TROYston Posted January 27, 2010 Report Share Posted January 27, 2010 Yup basically what are your thoughts on this little beast. 180mm disk = 129.99 . 300g. LOOKS BUFF. http://www.bikemagic.com/gear-news/ashima-...rakes/6860.html Quote Link to comment Share on other sites More sharing options...
ogre Posted January 27, 2010 Report Share Posted January 27, 2010 vee calipers look ACE! Quote Link to comment Share on other sites More sharing options...
Mark W Posted January 27, 2010 Report Share Posted January 27, 2010 Not convinced with those V arms - they just look a bit too... industrial, I guess. I kinda like the more sculpted look. Should be interesting seeing how the pistonless system works long-term. Be good to see how long the seals last for. Only thing with the other disc they did was that kinda variable power thing with it - Ali had the Shimano Saint discs with the servos in them and they were really weird. When you brake lightly, there's only a little power, then when you pull harder there's more. Sounds good, but if you're doing a stoppie (or something along those lines), you never really know what you're going to get. It almost sent me OTB when I was doing one and thought I needed a bit more braking so I pulled it expecting a fairly normal amount of extra power, but the servo setup kicked in and it just locked it. Ali got launched in a similar situation too. I just don't really like the idea of not really knowing how your braking's actually going to work. You get no real feel from it, and you never know what it's going to do next. Hopefully it won't be the same with that one. Quote Link to comment Share on other sites More sharing options...
6ft-midget Posted January 28, 2010 Report Share Posted January 28, 2010 In regards to the variable piston brake I think it comes down to the concept of if it isn't broke, don't fix it. I mean don't get me wrong i like innovation but I've never had a problem with getting different levels of power out of a standard disc brake. Its just something else to go wrong IMO. However the pistonless brake does seem to be a step forward as it means that calipers can be slimmer and lighter which lends itself well to trials, as long as it performs well in the real world. Quote Link to comment Share on other sites More sharing options...
Mark W Posted January 28, 2010 Report Share Posted January 28, 2010 Greater pad clearance too, so you can bend your megasuperultralight rotor and it won't really affect proceedings too much. Quote Link to comment Share on other sites More sharing options...
ogre Posted January 28, 2010 Report Share Posted January 28, 2010 dont understand the pcb Quote Link to comment Share on other sites More sharing options...
6ft-midget Posted January 28, 2010 Report Share Posted January 28, 2010 dont understand the pcb Basically on a normal brake caliper the piston is pushed out by something called a diaphragm. the diaphragm is what makes the piston and brake pad retract slightly when you release. For this brake they've ditched the piston and mounted the pads directly to the diaphragm. meaning the brake is lighter slimmer and possibly cheaper to make/sell. Also they're are claiming better rotor clearance so, as OBM pointed out, a slight bend in your rotor wont cock things up too much. Please someone correct me if I'm wrong, I know its not as simple as what I've put but its too early for my brain to function properly. Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted January 28, 2010 Report Share Posted January 28, 2010 Basically on a normal brake caliper the piston is pushed out by something called a diaphragm. the diaphragm is what makes the piston and brake pad retract slightly when you release. For this brake they've ditched the piston and mounted the pads directly to the diaphragm. meaning the brake is lighter slimmer and possibly cheaper to make/sell. Also they're are claiming better rotor clearance so, as OBM pointed out, a slight bend in your rotor wont cock things up too much. Please someone correct me if I'm wrong, I know its not as simple as what I've put but its too early for my brain to function properly. If there's more rotor clearance....then surely you could set the pads up closer and use a longer blade to deliver more power? Quote Link to comment Share on other sites More sharing options...
6ft-midget Posted January 28, 2010 Report Share Posted January 28, 2010 If they're adjustable at all, and i think it moves further than a piston and with equal pressure with the same amount of lever movement. I reckon if its used at all in trials it'll only be justifiable for comp riders and weight weenies. plus it would have to be kept clean seeing as there is no piston to protect the diaphragm seals. Quote Link to comment Share on other sites More sharing options...
PaRtZ Posted January 28, 2010 Report Share Posted January 28, 2010 Hmmm would be nice to see how long the seals between the pistons last... Its a great idea, but as mark said, a bit sketchy. 'Am i gna do this stoppie nice or faceplant...OHHH i faceplanted how fun' Quote Link to comment Share on other sites More sharing options...
psycholist Posted January 28, 2010 Report Share Posted January 28, 2010 (edited) The real question about the diaphragm brake is what happens as the pads wear. Standard brakes allow the resting position of the piston to move towards the disk as the pad wears. This looks like it'll either require a bite point adjustment at the caliper, much thinner brake pads replaced much more often, or a closed hydraulic system (Which will lock itself on as the disk gets hot and the brake fluid expands). Standard brakes have a diaphragm in the lever to seal the oil in but the diaphragm is not a pressure retaining part. At the caliper the pistons are sealed by o-rings fitted to grooves in piston holes in the brake caliper, so there's no diaphragm there (Unless like in some cars you have a rubber bellows that covers the piston to protect the sealing surfaces of the piston from dirt). Presumably what this system uses is a thin walled part on the piston which flexes when the oil pressure in the caliper increases and in flexing pushes the brake pads out - it has potential, but wear adjustment will be difficult as the diaphragm will always try to flex back to its original position when the lever is released. The piston within a piston idea seems a bit strange. Mostly because the laws of hydrostatics say that the biggest area piston will move first (Force = Pressure x Area) and not the small area piston, so there must be more friction or some other modification made to the system to make it behave as described. At the lever end the small diameter piston will be pushed in first for the same reason and again giving exactly the opposite effect to what the article describes the brakes as doing. I like the servo wave SLX brakes I have on my hardtail and haven't noticed them to be very non-linear. The Saints are different beasts though - It may be that the switch between low and high power on my brakes happens at a point that doesn't matter to me cycling them, though since it's a roller moving towards the lever pivot as its pulled there definitely shouldn't be an obvious step anywhere in the power output. Edited January 28, 2010 by psycholist Quote Link to comment Share on other sites More sharing options...
Ali C Posted January 28, 2010 Report Share Posted January 28, 2010 it wasn't a switch between less power and over the bars power, but when your on the balance point on the front wheel just needing a tad more power, it was harder to feather. Normally you would squeeze your finger in a progressive manner, with the servo wave, I had to pull the brake in an almost linear way.....most annoying. Quote Link to comment Share on other sites More sharing options...
psycholist Posted January 29, 2010 Report Share Posted January 29, 2010 I'm glad I stuck with the Louise up front now ... Hopefully it's a learning curve thing, but if you get used to the Saint you won't be able to ride anyone else's bike... Quote Link to comment Share on other sites More sharing options...
Mark W Posted January 29, 2010 Report Share Posted January 29, 2010 The whole thing is that you can't really get used to it as such, because it does kinda change the way it brakes as you brake, if that makes sense. I just don't think it's something you'd really get used to all that well, and it's something you shouldn't need to get used to - there's nothing wrong with how normal brakes work for trials. Quote Link to comment Share on other sites More sharing options...
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