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Disc Brake Noob – Tips Please!

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  • August 13, 2018 at 2:34 pm #28829
    ibr17xvii

    Just got a disc brake road bike for the 1st time so please be gentle!

    In the process of setting it up & pretty much every time I have the wheel off I’m getting rub. Is that just the way it is with disc brakes?

    I’ve read about undoing the 2 bolts, pressing on the lever to move the calipers & then do up the bolts again whilst the lever is still pressed to centre them but seems a faff to have to do that every time.

    Wondered if maybe I’m not reinserting the wheel correctly as it does seem to take me a couple of goes to get the hang of it. When I’m trying to line up the rotor in the caliper I’m finding it quite difficult so maybe I’m moving the pads / calipers then when I’m fiddling around? Not even attempted the back wheel yet Think that will staying on permanently at this rate!

    Any tips on wheel replacement, centreing the calipers or any disc brake stuff in general greatly appreciated!

     

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  • August 15, 2018 at 7:56 am #925035
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    hawkinspeter
    ibr17xvii wrote:
    jterrier wrote:
    Given that it is hydro with thru axles, its only down to caliper position. So its fixable by loosening the fixing bolts and making sure the gap either side of the rotor is the same. Put a piece of white paper behind it to help.

    So stand at the front of the bike & place a white piece of paper behind the calipers to eyeball the gap & then tighten the bolts? Good idea, like the sound of that.

    Thought maybe I was tightening the fixing bolts too much & pads were moving a little. Either way I must’ve loosened & tightened those bolts a dozen times before it stopped rubbing & not sure what I did differently when it worked all of a sudden.

    It’s much easier to see the gap with a white background and you need to get your head in just the right place to easily see the gaps as they’re usually around 1mm or so.

    I find it tricky to tighten up the bolts without the caliper moving, so I usually hold the caliper steady whilst putting just a little tension on the bolts. Once both bolts have a little tension, you can then tighten them up properly (don’t forget to tighten the bolts – I use a torque wrench to make sure they’re up to 5Nm).

    Once the caliper is aligned nicely, you shouldn’t have much of an issue with taking out the wheel and replacing it. I’m always removing the wheels when cleaning the bike and I don’t need to readjust the calipers for that.

    August 15, 2018 at 7:15 am #925033
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    ibr17xvii

    jterrier wrote:

    jterrier wrote:
    Given that it is hydro with thru axles, its only down to caliper position. So its fixable by loosening the fixing bolts and making sure the gap either side of the rotor is the same. Put a piece of white paper behind it to help.

    So stand at the front of the bike & place a white piece of paper behind the calipers to eyeball the gap & then tighten the bolts? Good idea, like the sound of that.

    Thought maybe I was tightening the fixing bolts too much & pads were moving a little. Either way I must’ve loosened & tightened those bolts a dozen times before it stopped rubbing & not sure what I did differently when it worked all of a sudden.

    August 15, 2018 at 6:38 am #925031
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    Jimthebikeguy.com

    Given that it is hydro with
    Given that it is hydro with thru axles, its only down to caliper position. So its fixable by loosening the fixing bolts and making sure the gap either side of the rotor is the same. Put a piece of white paper behind it to help.

    August 15, 2018 at 5:12 am #925029
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    ibr17xvii

    CXR94Di2 wrote:

    CXR94Di2 wrote:
    ibr17xvii wrote:

    Mungecrundle wrote:
    If hydraulic, they just sort themselves out.

    So if they are only rubbing a little best to leave it & as they are self centreing they will get back to how it should be?

    With anything mechanical and the reasonably close pad clearance. If you remove wheel, sometimes a minor tweak is required. Loosen bolts, so caliper is wobbly, apply brake lever and hold, tighten bolts. This should work in 95% of occasion. If doesn’t, lossen again and this time align by looking down the side of rotor, there should be a small even clearance from each pad. Carefully tighten , watching the caliper doesn’t move in the process. job done

    Had to do this a few times but got there eventually. The tolerances between the brake pad & the rotor are so small that with my (poor) eyesight I find it hard work to eyeball it correctly.

    Now that they are all set up should hopefully be just left alone although I’m dreading taking the wheel off & don’t even go there with the rear…..

    August 15, 2018 at 2:38 am #925027
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    CXR94Di2

    ibr17xvii wrote:

    ibr17xvii wrote:

    Mungecrundle wrote:
    If hydraulic, they just sort themselves out.

    So if they are only rubbing a little best to leave it & as they are self centreing they will get back to how it should be?

    With anything mechanical and the reasonably close pad clearance. If you remove wheel, sometimes a minor tweak is required. Loosen bolts, so caliper is wobbly, apply brake lever and hold, tighten bolts. This should work in 95% of occasion. If doesn’t, lossen again and this time align by looking down the side of rotor, there should be a small even clearance from each pad. Carefully tighten , watching the caliper doesn’t move in the process. job done

    August 14, 2018 at 6:49 am #925025
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    hawkinspeter

    When I’ve had a tiny bit of

    When I’ve had a tiny bit of rubbing, I’ve just loosened the two caliper bolts and, with the wheel still in, eyeball the tiny gaps between the rotor and the pads to get it even and then tighten up the caliper bolts whilst not moving the caliper. Once tightened, pump the brake lever a couple of times and spin the wheel to see if it rubs or not. If it’s still rubbing, eyeball the gap whilst the wheel is spinning to see if the rotor is spinning true or is bent.

    Once the caliper is positioned correctly, you shouldn’t get any issues with removing and replacing the wheel unless you’re doing something like altering the bearings.

    August 14, 2018 at 6:38 am #925023
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    ibr17xvii

    Mungecrundle wrote:

    Mungecrundle wrote:
    If hydraulic, they just sort themselves out.

    So if they are only rubbing a little best to leave it & as they are self centreing they will get back to how it should be?

    August 14, 2018 at 6:37 am #925021
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    ibr17xvii

    First of all thanks for the

    First of all thanks for the replies & apologies for my lack of information. Not sure how I expect help when you don’t know the full story……

    Bike is completely brand new (Canyon) & has hydraulic discs with thru axles. Rear wheel was fine but front rubbed straight out of the box. Obviously did a bit of Googling never having had them before & tried the loosening caliper trick a couple of times which made it better but still rubbed slightly.

    Fiddled around with it again last night & saw on a GCN video about folding a business card onto the rotor, putting this in between the calipers & placing the wheel around it then loosening & tightening the caliper bolts & that seems to have sorted it. Not overly happy with Canyon shipping it this way but I guess that’s the risk you take when you buy onlne & it was only rubbing a little to be fair.

    Now that it’s fine it shouldn’t need any further maintenance until pads need rreplacing or system needs bleeding?

    Paranoid that when I take the wheel out for whatever reason they will start rubbing again.

    August 13, 2018 at 9:22 pm #925019
    0
    don simon fbpe

    You should only have to set

    You should only have to set up the calipers once, especially on a new bike.

    A few more details would be useful, hydraulic or cable? New bike or new to you?

    If it’s new, get it back to the shop and get them to set up the brakes and show you how to do it. They will do that because it’s how they win customers.

    the following applies to hydraulic brakes.

    If it’s new to you, take the wheel out and get something the same width as the disc, put this thing that is the same width as the disc between the pistons (as if it were the disc) and pull the lever until the pistons are tight to this thing that is acting as the disc (the pistons shouldn’t pop out if the same width as the disc). Use a cotton bud and brake fluid to clean around the piston and lubricate it. Once cleaned and lubricated, push the pistons back. Repeat until the pistons move freely.

    Loosen the caliper.

    Put in the wheel and tighten up the wheel.

    Pull brake lever.

    Tighten caliper.

    If still rubbing it’s likely to be a warped disc.

    Whip it off and lie it on a flat surface to check, replace as necessary.

    August 13, 2018 at 8:10 pm #925017
    0
    Canyon48

    I’ve had mechanical disc

    I’ve had mechanical disc brakes and I now have hydraulic disc brakes.

    Hydraulics are really simple (believe it or not) and require very little maintenance once set up correctly. Mechanical brakes can be hideous – TRP Spyres are about the only mechanical disc brakes that are any good.

    QR’s are a pain too, they are hard to get the same each time. Thru axles are super easy.

    Flat mount discs are much easier to set up too in my experience. Post mount can be fiddly because of the conical washers.

    It sounds like you have the basics right. To centre both hydro and mechanical disc brakes, with the wheel in, slightly loosen the two bolts holding the calliper on the bike. Squeeze on the brakes and carefully tighten each bolt up a little at a time. Without knowing exactly what type of disc brakes you have its hard to give much more info…

    August 13, 2018 at 7:41 pm #925015
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    Mungecrundle

    If hydraulic, they just sort
    If hydraulic, they just sort themselves out. If you do need to manually push them apart for some reason (such as horrid offspring squeezing the brake levers while wheels are out) then use something blunt like a plastic tyre lever so as not to damage the brake pads.

    Worst case scenario is a warped disc causing a rub, but even this should auto adjust.

    Cable operated are a different kind of beastie, that I know nothing about.

    August 13, 2018 at 6:53 pm #925013
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    cqexbesd

    I have a piece of folded over

    I have a piece of folded over metal that fits over the rotor, between the pads. I put this on when centering the brakes as it forces the pads slightly further out than they would be and it helps stop rub. Some pads always rub for the first 50k or so though.

     

     

    August 13, 2018 at 6:31 pm #925011
    0
    TheHungryGhost
    kil0ran wrote:
    When you’ve got the wheels out don’t touch the brake levers, you risk pushing the pads too far out if they’re self-centring.

    If you are moving the bike around with the wheel out, then some sort of spacer to go between the pads – some cut up store/bank cards works well – to avoid this.

    August 13, 2018 at 6:12 pm #925009
    0
    kil0ran

    Are they cable-operated? And

    Are they cable-operated? And do you have QRs or thru-axles?

    QRs on the front can be a challenge to get everything centred, and with cable-operated calipers you tend to have to run the pads quite close to the rotor to get decent response. 

    My approach is to place the wheel in the dropouts, get the QR done almost all the way up, clamp on the front brake with the lever, and then finish clamping down the QR.

    Rear tends to be easier because the transmission and absence of lawyer lips tends to centre everything, at least in my experience.

    When you’ve got the wheels out don’t touch the brake levers, you risk pushing the pads too far out if they’re self-centring.

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