Bike porn

do cables really stretch, or is it the outers that compress?

My own idea for the 'ultimate' rim brakes is to take the arms of the EE brakes from the main pivots down, build them into the forks and drive them with hydraulics. The only reason conventional brakes need so much brake-drop adjustment range is to accommodate forks with different tyre clearances. Build the brakes into the fork and you can probably get away with no drop adjustment at all, leaving little more than the pads in the air-stream. The pipes would run down inside the steerer, and i'd build a progressive advantage linkage into the levers, where it can be designed to recalibrate automatically if it gets too close to bottoming out. (A good reason not to build progressive advantage linkages into cable brake levers is that the high leverage bit would be quite harsh on the cables. I think hydraulics would tolerate this better.) You might need to stiffen the forks a bit, but that should be more efficient than providing an entirely separate structure. I'd worry a bit about how brake heat is handled.

The rear brakes would be built into the chain-stays, as they are already pretty chunky.

dude the entire point of hydraulics is that you can manipulate the mechanical (bit of a misnomer here) advantages simply though the alteration in the size of the pistons at the action end and driving end of things. no moving parts are needed. the draw backs are the seals.

the advantage to cables is that they are reliable and easy to work on. They draw back is that they are mechanical and require moving parts.

you're taking the worst of both worlds and combining them.

also a progressive advantage (falling rate) makes very little sense, as the actual movenent in the system once the pads hit the rim is very tiny; whatever direction you make the rate change go, it's not gonna change much once things start to matter.

Rate changes are commonly done on rear suspension so that they never bottom out, so to speak. The advantage approaches zero and the shock is never sent through it's entire stroke. This gives a bottomless feel to the end of the compression and is easier on the shock. this works because the system is dynamic. Brakes are a static system, largely.

[quote cowhen]

also, rotors don't go out of true (ha!), so the pad can have a very short travel and therefore exert lots of pressure.

Ahh, rotors do go out of true when you hit a tree wit them, i tell you that :P and the main problem with hydraulics is when air gets into the system and they get all spongy, and bleeding is a bloody hassle, DOT fluid everywhere...

Ahh, rotors do go out of true when you hit a tree wit them, i tell you that :P and the main problem with hydraulics is when air gets into the system and they get all spongy, and bleeding is a bloody hassle, DOT fluid everywhere...

if you dont know what youre doing it is yeah, it is like anything, watch an expert, then have a go at it.

True, i tried it for the first time after reading it out've a book, ended up using most of the bottle of fluid... Great fun though :P i like teaching myself, tis more rewarding.

haudralics are a pain in the ass, and the fluid would probably dissolve a carbon frame if it spill were to happen, im guessing it could, certainly the paint and plastic parts would be vulnerable.
If haudralics break half way into a long ride, fixing it is less likely than with a cable brake.

haudralics are good no doubt but on such exposed things like bikes, i don't believe they provide an advantage across the whole user base for the reasons i stated above.

Downhill racing and so on, absolutely, anything else it's inapropriate.

shimano use mineral oil as do magura so no eating paintwork. sram(avid) use dot fluid

could debate the relative merits of brake systems for ever,-fun,
but simply put, riding faster necessitates better braking, i.e good hydraulics.
never tried drinking the fluid though.

also a progressive advantage (falling rate) makes very little sense, as the actual movenent in the system once the pads hit the rim is very tiny;

But it makes perfect sense with a rim brake, as the perennial problem is to provide the right mechanical advantage when the pad hits the rim and a large enough range of moment to allow for the inevitable axial runout of the rim. The issue, as was pointed out way up thread, is that brakes which attempt to do this at the calliper (Deltas, eebrakes) become a pain to set up because the pads wear and rims are not all the same width, by amounts which are large compared with the total pad movement. On these grounds, it's probably easier to keep everything working sweetly if you use a straight rate on the calliper and a falling rate at the lever, since the parked position of the lever is invariant. As long as you use the cable adjuster to keep the pads at a constant clearance from the rim as they wear, you should get the rate change to occur consistently at the pad contact point.

^^point taken, in theory, but i've never had a problem setting up road brakes. point taken though. Anyway, it was an issue for MTB brakes. True. Now that i think about it, MTB brake levers had a rather steep inhernet falling rate back when rim brakes were used. It was partly (the rate wasn't, just the y intercept) adjustable, even, thorugh very simple system.

edit: i can't find a pic, but there was an allen nut that would move the attach point of the cable fitting towards or away from the pivot.

now that i'm thinking about this, the whole problem was worsened by the fact that cantilever brakes has a rather rapid falling mechanical advantage, meaning if you wanted any power, you had to set of the brakes close to the rim with a low angle on the cross cable.
whole thing sucked.

V brakes partly solved the problem by being flat rate at the point of the brakes.

anyway

look bike looks really hot!

http://donalrey.tumblr.com/post/795096317/cannondale-tracksss

^ Some nice shots

What rack's on that?^^^

Tubus Vega? Logo.

I've been looking at some of the touring threads and getting excited about going away.

New Mercian Cycles website, click the image...

why?

Oh jog on you sigh >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> (PistaSlain™(c)2010)

first time in this thread,is this pornworthy enough.Hetchins magnum opus with campag 50th.

One of the nicest bikes ever !

About the Surly above, it's look like a great bike to ride, but not really porn, however If we're talking about a porn-worthy Surly, this one is definitely is;

Ohh yeah.

About the Surly above, it's look like a great bike to ride, but not really porn, however If we're talking about a porn-worthy Surly, this one is definitely is;

No.
Plastic pedals.
Knog.

is that bamboo? seeing more of these around...