is there a way to tell the difference between a standard (short) pull and a long pull flat bar/mountain brake lever? we have tons built up over the years at my co-op, but the bikes they came on are long gone.

the ONLY advice i have found for telling the difference is to draw (visualize) a line perpendicular to the bar through the pivot point of the lever. then make another line from the pivot point to the center of where the cable stop sits. if that angle is 28* or less, it's a short pull. if it's 35* or more, it's a long pull.

i took a protractor to assorted brakes throughout the shop and found that there is a definite difference between levers, however when i tested bikes we had that were still together, the rule didn't always hold true (in relation to the type of brake on the bike). this could just be lazy manufacturing though?

anyway, is there any truth to this test? is there any other way to tell?

THe angle has nothing to do with it. The real determining factor is the distance between the pivot and the effective cable anchor point. A larger distance means the cable will travel more for a given amount of lever pull; a shorter distance means the cable will travel less. SOme levers even come with a system allowing the calbe anchor point to be moved realative to the pivot to change the amount of cable pull.

But since there is no 'standard' it is really down to comparisons - if you have a lever you know works well with cantilevers or caliper brakes, then it is 'short pull,' and one that has a condiderably larger (like 1.5X or 2X) distance between pivot and cable anchor point is a long pull lever (or vice versa).

^ that was my initial thought as well, but i wasn't finding any info online to back it up, and i wasn't finding any correlation on the bikes i was measuring either

The pull radius is about 25-27mm for the vast majority of mtb flat bar brake levers designed for cantilever brakes, versus about 34-35mm for the vast majority of levers designed for V-brakes.

There are some freaks and outlier models, such as Dia-Compe 290 & 292 at 30mm. And there are some models that have a sliding pivot such as Shimano SL-M737 and Dia-Compe PC-7, where the pivot starts at around 32mm-ish and ends up pulling 19mm.

And some models such as Shimano Servo-Wave where the pivot can be fixed at about 25mm or 34mm.

I've measured many, many makes and models of mtn bike levers from the early 80s to the present..

measure the cable pulled. a piece of tape around the cable
with a sharpie mark on it will do.

I have found just by the feel, unfortunately, adding a Top mount brake lever
into the cable of an aero brake lever, ends up as an adjustment compromise
because the leverage of the 2 levers are entirely different.

More for the lever on the end, less for the ones in the middle,
so somewhere between pulling the aero lever to the bar with little effect
and having the top mount lever grab the rim with almost no motion at all,
but with significant, but very careful, effort.

+1

Pretty darn close to the measurements I've collected.

Most of the time they are marked, usually not obviously, but in some way. I know from digging through my co-ops parts drawer that a lot of the cheap levers are the same for long or short pull, except for where the mount for the cable end is drilled. If you look carefully there will often be the cable end receptacle, and a second divot. One is usually marked V and the other C.