fietsbob

NB, Magura makes an excellent hydraulic Rim Brake. has for 20 years.
mounts on V brake bosses, but does not use them as a pivot.

Bikernator

Hmm... I should have googled cable housing before my question. My bad, but makes sense, though the feeling of idiocy is notably more familiar than I'd like.

As for continuing the reason cable DISC (not v-brakes or cantilever, mind you) lack so much power when compared to its hydraulic counterpart, I'm still not sure I understand where the power loss is (which there is).

When you think about it, with hydro brakes, you pull the lever back, and and easily pulls back until the pads hit the brakes, then it become very difficult to continue to pull the lever back any significant amount (the miniscule amount of compression hydraulic fluid does was already mentioned).

With cable discs, once the pads contact the disc, you can apply a good amount of force and the lever will still come back quite a bit. What this tells me is that something is flexing or bending, otherwise, by use of leverage (force times distance), you could increase the amount of force exerted onto the disc untilil you have all the power you need. Such a small amount of actual movement is required to get the pads to the disc that it seems you should be able to get your power.

I realize that's limited as it increases the distance your lever must move, but it still makes me wonder about the amount you can still pull back the lever to get substantial power. Obviously I could expirement with my current bike to track down the movement, but I'm out of the country, so you're stuck listening to my continuous droning.

kevrider

my SS hardtail has v-brakes.
my geared hardtail has mechanical discs.
my full suspension has hydros.

i'll echo what Steelhammer says, you want the right tool for the job. back when my SS had gears, i took it mtn biking in the mtns for the first time. i bought the full sus with hydros immediately thereafter. right, i made the descents without hitting any trees with the v-brakes. but i have so much more power and control with the hydros there really is no comparison.

Stealthammer

I've got a Serotta T-Max framed "commuter" bike that is outfitted with mostly XTR and carbon parts including a set of old school Spynergy Rev-X-Roc wheels that I probably ride more than any of my other bikes just because its light, fast on the road, and a gas to ride. Although it is still definately not a road bike, I have suprised a lot of road bikers as I pass them because its so light and so quick. Disks would be a waste on this bike.

Andy_K 

Interesting.

The reason I asked about the circumstances where V-brakes would be preferable is that I just built a hardtail for short track racing. It's got V-brakes just because it seemed to me that a nice, older (pre-disc proliferation) bike would be better for my budget (<$400) than a newer, not-as-nice disc-equipped bike, but I'm on the verge of convincing myself that V-brakes are actually better for this purpose than disc brakes would have been anyway, mostly because of the weight. Then again, I realize that I may be fooling myself.

That said, I've got a front disc brake on my wet-weather commuter, and I am a believer in the general superiority of disc brakes for many uses.

RIC0

I guess the fact that it's 2011 and not 1975 is one good reason to go with better technology.

Konacrasher

Until seals fail and hoses start leaking, then those BB7s are looking pretty good.

kevrider

yeah, that happens all the time, especially on cars, eh? well, not my cars, motorbikes or bicycles, but i was born lucky.

Konacrasher

Apparently you were. How often do you subject your cars, motorbikes, etc to crashes and harsh treatment a mountain bike gets? Or maybe you just ride on the sidewalk.

dminor 

I would hazard a guess that the modern MX bike is subjected to much harsher treatment than we can exert with our pedal-toys. And, when you think of cars/trucks, remember that they have to be engineered to be fool-proof for millions of non-mechanically-inclined people in all road, weather and exposure conditions all over the world - - which gets delivered by disc brakes day-in and day-out. Hmmmm . . . seems like that is enough to recommend them.

mystolenbikes

Ok this is simply the dumbest thing ever said on this board.

ed 

OP: I've had my Elixir R's for a couple years now. (Code's and Juicys before that) No maintenance besides a couple of bleeds that took 10min. They never leak. They never need adjustment. They are much less maintenance intensive and easier to set up initially. I've got linears on my rigid bike b/c I built it out of dumpster parts. If I had the coin...it would have hydraulic discs as well.

Once you get past the "mystery" of bleeding...they become quite easy to understand and maintain.

crazzywolfie

i got a 30 year old truck and never seen a seal fail or a hose leak but i have seen brake lines fail but that is totally different. vehicles are exposed to way harsher conditions. salt and sand can be extremely hard on a vehicle unless you spend good money on the high end parts that are less prone to fail.

Konacrasher

Awesome, what did I win? Actually it very well may be. I was just echoing what I read on another forum. Never used the hydros myself. I just like jumping into the fray. Don't mind me.

Konacrasher

Just out of curiosity, is there any truth to the weight being substantially more on hydros than cable pull discs? Obviously there is some, but does it really matter?

dminor 

Anyone have time to crunch some numbers vs. a full set of, say, Avid Elixirs and report back?

BB7s: https://forums.mtbr.com/showthread.php?t=365630

Elixirs: https://www.sicklines.com/gallery/sho...hp/photo/10055

cryptid01

Brakeless weighs nothing and has a zero percent failure rate, so I'd recommend that.

Konacrasher

The weight weenie's Coup De Grace (Coup De Gras)

Konacrasher

Looks like a valid comparison would be complicated. I want to use mechanicals because I have XTR brake lever/shifter combos, which save weight.

Zephyr11

I can't imagine it would be a significant weight savings, and certainly not one that isn't made up for by the fact that hydros work THAT much better.

cryptid01

Ahh, now it all makes sense. Get the BB7's then, you'll have a fine setup as long as you're willing to sacrifice customization of your control geometry and brake performance to a degree.

mystolenbikes

Then you get a big old LOL.

dminor 

I hate to be the downer to point out that almost exactly this time next month will be Al Wong day. Just saying.

twobadfish

There is NO question. Disc brakes are superior in mountain biking and really any form of biking. If you have ever ridden on disc brakes this shouldn't be a question. Stop faster, takes less hand muscle, works on a bent rim, almost always consistent braking power, feels a lot better.

scyclops

The primary reason for the superior power of a hydraulic system is force multiplication, which is essentially using a smaller piston to move a larger piston.

How hydraulics work