Why are Brakes such a Drag?

How much drag on the brake calipers is too much? My Seca 900 has almost no drag to where the tire can turn freely for almost 3 revolutions off one push, however, my Seca 650 can barely make 1 revolution. When I was helping a friend work on his calipers for his 2011 Ducati his tire also barely turns once. I've seen this on several other more modern bikes. Now, I know both bikes as well as calipers are 35 years apart but I've noticed that there is no real standard to how much brake drag is acceptable before it starts hurting the overall performance of the bike. I've looked all over internet and couldn't find anything. Any ideas on this subject would be helpful.

 

Brakes Dragging | The Causes of Brake Drag Explained (freeasestudyguides.com)

 

Brakes should not "drag" at all. You must have an air gap between the pads and the rotor. This will keep them cool. Even a slightly dragging brake will get really hot and decrease braking ability.

 

The piston seals are shown here in this link.




There should be clearance between the pad and disc.

 

Great video!!! I never changed out the original caliper piston seals on my Seca 650. Even though I went through the calipers and made sure they were clean, I'm wondering if the seals t have lost their "buoyancy" and are not retracting the piston as much as they once did almost 40 years ago?

 

ihe brakesystem rebuild spec from Yamaha is Every 4 years. MC, Calipers, Brake lines. the SS lines last longer that 4 years.

you should do this with every used bike you get unless po has documentation as to it being done.
dont forget the rear shoes too. many years ago i had a set delaminate on me when riding down the road. total lock up of the rear tire. just came out of a hard corner.
peace of mind knowing the brakes are going to work when you need them is nice.
it will save you on brake pads too.

 

I'll buy the rebuild kits today. Thanks for the advice.

 

The seals must deteriorate and lose their elasticity and that combined with road dirt over time stop the piston retracting. My back wheel caliper was binding slightly before l dismantled the bike so new seals will be fitted to the three calipers before l put it back on the road.

 

Yes it's important to renew all seals etc when rebuilding the braking system.