Should disc brake pads bend the rotor when braking?

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Hulk_slogan

Active Member
I'll try to explain.

When I pull the lever on my mechanical disc brakes to use the front brake, the outer (moveable) pad moves in towards the rotor and touches the rotor, as I continue to squeeze the lever the pad is pushed further inwards obviously, bending the rotor slightly more until the rotor comes into contact with the inner (stationary) pad, at which point the rotor is now clamped between outer and inner pads.

Its gotta be normal operation if one pad doesn't move right?
 
Depends upon the brakes

Some have a single moving pad and a sinlgle fixed pad, others have two (or more) moving pads

In the case of a fixed pad version the mobile pad will "bend" the rotor on to the fixed pad as you describe
 

Tim Hall

Guest
Location
Crawley
I'll try to explain.

When I pull the lever on my mechanical disc brakes to use the front brake, the outer (moveable) pad moves in towards the rotor and touches the rotor, as I continue to squeeze the lever the pad is pushed further inwards obviously, bending the rotor slightly more until the rotor comes into contact with the inner (stationary) pad, at which point the rotor is now clamped between outer and inner pads.

Its gotta be normal operation if one pad doesn't move right?
As Cunobelin says, for a fixed/free pad system like you have, yes, it's how they work. As the pads wear down, keep them adjusted to be as close to the disc without rubbing as possible. The fixed pad will, hopefully, have an adjuster screw, accessible by threading an allen key through the spokes.
 

lpretro1

Guest
To avoid too much bend in the rotor the inside pad (i.e. the one on wheel side) should be adjusted so it is very close to the disk. Then adjust the outer one to suit.
 

Drago

Legendary Member
I'll try to explain.

When I pull the lever on my mechanical disc brakes to use the front brake, the outer (moveable) pad moves in towards the rotor and touches the rotor, as I continue to squeeze the lever the pad is pushed further inwards obviously, bending the rotor slightly more until the rotor comes into contact with the inner (stationary) pad, at which point the rotor is now clamped between outer and inner pads.

Its gotta be normal operation if one pad doesn't move right?

Almost certainly normal, you can minimise the effect by adjusting the inner pad correctly.
 

cyberknight

As long as I breathe, I attack.
Depends upon the brakes

Some have a single moving pad and a sinlgle fixed pad, others have two (or more) moving pads

In the case of a fixed pad version the mobile pad will "bend" the rotor on to the fixed pad as you describe
Yup my tektro discs with a single moving pad do this .
I think the clearance from fixed pad to disc is supposed to be a couple of mm ?
 

Mobytek

Well-Known Member
ey tis that. Not enought to affect the disk, 1 - 2 mm maybe. Other options are twin moving pads, hyraulics that piston from both sides, or a floating disk.
 

Tom B

Guru
Location
Lancashire
As others have said it's normal... Just be careful to keep it adusted. The more bend you get the harder you have to squeeze and the less feel you get.

I undo the slides, crank out the adjustment screw until it touches, wind it back a bugs dick, Apply the brake and then tighten the slides. I have no idea if that's a recommended way, but it's worked for 5years for me. Long Tbar Allen keys are great for reaching through spokes.

I do about 5-600 miles a month and adjust roughly monthly.
 
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