October 2, 2009

Low mount disc dropouts in the wild…

…or just installed on a frame. Got a couple requests for a few shots of these actually installed on a frame. Here they are. Also, as usual, my rambling thoughts.

I like the following about these dropouts:
-They save me time, since the disc tab is integrated to the dropout. Also, there’s no need for a seat/chainstay crossbrace. Very cool.
-They end up weighing only 15-20g more than a breezer/tab/brace setup. Pretty much insignificant. I can also cut down the driveside tab a bit and save about 10 of those precious grams if needed.
-They keep the caliper nicely out of the way of rack/fender/whatever mounts. Good stuff.
-I think they look pretty spiffy. I used to every once in a while be able to cram the disc mount down onto the chainstay on bigger bikes and loved the look. This is a much easier and more elegant way to do the same thing.

I don’t like:
-They’re hard to use with small frames, since the disc caliper won’t easily clear the seatstay. Extra bending on the seatstays is required on any frame much under 18″ (seat tube, center to center) or so.
-They cost a bit more than breezers. Not a big deal, really, but hey.
-The derailleur hanger is replaceable. Some people would list this as a positive, but not me – I have built probably 300 bikes with steel (integrated, non-replaceable) hangers and only ever had to fix *one*. I’d love to see the low disc mount dropouts made with an integrated steel hanger. I doubt Mark will do it anytime soon, though, so in the meantime, it’s probably a good idea to have an extra hanger in your pack in case of disaster.
-For some brakes, rear brake cable routing (especially for Avid mechanicals) is weird and ends up having to go down the downtube, under the BB shell, and along the chainstay. Not a big deal, but funky in some cases. Most hydros (though not all) can use more conventional routing along the seatstay as long as you’re willing to adjust the angle of the line where it enters the caliper.