Juddering front brake

[nashdm2]

I have realigned the brake, no joy. With regards the rotor bur, I have tried a different disc and it’s exactly the same. Thanks for the replies guys.

 

[MartsEbike]

I have MT5's on my bike and they do sometimes make a strange noise..... more like a juddering sound than feel. I have read on other forums that it is due to the Rotor, with some using Shimano Rotors.

As TomD suggested above try the Blue Comfort pads, they do help.

 

[nashdm2]

Ok, thanks guys, I will get some of those as I have the black on front and back at the moment.

 

[JVBulman]

Ok, thanks guys, I will get some of those as I have the black on front and back at the moment.

Oh yeah, that'll do it. I can't say I've had much luck quieting Performance pads.

 

[spokewrench]

2020 SD Rohloff.

I have the Magura MT5 at the front. When I pull the front brake it feels like it is juddering. If I clean the disc with brake cleaner and lightly sand the pads, the problem goes away for about a mile then slowly comes back again.

I replaced the front disc and pads thinking that will sort it, but, its exactly the same which is really strange.

The MT4 rear brake is as smooth as silk and works really well, better than the front in pure power terms which is why I think there is an issue as the front should be better than the back. Both front and back are 180's.

Any assistance will be appreciated guys. Thanks, Dave

It happened to me this year. If it's okay after cleaning but soon returns, the cause must be uneven deposits from the pads. With resin pads, I've found that dish liquid and water will clean a disc nicely. (One of these days I'll try water alone.)

Heat causes a transfer from the pad surface to the disc. The watts of heat on the pad surface are the product of the disc speed and the braking force. With equal lever pressure, I assume your front caliper squeezes harder than the back, meaning more resin transfer. That would explain why your rear stays smooth.

Before I experienced juddering, I had known that braking fairly hard from 20mph to a stop would leave a single high spot on the disc (which would soon wear away with normal braking). Juddering must involve lots of high spots. I think system elasticity causes it.

If I squeeze a lever until the pads contact the disc, more lever pressure will move the lever farther. That shows elasticity in the system. In normal braking, elasticity will let the pads ride smoothly over high spots, if they aren't too high. If I pull the lever harder, tauter elasticity can cause bouncing, rapid fluctuations in pad pressure, after hitting a high spot. That could cause more high spots, spaced according to the speed of the disc and the frequency of the bounce.

I have experienced juddering that occurs only in a narrow speed range as I brake hard. I think in this case, the high spots are low enough that the pads can ride smoothly over them unless the bumps come at the harmonic frequency of the caliper bounce.

I've figured out why I didn't have trouble until my fourth year of riding. The dew point has been in the 70s, week after week, just about as high as the temperature of a parked bike much of the 24-hour day. That means a relative humidity of nearly 100%. Like wooden doors, resin pads absorb moisture from humid air. That softens them, causing greater material transfer to the disc in hard braking. Warming brakes with a heat gun before a morning ride has helped.