Bicycle brakes - brake pads alignment

Bicycle brakes  - brake pads alignment

Bicycle brakes evolved over time, increasing stopping power, from inadequate low – so low, it is beyond useless, to insanely high – modern hydraulic disc brakes, offer incredible amount of braking power, by gently squeezing them with one finger. The biggest breakthrough came when engineers, realized 2 things:

1 That you can create insanely strong brakes, but if braking pads are NOT properly aligned, this braking power is lost. This is why adjustable brake pads were created, with some free play designed into them in order to allow them to align properly.

2. The brake must have proper balance left-to-right, in order to distribute brakeforce evenly.

 In this paper I will demonstrate a recent repair I made to a road bike, which was brought to me to repair it’s brakes, because the brakes were not good at stopping the bike in time, causing heavy accident and a dozen people being hurt, because of inefficient brakes.

The problem with this bike was simple. Old generation brakes, which are good and efficient model, regardless of their old generation, and old generation braking pads, which CANNOT be properly aligned to the rim. The result is inadequate stopping power, because there is not enough friction between the braking pad and the rim, to kill the speed of the bike in time.

How comes? If a braking pad is NOT aligned properly, it does not use it’s entire area, to create enough friction, and by using only fraction of it’s area, it wears out faster, uneven, and does not produce enough friction. Therefore properly aligning the braking pads, solves this problem. The fix of this bike was very easy and very simple one. Dispose of old generation braking pads, which cannot be properly aligned and use new generation braking pads which can be properly aligned.

Total time for repairs 30 – 45 minutes including diagnosing the problem, removing old generation brake pads, install new generation brake pads, align properly new generation brake pads, restore tension to braking cables to optimum level, setting braking levers to optimum position against the fingers of the rider, for maximum strength and comfort while using the brakes. No cables or cable housings were changed during this repair. Only specified repairs have been done.

This is the condition I got the bike, for repairs.

 On the picture is visible how the old generation brake pad is not properly aligned to the rim, reducing the efficiency, of the brake, down to inadequate level. The brake lever is pulled as hard as I can pull – full force pull all the way in, which must provide maximum braking force.

As you can see only small part of the braking pad touches  the rim, the bigger part of the braking pad is in the air. This means the braking pad is misaligned, and as we are going to see later, there is no particular way to actually align it. This is good enough reason to replace it with something newer and better. The problem of this misalignment is caused by brake pad mounting design.

At first it looks like the brake pad is reliably mounted to the brake itself, which must assure safe braking, but deeper look, shows that despite of the reliable mount, the brake pad is misaligned to the rim, and does not make good contact with the rim and does not provide secure braking. The problem is caused, by the simple design of the mounting – just put the brake pad and screw it in place, and it fits on the brake. But fitting on the brake does not mean it is aligned to the rim.

If it is not aligned to the rim, the brake cannot provide enough friction, and as result, cannot provide adequate brake force.

 Here is another problem affecting the brake pad – one washer is missing anyway, so best thing to do is dump it, is not working anyway, so why keeping it? As result of this simplistic design, the pad cannot be aligned to the rim, just because there is nothing to allow it to make the free play to do so.

The Following pictures show how the brake pad is misaligned to the rim and why it cannot be aligned to the rim.

 In new generation brake pads designed for v-brake brakes, this problem is solved by series of curved washers, which allow some free play of the brake pad, when it is loosely screwed, in order for the brake pad to align to the rim. Once it aligns, screw them tightly, to secure them reliably in place. Good thing is that the new generation brake pads are backward compatible with old brakes, which allow us to mount them on older brakes, allowing us to use the full potential of the brakes, ensuring fast and safe stop, and no other people injured. Remember that this bike was brought to me for repairs, after a dozen of people were injured because of inadequate braking.

 As you can see on this picture, there are 5 washers and a nut for each brake pad. As you can see washers 1 trough 4 are curved. This curviness, allows some free play of the brake pad, to align to the rim. This is where the magic happens.

 

This is the proper order of all five washers, starting from inner to outer – small flush washer thick curved flush side turned inwards, small curved washer, with flush side turned outwards, another small washer, with flush side turned inwards, medium curved washer with flush side turned outwards, tightening nut, flush side turned inwards.

 As you can see, the newer generation brake pad fits perfectly, and washers are in their correct order and orientation. The pad it loosely screwed, to hold in place but to allow, the free play to align it to the rim. A gentle squeeze of the brake lever will push the brake pads against the rims, and the free play, will allow the brake pads to align properly, to the rim. As mentioned before, the curved washers are designed to allow this free play to align the brake pad to the rim and when tightly screwed, these washers will hold reliably the brake pad in it’s place.

 

This is the new generation brake pads, tightly screwed, and properly aligned to the rim. Here it is visible how the free play by the curved washers, took part in alignment. We can also se how the new generation brake pads are directly compatible with old generation brakes.

The result, is correct alignment of the brake pads to the rim, which allows the rider to use the full potential of the brake, and stop safely in time.

 

The brake lever is gently pulled, barely enough for the brake pads to touch the rim. As you can see, now the brake pads is properly aligned, and uses it’s entire area to provide enough friction and brake force, to stop the bike reliably in time.

Safety tip:

Always maintain your brakes in top condition, in the city, you never know, how other people, or intensive traffic will surprise you, and when. Being able to stop before is to late, means that you will spare yourself a lot of trouble. If you do not maintain your brakes in proper condition, you may ride fast and ram the surprise, this may cause you and other people being injured, further damaging the bike and if you hit a car, you can damage the car as well as your bike, injuring yourself in the process.