Kontact

As I already described, your pads are mounted at different height and different angles compared to the brake arm. I even estimated those angles as 90 on the left and more like 60 degrees on the right, and the right should also be closer to 90. Take a look.

Yeah, I'm just kidding with you because I wrote the same thing.

oldbobcat

First, it looks like your rear wheel is improperly dished. But you didn't ask about that, so I'll set that aside for now.

Second, your entire brake adjustment is wonky. If I were working on your bike I'd start from scratch, and I'm not going to go into that here. But this here is how the pros at Park Tool would approach it. https://www.parktool.com/en-us/blog/...-brake-service I suggest you follow it to a T.

Kontact

Yet:

grumpus

Ah okay you got me. I just started from the top again because the OP seems to be having difficulty approaching the problem methodically. Whatever is out of alignment you need to start from somewhere and move logically through the possibilities until you have a complete picture. It's pretty simple (put it in backwards) to check correct dish and hopefully eliminate that as part of the problem. The problem just got smaller. You know this already.

pstock

with the wheel min the correct orientation I get a gap between the side if the seat stay and the top of the brake track:

LH side 27mm
RH side about 34mm

with the wheel flipped. about the same
27 vs 34mm

I am off now to show it to Malcolm at Biseagal, a good (if woefully slow) bike guy n Toronto

grumpus

OK, now we know the wheel is correctly dished, and the dropouts need to move approximately 3.5 mm to the drive side, or at least they need to move so the rim moves 3.5 mm. That's not a lot, but it's a start. Next it might be good to check head tube to seat tube to rear axle alignment on both sides - hopefully this also shows only the 3.5 mm error. You can do it by stretching a length of string if you don't have a suitable straight edge. While you're doing this you can also eyeball the head tube to seat tube parallel alignment, or check with an inclinometer or level if you have one.

Andrew R Stewart 

I don't think we can make this assumption yet. The frame can be straight, the chain and seat stays being the same length and centered laterally WRT the front triangle, but for some reason the wheel isn't seated in the dropouts the same amount on both sides. If the axle's center can't be located WRT the dropout slot's top the same on both sides the wheel will sit cockeyed. Andy

grumpus

Yes I'm making assumptions, I'm trying to not get bogged down, to just get an overview of the situation. The unposted version did babble a bit about dropout alignment, it also jumped ahead and speculated some, neither constructive at this point, so I cut it.

Andrew R Stewart 

Understood. I just get nervous when frame mods are mentioned with less than full information. Andy

grumpus

We're not bending anything yet, just assessing.

pstock

well. it seems to be a frame alignment problem.
Malcom has the needed tools (see attached)
the drop out alignment too photo is the After Photo. it was woefully off level and not parallels initially.

the other tool shows how off the rear triangle is.

I am not sure if this was a factory flaw or something that developed in course of this frames 20 year life.

to note it has always had a wheel installed in the rear triangle




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Aubergine 

I'm glad you're finally getting to a solution!

Andrew R Stewart 

Great to see progress on the problems. Did Malcom also fix the "T" tool misalignment aspect? Was there a front triangle to dropouts centering issue also? Bike Fridays do have fairly small diameter stays and a lot of odd brackets incorporating the hinges. No big surprise if it was learned that there had been an "incident" during travel, when the bike was folded and thus less able to resist the forces. I hope this fixes the problems. Andy

grumpus

Has it ever been left near cars? Just a tiny accidental nudge with a bumper can do that, in your garage or locked up in the street.