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Disc Brake Noob - Tips Please!
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!
If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.
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59 comments
Good advice about the pin, hate spending ages fiddling with stuff like that.
I take it the pads are resin from the factory so best to stick with them?
My bike had metal pads originally, so I replaced like with like.
The part number will be printed on the pads, so if you take them out, you can figure out which ones to get e.g. L02A is resin and L04C is metal if you have the 805 brakes.
The reason you don't want to use different pads is due to material transfer onto the rotor. That would cause poor braking performance unless you gave your rotor a good sandpapering.
Can I just undo the pin, take them out & put them back without faffing around taking the wheel off & potentially realigning the calipers etc?
If not I'll wait for them to wear down a bit & buy some when they need replacing. The bike is brand new & hardly ridden so was just thinking ahead.
It should only take a few seconds to remove the retaining pin and then both the pads should just lift out and can go back in again easily enough. Removing the wheel might be needed for putting in new pads as they'll be thicker than the worn pads, so you may need to carefully push the brake pistons in slightly to make enough room for them.
Cheers, sounds easy enough in theory.........
Might just take them out to see what's in there so I can make sure I get the same when they start wearing out.
That'll prevent your retaining pin getting stuck as well. The type of pin that has the issues is the one that screws in and has a useless flat-head screwdriver head so you can't use any force on it without ruining it.
Make a note of the pad part number as it can be confusing getting the right replacement, or at least I managed to order the wrong pads and didn't realise until I came to fit them.
30015.jpg
Pretty sure it's a flat head screw securing the pads.
No desperate rush to check them at the minute so might leave it until I don't need the bike for a few days in case I make a dogs breakfast of it - then spend hours fiddling to get it back to how it was before & wish I'd not bothered!
Turns out you were spot on with this
Tried to get the screw out & now it's completely knackered & won't come out. You simply can't put any force onto it without it disintegrating apparently.
Not vital as the pads shouldn't need changing as yet but pretty clueless how I can get it out.
Looks like LBS will have to change the pads when they need it.
I have the BR505's and have just exchanged the front pads for another set of Shimano. To keep the price down i have bought the ones without the big backing plate and fins on top. Probably saves £5/6 a set. Still slightly more expensive than an aftermarket brand but i've always preferred original disc brake pads.
Slightly OT, can anyone recommend any pads? Don't need any as yet, just so I have some on the radar.
Brakes are Shimano 105 Disc, Flat Mount, ST - BR 505 & as this is my winter bike would like some that are best for bad weather conditions.
I use Swisstop on my rim brakes & really like them but open to other suggestions.
I personally just prefer the feel, control and modulation all round, in all conditions, wet/gritty or dry/dusty..... plus the fact that I am not gradually trashing my rims. So on my disc braked bikes I have actually upgraded rims safe in the knowledge that they are going to last a long time without getting chewed each time I brake! I could never see the point on my rim braked bikes!
I still have a rim-braked bike, which is still my lightest bike (for now), but I don't think I would ever go out and buy a new road/race bike that doesn't have disc brakes now.
It will certainly be interesting to see how I feel when I go back to my rim barked bike. Discs just work whereas rims just don't sometimes.
Will it be an excuse that I have to get a new best bike?!
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.
I think that's what was happening to me & it was driving me nuts. I guess the trick is to tighten them alternately a little at a time to stop the caliper moving.
I use the method mentioned by Jterrier and Hawkinspeter. With hydraulic calipers I've never had much success with the 'insert-something-thin-between-the-pads-and-disc, pull-on-the-lever-and-then-nip-up-the-previously-loosened-caliper-bolts' method and find that the calibrated eye is much better. I usually get myself into a darkish room or garage, so that the caliper and pads at least, are in shadow, then put a white piece of paper on the floor underneath the caliper or wherever you need to put it so you can look straight down through the caliper body and easily see the clearance between the pads and the disc. Then I shine a torch onto the paper so that the contrast is even greater. This way you can much more easily see the gap. I then tighten the bolts just enough (i.e. just using my fingers) to stop the caliper 'rattling' but enough so I can move it and it stays where I've moved it to. It usually takes a bit of playing around to get to this point.
I normally then just nip up the two bolts when it looks right with equal clearance either side and pads aligned with disc also and usually they don't budge any further once you fully tighten the bolts. However, I have had one where the caliper adaptor wasn't perfectly machined and the whole thing moved slightly when fully tightened. Sometimes a thin washer under the caliper bolt head (if not already fitted) can reduce any tendency for the whole thing to move during final torque tightening.
With flat-mount and through-axles (as I think you have) I have found set up to be much easier as the mount/adaptor is usually less sensitive to movement when you tighten the bolts up and on my through axle bike I can take the wheel in and out numerous times with no need to realign the caliper whereas with my QR disc bikes (past and present) it seems you have to re-align almost every time you remove the wheel. On my commuting bike I have stuck with cable discs (Spyre SLC) so I can adjust each pad individually to give more or less clearance depending on the riding conditions - i.e. more clearance in the winter when there is more rain, dirt and grit getting stuck betwixt pad and disc! I also find cable discs need less maintaining than hydraulics as over time the fluid in a hydraulic system will absorb moisture (hydroscopic) and fill up the system eventually causing disc rub and zero clearance at which point you have to drain a bit of fluid out (or better still, flush/bleed the system with new fluid). I doubt you will be having this problem yet though as it is still new.
You can get any Shimano or SRAM hydraulic flat-mount/through-axle combination set up correctly so that you shouldn't get any disc rub at all unless you are riding in really foul conditions or you are built like Chris Hoy and putting in some huge loads into the forks during out of the saddle accelerations!
Hope you get it sorted!
That's really detailed & helpful mate thanks for that.
Just a whole different ball game than rims but hopeful that I'll get used to it in time.
Once they are set up the performance is outstanding especially in the wet when you've been used to rims. Although I don't normally like getting wet I was itching to try them in damp conditions just to see if they really are any better.
Once they'd bedded in I was left in no doubt.
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.
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.
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.
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...
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.
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.....
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.
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.
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.
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