How to Adjust Your Disc Brakes - Electric Bike & Standard Bicycles

Hey, everyone. Peter Kaltreider here, chief operating officer at Sixthreezero. I am going to help you all adjust your disc brake. It's pretty easy to do, but sometimes it takes a little bit of extra work. Let's get into it. You can do it.

Hey, guys. So all you need is a five-millimeter Allen wrench. One like this is very nice. You may not have one like this, but it's nice to have a long one. Also, it has the pivot tip here that you can use for different angles. So anyway, a five-millimeter Allen wrench is really all you're going to need to do these adjustments. I'm going to show you how to do it. First, kind of the hack way, and if the hack doesn't work, then we've got to do a few other adjustments and I'll show you what to do. All right, so Nate's going to come on up and we'll show you how it's done.

All right, so here's our disc brake. Here's the rear one. Take a look at the rear one. Here's our disc brake. Now, it is August 2022 right now. We will probably change these brakes at some point, so I just want you to know that we may have a newer video in the future. So anyway, these apply to brakes now and probably what we'll be selling in the next year or so, but then they may change. One thing about this is that it has only one of the pads adjusted, so that's something important to remember in the future. We may have one that has both pads adjusted, but I'll show you how to adjust this disc brake here. All right? Cool.

So anyway, obviously the disc brake is actuated by the brake lever up here at the handlebar. And there's an important little feature here on the brake lever. It's right here. Can you catch that, Nate?

This is called the barrel adjuster. This is also on regular bikes and this can be used. You can back this out like this and see how I'm starting to see a little bit of thread. And then you can put this lock nut back in there to hold it in place. Anyway, that will tighten. If you back it out, it will put more tension on the cable. That can be helpful, and useful later on if the cable slackens or settles in a little bit, which can happen, or actually is expected to happen. But for now, we're going to run the barrel adjuster all the way in.

There's also one over on your disc brake, so you've got a barrel adjuster on both ends here. This one too, right here. Now when you tighten this one, this one tightens down with this nut here. It's not tightened by fingers. You can actually put a little wrench on there to tighten that lock nut down. But again, I'm going to back the lock nut off and I'm going to run the barrel adjuster all the way in, meaning turning it clockwise, which although that's tightening the barrel adjuster in, it will give the cable a little more slack.

So now, Nate, stay here. I'm going to squeeze the brake lever a couple of times. You can see it actuate. So here, this is the actuation of the disc brake. Cool. And these are mechanical disc brakes, meaning that they use a cable and not hydraulics. You can go either way. I don't think it really matters on an e-bike particularly. I think it may matter if you're doing technical riding on maybe an e-mountain bike, perhaps. You may prefer hydraulics also because it's an enclosed system, it keeps dust out. But for general recreational riding, I don't think it matters at all. In fact, I personally think you could get away with just V-brakes, just the simple brakes on an e-bike. But disc brakes are pretty much now the standard. So let me show you how they work.

The first thing we're going to do is there are two components to the braking system, basically. Of course, there's the rotor, which is the disc, which gives the brake its name, disc brake. And then there's the caliper, which just squeezes around the rotor and slows the bike down. So we want to make sure the rotor is straight. These can get bent or warped a little bit. I don't expect it to happen, but you just want to make sure that you're not working, that you're not trying to swim upstream.

So what you can do is you can lift the bike, and then referencing the caliper here, you can spin the wheel and you can see if there's any deflection going back and forth by referencing a fixed point. So that rotor looks very straight to me. Now the thing about disc brakes is that there are very, very tight tolerances. Of course, if there's a little bit of rubbing on the rotor, of the rotor onto the pad, it's not that big of a deal. And quite frankly, the pad will wear away a little bit with some riding and almost kind of self-correct.

But let me show you how to adjust it. So first of all, there are mounting bolts, these two guys right here, and those simply mount the calipers to the bike. These don't ever need to be adjusted or messed with. These are fixed.

But then there are two bolts here. There's one here and one here. Now, these are the ones that allow for adjusting. So what I'm going to do, first of all, is I'm going to loosen the cable here. So I'm loosening the cable pinch bolt which will allow the cable to have slack, and that allows this arm to come all the way back. We want that so that we can start at the right position and then make adjustments later.

So this arm, instead of being already kind of pulled in like it will do when it's actuated, we want to go ahead and make sure it's got the full range to start with. And then we'll take out any slack that's in the cable just by giving a little bit of a tug, and then we'll tighten the pinch bolt. While we're doing this, we want to make sure that we don't move the arm here because then we'll have the cable attached to the wrong spot. So we've got the arm all the way open, and then taking the slack out of the cable as best we can, and then we're going to go ahead and tighten it back down. There we go.

Now, I'm going to go ahead and loosen the adjustment bolts. Those are pretty tight. So you can see how handy this tool is for getting into tight spots. So if I loosen this, there are kind of open slots on the caliper here, and I'll show you how it works.

So once these guys are loosened, now the caliper can flop around. It can do exactly the adjustment that it needs because there are wide slots here where the bolts go in. So again, we don't mess with the mounting bolts. Those are fixed. But for these two adjustment bolts, we can just loosen those. Now the caliper can be adjusted however it has to be adjusted in relation to the rotor, which the position of the rotor is basically fixed.

Now, I'm going to go around to the other side here. You can probably stay there, Nate. Now, since only one of these pads is adjustable, we're going to adjust that one and it's the inner one. And that's adjustable by this bolt here. It's also a five-millimeter. Now again, this one's kind of a hard one to reach with a shorter Allen wrench. Also, this one has the little pivot end there, so...

But what I'm going to do is I'm going to go ahead and I'm going to run that pad in all the way so it's all the way in towards the rotor. So it's basically, it's touching it already. And now, so this is kind of the hack. This is the basic way to do it. Now what happens is when I go ahead and squeeze the lever up here, the brake is going to close, and in theory, it will self-position. So then what I can do is while I'm holding the brake closed, and I have that inner pad run all the way in, I can go ahead and tighten down the adjustment bolts.

Now, a lot of times this works and then a lot of times you have to make other adjustments. You may have seen when I was just tightening this upper adjustment bolt here that the caliper shifted a little bit, so it's probably going to be off a bit. But we'll find out and then we'll continue and fine-tune it. So I'm going to let go here. Now, it's quite tight. It's obviously because we have the inner pad run all the way in. So we're going to back this off a little bit. You can see the caliper relaxing there a little bit. Let me just make sure that the adjustment bolts are... These need to be a little tighter, actually, here. I'm going to squeeze the brake again. I didn't make the adjustment bolts tight enough, so we'll fix that right here, right now. There we go.

There we go. All right, so now when we open it, it feels a little loose to me. I'm going to put the inner pad in a little bit, but then what we want to do is go ahead and see if the rotor is clearing now from the adjustment we just made. So we're going to run it like this. It's pretty nice. I don't know if you can hear, probably can't hear, but it's rubbing a little bit on one of the pads.

Just barely. But we can make a fine-tune adjustment. But what you want to do when you're doing that is it's nice to find a lot of times white sheet of paper and you can put it behind where you're looking. You can look this way up into between the rotor and the pad. On the front brake, it's easier where you can hold it back here and then look from the front of the bike. But what you want to see is that the rotor is clearing the pads by just a little bit. You want to see a little bit of daylight and that's all the way around.

Now again, if you hear a little bit of noise, it's not that big of a deal. They'll settle in, so I wouldn't worry about that much. So anyway, let me take a look here and see how these look to me. Let's see.

Okay. So when I'm looking in here, I can see that the outer pad is a little bit farther from the rotor than it should be. A lot of times you can do this one adjustment bolt at a time or you can loosen both. And so I could just leave it how I already had it adjusted. I think it was fine. It was barely touching. I think it was quite nice, but now it's a little bit loose and I'm actually going to, by sight, adjust the caliper until there's just a little bit of daylight between each pad and the rotor.

And then we'll gently tighten these down. Not all the way, but just enough so it kind of holds its spot, and I'm going to continue to look and see if we have clearance here. Yeah, it's clearing on both sides, actually. It looks really nice and even. I don't think there's any way you can catch that, Nate. Probably it's too close, but I'm going to go ahead and tighten it all the way down.

Sometimes the caliber will shift just a little bit when you tighten down. So anyway, just make sure that you check for that and compensate if you need to. So at this point, I have just a hair's clearance between each pad and the rotor. So if I pick the rear end of the bike up and spin the wheel, you'll see it spinning very freely like that. Okay.

Now there's one other thing, though. When I'm squeezing the brake here, it feels a little loose to me. You should start to feel resistance about halfway, about halfway through the pull there. I'm actually able to pull this pretty much all the way to the grip, so that's a little bit too loose there.

So what I'm going to do is there are a number of ways to tighten it, but the best way, the proper way is to adjust the pads a little bit. So I'm going to tighten that inner pad a little bit more, get it a little closer, and then that'll give less clearance, so there'll be less pull on the brake.

And then you can also check to see if there's any cable slack, which a lot of times there is. And so you can go ahead and use the barrel adjuster just a little bit. Be careful with the barrel adjusters. You don't want to use these to actually adjust the clearance of the brakes so much as taking the cable slack out because eventually, you'll be pulling the arm in too much, and then you won't have the full range of the brake that you need.

So I'm just adjusting these barrel adjusters just a little bit to take a little bit of slack out of the cable, but not affecting, not actually pulling the arm forward, which would reduce our brake range here. So now when I feel it, yeah, it feels much more firm and positive. I'm going to back off just a touch more. Yeah. And that feels really great. So right about halfway through the stroke, it starts to really firm up there, and that's going to stop the wheel really quickly. Let's just do a quick demonstration. I'll just rotate the wheel and then there it is. Stops it just like that.

So anyway, that was a pretty quick demonstration. I hope that it gave you a really good overview. The main thing is you can use that hack, that first thing that I showed you where you run the inner pad all the way in, go ahead and give a squeeze after you... And then you loosen the adjustment bolts, squeeze the lever, and then while it's squeezed like that, it should self-align, right? Because it's squeezing where it's going to grab the rotor and the adjustment bolts are loose. So while that lever is squeezed, you go ahead and tighten the adjustment bolts. A lot of times that will get the caliper either where it should be or really close to it.

Then if you need to do some more work, you can fine-tune it by working with the two adjustment bolts, and then looking for just a little sliver of daylight between the rotor and each pad. A lot of times it helps a lot to use it like a white sheet of paper behind the caliper from where you're looking. You can also use a flashlight to help you. And then you want to make sure that the feel on the brake lever is neither too tight, nor too loose. Should start to give you resistance about halfway through the stroke and should not reach the grip by any means.

Okay, there you go. I hope that helps a lot. Again, this is August 2022. We may have another version of brakes coming out, so check back if it's a couple of years in the future.

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