Muel Posted March 3, 2008 Report Share Posted March 3, 2008 Oh god, the physics is coming out...I did AS Physics, I remember the name Pascal, but nothing of what your wrote! I understood it though, interesting. Quote Link to comment Share on other sites More sharing options...
Muel Posted March 3, 2008 Report Share Posted March 3, 2008 Here's my attempt at working it out.If you imagine the piston in the lever, it runs inside a cylinder, pushing the fluid out of the cylinder and down the hose to make the pads move.If the piston and cylinder are bigger in diameter, then as the piston moves down the cylinder, then more fluid is pushed down the hose than with a smaller cylinder, for the same amount of lever travel.A magura rim brake works on ratios, with a 14mm piston and great big slaves, so whichever volume of liquid is displaced at the lever, is the same volume split between the slaves.The slaves have massive pistons, like 20/22mm I think.That's it, I don't know how to word the rest! Someone else finish this rambling off? Quote Link to comment Share on other sites More sharing options...
Revolver Posted March 3, 2008 Report Share Posted March 3, 2008 and they lived happily ever after Quote Link to comment Share on other sites More sharing options...
PaRtZ Posted March 3, 2008 Report Share Posted March 3, 2008 Here's my attempt at working it out.If you imagine the piston in the lever, it runs inside a cylinder, pushing the fluid out of the cylinder and down the hose to make the pads move.If the piston and cylinder are bigger in diameter, then as the piston moves down the cylinder, then more fluid is pushed down the hose than with a smaller cylinder, for the same amount of lever travel.A magura rim brake works on ratios, with a 14mm piston and great big slaves, so whichever volume of liquid is displaced at the lever, is the same volume split between the slaves.The slaves have massive pistons, like 20/22mm I think.That's it, I don't know how to word the rest! Someone else finish this rambling off?Youre making sense, but thats only half the story. The other half was my boring calculations bit Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted March 3, 2008 Report Share Posted March 3, 2008 yep..so basically large master piston=less power...So these levers will make your brakes LESS POWERFUL Quote Link to comment Share on other sites More sharing options...
PaRtZ Posted March 3, 2008 Report Share Posted March 3, 2008 So these levers will make your brakes LESS POWERFUL Thats probably the most crucial part of this thread Unless as Adam says you can machine a 16-14mm "sleeve" and then use a magura piston. But thats a lot of work for what? a snazzy colour? Besides I looked this kooka up last night, I can't find any information anywhere on the company or even where to buy them full price. Quote Link to comment Share on other sites More sharing options...
Muel Posted March 3, 2008 Report Share Posted March 3, 2008 These levers would be good for an idea I have had.4 bolt mounts on the top and the underneath of the seatstays, so you have 4 slaves connected to one lever.Obviously you'd need a posh frame aswell, but these levers could sort out the problem whereby the lever would travel too far for a small movement in the pads.I'm basically trying to think of a way of increasing the leverage ratio between the lever movement and the pad movement. Maybe use a maggy disc lever? Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted March 3, 2008 Report Share Posted March 3, 2008 would be pointless...you'd need a far bigger master cylinder...the pistons would never hit at the same time...therefore only being as powerful as the ones that hit the rim first Quote Link to comment Share on other sites More sharing options...
JonMack Posted March 3, 2008 Report Share Posted March 3, 2008 would be pointless...you'd need a far bigger master cylinder...the pistons would never hit at the same time...therefore only being as powerful as the ones that hit the rim firstEventually they would all hit though... as soon as one hit, the fluid would go to the next one, then the next one, then the next one, until they were all pressed against the rim.But surely that would just be similar to a 4 pot brake, which we all know suck for trials, because it offers more modulation than bite, and that's not what we want. Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted March 3, 2008 Report Share Posted March 3, 2008 but it would offer less hold.... a dual piston setup is better...end of...at least for hold anyway. the only reason for multi pot disc brakes is to try and decrease the risk of the brakes boiling..something to do with increased surface area. Quote Link to comment Share on other sites More sharing options...
JonMack Posted March 3, 2008 Report Share Posted March 3, 2008 That's what I meant when I saidBut surely that would just be similar to a 4 pot brake, which we all know suck for trials, because it offers more modulation than bite, and that's not what we want. Quote Link to comment Share on other sites More sharing options...
psycholist Posted March 3, 2008 Report Share Posted March 3, 2008 Area = 7mm2 (radius) X π (pi) = 153.938mm2 = 0.1539metres2EDIT: Is that right? Have I converted to metres squared when I wasn't supposed to? At any rate, the method is the same, and the answer still indicate smaller master = better The easiest way to convert units is to multiply the unit you have by a mix of units you know to be equal to 1. In the case of mm2 to m2, the conversion is done by multiplying by (1m/1000mm)2 as 1m = 1000mm, so the term you're multiplying by is equal to 1 (And remains equal to 1 regardless of the power you raise it to). You then cancel the mm2 you have over the line with the same unit under the line and are left with a value in m2. Simple enough really, and it works with all units.This means that 1mm2 = 1/1000000m2. Quote Link to comment Share on other sites More sharing options...
Bionic Balls Posted March 3, 2008 Report Share Posted March 3, 2008 which we all know suck for trials, because it offers more modulation than bite, and that's not what we want.i'v actually just gone vee brake...and i really like the modulation whilst still having super lock you're missing out! i can manual adam Quote Link to comment Share on other sites More sharing options...
cai Posted March 3, 2008 Author Report Share Posted March 3, 2008 Thanks for all the comments so far guys!I'm failing at phsyics but I understood what you said Partz!But going back to the original point,will you be able to feel the difference in hold or is it just minor differences that you can't actually feel?Also how hard would it be to make a 14mm-16mm sleeve? Quote Link to comment Share on other sites More sharing options...
ZeroMatt Posted March 3, 2008 Report Share Posted March 3, 2008 I think you will deffinately feel a difference if the levers are the same length and the pivot the same distance away and I don't know how hard it would be as haven't had a look at internals and spacing etcA far better way I'd imagine would be just to get a RB piston and just shim it out to work with the larger clamp on the kooka.This is still pretty silly though as what's wrong with a Magura? There are much more spares available and they are really cheap. Quote Link to comment Share on other sites More sharing options...
cai Posted March 3, 2008 Author Report Share Posted March 3, 2008 This is still pretty silly though as what's wrong with a Magura? There are much more spares available and they are really cheap.Oh I know, it's just at £1-70 I thought I might buy as a cheap replacement for my maggies if ever they shall die. Quote Link to comment Share on other sites More sharing options...
0zzy Posted March 3, 2008 Report Share Posted March 3, 2008 (edited) Oh I know, it's just at £1-70 I thought I might buy as a cheap replacement for my maggies when they shall die. Edited March 3, 2008 by 0zzy Quote Link to comment Share on other sites More sharing options...
cai Posted March 3, 2008 Author Report Share Posted March 3, 2008 Amazing post there Oz Quote Link to comment Share on other sites More sharing options...
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