Non level rear dropout
 

I am a C&V poster, but thought I might get more advice here. I recently purchased 2 bicycles that it seems came from Scotland. Research and correspondence pretty much confirm them to being built by Andy McNeil from Glasgow. I started a C&V thread;

https://www.bikeforums.net/classic-v...ike-s-day.html

So I disassembled the green bike. It was a mix of parts but seemed interesting. Looks like Reynolds 531 throughout. I did put a string on the frame to use my little knowledge for a rudimentary frame alignment check. This came out seeming straight and the rear Zeus dropout spacing is about 125mm and seemed pretty square. A wheel put into the frame however doesn’t sit square in the frame. This test wheel is true with good dish and flipping it gives the same results.


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This seems to be a pretty nice frame. Putting a 3/8” aluminum rod in the dropouts and siting from the back shows the rod to be not on the same level as the BB. It would seem that the nds sits ever so slightly lower. I was wondering what an actual frame builder would do that was non destructive. My thought is filing perhaps 1mm off the upper side of the left dropout, but that isn’t really non destructive. Would this be something that a frame builder would put in a jig to bend to straighten? Any advice appreciated.

How do you know that the dropouts are actually centered on the BB shell? If the stays are both off to the left or right, that will have the effect of making them not level when you center the wheel visually.

Check the dropout centering first with at lease a string that goes from right dropout, wraps around the headtube and goes to the left dropout. If the stays are centered, the space between string and seat tube will be the same on both sides.

Unfortunately there really aren't any secret techniques. You can file one dropout, but with horizontal dropouts that's not a great solution.

It's not too surprising that one dropout would be low, but I would definitely make sure before cutting metal. So many ways to measure wrong. With horizontal dropouts, you might be able to find a magic spot where everything lines up by moving the axle.

I did try the string test first and they seemed lined up nicely. I also have a nice 4’ aluminum “yardstick” perhaps 2” wide holding that width wise against the headtube then against the seat tube, and then reaching to the dropouts lined up the same on both sides.

I forgot to add that I did try the axle in various spots. Also with the wheel installed, and just sighting from the rear, one can see the wheel canted relative to the seat tube. They aren’t perpendicular with each other. It is fairly easy to see when standing back a bit and sighting. I find this a nice visual test for chain line too. The eye notices discrepancies like that I think.

The flip side of all this - the bike will ride just fine with the cocked wheel. May be a touch of work to correct when riding no-hands but I'll bet it takes so little that you will quickly adopt and never think about it again - unless your brain's gotta know that wheel MUST be straight. Yes, the brake will be a little askew to work properly but that's easy on most bikes and brakes. You've got fender eyes and presumably room for them so you can disguise the skew and not have to look at it.

Second thought - how much vertical play do you have in the dropouts? If enough, I'd try epoxying a thin steel sheet along the top face of the lower dropout. Easy, non-destructive, cheap and not too hard to remove if it doesn't work. I'd use an epoxy like Marine Tex or JB Weld and "cook" it with a heat lamp or 100 watt incandescent bulb with tinfoil around the dropout and bulb.

I guess OP is convinced it's crooked. I would still advise watching this video on the Ellis Briggs channel
There is another video about alignment on the same channel

I’ve tried to use the very limited vertical slop in the dropouts already. It’s maybe at most 1 mm on each side. If this bike didn’t have those cool shot in style seat stays, one probably wouldn’t even notice. My other latest thought after getting some proper dropout adjusters is a round file on the top side of the left dropout but just in one localized spot. One could carefully take off a bit at a time until the angle is correct. I wouldn’t think it would take too much more than 1 mm. One could then slide the wheel in as far as the adjusters which would locate the sweet spot. Setting weight back down on the bike then would then locate the axle in the little rounded notch before tightening the QR.

That’s kinda why I was asking here, as I wouldn’t think this is all that uncommon. Another frame observation with that seat stay style is perhaps that contributed to the problem in the first place. The stays are brazed on either side of the seat post pinch slot. The post I pulled out was no longer round. It was about 26.9mm front to back and 27.3 side to side as if it was crushed a bit by forces from riding. Perhaps that is why this style isn’t common although I think I see it on Raleigh Professionals on some years. The post had no markings and seemed thin and lower quality. I have a beefier 27.2 in it now. One does have to pry the ears on the clamp open a bit for insertion though. It seems there is some upward forces on it even in its static state.

I did just watch a couple of those videos. Thanks.

I'm on lunch break teaching a framebuilding class so this has to be quick. SD5782 is a buddy that has some mutual interests in old Schwinn Super Sports. I don't have time to properly explain how to better check alignment than methods often advocated in the general C & V discussion forums. I learned at Ellis Briggs 50 years ago and the latest owner Paul Gibson took my class many years ago so I'm pretty sure what Paul said in his video would agree with my philosophies (even though I haven't had a chance to look at it yet).

British made frames were often poorly made and having seat stays not equal in length is not surprising. One thing that can be done (after properly aligning everything else) is the bend the bottom of the dropout down just a little. In other words widening the slot. When the wheel axle rests on the bottom of the front of the slot, it is possible to get the wheel closer to center after bending it a bit. I think regular steel frame usurers would be shocked at how poorly many frames are out of alignment from poor building methods. .

As the backyard hack,
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I use my level balanced with a couple of match nuts taped on to check the bb face to the seat and down tubes. I need to make sure its flush with the bb. I try multiple times making sure that my measurements are repeatable.

One thing to consider about using the bb face as a reference is that they are often distorted in (narrower) towards the top. Got to check from both sides. Paul Brodie has some videos about that. This is why a lot of builders use the head tube as the reference. Of course, that's not a low-cost quick method.

OP's frame appears to have a crooked brake bridge, so the dropouts not being even would not be surprising in the least. I used to tell people that it's not that hard to build a frame without a fixture. Then later I found out that the one time I build one that way, it was poorly aligned. But at least the dropouts were even and I eventually got it aligned and it's a really good frame. British builders often built by eye, and it shows.

I have a bike that came with the back end out of alignment and the vertical dropouts too open as if too large an axle was inserted. After straightening the rear, I clamped the tops of the dropouts in a bench vice and gently closed the dropout slots with a deadblow hammer.

In this case, it might be possible to file the top of the opening on the low dropout, and then raise the bottom by bending followed by filing it back to parallel. I could see that buying you a mm or two.

These observations point to some cottage industry type stuff. Indeed, that is why I went to a British site for frame identification. The bikes came from a recently closed old time bicycle shop in Dundee Scotland but somehow got to Ohio by the early 1990s. The owner sold high end frames decades ago, but also had frame builders help out some customers for less money than the high end marques that they sold. Andy McNeil was a builder for Flying Scot pre and possibly post war. I have posted on Retrobikes in England and gotten info from people somewhat associated with the principals and area and timeframe. One also posted this bike:


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It was said as mentioned by Doug Fattic that some of the details could be lacking in some of these frames. In defense of this, this builder was doing side jobs to a price point and if this was a mid 80s frame, he wasn’t perhaps in his prime. I probably kept these frames from the scrap heap, and I bet the ride might be interesting when built up. A phone app angle finder looks as though this frame might have 72 degree head and seat tube angles with maybe around 50mm of trail and over 41” of wheelbase to the center of the dropouts. I don’t have much invested, so a tweak or two might be warranted. It’s kinda a cool history anyway.

I'm not judging those builders, and people enjoyed those bikes for a long time. But I always wondered if un-remarked alignment issues were a factor in saying some bikes rode better than others. My misaligned frame rode great, but it had a low speed shimmy when ridden no handed. That's really the only reason I looked. Then it turned out to be really easy to fix. I have a production frame with the same problem, some day I'm going to strip it down and check the alignment. So far it rides great and I don't care about riding no-handed.

As with a lot of things, we have high standards for things that may not be that important. I'd rather know a frame was built by a craftsman than have one that is perfect.

Just file the goddamn dropout a little - stop overthinking a million ways to avoid it. There doesn't seem to be a single thing that makes this particular frame stand out from the tens of thousands of similiar 531 frames made over the years.

Your idea of doing a single spot with the dropout adjuster screw is an elegant way to try this out.

The people who say to just leave it are underestimating how much the crooked wheel will ALWAYS catch the owners eye just like a nagging wife.

Damn shame to file the dropout if the cause of the apparent misalignment is something else, like both seatstays being bent over to one side (surprisingly common).
I'd rather have the wheel be in the right place even if the seatstays are not.

Why would a "nagging wife" catch your eye? I guess I'm unclear on the concept. Never mind, please don't explain it.

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I guess the "if it looks straight" poster is somewhat at odds with the height gauge that measures to the thousandth of an inch. ;)
But I never look at the number on the gauge, I just set the height using the Vee in the center of the rear triangle indicator, pressed up against a tube that's known to be on-center. That's done visually or by feel, then the dropouts need to "look" centered on the indicator. In this case "looks straight" is probably within a half-millimeter.

That is something I haven’t thought about, both drops being tilted. That’s why I’m here to get ideas. I’ll look at it from that perspective too, as a little tweak on each might be all I need. Not sure how a mere mortal would check, but perhaps a square would come into play and a good eye for us mere mortals without frame table equipment.
The seatstays did seem to be in alignment as relates to the front triangle however with a couple checks.
Even if both stays were offset to one side, wouldn’t the wheel still be perpendicular to the seat tube but just offset? In my case it is not, and it is easy to see the tilt by eye with no fancy measuring.

One could file the axle, at least it's replaceable. Andy

That sounds like a winning idea and no damage done. It would also point to how much one would need to “adjust” the drop out if and when someone decided to go that way. Currently the hub set that was in there were Campy Record low flange with 74 on the lock nut on front IIRC. The rear was also for a 120 OLD dropout so it needs a longer axle and adjusted. This frame is 125 now although it may have started life as 120 in the 70s when this was probably made before it was updated.

They would not, because you are fudging the wheel position by trying to line it up with seat tube. But the offset is not simple - the stays are pivoting around a line somewhat parallel to the seat tube.

My guess is that Unterhausen hasn't cleaned the gutters like his wife asked - several times per month, since Fall of 2024. :lol:

I didn't say anything about my wife nagging anyone, she's a very patient person. Sometimes I worry there is going to be payback though.

on edit: I don't think the dropouts can be out of alignment enough to cause the wheel to sit crooked, but it makes sense to check every bike for that anyway. Lots of bike problems can be fixed by having the dropouts and derailleur hanger properly aligned.

And this is just what I did. As mentioned, it doesn’t really change the frame itself. Researching, I’m also thinking this frame originated in perhaps the late 60s or early 70s at the latest, and has probably been through several updates. Filing on the axle did get the wheel to sit straight. I did do a string check on the rear triangle first. It seemed like a lot in the pics to file off the axle, but it was just slightly less than 1.5mm. File install, file install, etc until satisfied. Pretty easy. Also discovered after getting dropout adjuster screws is that the dropout doesn’t sit the same distance back from the BB. The adjuster screws are about 2mm different in depth for the rear wheel to be aligned near the BB. This was probably part of the problem too.

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A mark on spacer for reference
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Dropout adjuster screws at non equal depths

So, progress made while also doing some winter reconditioning on bikes for family members. Fun winter projects. This one is looking to be a half step plus granny. The fork legs are also quite long on this frame requiring long reach brakes. It looks like a Tektro 559 will reach a 700c though, and a 35mm tire will just fit width wise in back. The interest in this frame is the long front center, relaxed head tube angle, and longish chainstays. It sounds kinda floaty considering 35mm tires and the 531 tubing.

I have long assumed that was really the purpose of that style of dropout. You can wiggle things around a bit until the wheel is right even if the craftsman who made the frame had had one beer too many at lunch. It helps if the slots kind of angle upwards. These look perhaps a bit too actually horizontal.

Rear dropout slots horizontal to the ground are about maintaining the geometry regardless of the axle position within the slot, say when track riders change out cogs to suit the track and retension the chain. Angled dropouts are about maintaining the rear brake reach as the axle travels along the slot. Or that's what I was taught. Andy