speedy sie Posted May 26, 2011 Report Share Posted May 26, 2011 on some of the top end car race callipers the pistons are drilled like you get on your disks,it is one the rim of the first part thet is exposed,will this be ok on a bike calliper piston,to help break cooling?? Uploaded with ImageShack.us Uploaded with ImageShack.us Link to comment Share on other sites More sharing options...
Grumpyduck Posted May 26, 2011 Report Share Posted May 26, 2011 Seems like it'll fill with all kinds of crap (affecting braking) pretty dam quickly... IMHO GD Link to comment Share on other sites More sharing options...
cagimaha Posted May 26, 2011 Report Share Posted May 26, 2011 There are a few brembo calipers that come with drilled pistons as shown in the 2nd picture. For a race application where the brakes will be regularly stripped and cleaned and you're chasing the last nth of braking performance it's probably not a bad idea. I assume they're also used without dust seals so the dirt buildup wouldn't be any more of an issue I guess. Link to comment Share on other sites More sharing options...
speedy sie Posted May 26, 2011 Author Report Share Posted May 26, 2011 i love brake strip downs so the dirt would.be no problem,as i strip the callipers once a week. Link to comment Share on other sites More sharing options...
YZ faybo Posted May 26, 2011 Report Share Posted May 26, 2011 Could be many reason Sie, the holes may offer a damping effect from speed vibration/osalations that cause squeeling and piston to pad suface movment, maybe act a bit like a heat sink to reduce temp passing through from the pad to the piston to the fluid over long periods of time for endurance racing. Dont tell me your going to make cut outs on your XRO pistons? Link to comment Share on other sites More sharing options...
chancho196 Posted May 26, 2011 Report Share Posted May 26, 2011 i love brake strip downs so the dirt would.be no problem,as i strip the callipers once a week. Why? Link to comment Share on other sites More sharing options...
kanerdog1x1 Posted May 26, 2011 Report Share Posted May 26, 2011 assuming you ditch the dust seals, do it. then get the pistons coated, either TiN or DLC ftw. Link to comment Share on other sites More sharing options...
speedy sie Posted May 26, 2011 Author Report Share Posted May 26, 2011 Why? because they get that much hammer!!...last year brembo sintered front pads ...yes only lasted 3 weeks!! Link to comment Share on other sites More sharing options...
lorenzo Posted May 26, 2011 Report Share Posted May 26, 2011 You'll get a similar weight reduction from spitting twice before you get on your bike. Link to comment Share on other sites More sharing options...
speedy sie Posted May 26, 2011 Author Report Share Posted May 26, 2011 i was on the thinking it would help keep the brake fuild down,and keep the callipers cooler with less heat transfer.. Link to comment Share on other sites More sharing options...
speedy sie Posted May 26, 2011 Author Report Share Posted May 26, 2011 well said Link to comment Share on other sites More sharing options...
speedy sie Posted May 26, 2011 Author Report Share Posted May 26, 2011 if you did the same as in the top pic,would air passing through the piston help cooling?...iv already out board the disk,s(to get them in clear air) running dot 5,brembo superbike disk's,4 pad cailpers(tokico std)with brembo sintered pads,radial m/c..all the usual up grades ,but last year on long blasts with heave breaking still got some break fade,just thought this might help.. Link to comment Share on other sites More sharing options...
Superdunc Posted May 26, 2011 Report Share Posted May 26, 2011 The holes are purely for weight saving Sie. if your concerned about heat transfer from pad to fluid, you need to machine up a phenolic top hat washer which you fit betwwen the pad and the piston to act as an insulator. Considering the carbon/carbon pads and discs on a Motogp bike run at 700 degrees C plus and they have no more cooling than your SRAD, I don't think it's really an issue. Link to comment Share on other sites More sharing options...
speedy sie Posted May 26, 2011 Author Report Share Posted May 26, 2011 humm... interesting. Link to comment Share on other sites More sharing options...
wavydavy Posted May 26, 2011 Report Share Posted May 26, 2011 Si, if you're caning the brakes that much you need to go racing Or is it possible it isn't a fluid issue and the problem lies elsewhere? if you did the same as in the top pic,would air passing through the piston help cooling? Well if he's got *air* passing through the piston, I'm guessing there might be another problem........ Link to comment Share on other sites More sharing options...
Adam Posted May 26, 2011 Report Share Posted May 26, 2011 on some of the top end car race callipers the pistons are drilled like you get on your disks,it is one the rim of the first part thet is exposed,will this be ok on a bike calliper piston,to help break cooling?? Uploaded with ImageShack.us Uploaded with ImageShack.us Supposed to reduce heat transfer to the fluid. My pushbike brakes have them. Link to comment Share on other sites More sharing options...
Superdunc Posted May 26, 2011 Report Share Posted May 26, 2011 Trouble with insulating the pad backing material from the pistons is, in my experience, that you remove or significantly reduce the heatsink effect given by the caliper and fluid in drawing heat away from the pads and you end up with the pads getting properly cooked - had some experience of this with SBS pads being used on a BSB superstock bike when they were fitted with a perforated plate on the back of the pad to reduce heat transfer. Si, if you're caning the brakes that much you need to go racing - superstock bikes using oem disks, pads and calipers can win BSB races without any brake fade issues. If you are working them that hard that with decent fluid they are fading because of the fluid overheating then you are an undiscovered riding god. Or is it possible it isn't a fluid issue and the problem lies elsewhere? Like maybe the fact that you say you are taking the fucking things to bits every week??!!!??? Using the fluid as a heat sink isn't a good idea as, other than in Nascar* it's not circulated and you end up with localised boiling. I've used several set ups on cars that hve used phenolic spacers in the pistons with only positive results. * some Nascar set ups have check vavles which circulate the fluid around the system. when you press the brake pedal to aid cooling. Link to comment Share on other sites More sharing options...
Adam Posted May 27, 2011 Report Share Posted May 27, 2011 How? Well to be honest I'm just guessing bit I reckoned the reduction in cross-sectional area through the axis of the drilling would result in a lower rate of heat transfer for a given temp differential. Link to comment Share on other sites More sharing options...
speedy sie Posted May 27, 2011 Author Report Share Posted May 27, 2011 Trouble with insulating the pad backing material from the pistons is, in my experience, that you remove or significantly reduce the heatsink effect given by the caliper and fluid in drawing heat away from the pads and you end up with the pads getting properly cooked - had some experience of this with SBS pads being used on a BSB superstock bike when they were fitted with a perforated plate on the back of the pad to reduce heat transfer. Si, if you're caning the brakes that much you need to go racing - superstock bikes using oem disks, pads and calipers can win BSB races without any brake fade issues. If you are working them that hard that with decent fluid they are fading because of the fluid overheating then you are an undiscovered riding god. Or is it possible it isn't a fluid issue and the problem lies elsewhere? Like maybe the fact that you say you are taking the fucking things to bits every week??!!!??? mike im not bigging me up,but i love my brakes,each sunday i do a full strip of the pads clean them,clean the disks,check them all over ,blead them through,and it is not air in the lines,!!! and yes i do cane the bike that much,the pore old srad is thrashed to death each time i go for a blast....and as for racing...im 40 and it is my lifes long urge to go,but im no chicken,but the roads are my love,yes iv been on the track,and do like it,but the hedge and brick wall,the old oak tree,the barbed wire feance,this is wot i like the shear thrill of fast road riding,and yes im a nod for doing it ,but to come home with tyres that well used and the cheear thrill of the roads is my love,and pushing the bike to the limmet is to me like being alive,the rest of life is just poo.. go racing....... Link to comment Share on other sites More sharing options...
Gregorious77 Posted May 27, 2011 Report Share Posted May 27, 2011 mike im not bigging me up,but i love my brakes,each sunday i do a full strip of the pads clean them,clean the disks,check them all over ,blead them through,and it is not air in the lines,!!! and yes i do cane the bike that much,the pore old srad is thrashed to death each time i go for a blast....and as for racing...im 40 and it is my lifes long urge to go,but im no chicken,but the roads are my love,yes iv been on the track,and do like it,but the hedge and brick wall,the old oak tree,the barbed wire feance,this is wot i like the shear thrill of fast road riding,and yes im a nod for doing it ,but to come home with tyres that well used and the cheear thrill of the roads is my love,and pushing the bike to the limmet is to me like being alive,the rest of life is just poo.. go racing....... Road racing then!! Link to comment Share on other sites More sharing options...
lorenzo Posted May 27, 2011 Report Share Posted May 27, 2011 Sie, 2 things. Firstly I know loads of people who say they like the thrill that you get on the roads, the potential hazards etc. All of them, to some extent, changed their mind when they went on track. Secondly, the problem is with the tokicos themselves, 4 or 6 pot, not with the pistons etc. They're OK for road riding, but they're never going to be great brakes, even the older nissins that the tokicos replaced on many suzukis were better calipers (must've been a budget decision from suzuki I guess). As you're a highly skilled machinist and business man etc, make some adaptors to take brembos off ducatis and milles etc. There was a set on ebay about a month back that went for £150 or something silly 2nd hand (calipers not included, but with stainless bolts). Make up 4 or 5 sets and you'll have enough to buy brembo calipers, top spec pads, fresh top quality race spec fluid and a track day to make you realise that fast is a whole different ball game to what you're used to. Link to comment Share on other sites More sharing options...
alexp5 Posted May 27, 2011 Report Share Posted May 27, 2011 Those Yoyodyne caliper pistons in Sie's pic are titanium, or at least they're Ti coated. Titanium has 7 times lower heat conductivity than steel and 3 times lower conductivity than stainless, so I'd think the hole drilling would be pretty pointless with regards to heat transfer from pad to fluid. Also, as a weight saving exercise, you're talking a few grammes, if that. Some Wilwood car race spec calipers use a Ti plate as a heat sink between the pad and piston. Go on then... who googled Yoyodyne? Sploink and indeed, wibble. Link to comment Share on other sites More sharing options...
speedy sie Posted May 27, 2011 Author Report Share Posted May 27, 2011 the bike has a k4 front end. Link to comment Share on other sites More sharing options...
gsxr renegade Posted May 27, 2011 Report Share Posted May 27, 2011 Well to be honest I'm just guessing bit I reckoned the reduction in cross-sectional area through the axis of the drilling would result in a lower rate of heat transfer for a given temp differential. But the area of the piston in contact with the back of the pad is the same as non-drilled pistons, so shirley they'd still be subject to the same amount of heat transfer into the piston itself from the pads? Link to comment Share on other sites More sharing options...
Mark/Foggy Posted May 27, 2011 Report Share Posted May 27, 2011 But the area of the piston in contact with the back of the pad is the same as non-drilled pistons, so shirley they'd still be subject to the same amount of heat transfer into the piston itself from the pads? Ther you go Si, drill holes in the back of the pistons, Job Jobbed. Oh and as a plus you'll probably never wear out a set of pads again. Link to comment Share on other sites More sharing options...
lorenzo Posted May 27, 2011 Report Share Posted May 27, 2011 the bike has a k4 front end. Stick the calipers off an R1 on there with 5mm spacers then. Link to comment Share on other sites More sharing options...
speedy sie Posted May 27, 2011 Author Report Share Posted May 27, 2011 was thinking of doing this. Link to comment Share on other sites More sharing options...
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