Mountain Bike Reviews Forum banner
1 - 10 of 10 Posts

·
Registered
Joined
·
6,237 Posts
Discussion Starter · #1 ·
Well……at least for me. :) I have a set of M4’s and Mini’s (both with 180mm rotors) The Mini’s are absolutely quiet and work great. The M4’s squeal like crazy. I have tried most of the fixes and they still squeeeeeeeeeeeeeeal!! :mad: :mad: Decided to swallow my pride :eek: and take them to my LBS and have that them use the facing tool and replace the pads (my bike with the Mini’s was never faced). In additon to the facing their fix was to put a Kool Stop pad on one side and a XT on the other. Guess what?…… squeeeeeeeeeeeeeal!!! On the work stand I can apply the brake and turn the wheel with my hand and it is loud enough to wake the dead.

Today I had some free time and decided to look at the two brake systems and see what was different (besides the pistons). I then remembered that the rotors were different.

OK time to experiment. I took the rotors from the Mini’s and put them on the M4’s.

AHHH………….now they are as quiet as the Mini’s. Is this just dumb luck or ???? :rolleyes:
 

Attachments

·
Registered
Joined
·
495 Posts
Galfer Pads

I don't own Hope brakes but have been looking into getting a pair of Minis. But I have been told by several people that Galfer pads solve the noise problem-
As to your fix, who knows? I think it was more of a coincidence? Nice work though!
 

·
Registered
Joined
·
6,237 Posts
Discussion Starter · #5 ·
Galfer Pads

altaskier said:
I don't own Hope brakes but have been looking into getting a pair of Minis. But I have been told by several people that Galfer pads solve the noise problem-
As to your fix, who knows? I think it was more of a coincidence? Nice work though!
You maybe right. However the old stock pads and the Kool Stop / XT combo make the same exact noise. Maybe I should try the pads before spending the $$$ on new rotors. :confused:
 

·
Registered
Joined
·
734 Posts
The rotors are just new. Hope uses sintered pads (which have a long life and low rotor abrasion) so it takes a looong time to break in the pads and rotors.

To get yourself onto the right foot take the rotors and the stock sintered pads and put them in the dishwasher (with detergent.) This will clean any contaminants an will pickle (micro etch) the rotors.
Put the pads and rotors back on (pads and rotors in their original places if you marked them) and head for a small hill to initially bed the pads. Apply the brakes gently at first, do not squeeze hard enough to make them squeal. You will find that fairly quickly you will be able to apply more and more pressure without eliciting a shriek from the brakes. When you can do silent nose wheelies you have completed the initial bedding. If the squeal returns try to re-bed them (progressive pressure on a gentle hill) if that fails you can put them in the dishwasher for another go round (bed them again afterwards)

A nice muddy ride helps speed break in (the mud is abrasive) but it could take a dozen (or more) rides to fully break in the pads and rotors. The good news is that after you are done breaking them in the mono4's are less likely to squeal than the monomini's due to better pad control (4 pistons), toe in pressure (the trailing piston is slightly larger) and better pad aspect ratio (more rectangular pad area).

PS The stock sintered pads are more likely to squeal and take longer to break in than organic pads but IMHO are worth the trouble. They will last several times as long and have superior power and modulation characteristics. Also be aware that the power of the pads is initially low but increases (substantially) as the pads break in.

PPS I don't think ordering the mini rotors is a bad idea they are a lot lighter and you don't need the heavy rotors unless you are doing downhill. But you will need to break the new mini rotors as well.
 

·
Registered
Joined
·
6,237 Posts
Discussion Starter · #7 ·
Not new Rotors

Grumpy said:
The rotors are just new. Hope uses sintered pads (which have a long life and low rotor abrasion) so it takes a looong time to break in the pads and rotors.

To get yourself onto the right foot take the rotors and the stock sintered pads and put them in the dishwasher (with detergent.) This will clean any contaminants an will pickle (micro etch) the rotors.
Put the pads and rotors back on (pads and rotors in their original places if you marked them) and head for a small hill to initially bed the pads. Apply the brakes gently at first, do not squeeze hard enough to make them squeal. You will find that fairly quickly you will be able to apply more and more pressure without eliciting a shriek from the brakes. When you can do silent nose wheelies you have completed the initial bedding. If the squeal returns try to re-bed them (progressive pressure on a gentle hill) if that fails you can put them in the dishwasher for another go round (bed them again afterwards)

A nice muddy ride helps speed break in (the mud is abrasive) but it could take a dozen (or more) rides to fully break in the pads and rotors. The good news is that after you are done breaking them in the mono4's are less likely to squeal than the monomini's due to better pad control (4 pistons), toe in pressure (the trailing piston is slightly larger) and better pad aspect ratio (more rectangular pad area).

PS The stock sintered pads are more likely to squeal and take longer to break in than organic pads but IMHO are worth the trouble. They will last several times as long and have superior power and modulation characteristics. Also be aware that the power of the pads is initially low but increases (substantially) as the pads break in.

PPS I don't think ordering the mini rotors is a bad idea they are a lot lighter and you don't need the heavy rotors unless you are doing downhill. But you will need to break the new mini rotors as well.
Both sets are two years old.

In the past I would use wet / dry sand paper to clean and resurface the rotors. Worked good (for awhile). ;)

It is bizarre. New pads with two year old M4 rotors squeal. New pads with two year old Mini rotors do not squeal. :confused:
 

·
Registered
Joined
·
734 Posts
Yeah that is a puzzler... but it has to be related to mating the pads and rotor together. I would still suggest the bedding procedure I outlined (by the way that was given to me by a tech at Hope US) IMHO you should never sand your rotors, (a scotch bright at most) The dishwasher trick really works well to "reset" a system that has gone over to the dark (noisy) side;-)

Another thought, are the brake tabs well faced? The M4 brakes are actually more sensitive to yaw (being rotated with respect to an axis from the axle through the center of the brake) If your tabs are not coplanar (in the same plane) it makes it very difficult too keep the brakes quiet (particularly with sintered pads, which can easily become noisy) (the mini rotor being more flexible might be more forgiving to a brake with a slight yaw error.) Just a thought...

Good luck

If you want to through in the towel just switch to resin (organic) pads. They are normally very easy to quiet, but you will have to change them ever 6 mo or so.
 

·
Registered
Joined
·
6,237 Posts
Discussion Starter · #9 ·
Thanks for the advise!

Grumpy said:
Yeah that is a puzzler... but it has to be related to mating the pads and rotor together. I would still suggest the bedding procedure I outlined (by the way that was given to me by a tech at Hope US) IMHO you should never sand your rotors, (a scotch bright at most) The dishwasher trick really works well to "reset" a system that has gone over to the dark (noisy) side;-)

Another thought, are the brake tabs well faced? The M4 brakes are actually more sensitive to yaw (being rotated with respect to an axis from the axle through the center of the brake) If your tabs are not coplanar (in the same plane) it makes it very difficult too keep the brakes quiet (particularly with sintered pads, which can easily become noisy) (the mini rotor being more flexible might be more forgiving to a brake with a slight yaw error.) Just a thought...

Good luck

If you want to through in the towel just switch to resin (organic) pads. They are normally very easy to quiet, but you will have to change them ever 6 mo or so.
LOL! I guess it is really a crap shoot. I am going to the LBS today and get a rotor and will report back later. Thanks again for the advise!
 

·
Registered
Joined
·
6,237 Posts
Discussion Starter · #10 ·
180mm Mini Rotors

DeeZee said:
LOL! I guess it is really a crap shoot. I am going to the LBS today and get a rotor and will report back later. Thanks again for the advise!
Well last night I put the Mini 180mm rotors to the test. One of the rotors was a year old and has a wobble in it. The other is brand new.

Happy to say that the M4's are now absolutely quiet :D
 
1 - 10 of 10 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top