(08-23-2020, 08:50 AM)BobAintStoppin Wrote: I'm not sure I quite get this. The calipers are a single hydraulic circuit. When you apply pressure all the pistons push equally. Any off center of the mount should be of no consequence.

I agree. I would expect that slightly tapered wear (along the length of the pad) comes because the calipers are floating and the bottom end of the pads would tend to see the disk first and the top end last. With more pistons, this tendency for imbalance would decrease as the clamping load is more spread out.

Having said that, pads can wear differently side to side within the caliper, i.e. the outer pad vs the inner pad, if the caliper is fixed slightly off-center w.r.t the disk. That is what applying pressure while torquing the caliper bolts is intending to minimize.

I just did a brake service on the RS yesterday, replacing the front pads. The video, which might be useful to some, is here. I have close-up photos of the pads front and rear.

(08-23-2020, 08:50 AM)BobAintStoppin Wrote: I'm not sure I quite get this. The calipers are a single hydraulic circuit. When you apply pressure all the pistons push equally. Any off center of the mount should be of no consequence.

Now you got me wondering.
With the way the calipers are mounted it's hard to see how it would be possible to get off center.
The calipers have those little sleeves to slide onto.

   

(08-23-2020, 10:40 AM)Lee Wrote: Now you got me wondering.
With the way the calipers are mounted it's hard to see how it would be possible to get off center.
The calipers have those little sleeves to slide onto.

This is true, and there should be little side to side movement, but I figure it can't hurt to pump the front brakes before tightening the caliper bolts.

I just did a brake service on the RS yesterday, replacing the front pads. The video, which might be useful to some, is here. I have close-up photos of the pads front and rear.

[/quote]


Nice video Wayne. I learned something.... I typically reassemble the brake
caliper before I reinstall the caliper on the bike. Doing it that way is not easy as I only have two hands.
I will follow your procedure and mount the caliper to the bike and then install the pads. Thanks!

One thing I do before replacing pads is remove some brake fluid if the fluid is at the max line. With the thicker new pads the fluid may be overfilled causing a leak or making a mess the next time you remove the reservoir cover.

My BMW manual tells you to remove the speed sensor when removing the left caliper but I never had to do that when changing tires.

At first I was surprised your front pads are so thin, but I'm guessing commuting uses more brakes.
I went out and looked at my front pads with a mirror and they look pretty thick.
My rear pads look thicker than yours but I still plan to replace them before the trip.

Maybe it's all in my head but I swear brakes don't feel as good once they are half worn.

"Maybe it's all in my head but I swear brakes don't feel as good once they are half worn."
I'm with you on this one, Lee. My '16 RS has around 26K with decent pad left. Slightly different feel than when new (to me), and the 1250 I rode. It's not that they're weak, at all. It's the initial bite that's less now.

(08-23-2020, 03:25 PM)Lee Wrote: One thing I do before replacing pads is remove some brake fluid if the fluid is at the max line. With the thicker new pads the fluid may be overfilled causing a leak or making a mess the next time you remove the reservoir cover.

My BMW manual tells you to remove the speed sensor when removing the left caliper but I never had to do that when changing tires.

Yes, I knew about the technique of removing some brake fluid but since I was in there recently (for the fluid change) I figured I had the room in the reservoir.

As for the speed sensor - it is pretty close to the ABS ring and since it is only a small screw I rather play it safe and remove it. I certainly don't want to risk giving BMW any more money than I have to.

(08-23-2020, 03:25 PM)Lee Wrote: At first I was surprised your front pads are so thin, but I'm guessing commuting uses more brakes.
I went out and looked at my front pads with a mirror and they look pretty thick.
My rear pads look thicker than yours but I still plan to replace them before the trip.

Maybe it's all in my head but I swear brakes don't feel as good once they are half worn.

Yes, commuting does use more brakes and also riding style. It appears that I sometimes ride aggressively(-ish) and that would also suggest more brake wear.

The lever is a tad higher with the new pads in place which is nice. Still squishy compared to the S1000R though. They stop well enough. I did about 5 hard brakings from close to 60 while on the "bedding-in" run, and they felt great again today when I took it out to warm up the final drive prior to changing the FD oil. I also changed out the drain plug for one with a stronger magnet (Dimple) bought from Beemer Boneyard.

(08-23-2020, 07:45 PM)Grumpy Goat Wrote: Yes, I knew about the technique of removing some brake fluid but since I was in there recently (for the fluid change) I figured I had the room in the reservoir.

I don't understand your statement.
If you recently changed your brake fluid you probably filled the reservoir to the max level.
With new thicker pads your level is now too high.

With new thicker pads your level is now too high.
[/quote]
<nodding>

(08-24-2020, 06:20 AM)Lee Wrote: I don't understand your statement.
If you recently changed your brake fluid you probably filled the reservoir to the max level.
With new thicker pads your level is now too high.

Well ... yes and no. It was a bit high, but maybe not as much as you might think. I checked it and made a video just for this thread.