I ride it.

When the chain stays are equal, but one of the other of the seat stays is longer/shorter, horizontal dropouts tend to be not aligned horizontally. This often gives you one spot where they match up, so the wheel centers between the stays. If that won't work, the filing thing is your next option.

Because the top is the surface the axle is most likely to rest against after installation.
filing the bottom would work, but then you’d have to remember always to have the wheel off the ground when tighening the axle nuts.

The add on derailleur hanger pretty much determines where the axle can go. Not a lot of play there. I was actually thinking of putting one on the other side, just to see if it makes any difference. But I will check through all these things. My wife asked why spend so much time on a bike you're going to give away. Because I'm learning all this good stuff is why. Stuff I've read about here, and never experienced.

Of course. Thanks for pointing this out.

Go easy with the file, and check your work frequently so you don't overdo it.

https://cimg9.ibsrv.net/gimg/bikefor...25f7edb630.jpg


...the old ones used to mount like this. I don't know what you've got, but with this older style, you can slide them forward and back in the dropout slot.
It's a little bit limited in terms of how far you can move it backward, but you can move the axle pretty much all the way forward, moving the claw thingy right along with it.

Then, if you find a spot that works, on the other dropout you can put in one of the old French axle position adjusters, for dropouts without an adjustment screw for wheel position.

Most people just shove them all the way back, but there's no real reason that you have to do so. The derailleur maintains the same position relative to the freewheel cogs.

I had this problem with an old Huffy that had a hanger just like the one 3Alarmer pictured. I set that side in as far as it would seat and made sure the chain line looked good and then took a rat tail file to the non-drive side. You need to determine by sight approximately where in the dropout you want the axle to sit and then very cautiously take a couple swipes with the file. You will find the metal is really soft and it won't take much with the file before the wheel will seat in the new position. Good luck and keep us posted.
FWIW-on a much nicer bike that I ran into this with I actually line-bored the drop outs. This was much more complicated and I had access to a metal shop at the time.

I was assuming vertical dropouts in which case the bottom doesn't exist :) If they're horizontal dropouts I would file the top of one and the bottom of the other one. This way you're removing less material from each. But it doesn't make a huge amount of difference and it will be a very small amount of material anyway.

I think those old-school diagonal horizontal dropouts were designed to allow the frame to be a bit less than perfect. Most other dropouts can be filed a bit if necessary. Thru-axles are the only ones where there is absolutely no wiggle room of any kind.

Well I was building that bike for a friend who is visiting. Rather than put more time into that frame, we've decided on a different frame, a '87 Prelude.
I'm building that one today. I don't know when I'll get back to the 78, but I will post my results when I do it. It does have the hanger that 3alarmer showed, and sloping dropouts.