F800GS front brake rotors.

Discussion in 'Parallel Universe' started by The Griz, Feb 25, 2009.

  1. señormoto

    señormoto Supermoto Abuser

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    It all depends what priority you put on the moto I guess. That and income level helps too. For a lot of people a $300 rotor isn't much money (one to two hours or less of work for most lawyers, engineers, c-level corp, doctors, etc)
    #41
  2. Motoriley

    Motoriley Even my posing is virtual

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    I have two sets of wheels and have also bent rotors...they are a wear item.


    #42
  3. Hicks

    Hicks der Überluber

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    from czech Twalcom... the dealer is my friend.

    Just before they raised the prices last year...
    #43
  4. Hicks

    Hicks der Überluber

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    +1
    #44
  5. Tryagain

    Tryagain n00b

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    My F800GS, like many others, has an annoying rattle on washboard roads. The front brake rotor is loose in the radial direction and allows the rotor to strike its mounting hub. The caliper appears to need the axial play in the rotor but not the radial play. Four leaf springs harvested from old window screens were modified and slipped into the axial gap between the rotor and its hub. Each rotor gets two springs located about 90 degrees apart to stop the free play. The rotors can still move axially to self align with the caliper.

    I'll get some new springs and make a cleaner installation but the setup pictured works fine and now has about 1000 miles on it. The bike is much nicer to ride when it sounds good. Of course you modify your brakes at your own risk.

    The springs were lifted out of the top edge of screens for casement windows. The ends have tabs that are bent down; these need to be straightened to fit into the rotor/hub gap and slide between the end flanges on the big rivit that holds the rotor in place. The spring needs to be cut to length. I used about 1.875 inches of length but less may work. The springs can be snapped in by hand, needle nose pliers can help. If you try this let us all know how it works. Thanks.

    One of the two springs on a rotor.
    [​IMG]

    [​IMG]

    One spring ready for use.
    [​IMG]
    #45
  6. bxr140

    bxr140 Flame Bait

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    ...but the thermal expansion of the rotor assembly does need [at least some of] that radial play.

    IMHO, it's not worth a warped (or worst case, cracked) rotor just because it makes a little bit of noise. If it really bothers you, do the zip tie thing.
    #46
  7. Indy Unlimited

    Indy Unlimited Long timer

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    Just ride more dirt and the play is tightened right up on the floating disc.:lol3
    #47
  8. Tryagain

    Tryagain n00b

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    Packing the brakes discs with dirt might reduce the rattle but its not a vey "clean" solution. As for possible thermal expansion troubles, I believe the inside diameter of the brake disc gets larger when it is hot. That means increased clearance to the hub since the hub is cooler. Those who are tired of the rattle might consider the little springs I described above. They're working fine for me.
    #48
  9. bxr140

    bxr140 Flame Bait

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    Except that the carrier material expands significantly faster than the rotor material. So then its a matter of how much cooler the carrier is than the rotor.

    I'm not saying the world is going to end if you stuff something from a screen window in your rotor, I'm just not as willing to accept the no-so-technical dismissal that "its probably okay"...

    :freaky
    #49
  10. MotoLara

    MotoLara ADV rider wannabe

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    Interesting... how many kms on your bike @ the time of warranty replacement? are you located in N.America?
    My floating disc rotors are more like 'dancing' disc rotors.. VERY VERY lose ... and my local dealer said: $500 a piece (That's a total of $2,000 for both my F8GSs that have the same problem)
    :ear
    #50
  11. wizze

    wizze Wizze = Wise

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    Thought I would share some info. I just put Braking front rotors on my 2nd wheel set. I got them from www.pureperformancecycles.com Talked to Dan after ordering the EBC disks. He recommended the Braking. I just put them on and went for a spin around the block. Everything felt good and stopped well but they still need broken in of course.
    #51
  12. MotoLara

    MotoLara ADV rider wannabe

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    +1
    great info thx!
    #52
  13. Rider 101

    Rider 101 Highly paid idiot

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    #53
  14. Reaver

    Reaver Outta Here

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    Ad says it's for a set. Aluminum centre and stainless rotor? Sounds like they'll get sloppy with wear.
    #54
  15. Snowy

    Snowy Long timer

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    It cost me $180 for a rear rotor. I have only one front rotor on the Showa front end. I've already ruined one because the floating center is too worn. The 2nd isn't far off. It makes a hell of a lot of noise when they go. I've gone through 3 sets of front pads and about 7 sets of rear pads.

    But with my Showa front end I can run a aftermarket wheel for a Suzuki RMZ, with a 320mm disc and a 4 piston caliper. All I need is the $1200 of disposable income to pay for it.

    So do tell me of expensive rotor options. For now it's far cheaper to just keep putting new standard rotors on the front.
    #55
  16. jttele

    jttele Been here awhile

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    Isn't the stock rotor aluminum center with stainless rotor? I'm pretty sure on my 2011 it is anyway.
    #56
  17. Reaver

    Reaver Outta Here

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    I've just moved and may have gotten my aluminum magnets mixed up with the iron, but they all stick to the centre of the front discs so my experiment was ruined.

    Sorry.
    #57
  18. Singletrack_mind

    Singletrack_mind Cave Man

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    All floating rotors wear, but based on my own personal experience, these OEM rotors have worn out surprisingly quickly. And when I say "worn out", the rotors are fine, plenty of thickness and nice & straight, but the carriers and the buttons have developed a dangerous amount of play. More precisely, the rotor on the right side has reached a dangerous state, the rotor on the left is no where near as bad. I've shown this to the mechanics at my dealer and they are perplexed, "never seen that before", and none of us can figure out why one side would wear more than the other. At 46K miles, this is what I'm talking about:
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    BMW does not offer the buttons separately from the rotor, or I would have tried replacing them a year ago or so. At this point the carrier is so worn that would be a waste of time anyway. The new rotors are right around $500 apiece from BMW, which is clearly ridiculous, so I will certainly go after-market. I spent some time this afternoon looking for all my options, and would be interested if anyone can provide feedback on any of them, or inform me if I've missed one. Here's the list, in the order I happened to think of the companies. Yellow highlights mean the company does offer rotors for the F800GS:

    Beringer: doesn’t seem to have any rotors at all, brake parts shown as fitting my GS look suspiciously like they’d better fit the RR1000.

    Galfer: Yes, full floating wave rotors, not pictures on website. #DF664CEWD is right side, #DF664CEWI is left. $338 apiece.

    EBC floating V-Rotors: Maybe someday, but not now. Their product catalog is sorted by rotor number rather than by motorcycle and there are more than 100 pages of applications. I called them and the answer was "To be announced", which I am told means they will release rotors for the F800GS at some point, but don't have them as of 6/27/16.

    SBS seems to make only pads.

    Ferodo does not offer disks for this bike.

    Brembo Yes: makes several lines, it appears the only one in which they have a disk for the GS800 is “Seri Oro” which is their “replacement” level line, but not “OEM replacement” so might or might not be identical to what they provide to BMW as original equipment. product code # 78.B408.96

    DP only makes pads.

    Nissin seems to make calipers and levers, but not pads or disks

    Hayes seems to only offer calipers and levers for motorcycles, not disks

    Bike Master, available through Bike Bandit, $108 apiece. Look like very conventional drilled floating rotors, no wave or petal, made in Spain by un-named major manufacturer. WRONG! The website claims to have rotors that fit the front wheel of the GS, but when ordered what I got was not even a floating rotor, it fit F800 models with cast wheels. Bike Bandit looked into this when I notified them and they told me they were going to correct the website. this was 6/30/16. I knew the price was too good to be true . . .

    Brake Tech has some problem with their server host, their site is being blocked.

    Performance Machine: useless bling.

    Braking: Yes. Wide range of disk products: “Batfly” is their wave rotor with surface cut-outs instead of drilling. They make a “challenge” level (better than OEM, but not race) Batfly rotor for the GS800: # BY102L for the left and # BY102R for the right, $326 apiece. There is also a standard-looking drilled round floating disk on a steel carrier, # RL7006, $200 apiece, bi-directional.

    Lucas: Yes, available through Wunderlich America, look like very conventional round cross-drilled floating rotors, $350 apiece, part number 7882566

    I'll come back and let y'all know which ones I choose and how I like them once I get them.
    #58
  19. Rider 101

    Rider 101 Highly paid idiot

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    Having a laugh
  20. Loutre

    Loutre Cosmopolitan Adv

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    those might be the rotors I just bought :lol3
    #60