Rear Rotor Replacement?

rideoregon · 06-16-2011, 06:56 PM

My 2009 F800 GS was in the shop today for a 12K mile checkup. I was told that my rear brake rotor was under minimum spec at 4.43 mm and should be replaced. The cost? $300 plus. I was none too thrilled to hear this and asked "how common is it for an F800 GS to need a new rear rotor at 12K miles?" The answer I got was vague. I decided not to have the work done. I want to gather more information and likely will replace the rotor myself possibly with an after market brand. Has anyone else had to replace their rotor this soon? I did a search and did not find discussion on this but surely this has come up. What are others experiencing with rear rotor wear/replacement? Any feedback is appreciated.

Bayner · 06-16-2011, 08:27 PM

How many sets of pads have you gone through? If it's more than one, I would say it's at least plausible it needs replacing.

ebrabaek · 06-16-2011, 08:30 PM

Quote:

Originally Posted by rideoregon

My 2009 F800 GS was in the shop today for a 12K mile checkup. I was told that my rear brake rotor was under minimum spec at 4.43 mm and should be replaced. The cost? $300 plus. I was none too thrilled to hear this and asked "how common is it for an F800 GS to need a new rear rotor at 12K miles?" The answer I got was vague. I decided not to have the work done. I want to gather more information and likely will replace the rotor myself possibly with an after market brand. Has anyone else had to replace their rotor this soon? I did a search and did not find discussion on this but surely this has come up. What are others experiencing with rear rotor wear/replacement? Any feedback is appreciated.

That seems odd..... Unless you are dragging the rear brake off course. I just measured mine..... 7800 miles..... 4.98mm. You might want to measure it yourself for good measure.....

Erling

johngil · 06-16-2011, 09:15 PM

I'm at 4.6 - 4.7 on the brokeback beemer with just under 18,000 miles. I believe I'm on my fourth set of pads. Lots and lots of dirt and some mud.
Pads were OEM, then Galfer black. Maybe a set of Galfer gold on now. I can't remember.

JRWooden · 06-17-2011, 05:33 AM

I'm still on the original set @ 17K miles, but they will be gone before much longer. I have a set of Galfer Greens ready to slap on, I bought the greens as the pkg said the greens were the easiest on the rotors.

I've got 4.8 for thickness right now....

rideoregon · 06-18-2011, 05:52 PM

I'm on my second pair of rear break pads having replaced the first set after 10.5K miles. I don't drag the brake. What I'm curious to know is what is typical mileage for replacing the rear rotor on the F8?

ScienceOfDirt · 06-18-2011, 08:24 PM

What is the minimum spec?

itsatdm · 06-18-2011, 09:04 PM

New is 5mm. wear limit is 4.5mm

JRWooden · 06-19-2011, 04:07 PM

Quote:

Originally Posted by ChiTown

...

Maybe I don't ride hard enough.

Right .................

rideoregon · 06-20-2011, 01:19 PM

The OEM rear rotor is $271.99 plus $1.59 ea. for the one time use bolts. Galfer sells a rotor for the F8, part # DF763W, MSRP-- $139.00. Much more like it! I'll be ordering the Galfer rotor from the local Cycle Gear along with a set of Galfer pads.

rideoregon · 06-20-2011, 02:24 PM

Galfer misquoted the price. It's $186.00 not $139.00. Still better than $272.00 for the OEM.

Hayate · 11-19-2012, 03:00 PM

A friend of mine was surprised by the ridge on my rear rotor so mentioned I better get it measured. If my crappy old caliper is right and I'm reading it correctly I'm down to .133 inches, or 3.38mm. Way under spec eh? I just put my 5th set of rear pads on at 42,907 miles (2nd-4th, 7459, 18,200, 32,971 so about 10k each).

So I'm wondering a couple things...

First off a line of questions about rotor wear. So 4 sets of pads burnt 1.62mm of rear rotor and I was supposed to replace it after .50mm used? By my math that means a bit into the 2nd set of pads I'd be out of spec on the rotor? Like 15k miles and the rotor is done for? Is that normal? Can I do anything to prolong my next rotors life?

The other set relate to the 4.5mm minimum spec. Why is that the minimum? Is it because the thinner the rotor gets the less it is able to absorb and dispense heat or is it because you need the width to get full pressure from the caliper? I don't sense a lack of rear brake power and mine is way past that point (I can easily get the ABS to engage using only rear brake on dry pavement and a rear Metzler Tourance for instance).

I guess if I'm going to be replacing these things every 15k miles or anywhere in between that and my current 43k miles I'm not willing to pay what is it, $300? The Galfer option sounds better but what type of comparable wear factor will I get there? Are there other options?

I love riding this thing, but I'm getting a bit overwhelmed this last riding season with the expenses involved in maintaining it... and I'm even doing it all in my garage now :(

Hayate · 11-19-2012, 03:04 PM

Quote:

Originally Posted by rideoregon

The OEM rear rotor is $271.99 plus $1.59 ea. for the one time use bolts. Galfer sells a rotor for the F8, part # DF763W, MSRP-- $139.00. Much more like it! I'll be ordering the Galfer rotor from the local Cycle Gear along with a set of Galfer pads.

Are you sure that's the Galfer Roter for the 800gs? I just searched on it and found it on Amazon for $167 but plugging in BMW F800GS '09 it replied, this product does not fit. That and the pic shows only 4 bolt holes...

Guess I'll search some more?

... More research confirmed that DF763W is our rear rotor... at least the catalog http://galferusa.com/catalog/ says "763" for the rear rotor. I guess the pic on amazon is just a stock photo of a Galfer wave rotor. I'm not sure why the match tool on Amazon says it isn't compatible. I'm pretty sure I'll order one.

Best price seems to be Amazon for $167 with free shipping btw... I'll come back and update this if it works out.

Hamish71 · 11-19-2012, 05:49 PM

try www.metalgear.com.au

Reaver · 11-19-2012, 07:13 PM

A 2009 with only 12k miles on it? That's also a problem!

As I see it, there's three common ways to wear out a rear rotor. Normal use high mileage, lots of dirt/mud riding or you're a tail dragger. Riders who start out in the dirt tend to use the rear brakes a lot on the street. Now I'm not looking to start a "how to ride" thread nor am I saying I'm all that, but you really don't need your rear brake on the pavement. It has little effect anyway. My F8 has 45k kms on it with the original pads and rotor that's barely worn. It's been to Alaska and back so it's far from being a poser. The front brakes have two discs and four pads which are a lot more effective for stopping and wear better. Not saying your a bad rider but take note of how much you use the rear.

To answer another question, the rotors have a minimum spec for a reason. If the rotor is thin AND the pads are really worn then you run the risk of blowing a puck and possibly locking the wheel. Rotors are often run past the limit but with thick pads. Under 4 mm is a bit excessive though, not worth the risk but YMMV.

I've seen riders trade in their bike with shot rear brakes then bring their new bike (different model) shortly after and have the same complaint. Problem follows the rider.

Just sayin'.

06-16-2011, 06:56 PM	#1
rideoregon ^OP Adventurer Joined: Apr 2008 Location: Eugene, Oregon, USA Oddometer: 10	Rear Rotor Replacement? My 2009 F800 GS was in the shop today for a 12K mile checkup. I was told that my rear brake rotor was under minimum spec at 4.43 mm and should be replaced. The cost? $300 plus. I was none too thrilled to hear this and asked "how common is it for an F800 GS to need a new rear rotor at 12K miles?" The answer I got was vague. I decided not to have the work done. I want to gather more information and likely will replace the rotor myself possibly with an after market brand. Has anyone else had to replace their rotor this soon? I did a search and did not find discussion on this but surely this has come up. What are others experiencing with rear rotor wear/replacement? Any feedback is appreciated.

06-16-2011, 09:15 PM	#4
johngil Reseda, CA Joined: Jun 2007 Oddometer: 3,489	I'm at 4.6 - 4.7 on the brokeback beemer with just under 18,000 miles. I believe I'm on my fourth set of pads. Lots and lots of dirt and some mud. Pads were OEM, then Galfer black. Maybe a set of Galfer gold on now. I can't remember. __________________ http://johngil.whereamiriding.com

06-18-2011, 08:24 PM	#7
ScienceOfDirt U-Boat Rider Joined: May 2010 Location: Snowbelt/Rustbelt of Northeast Ohio Oddometer: 1,494	What is the minimum spec? __________________ Friend: That was some trail shortcut. Me: Yep. See how fast we got lost.

06-18-2011, 09:04 PM	#8
itsatdm NoMoTDM still Gary Joined: Jun 2004 Location: Columbia, Ca. Oddometer: 3,707	New is 5mm. wear limit is 4.5mm __________________ BMW Motorrad USA customer service: "We make superior motorcycles and continue to improve them."

11-19-2012, 03:00 PM	#12
Hayate ADV Monkey Joined: Aug 2010 Location: Slabland Hopkins MN Oddometer: 53	A friend of mine was surprised by the ridge on my rear rotor so mentioned I better get it measured. If my crappy old caliper is right and I'm reading it correctly I'm down to .133 inches, or 3.38mm. Way under spec eh? I just put my 5th set of rear pads on at 42,907 miles (2nd-4th, 7459, 18,200, 32,971 so about 10k each). So I'm wondering a couple things... First off a line of questions about rotor wear. So 4 sets of pads burnt 1.62mm of rear rotor and I was supposed to replace it after .50mm used? By my math that means a bit into the 2nd set of pads I'd be out of spec on the rotor? Like 15k miles and the rotor is done for? Is that normal? Can I do anything to prolong my next rotors life? The other set relate to the 4.5mm minimum spec. Why is that the minimum? Is it because the thinner the rotor gets the less it is able to absorb and dispense heat or is it because you need the width to get full pressure from the caliper? I don't sense a lack of rear brake power and mine is way past that point (I can easily get the ABS to engage using only rear brake on dry pavement and a rear Metzler Tourance for instance). I guess if I'm going to be replacing these things every 15k miles or anywhere in between that and my current 43k miles I'm not willing to pay what is it, $300? The Galfer option sounds better but what type of comparable wear factor will I get there? Are there other options? I love riding this thing, but I'm getting a bit overwhelmed this last riding season with the expenses involved in maintaining it... and I'm even doing it all in my garage now :( __________________ ad·ven·ture 1.an exciting or very unusual experience. What a great 40,000 mile adventure on the trusty F800GS. Looking forward to the next 40k. Minnesota Parallel "Twin" Cities GS Riders Daniel Betlock Adventure Rider

06-16-2011, 08:27 PM	#2
Bayner Beastly Adventurer Joined: Mar 2008 Location: Penticton, BC Oddometer: 1,237	How many sets of pads have you gone through? If it's more than one, I would say it's at least plausible it needs replacing.

06-17-2011, 05:33 AM	#5
JRWooden Beastly Adventurer Joined: Jul 2008 Location: The great state of confusion Oddometer: 3,438	I'm still on the original set @ 17K miles, but they will be gone before much longer. I have a set of Galfer Greens ready to slap on, I bought the greens as the pkg said the greens were the easiest on the rotors. I've got 4.8 for thickness right now....

06-18-2011, 05:52 PM	#6
rideoregon ^OP Adventurer Joined: Apr 2008 Location: Eugene, Oregon, USA Oddometer: 10	I'm on my second pair of rear break pads having replaced the first set after 10.5K miles. I don't drag the brake. What I'm curious to know is what is typical mileage for replacing the rear rotor on the F8?

06-20-2011, 01:19 PM	#10
rideoregon ^OP Adventurer Joined: Apr 2008 Location: Eugene, Oregon, USA Oddometer: 10	The OEM rear rotor is $271.99 plus $1.59 ea. for the one time use bolts. Galfer sells a rotor for the F8, part # DF763W, MSRP-- $139.00. Much more like it! I'll be ordering the Galfer rotor from the local Cycle Gear along with a set of Galfer pads.

06-20-2011, 02:24 PM	#11
rideoregon ^OP Adventurer Joined: Apr 2008 Location: Eugene, Oregon, USA Oddometer: 10	Galfer misquoted the price. It's $186.00 not $139.00. Still better than $272.00 for the OEM.

11-19-2012, 05:49 PM	#14
Hamish71 Gnarly Adventurer Joined: Mar 2011 Location: Australia Oddometer: 100	try www.metalgear.com.au

11-19-2012, 07:13 PM	#15
Reaver Amusing Myself Again Joined: Aug 2008 Location: In Transition, Ontario Oddometer: 584	A 2009 with only 12k miles on it? That's also a problem! As I see it, there's three common ways to wear out a rear rotor. Normal use high mileage, lots of dirt/mud riding or you're a tail dragger. Riders who start out in the dirt tend to use the rear brakes a lot on the street. Now I'm not looking to start a "how to ride" thread nor am I saying I'm all that, but you really don't need your rear brake on the pavement. It has little effect anyway. My F8 has 45k kms on it with the original pads and rotor that's barely worn. It's been to Alaska and back so it's far from being a poser. The front brakes have two discs and four pads which are a lot more effective for stopping and wear better. Not saying your a bad rider but take note of how much you use the rear. To answer another question, the rotors have a minimum spec for a reason. If the rotor is thin AND the pads are really worn then you run the risk of blowing a puck and possibly locking the wheel. Rotors are often run past the limit but with thick pads. Under 4 mm is a bit excessive though, not worth the risk but YMMV. I've seen riders trade in their bike with shot rear brakes then bring their new bike (different model) shortly after and have the same complaint. Problem follows the rider. Just sayin'. __________________ Life is a rollercoaster........and I'm not strapped in! Reaver screwed with this post 11-19-2012 at 07:18 PM

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