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Thread: Standard front caliper piston size

  1. 7th January 2021, 11:34 PM #1
    Biker
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    Standard front caliper piston size

    Hi all

    Does anyone know what dimensions the stock front caliper pistons are (2009-2018).

    I'm getting pretty sick of mine locking up in winter so was looking at trying out some titanium pistons to see if that helps
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  2. 8th January 2021, 06:38 AM #2
    JamieMac
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    Re: Standard front caliper piston size

    To be honest, it’s not corrosion on the pistons that seize the calipers, it’s corrosion in the grooves the seals sit in that seize them. It forces the seals against the pistons.
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  3. 8th January 2021, 07:40 AM #3
    roadrunner
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    Re: Standard front caliper piston size

    Quote Originally Posted by JamieMac View Post
    To be honest, it’s not corrosion on the pistons that seize the calipers, it’s corrosion in the grooves the seals sit in that seize them. It forces the seals against the pistons.
    +1. If you dismantle the callipers and clean out the corrosion from the seal grooves, that should sort it.
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  4. 8th January 2021, 11:30 AM #4
    Biker
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    Re: Standard front caliper piston size

    But But But... Titanium pistons!!!!



    Ok cool... when I eventually get some downtime I will strip them and give them a clean
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  6. 8th January 2021, 01:40 PM #5
    alex
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    Re: Standard front caliper piston size

    Alpha Racing have the right sized pistons in Ti. I think they are 32mm but I'd need to check.

    Edit checked: height = 19,5 mm, D = 34 mm

    https://shop.alpharacing.com/shop/in...92&language=en
    Last edited by alex; 8th January 2021 at 02:16 PM.
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  7. 9th January 2021, 03:47 AM #6
    Biker
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    Re: Standard front caliper piston size

    Thanks Alex

    34mm...

    Was thinking of maybe upgrading the MC too (lurking in the VRC thread awaiting more details )...
    Last edited by Biker; 9th January 2021 at 03:50 AM.
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  8. 9th January 2021, 11:19 AM #7
    alex
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    Re: Standard front caliper piston size

    I emailed a UK firm that me M4 Brembo Ti pistons yesterday. They may be significantly cheaper than Alpha. Waiting hear back...

    Sent from my SM-G965F using Tapatalk
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  10. 9th January 2021, 11:31 AM #8
    Katie
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    Re: Standard front caliper piston size

    Quote Originally Posted by Biker View Post
    But But But... Titanium pistons!!!!


    Made me laugh
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  11. 9th January 2021, 11:59 AM #9
    bananaman
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    Re: Standard front caliper piston size

    Seems to be a common problem whatever you do. Cleaned mine numerous times, eventually bought complete kit and fitted to spotless calipers. Within a couple of weeks the problem was back. I found that at cold they would bind, immediately after a ride they were free....
    Speed doesnt kill, its how fast you stop.......
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  13. 9th January 2021, 11:45 PM #10
    Biker
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    Re: Standard front caliper piston size

    This is my experience as well, hence the incentive to try the titanium pistons... however... if the problem presents far more frequently when they are cold fitting titanium pistons might just make the problem worse!

    How about those who have fitted the M4 / M50 calipers?

    Same issue or problem solved?
    Last edited by Biker; 9th January 2021 at 11:45 PM.
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