Front brake drag '02 R1150RT??

[50Joe]

I did not have front brake drag on the bike prior to a tire change done last Saturday. I pulled the wheels off myself. Had the tire changed. Remounted the wheels myself. Brakes seemed to drag when I first mounted the wheel which I thought was due to pumping the brakes up after install. I just went for a 20 mile ride to scrub in the tires and see if the brakes still dragged. Well, they still do slightly. The brakes perform and feel exactly as they did before. No pulsing, good, even braking power, etc. I then loosened everything up, bounced on the suspension a bit and torqued everything down. Went for another short ride and I still have the drag. Any thoughts?

[ShovelStrokeEd]

Some light drag is normal. There is nothing to retract the pistons and pads but the discs pushing against them as they go round.

 

With the front wheel off the ground, you should hear/feel the pads kissing the rotors as you spin the front wheel. I can't give an exact number but a healthy spin should let the front wheel go through a couple of revolutions with no problems.

 

On the drag bikes, we used rigid mount discs and floating calipers and the crew guy would wiggle the calipers a bit to back off the pads after we came out of the water box. Never touched the front brake after that till the run was over. Of course with a 600 lb rider/bike combination, 160 plus mph trap speeds and a shaved front tire from a 125 GP bike, you didn't use a whole bunch of front brake anyway.

 

A couple of things come to mind here. Did you have to pry the pads apart to remount the calipers to the forks? You might have forced some dirt on the pistons into the seals and increased drag there so they are not retracting quite so easily anymore. A hint to avoid this is to use some double taper shims to maintain pad clearance when you pull the calipers. The pistons tend to creep out a bit due to the weight of the hydraulic fluid in the lines. Find somebody who is putting Cedar shakes on their house or wood shingles on the roof. A couple of scraps and your good to go. They have the nearly perfect taper.

[Ken/OC]

I've had serious brake drag twice, the second time after a tire change. By serious I mean that if you let off the gas and pulled in the clutch the bike would come to a stop quite quickly. Also a good heavy puck-stink within half a mile.

 

Both times the problem cleared itself after vigorous pumping of the brakes.

[50Joe]

I did have to pry the pads slightly to get the calipers back on. I bet I did get some dirt in there.

 

With the wheel off the ground, a healthy pull on the wheel causes about a rotation. Before, I would get several rotations. I did put the bike through several heavy braking stops but the slight drag continues. The drag isn't enough to feel while riding the bike though. I mainly notice it when trying to roll the bike around the garage since I'm a bit on the small side (5'7", 150 lbs). I especially notice it trying to back the bike out of the garage while in the saddle (I have to negotiate the bike through tight quarters between two cars).

[Ken H.]

Try this test. With the bike cold go for a ride, 1/2 mile or so without ever touching the brakes. Including coasting to a final stop. Takes some planning I know.

 

Are the front rotors now hot? Not a slight bit warm, but approaching too hot to touch. If so, you probably have a problem. If not, the drag you are feeling is normal.

[50Joe]

Problem solved after talking to my friend who has had several RT's. I loosened all bolts up again. Tightened the axle bolt, jumped on suspension, tighened left pinch bolt, jumped on suspension, tighened right pinch bolt. Wheel now rotates much better. My variation to this method was to tighen the right pinch bolt before the left one - not good. So, I'm happy now.