brake pad question

[rprothero]

Guys,

How do you know when its time to change out the brake pads on a bike? Are there wear bars that will tell you?

[Sunbeemer]

For the rear brake, the pad closest to the wheel has two round depressions on the backside that you can view from the left-hand side of the bike (through the tire). If you can see the rotor through the forward depression, it is time to replace both pads in that caliper.

On the front brakes, use a flashlight to inspect the bottom of the inner and outer pads in both calipers to see if they have worn below the small wear slits (grooves in the pads) you should see there, which means they are less than 2mm thick and should be replaced (in pairs).

[MIXR]

Minimum BMW shop manual thickness on the R is 1.0 mm front and rear. However, you need to consider uneven wear patterns between inner and outer caliper pistons. Some brake pads have grooves in them, but this is for water shedding or grit/dust shedding more than as wear indicators. Some pads are fully covered in material.

The check is mostly visual for in-between servicings. You can see the pads with a strong flashlight. 1.0 mm is 0.039 thou ("), so easy enough to judge when it's getting close. Running the pads down to the metal backing plate is not a good idea, for obvious reasons. The manual (as I recall it) also references a method for checking wear external to viewing the pads themselves, but I've always found it easier to just check the actual thicness of pad lining material.

Like Sunbeemer says, I'd change them out at more than 1.0 mm, so 2.0 mm sounds good.

[foobar]

Pads are ~ $30 a set if you shop around-- just change them if you are in doubt. No sense messing with brakes. Chewing up your rotors will cost you a whole bunch more-- about $170 per if you are lucky.

Like what's 30 bucks? 2 or 3 cups of Starbucks, right?

[rprothero]

any of you guys have a post on how to swap out the pads? instructions that is..still a newbie at this stuff ...

[towerworker]

Go here............... http://home.mindspring.com/~jabrooks/

All you ever need to know.

[rdsmith3]

Don't let your pads get down to this (old pads in the back, obviously)

[foobar]

Swapping pads is not too involved and it is all you need to do if your rotors are in good shape. I'll try to do a cliff notes version from memory-- I last did pads and a rotor on the rear 6 mos ago. Maybe someone can fill in any blanks if I leave a step off.

Basically, you need to remove the caliper from the bike, but leave the brake hose connected. You'll have enough slack in the brake hose to hold the caliper in your hand and move it around a bit. Don't ever let the caliper' weight be supported only by the brake hose! If you have to let the caliper go to get another beer or something, hang it from the handle bars with some string or place it on a stack of books... just don't let it hang from the still-connected brake hose.

As you pull the caliper off the rotor, try to keep the (worn) pads in place-- this will help you see how to fit the new pads. Keep an eye out for a small clip/leaf spring. This helps keep the pads from moving around and squeaking... you can reuse or replace this item. Your preference for one or the other is basically determined religious conviction or convenience.

The actual pad swap is tool-less. They just drop right in. Make sure your new/reused clip/sping is in the proper place.

Slip the entire assembly over the rotor and screw in back to the bike. Use blue locktite on the threads (yes, really, go buy it if you don't have it-- it's cheap-- like a buck).

If memory serves, you'll need a torx socket (T-45 on my bike, I believe), blue locktite, replacement pads and some string... The job should take 1/2 hr-45min for a first time and 10min thereafter.

Replacing the rotor, disconnecting the brake line/hose or changing the brake fluid is a significant change of scope. Not hard, mind you, just a bigger job than swapping pads.

AND, if you are the least bit uncomfortable with anything that I have typed here, leave the brakes alone and experiment on things that make the bike go, rather than things that make the bike stop

[foobar]

Would those be the EBC Double-H pads? That's what I put on-- they work well and the price was right.

[rdsmith3]

Would those be the EBC Double-H pads? That's what I put on-- they work well and the price was right.

Yes, I believe they are.