Disc brake drag?

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Zippy

New Member
I have just taken ownership of my first road bike which has disc brakes. Usually with rim brakes you can spin the wheel and the valve will settle eventually at the bottom as it is the heaviest part of the wheel.

However, when I spin the front wheel with disc brakes there is a swishing sound through the disc brake mech and the wheel stops as a result of drag. Is this normal with disc brakes and does it mean I am cycling against a smal amount of drag? Only just taken it from good LBS so it should be set up correctly.
 

byegad

Legendary Member
Location
NE England
It shouldn't drag and you can adjust them to avoid that noise. .

Which brake have you got? Some are a lot better, and easier to adjust, than others.
 

Globalti

Legendary Member
Don't worry, the pads will soon wear and the wheel will free up. Try riding down a hill fast with the brakes applied, that might do it. If you're really bothered, take out the wheel and force the pads apart a little with a screwdriver blade. Go on; they're quite robust!

Note that the pads will always sit very close to the discs and when you apply the brakes, the tiny amount of movement needed is accommodated by the flexibility of the piston seals. The seals are extremely tight, as you will discover if you ever try to remove them (compressed air needed) so the pistons don't move in the seals for normal braking. However as the pads wear the pistons will slowly creep through the seals to take up the wear. If anybody squeezes the brake lever with the wheels out they will push the pistons through the seals and you will need to force them back with a screwdriver.
 

jimboalee

New Member
Location
Solihull
As Globalti says, they eventually wear and free up. Consider it a bit of extra training.

I have mechanical Tektro Disks. The moving pad is adjusted by cable tension and the fixed pad has a screw adjusted backstop.

Easy peasy.

Pad wear is equilised by flexure in the rotor spokes.

I apply the brakes so infrequently, I decided to do the adjustments rather than wait for them to 'run in'.
 

Andrew_P

In between here and there
I have BB5's and I am forever adjusting them they drive me CRAZY! There had to get that off my chest...

NEVER ever again.

Mine last about three days before they need adjustment, seems crazy to me and a step backwards
 

Captain

New Member
I have BB5's aswell and I have to adjust the front one endlessly. - also I still havent managed to get it adjusted correctly, there is always some drag on the disk. however my rear one only very rarely needs me to move the pad in.
 

Andrew_P

In between here and there
I have BB5's aswell and I have to adjust the front one endlessly. - also I still havent managed to get it adjusted correctly, there is always some drag on the disk. however my rear one only very rarely needs me to move the pad in.


Identical to me, it has gotten so bad I have hardly any braking on the front and rely on the back, apart from the drag effect it was the noise form the front that was driving me insane
 

Howard

Senior Member
If they don't bed in properly you can also try this tip that works for both hydraulics and mechanicals.

Loosen the two bolts that lock the disc brake assembly to the frame / fork. Squeeze the brake lever. With the lever squeezed, tighten the two bolts to lock the assembly in place.

This procedure re-centers the pads on the rotor ensuring they are both equally spaced, and fixes the situation where the rotor catches either pad but not both.
 

Captain

New Member
If they don't bed in properly you can also try this tip that works for both hydraulics and mechanicals.

Loosen the two bolts that lock the disc brake assembly to the frame / fork. Squeeze the brake lever. With the lever squeezed, tighten the two bolts to lock the assembly in place.

This procedure re-centers the pads on the rotor ensuring they are both equally spaced, and fixes the situation where the rotor catches either pad but not both.


Will do it before i leave work this afternoon.
I have been trying this method but I have always rolled the pad away first (which is how I read it in the instructions) but I will try again and hopefully the hills on my commute will be nicer.
 

byegad

Legendary Member
Location
NE England
I have BB5's and I am forever adjusting them they drive me CRAZY! There had to get that off my chest...

NEVER ever again.

Mine last about three days before they need adjustment, seems crazy to me and a step backwards

I had them on my Kettwiesel and had similar problems, they simply wouldn't stay in adjustment. At 1000 miles one set of pads was worn out (The other side was fine, bizarre or what?) so I replaced them with BB7s. After 3000 miles on the same pads they are still good for more miles. AND They stay in adjustment for ages and when they need adjusting they are simple to work on having adjusters on both sides.

IMHO BB5s are the spawn of the devil and BB7s are ace.
 
Not sure what type I have - the bike is Kona Honky Inc 2010. Bike hasn't been out yet so I guess it could be a case of wearing them in a bit.

The 2010 Honky Inc has Avid BB7 disk brakes, so adjusting the pads as Byegad states is straight forward - there are adjusters on both sides of the caliper to set the clearance.
 

Andrew_P

In between here and there
I had them on my Kettwiesel and had similar problems, they simply wouldn't stay in adjustment. At 1000 miles one set of pads was worn out (The other side was fine, bizarre or what?) so I replaced them with BB7s. After 3000 miles on the same pads they are still good for more miles. AND They stay in adjustment for ages and when they need adjusting they are simple to work on having adjusters on both sides.

IMHO BB5s are the spawn of the devil and BB7s are ace.

Silly question are the BB7 a straight bolt on replacement?
 
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