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moved up to 180 rotors about 150 miles ago but the front feels under braked and has been prone to squeeling, today I could (just) pedal with the front on hard.Have tried: 2 sets of pads both sinterd and organic,bled the system cleaned the rotors and oiled the pistons (put a hankie on my head and danced round them threatning them with the bin :wink:).Brakes are shimano lx had them Year and a half always been fine, bled and cleand when needed, pads today were glassy looking dont think its oil help please
Fit the smaller rotor back on. You're glazing the pads as they're never getting hot enough (PS - why did you change anyway?)
wanted more grunt on the cheap (one finger braking) have had the rotors glove burning hot still not hot enough? interesting thought on glazing dont think I can sqeeze the lever any harder the hills hear arent long but are steep :Calderdale
i am having the same problem withn a 160 rotor. splined shimano centre lock. going to try a 203mm sanded the pads down with virginal sand paper. cleaned the disk with lynx(methyl alcohol) out of interest what forks do you have and what type of calliper fitting arrangement?
lefty with a post to is. Have you tried the hanky on the head and ridiculing the pads? 😉
I had exactly the same problem. Fitted a 180(XT) rotor in place of a 160(XT) rotor. Symptoms were a lack of immediate stopping power (especially worse after a long climb - and if the air was cold) and a subsequent squeeling and overall lack of bite. No difference in pads. 180 rotor went through the whole clean/sand etc. rigmaroll, bedded in by powering down tarmac hills and getting the system really hot several times.
Fitted 160 back on and it was just fine.
6 bolt rotors, XT Post mount calipers (if that makes any difference
not yet, email me from profile and i will let you know if i discover any tricks to cure it. going to spend time till i sort it hopefully as it is stopping me going out on it as its bloody embarrassing!
mine is xtr m960 calliper with a converter from post to is with 160mm rotor at present.
today fitted my emergency part worn pads all seemed fine again wich made me think about the bedding in. Druidh could you be generating too much heat in the initial bedding in starting the glaze process? In my motorbike days glazing was an issue of too much heat.
Interesting topic, i'v just glazed the pads on my rear hayes 9 so would be interested to here if its too much heat or too little?
what is the method for bedding in brakes? just repeated stops?
I have never conciously gone out to bed-in pads for this very reason. With a new set of pads just go out as normal and for the first couple of uses just give them a bit of over braking. That will do it.
I see people hammering down tarmac hills with their brakes on 'bedding-in' and all they are doing is glazing them over!
Same here never beded a set of brake pads in and not any problems.
I tend to just sprint up and down the road half a dozen times with some sharp stops. Once I can get the brakes to lock up without putting massive effort into it, we're done.
Dale, are you sure your lefty hasn't contaminated the pads?
If any oil or grease gets out from the bottom of the boot (not unusual, especially if the is a leak from the damper), it can easily get onto the brake.
Glazing - there seems to be two effects - one the classic glazing from overheating the pads but also I have experienced both on motorcycles and MTBs a "polishing" of pads from gentle use only. This leads to a wooden feel, squealing and lack of power. Solution - sand them down and re bed in. I suspect this is what has happened to the OP
As regards bedding in of brakes. It is only in the MTB forum world that this is at all controversial. All the manufacturers of brakes and in car and motorcycle world it is accepted.
From what I have seen and read:
some brakes bed in easily in normal riding. Some need a deliberate bedding in. some folks riding styles will tend to bed in brakes easier than others.
glenh one of the first things i checked no leaking quad seal.still reading up I think local terrain is a factor in the do you dont you bed in
Ime swayed by the bed in on the flat at 15mph come to almost stop do again
15 times type thing.A slow build of heat allowing pad to conform to disk then build more heat to harden.
Bedding in is a myth. If pads were meant to be bedded in they would state how to do it on the pack. The manufacturers would always want to ensure best performance and cover themselves against any legal claim for poor performance.
All I ever do is sand the rotor and pads with 120 grade paper then go and ride. I reckon the only thing that will glaze them is repeated light braking before they have keyed to the rotor
I never do anything more than ride up & down the street a bit to make sure they're OK
"If pads were meant to be bedded in they would state how to do it on the pack."
Like Magura do.
All I ever do is sand the rotor and pads with 120 grade paper then go and ride.
do they tell you to do that on the pack?
do they tell you to do that on the pack?
Not on my Hope pads, but did on some either Hopes or XT's I had some time back and done it on most pad changes since. You don't need to but it does speed up the process of getting maximum power. Rotors will always score slightly, and sanding helps remove some of the high points. The abrasive dust and metal particles from the sanding also probably helps the process.
Actually told a porky. I don't sand new pads - only old ones if I am swapping front/back, or replacing the rotor
[i]If pads were meant to be bedded in they would state how to do it on the pack.[/i]
Some do but I still have my doubts as the bedding in describes pretty much what happens in a ride anyway.