TheCannon

I got my first flat today on my new bike. I have quick release tires with disk brakes. I disconnected the wheel and replaced the tube. When I put it back on the brake pads were rubbing on the rotor. I tried re-aligning and adjusted quick release tension but nothing worked. Finally I just readjusted the brake pads until there was no rubbing. I don't understand how things got messed up by just removing the tire. Is there a trick to getting everything the way it was before the flat tire? I don't want to mess with the brakes every time I get a flat. Now it's fine but slightly rubs when making a turn.

Neverseconds

for you safety, go to the bike shop and have someone check for you
and ask them how to do it well, maybe you can learn and do it yourself next time

Retro Grouch 

Mechanical disc brakes or hydraulic?

With hydraulic brakes it's important not to pull the brake lever while the wheel is out.

cale

It isn't critical but a smart choice for sure. If you pull the lever while the wheel is out, the brake pads can be pushed back in, gently with "something on your multitool" or tire levers.

cale

Now that I've made a stupid comment to Retro Grouch that is nothing more than sifting through fly-speck minutia.... I see that you have mechanical brakes. The most common cause of rubbing after replacing a repaired wheel is not seating the wheel squarely between the fork drop outs. The pads run close to the disc, for sure, so if you pop the wheel back in, give it an upwards tug to make it seat and throw the QR lever over, you may not have aligned the wheel with enough precision to avoid a small amount of rubbing.

I found that the rubbing, even if you do nothing, typically goes away quickly with additional applications of the brakes. A truely horrible squeal would suggest more serious problem. Did you lay your wheel disc side down while you repaired the tube? In other words, is it possible that the disc got pushed against? That might be enough to cause a slight warp.

Your first flat on a disc brake equipped bike will certainly "test" if you've fully made a transition to thinking like a disc brake rider, whatever THAT means. You know, take extra care to seat the wheels between the drop outs, don't lay a wheel disc side down, and don't worry unnecessarily about a small bit of rubbing, especially if it is likely to sort itself out with a few tugs of the levers.

Hypno Toad

I have three bikes with disc brakes, and I remove wheels very often to change tires. The most common issue is the alignment of the wheel in the drop out. I find it helpful to use a rag to wipe the drop out and the skewer, be sure there's no grit that is interfering with seating the wheel. I find it easier to align the wheel on the ground, not on a stand. If you're using a stand, get the wheel mounted, then remove it from the stand, and with the bike on its tires and balances (not leaning to one side), release the skewer and close it.

If this doesn't work, it's possible that when the bike was assembled, that the wheel was out of alignment when they assembled and tuned the brakes. Therefore, you know get the wheel installed and correctly aligned, but you get rubbing. In this case, go back to the shop for some help with brakes. Additionally, if this is a new bike, the shop should offer a free tune up after the first couple months, to adjust cables that will stretch when brand new.

Make sure you do not touch the rotors, the oils on your skin will cause brake squeal. To clean the rotors, use rubbing alcohol and a clean rag. I typically clean my rotors when I clean my chain.

Lastly, I've found that the rotors that come with a new bike are kinda cheap. The rotors that came with my Marin and Kona were both prone to warp. I've upgraded the rotors on these bikes and this has really helped reduce warp.

BobbyG

I got a new bike 6 months ago with my first set of disc brakes (cable). The first few times I removed the wheels I had a tough time aligning the disc in the calipers. The last few times...no problem. I wish I knew why so I could tell you.

TheCannon

Thanks for the replies!

I'm pretty sure the wheel was all the way in the drops. The wheel was also perfectly centered between the forks and I didn't have the bike in a stand. I think maybe the rotor was slightly warped from changing the tube because I don't remember if I put the wheel down on the rotor while changing the tube. I put the wheel in the best I could and then I adjusted the brake pads away from the rotor, it didn't take much adjustment. It's all good now except for a bit of rubbing when making turns.

cale

If you don't remember sitting on the rotor or whacking it, there's almost no reason to think it was warped. I mentioned it because keeping the disc free of contamination is important. This doesn't mean that it is in any way "fragile".

cale

Maybe you just got better at it? You know, more comfortable with the procedure. I know when I first installed disc brakes I thought that I had to align the rotor before aligning the dropouts. Now I align to the drop outs and trust that the rotor will be guided in.

Looigi

To reproducibly install a wheel, put it in the dropouts with the the skewer loose, set the wheel on on the ground and while pushing down with some force on the stem (saddle for rear wheel) to hold the wheel's axle firmly seated in the dropouts, clamp the skewer shut.

Garfield Cat

Is there a good You Tube on this?

dynaryder

Count the number of turns when you open the skewer,then tighten it the same number when you close it. If you use a different number of turns on the skewer,it will make it tighter or looser than before,which can cause the caliper to move slightly in or out,and this will cause rub. You could also use something like this.

Looigi

When a skewer properly tightened the dropouts are pressed firmly against the flanges of the axle. A bit looser or tighter won't consequentially move or change the alignment of anything.

rydabent

Its possible when the bike was delivered, the wheel wasnt seated right, and the the brakes were adjusted to that position. Also as the bike is ridden, there may be a slight shifting of where the wheel seats, and in time it will take it final position.

dynaryder

Own a disc bike? Try changing the skewer tension and watch the brake rub. You did notice the fleet of disc bikes in my sig? I've also run a free bike clinic for 6yrs and this is in fact a thing with disc brakes.

cale

There are ways to repeatedly achieve the same tension. It's just a matter of practice and technique.

TGT1

don't know about a youtube, but,

Stand in front of the bike, lean over the handlebars and reach down to the skewer on the bike side of the bars while pressing down on the bars with your chest and shut the lever.

(may be a problem if your arms are too short on one end)

For the rear do the same thing except press down on the saddle with your chest.