CityCyclingEdinburgh Forum » Questions/Support/Help

Regarding Hydraulics

(11 posts)
  • Started 9 years ago by Uberuce
  • Latest reply from eastsidebikes
  • This topic is not resolved

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  1. Uberuce
    Member

    Got another slow puncture overnight on disco floofy, which makes me very inclined to change back to the slicks.

    Before I do that I want to sound out two notes of caution in my head that may be urban myths:

    - Is it true that putting a hydro-braked bike upside down is a Really Bad Thing and mean the brakes need bled again(or some other wizardry that means a trip to LBS)?

    - Do I need to put a spacer between the pads, and if so what?

    I can just about imagine me being sensible enough not to hammer the brake lever while the front wheel's off, but why take chances?

    Posted 9 years ago #

  2. I were right about that saddle
    Member

    On 1 - no (but Shimano brakes come with a disclaimer that they may not operate properly when the bike is upside down).

    On 2 - it is wise but not necessary. Bit of wood, child's finger (if clean) etc etc. I have the Shimano SLX official spacer if that's any use.

    Posted 9 years ago #

  3. Roibeard
    Member

    You may find the brakes need to be primed once the bike is back on its wheels.

    When I've inverted a bike (Avid Juicy 3 brakes), shaken it liberally for 20 minutes, and then tried to ride it, the brakes have been very spongy to start with - this could have just been the calipers been shaken back a bit and needing to close up before braking effectively.

    In any case, repeated brake/release cycles sorted it out.

    Robert

    Posted 9 years ago #

  4. Roibeard
    Member

    BTW, if you do forget the spacer, it's possible to pry the pistons apart and back home again with a bit of care.

    Robert
    Yep, speaking from experience...

    Posted 9 years ago #

  5. CycleCommute.CC
    Member

    What's the spacer for and where does it go?

    Posted 9 years ago #

  6. Arellcat
    Moderator

    The spacer simply takes the place of the disc to prevent the pistons from being inadvertently* pushed all the way out of the caliper.

    I've inverted my Hope Mini brakes many times. If the brake is properly bled and the master cylinder has good seals there should be no movement of air to affect the diaphragm and upset the adjustment.

    * Or advertently. Sometimes if the pistons are old and a bit corroded, this is actually the easiest and messiest way to remove them.

    Posted 9 years ago #

  7. neddie
    Member

    Is it true that putting a hydro-braked bike upside down is a Really Bad Thing and mean the brakes need bled again

    Well my mountain bike has been upside down with me on it, and the hydro brakes were no worse for wear. In fact the bike was not even scratched, it was me that came off worst.

    Posted 9 years ago #

  8. Snowy
    Member

    +1 eddie_h You know it's been a good stack when you sit up and can't see your bike anywhere within 10 yards.

    My mtb is upside down frequently for maintenance and the brakes just require a couple of pulls to be back to normal.

    Posted 9 years ago #

  9. neddie
    Member

    @Snowy

    LOL.

    Yeah, the bike ended up a good way down the hill and I sat up and went "owww, owwww, owwww, that really hurts" (Hot Fuzz style). I thought the bike was going to be completely buckled, but not in the slightest. My mate then informed me "Don't worry, they're more or less indestructible"

    Posted 9 years ago #

  10. I were right about that saddle
    Member

    @Snowy

    A really good stack is when you sit up, look round and the bike comes tumbling down the hill and hits you in the face. Happened to me once when I accidentally engaged in a trail beyond my skills or courage. Cable brakes though, so no worries.

    Posted 9 years ago #

  11. eastsidebikes
    Member

    You may find the brakes need to be primed once the bike is back on its wheels.

    When I've inverted a bike (Avid Juicy 3 brakes), shaken it liberally for 20 minutes, and then tried to ride it, the brakes have been very spongy to start with - this could have just been the calipers been shaken back a bit and needing to close up before braking effectively.

    In any case, repeated brake/release cycles sorted it out.

    Robert

    This is because there was air in your lever reservoir; it floated up to the caliper/hose and therefore into the circuit when you inverted the bike. It eventually floated back up to the lever and out if the circuit when it was righted/used.

    Generally a bad idea to put the bike upside down anyway - it'll scratch the stem/shifters. Put it on it's side. It can't fall over if it's already on the ground :-)

    Posted 9 years ago #

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