"warped" discs
Discussion
Whilst "racing" at the weekend, I discovered on track my front brakes were pulsing like mad in hard braking zones. Very unsettling.
Now I haven't used these discs in 6+ months and they have been stored in my shed off the bike on the wall.
I never had this issue with my wets on in the morning.
I bled the system, cleaned up the pistons, had new pads in, cleaned up the sliders and it still happened the next race, i then changed the front tyre on to my wet and went out on that and it was gone.
Is it new disc time or can these be saved? I've heard a lot of talk that its normally just the bobbins, the move freely but I've never cleaned them up. Could this be the cause because its only at 100+
Now I haven't used these discs in 6+ months and they have been stored in my shed off the bike on the wall.
I never had this issue with my wets on in the morning.
I bled the system, cleaned up the pistons, had new pads in, cleaned up the sliders and it still happened the next race, i then changed the front tyre on to my wet and went out on that and it was gone.
Is it new disc time or can these be saved? I've heard a lot of talk that its normally just the bobbins, the move freely but I've never cleaned them up. Could this be the cause because its only at 100+
before you condemn the discs, buy a cheap dial gauge and check the run out. Also look the surface of the disc and see if there's ribbing or uneven surface wear.
Also, check for odd spots on the disc surface if they've been hung up for a while, corrosion etc.
Re the pulsing. At the lever or like the pads were gripping unevenly as the disc rotated?
Also, check for odd spots on the disc surface if they've been hung up for a while, corrosion etc.
Re the pulsing. At the lever or like the pads were gripping unevenly as the disc rotated?
Steve Bass said:
before you condemn the discs, buy a cheap dial gauge and check the run out. Also look the surface of the disc and see if there's ribbing or uneven surface wear.
Also, check for odd spots on the disc surface if they've been hung up for a while, corrosion etc.
Re the pulsing. At the lever or like the pads were gripping unevenly as the disc rotated?
pulsing at lever feeling. Also, check for odd spots on the disc surface if they've been hung up for a while, corrosion etc.
Re the pulsing. At the lever or like the pads were gripping unevenly as the disc rotated?
I have a dial gauge at work wouldn't hurt to fit the front and see.
It may be that one or two of the bobbins the discs float on is stuck, put a nut and bolt through the hole in the bobbin and try and rotate them all whilst using brake cleaner, Triumphs traditionally have had a lot of play in the bobbins and a stuck one will feel like a warped disc.
Edit, must read first post more carefully....
Edit, must read first post more carefully....
Edited by Jazoli on Tuesday 17th April 13:25
Without sounding too much of a douche here I'm quite hard on my brakes and had the same on my road and track bike
You can clean them up a bit with some fine 60 grit and paper and wire wool. Brake cleaner or similar to get all the grit off
I got one set under warranty and I'm currently working on a second set
As for the road bike decent discs and pads is all I can say. You are working them hard and they've gone for whatever reason
I tried twice getting mine trued, skimmed, whatever you want to call it. Didn't fix it
My road bike is doing it a bit now but I can live with it until its next big service
You can clean them up a bit with some fine 60 grit and paper and wire wool. Brake cleaner or similar to get all the grit off
I got one set under warranty and I'm currently working on a second set
As for the road bike decent discs and pads is all I can say. You are working them hard and they've gone for whatever reason
I tried twice getting mine trued, skimmed, whatever you want to call it. Didn't fix it
My road bike is doing it a bit now but I can live with it until its next big service
moanthebairns said:
Steve Bass said:
before you condemn the discs, buy a cheap dial gauge and check the run out. Also look the surface of the disc and see if there's ribbing or uneven surface wear.
Also, check for odd spots on the disc surface if they've been hung up for a while, corrosion etc.
Re the pulsing. At the lever or like the pads were gripping unevenly as the disc rotated?
pulsing at lever feeling. Also, check for odd spots on the disc surface if they've been hung up for a while, corrosion etc.
Re the pulsing. At the lever or like the pads were gripping unevenly as the disc rotated?
I have a dial gauge at work wouldn't hurt to fit the front and see.
Ronzx6r said:
iv got this on my track bike and just put up with it ha, should the bobbins spin freely then?! pretty sure none of mine do if that's the case
Take a look at this, goes through how to free up the bobbins. https://www.youtube.com/watch?v=1qoPqN2GBdw
I always liked this channel, seems like a nice bloke and very helpful.
moanthebairns said:
pulsing at lever feeling.
Then its likely there's a deflection causing a pumping effect on a piston. Look for run out or (as said above) look for a poorly seated disc to hub. Might be debris between the two causing the run out. Also check the disc is sitting true on the bobbins, regardless of whether they're spinning Obviously run your fingers over the disc surfaces and you might feel an inconsistency.
Cheap and easy way if to lay the disc on a large enough mirror and look for light underneath from a torch. Soon see any warping or ridges...
Ronzx6r said:
iv got this on my track bike and just put up with it ha, should the bobbins spin freely then?! pretty sure none of mine do if that's the case
I believe some move more freely than others. Mine don't, gave them a right good cleaning and still can't move them with my fingers.Ok, ill do the above and see how I get on its the original 12 year old disc that's never had a good clean up, something I've obviously neglected.
The bobbins do all move freely but it could be that one or two are just sticking at high speeds.
If i have to buy new discs i'll get them, its on my wets now anyway. Best also check the thickness of the disc.
The bobbins do all move freely but it could be that one or two are just sticking at high speeds.
If i have to buy new discs i'll get them, its on my wets now anyway. Best also check the thickness of the disc.
A couple of years ago I got a local highly regarded garage to do some work on my car. Timing belt, suspension work and it also needed new front discs and brakes (which I knew beforehand).
When I picked it up the guy gave me what seemed like a lecture on how to run the new brakes in. I was a bit put out to be honest as I thought I knew enough about cars and was quite capable of doing all the work myself but I had no spare time.
Seems every day is a school day! There is a lot more to it than I thought. Humble pie time haha.
Have a look at this Alex, especially relevant since you do trackdays. Hope it helps.
http://www.mossmotoring.com/warped-brake-rotors-th...
When I picked it up the guy gave me what seemed like a lecture on how to run the new brakes in. I was a bit put out to be honest as I thought I knew enough about cars and was quite capable of doing all the work myself but I had no spare time.
Seems every day is a school day! There is a lot more to it than I thought. Humble pie time haha.
Have a look at this Alex, especially relevant since you do trackdays. Hope it helps.
http://www.mossmotoring.com/warped-brake-rotors-th...
Check thickness, if it's ok then, check the mounts, clean everything with a stanley blade if painted. then measure run out, that'll be hard if they're floating and loose. All that ok, then it's pad deposits. Get up to a decent speed and brake hard 5-6 times, don't let them cool too much. Pad deposits are often wrongly diagnosed as warped discs IME.
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