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Education We Like to Ride Bicycles

Discussion in 'General' started by RTT, 8 May 2008.

  1. Malvolio

    Malvolio .

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    Let me be the first to say: no.

    From the first disk-braking system (for a bike) right up to the most bleeding-edge technology out there now, pad retraction is handled almost exclusively by one thing: a spring. Try ripping the spring out of your master-cylinder and see how well they work! Rotational force won't do much, as the pads retract in entirely the wrong direction for the rotor to have much effect on their retraction, whereas if the opposite were true then you'd be constantly fighting rotational forces through your lever blade, making braking at high-speed a task only suited for the burliest of loggers!

    Here is a diagram I prepared earlier:

    Code:
        |        ^ || ^        |
        |        ^ || ^        |
        |<--     ^ || ^     -->|
        |        ^ || ^        |
        |        ^ || ^        |
    (pad)        (rotor)       (pad)
    
    Arrows denote direction of primary movement during pad retraction and brake rotor operation.
    See how they move in two different directions? If the rotor kept the pads away, one would expect pad retraction to be 45 degrees from the reference rotational direction. This would force them away from the braking surface with minimal drag, but would require a herculean effort to come to a stop due to the rotor forever fighting to throw the pads back into their bore.

    To the topic at hand: could be any number of things. Rotor/pad contamination, poor rotor quality, poor selection of pad compound to the conditions, improper break-in period/technique, too much fudge on the braking surface... really just about anything causes minor vibration in a high-friction environment, which leads to the audible feedback you find yourself bothered with now. If they were my brakes I'd first resurface the rotor (take about an 80 to 100grit piece of sand paper and sand the surface quite well without taking too much material off; spray the rotor down rather well with Brake and Parts cleaner/rubbing alcohol; burn off the residue with a blow-torch or lighter), check to see if the pads are contaminated (discolouration that doesn't go away after buffing down the surface layer of the pad) or if you have a leak of hydraulic fluid, then either resurface the pads (same as for the rotor, but be super gentle with the fire, as they'll sometimes go right up in flames) or replace them. If you've a leak, then rebuild your calliper (or get a shop to do it). Though as the brake at hand is a Shimano, you may be looking at just buying a new calliper.

    If all this doesn't make a difference, then I'd try a new rotor. Believe it or not but rotor design/material does make a difference in noise/heat. Grab yourself an Avid G3CS and a new set of pads, follow proper break-in procedure (Avid and Shimano have great write-ups on how to do this - google is your friend), and you'll be set.
     
    Mik3yB @ CCL likes this.
  2. Jamie

    Jamie ex-Bit-Tech code junkie

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    Sintered usually squeel, I recommend a2z blue organic pads, try wooly hat shop.
     
  3. russell16688

    russell16688 New Member

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    For anyone commuting short distances have you ever considered a fixed wheel bike? not ina trendy unrideable fashion but in a useable, cost and time efficient way?
    Recently set one up for riding to and from uni and its been brillaint, well once i got used to the fixed wheel part. great stopping with a front brake on and nothing to break or for chavs to kick in.
    Ill try and post some pics.
     
    Mik3yB @ CCL likes this.
  4. Bufo802

    Bufo802 New Member

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    Would definitely like to do that if I can get one cheap enough (and the old bike I use currently breaks), where did you get yours from?
     
  5. Mik3yB @ CCL

    Mik3yB @ CCL Everything is not going to be OK

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    Thanks for the input guys. I've ordered a set of cheap Kevlar ones at £7 a pair.
    I'll see if the combination of pads and sanded rotors helps - I think it may do. They also need bleeding too, I've not done it for a while.

    To be honest, I've had this set of brakes for years now and the they are starting to look like sh*t. The screws on the mounts have corroded a lot and they are just getting old.

    Most of the newer brakes at around £60 a unit look a lot smaller and lighter. Was looking at some Juicy 3's on CRC which get decent reviews - might pick some up in the next few months.

    @ Russell16688 I've been tempted to convert my bike into a singlespeed or buy a new bike as it's almost exclusively used for commuting now. I ride to CCL and back everyday which is over 50 miles a week.
     
  6. russell16688

    russell16688 New Member

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    @Bufo802 I slowly acquired all the parts i needed and then converted a 10_speed road chainset using bolt shims and then used an 8speed chain.
    The frame i got was a tifosi pista frame. Alu and light and cheapish but on ebay there are some serisouly cheap frame if you want it to commute on.
    I then had the rear wheel built up and spent around £70-80 on this so it would last, as it gets a lot of stress from the hub.
    Alternatively you could get a Specialized langster/giant Bowry which are fairly cheap and decent.
     
  7. Mik3yB @ CCL

    Mik3yB @ CCL Everything is not going to be OK

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    Sorted my brakes - ta!

    Right, why is it so difficult to choose the colour of an On-One 456 Summer Season Frame?
    Do I go Orange, Lime Green or Royal Blue (or even Pink?!?)

    Ta!!
     
  8. soopahfly

    soopahfly New Member

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    Easy task. Raw :D
     
  9. FIBRE+

    FIBRE+ Active Member

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    The green is nice and wild but you'll actually melt if you get too close to it . I like the orange, colourful and bright but won't make you go blind :thumb:.

    I want the Ti 456 Frame :hip:
     
  10. Cookie Monster

    Cookie Monster Well-Known Member

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    Get the Green, I had my Giant STP (which I sold :( and is now back on ebay) powder coated Kawasaki Green. Looked amazing clean with white forks and bar / stem combo.

    edit, image added :D

    [​IMG]
     
    Last edited: 16 Feb 2011
  11. wst

    wst Active Member

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    That thing's going to cause cars to crash and pedestrians to walk into lampposts. Nice!

    I haven't ridden for ages, my eyes water in a mild wind at this temperature :( and I don't want to learn to ride with clipless when unable to see where I'm going!
     
  12. Cookie Monster

    Cookie Monster Well-Known Member

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    It was a sexy bike when I finished building it up, gutted I sold it though :(
     
  13. bagman

    bagman Well-Known Member

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  14. jhanlon303

    jhanlon303 The Keeper of History

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    My Shwinn 26" cruiser has GOT to made into Pee Wee Herman's bike before I die.

    [​IMG]

    into this:

    [​IMG]
     
  15. Gryphon

    Gryphon New Member

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    My dad just bought this:

    [​IMG]

    I got a short ride on it while he was down in southampton. Feels AMAZING. I think i need to either replace pretty much everything on my GT or get a new bike... I certainly need a new chain and cassette, and maybe new forks too :/
     
  16. Mik3yB @ CCL

    Mik3yB @ CCL Everything is not going to be OK

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    I'm swaying towards the Lime Green mate definitely.
    On-One also do a glow in the dark paintjob which looks awesome in the dark but looks kind of washed out in the daylight...

    Current components might not match green but I can soon sort that though!
     
  17. Jamie

    Jamie ex-Bit-Tech code junkie

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    Green looks great, I'm really loving my new green holeshot.
     
  18. Jipa

    Jipa Avoiding the "I guess.." since 2004

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    Turns out also the cassette is shot. How much does it about take time(cost) to get it changed? I don't have the tools to do that myself.. Also thinking if I should just go single speed. It's not like I ride up hill anyway and on the flat I barely ever use anything but "4". (8-speed cassette, dirt bike)
     
  19. Cookie Monster

    Cookie Monster Well-Known Member

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    A bike shop should be able to change a cassette in a matter of minutes, depending on the shop and how happy the mechanic is that day should only cost you a few of your finnish pennies.

    Something to think about though is your chain is probably worn so it may need replacing too depending on how many miles it has done, as your chain wears it streches making the gaps between the teeth on the cassette larger, when putting on a new cassette the gaps are not as wide as your chain is now expecting so your chain will now slip over the top of 1 or 2 teeth per revolutiuon of the cassette.

    This can also sometimes mean replacing your favourite chainring or the whole chainset.

    edit, one more thing

    Changing to single speed can be a pain due to vertical dropouts which I guess your bike will have (being a geared bike), in order to get your chain tight you may need to run a chain tensioner.
     
  20. Jipa

    Jipa Avoiding the "I guess.." since 2004

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    Oh indeed didn't think about the drop-outs. Thanks for the heads-up!

    And the story is that I wrecked the front sprocket, changed it, then changed the chain to match and hoped the cassette wasn't too worn, but it really is, so I'll be running all new drive train when I get the new cassette in place.

    Oh and a small rant:

    No wonder Finns seem to buy EVERYTHING hobby-related abroad when the sites of the Finnish stores blow so massively! Can't find any prices for cassettes on the local stores. Chances are if I walk to the store with the rim and ask them to fit a suitable cassette, they don't have one, need to order it from somewhere and completely rip me off in the process. Sigh.
     

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