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Brake Master

Discussion in 'Parts for Sale' started by 905, Apr 21, 2020.

  1. 905

    905 Active Member

    What is the best brake master you can buy for a super bike $400 usd or under? I have tried the rcs 19 and it’s my least favourite of masters that I have used.


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  2. chrisplm

    chrisplm Well-Known Member

    Regardless of brand, making sure that your running the correct size is key. RCS19 is super popular, but many of the newer bikes run Calipers with smaller pistons that actually require the RCS17. I've seen guys running 19s where they should have had 17s and they wonder why their brake lever has no "feel"
     
  3. 905

    905 Active Member

    Any idea what would be the correct size for a 2020 r1m? Stock callipers


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  4. Lando

    Lando Well-Known Member

    If the R1M has 30mm pistons* then the RCS19 will have less brake lever travel (less "feel")
    *I have not confirmed the 2020 R1M caliper piston size is 30mm - but here is what a quick search came up with...

    HustleHard sells the RCS17, with the following explanation -"The 17mm version is designed to respond optimally to the needs of a growing number of motorbikes using brake calipers with 30 mm diameter pistons: Ducati Panigale and Monster 1200, Kawasaki H2 and ZX10R, YAMAHA R1 and R6, KTM Superduke and MV Agusta F4RR."

    https://hhrperformance.com/i-316358...-rcs-corsa-corta-long-lever-radial-front.html
     
  5. 905

    905 Active Member

    There are 2 different size pistons in the calliper. A 30mm and a 27mm not sure if that changes anything.


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  6. rice r0cket

    rice r0cket Well-Known Member

    Try the Galespeeds. Smaller Japanese brand, but seem to be top quality. I like mine, I think they're pretty well liked for those who have tried them.

    The VRC series is nice, either 17 or 16 would be appropriate. They provide a hydraulic/leverage ratio calculator which you can plug your numbers into:

    http://www.acv.co.jp/galespeed_en/01_master_ratio_d.html


    https://www.superbikeunlimited.com/galespeed-vrc-variable-lever-ratio-control-master-cylinder
    https://www.gravesport.com/products/galespeed-vrc-variable-lever-ratio-control-mastercylinders.html
     
    Last edited: Apr 21, 2020
  7. 2blueYam

    2blueYam Track Day Addict

    I am quite happy with my Magura HC1 on my 2003 R1, so you could give it a try. The recommend size is 18mm for the current R1 and R1M.
     
  8. 905

    905 Active Member

    So where is it written what size you should use for the piston is there a chart of some sort?


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  9. 2blueYam

    2blueYam Track Day Addict

    905 likes this.
  10. Lando

    Lando Well-Known Member

    Here's simplified breakdown of the ratios between TOTAL caliper piston area and MC piston area. -- which would suggest that the R1M uses a 16mm MC piston (Please verify!).
    Feel free to check around, but I think most of us like 25-28 ratios, so I've highlighted those options.
    Ratio of 18 feels like a BRICK (very little lever travel)
    Ratio of 36 feels like a SPONGE (lever might pull to the grip before providing any braking)
    Remember that master cylinders with fulcrum/pivot adjustments (Brembo RCS, Accossato PRS, etc) can help to dial in the "feel", or lever travel, a rider prefers.

    I've highlighted the choice I would make (Green + BOLD), given the different caliper/MC options out there :)
    upload_2020-4-21_13-54-14.png
     
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  11. 905

    905 Active Member

    Perfect thanks. That’s what I’ve been looking for.


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  12. rice r0cket

    rice r0cket Well-Known Member

    How about lever ratios though, since we're all buying adjustable lever ratio MCs now? :) Lever ratio is separate from the pre-travel adjustment and changes the mechanical advantage, not just the engagement point.

    That's why I linked the calculator from Galespeed, it seems to account for all the variables.
     
  13. 905

    905 Active Member

    Just when I thought it was simple I put in the piston dimensions and now I’m lost again


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  14. warclok

    warclok Well-Known Member

    I’m running a 19x18 GP master with GP calipers that measure 40mm pistons all around. What says that chart for me...[emoji23]


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  15. 905

    905 Active Member

    So by my calculations on the gale speed chart ur full of crap lol insufficient apparently


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  16. warclok

    warclok Well-Known Member

    I was being serious, not full of crap, see below...[emoji18]

    [​IMG]


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  17. 905

    905 Active Member

    Lol I was kidding but the chart broke when I punched in 40mm pistons. Are you sure they aren’t 32mm?


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  18. warclok

    warclok Well-Known Member

    [emoji23][emoji23][emoji23]

    Positive, 40MM vented on one side and symmetrical...

    [​IMG]

    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]


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  19. 905

    905 Active Member

    Those are insane!


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    warclok likes this.
  20. tgold

    tgold Well-Known Member

    I've been thinking about this because I'm trying to figure out what size MC to use for my lightweight project bike that will use one Yamaha "blue dot" four piston caliper. I think the piston sizes are 30mm and 28mm, but the original MC for dual calipers is a 14mm bore. Seems quite small so I'm not sure what bore size for the single caliper. Aside from that confusion, it just occurred to me that the surface area of the pads, the coefficient of friction of the pads, and the rotor diameter are all factors that seem like they should play into MC bore selection as well but I've never hear anybody mention those factors before.
     

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