TrialZonn Posted July 28, 2009 Report Share Posted July 28, 2009 Hello.I'm using a mechanical disk brake on the front (Onza Dual-Pull Mechanical)After the contamination of my pads I decided to buy new ones.So I bought some Shimano Diore pads that are the same size as the contaminated set.I installed them but the braking power seems to remain low compared to the power I had before the contamination.So...am I doing something wrong?Or the pads needs some ''burn-in'' time and if yes how much time is that?I followed the instructions at the wiki about how to re-setup my brake but nothing seems to work.The brake feels spongy and it won't stop me if I do a gap to front.It only slow me down.Every advice appreciated.Please help.Thanks Quote Link to comment Share on other sites More sharing options...
J Trials 31 Posted July 28, 2009 Report Share Posted July 28, 2009 Throw some mud on there, then go down a big hill and grab your brakes. If that doesn't work do the same with water. I usually do both then it starts working again. Also, did you check about getting the Onza pads the original's might actually be better pads than the Shimano's. Quote Link to comment Share on other sites More sharing options...
monkeyseemonkeydo Posted July 28, 2009 Report Share Posted July 28, 2009 What was the disc contaminated with? Did you clean the disc rotor before putting the new pads on? Otherwise yeah chuck some water on there and ride around with the brake rubbing to get it good and hot and it should bed in reasonably quickly. Also worth scuffing up the pads before putting them in (rub them over some concrete or file them a bit) to get the glaze off. Quote Link to comment Share on other sites More sharing options...
TrialZonn Posted July 29, 2009 Author Report Share Posted July 29, 2009 Yep I have cleaned the rotor with hot soapy water.As for the pads...I couldn't find the original that Onza uses so I got a Shimano set as they are the same size...I will try and see if it works.Many thanks Quote Link to comment Share on other sites More sharing options...
TrialsMan Dan Posted July 29, 2009 Report Share Posted July 29, 2009 With mechanical disc brakes, you need to make sure the caliper is set up straight. Or else you get a spongey feeling, not the on/off power you are looking for. When i bed in disc brakes, i drag them on for a bit then spray some water on the disc then repeat about 10 times until it becomes fairly grabby. This way, you get a little bit of pad material on the disc at a time, which results in good all round braking power. Quote Link to comment Share on other sites More sharing options...
TrialZonn Posted July 29, 2009 Author Report Share Posted July 29, 2009 (edited) Yes,I tried aligning the caliper again so that the pads hit the rotor parallel and not with an angle but the brake keeps not performing as good as before.Even if I get the pads tight enough on the rotor with an allen key (I do this to keep the caliper to the right angle and tighten the caliper bolts on the adapter) the wheel keeps moving if I use enough power.Should this happen?And if that helps the new pads are the Shimano M08 Resin Pads Edited July 29, 2009 by TrialZonn Quote Link to comment Share on other sites More sharing options...
Redneck Posted July 30, 2009 Report Share Posted July 30, 2009 sand the rim and pads a bit then just ride on it. get the disk as hot as possible, ive been told to even be pulled around the block by a car a few times with the brakes on, then that will make the pads and the rotor mate well. i had an issue with my MTB where the rear brake didnt do much but look nice because of contaminated pads, once i got dirt and gunk in there and bedded the pads with lots of heat and down hill descents they now work great. Quote Link to comment Share on other sites More sharing options...
psycholist Posted July 30, 2009 Report Share Posted July 30, 2009 I resurrected my front disk yesterday by wiping its surface with wet grass cuttings and dirt sprinting the bike as fast I could pedal it and pulling the brake full on about 3 times. No idea what happened it though - on Monday it worked perfectly and its sat in my garage since. I do find the rear Magura loses bite if I leave it in the car on a sunny day... Quote Link to comment Share on other sites More sharing options...
Fixed Pants™ Posted July 30, 2009 Report Share Posted July 30, 2009 Your problem is you have bought resin pads, designed for a resin specific disc.They're a different compound and work badly on normal discs.You need to buy sintered or organic replacements.Sintered has more bite but will wear down quicker (only a small difference) Quote Link to comment Share on other sites More sharing options...
N.Wood Posted July 30, 2009 Report Share Posted July 30, 2009 Your problem is you have bought resin pads, designed for a resin specific disc.They're a different compound and work badly on normal discs.You need to buy sintered or organic replacements.Sintered has more bite but will wear down quicker (only a small difference)I don't agree. Sintered have a longer wear life at the detriment to performance. Quote Link to comment Share on other sites More sharing options...
TrialZonn Posted July 30, 2009 Author Report Share Posted July 30, 2009 Ok so the resin pads are the problem!Many thanks I'll get a pair of organic or sintered!How about these Pads I think I should go with the red ones? Quote Link to comment Share on other sites More sharing options...
psycholist Posted July 30, 2009 Report Share Posted July 30, 2009 I've never heard of a resin specific disk in my life, they all run on the same disks - 1.5mm thick stainless steel with holes in them. Resin pads are better insulating (Les heat to brake fluid so less boiling - useful for DH, irrelevant for trials), softer material (Better conforming around the holes in the disk leading to more bite at the expense of wear rate), quicker wearing (Pretty much irrelevant in trials since you'll still probably get a year out of them) and usually slightly cheaper than sintered. Sintered are useful for wet, muddy, gritty off road riding where a set of resin pads can be worn through to the backing in a matter of hours (I've seen this first hand). Quote Link to comment Share on other sites More sharing options...
TrialZonn Posted July 30, 2009 Author Report Share Posted July 30, 2009 (edited) I've never heard of a resin specific disk in my life, they all run on the same disks - 1.5mm thick stainless steel with holes in them. Resin pads are better insulating (Les heat to brake fluid so less boiling - useful for DH, irrelevant for trials), softer material (Better conforming around the holes in the disk leading to more bite at the expense of wear rate), quicker wearing (Pretty much irrelevant in trials since you'll still probably get a year out of them) and usually slightly cheaper than sintered. Sintered are useful for wet, muddy, gritty off road riding where a set of resin pads can be worn through to the backing in a matter of hours (I've seen this first hand).So buying a set of organic or sintered would not make a difference in the bite of the brake....I will try the method you discribed above and see if it works for me.Thanks anywayHowever I still can't rely on my brake.Yesterday I had a ride and used the front only a little as it felt spongy and irreliable.While returning home I was pushing the lever the whole time to ''help'' the disk get hot and bed in but the brake continue to lack power and bite even today.I'm really dissapointed... Edited July 30, 2009 by TrialZonn Quote Link to comment Share on other sites More sharing options...
psycholist Posted July 30, 2009 Report Share Posted July 30, 2009 Sintered tend to bite less well than organic, but it varies between manufacturers. Definitely Shimano Organic are a lot better (And quieter) in terms of bite and hold than sintered in the XT brakes. I use a Louise on the front of my bike and the Magura pads are organic too AFAIK... Quote Link to comment Share on other sites More sharing options...
Fixed Pants™ Posted July 31, 2009 Report Share Posted July 31, 2009 (edited) Sintered has bits of metal like stuff in it, which makes it bite a bit more?Resin specific discs do exist i believe... IE, shimano deore discs generally come with writing on them saying 'use resin pad only' n stuff.This is the stuff that confuses me, i keep getting terms mixed up.EDIT: Yep, sintered statement is true, not 100% about the resin but some discs like the deore ones do prefer resin pads... Edited July 31, 2009 by Fixed Pants™ Quote Link to comment Share on other sites More sharing options...
Jack_M Posted July 31, 2009 Report Share Posted July 31, 2009 Fixed Pants, when you say some 'discs' prefer resin pads, are you refering to the disc rotor or disc caliper? I am of the opinion that rotors do not have any real preference. I have however seen warning about not using sintered pads in certain calipers. Shimano calipers tend to come with such warnings. This however is because they are made to work with resin pads which insulate the caliper from heat quite effectively. The fear they have is that sintered pads without such good insulation will cause the brake system to overheat and fail, hence the warning. A number of after market pad manufacturers such as EBC also have similar warnings not to put their sintered pads in certain brakes.Having said all that theres two reasons it doesn't matter in this case. Firstly its a trials brake so it wont get enough heat into it to cause problems with either pad type, and its a mechanical disc with no fluid to overheat.Sintered versus resin for bite? I personally don't know. Conventional thinking says resin bites more but some brakes like BB7s have emmense bite with sintered pads.Sintered pads defintately have better wear life on a mountain bike, for trials maybe its less of a difference.Back to the original question. When i have tried to clean a rotor with hot soapy water I have never had much success. Some people swear by I can't make it work. I'm a little concerned that like me, you havn't cleaned the rotor well with the soapy water and you've contaminated the new pads.Hope thats all useful to someone. Quote Link to comment Share on other sites More sharing options...
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