Rim Brake Adjustment
Welcome to the Workshop Series. Today we’ll be guiding you through the rim brake adjustments.
The basic tools you may need for this job are: a 2mm, 4mm and a 5mm hex keys , a phillips head screwdriver and a torque wrench.
The reason for this adjustment would be if you’re experiencing poor braking performance or brake rub.
First thing to check when adjusting your brakes is the wear on your pads. For optimal braking it is critical to have enough material left on your pads. You should be able to spot a wear limit mark on the pads, if you’re getting close or not able to see it at all, it’s likely time to replace your pads.
Sometimes you can have brake rub even with perfectly adjusted brakes, and that’s due to the wheel being installed incorrectly and out of alignment. This would affect the braking track position and potentially cause brake rub. So before starting any work on your brakes, be sure to check the wheels are installed correctly.
This may sound crazy but your rims are also subject to wear and will have a defined lifespan. Checking the rim wear level is a little more involved and we suggest getting that done by your local bike shop. If your rims are worn beyond the limit, the only solution would be to replace the rims or the entire wheelset.
Another important thing to check is the conditions of the brake cables. If you have damaged cables with splints or kinks, it’s a good time to get them replaced. The process of replacing your brake cable will be covered in a future video.
PAD POSITION AND SPRING LOAD
With that out of the way we can start to adjust the brakes. Undoubtedly the most important factor that will affect brake performance is the pads position in relation to the braking track on the rim. Both pads must be in line, parallel and centered in relation to the braking track.
In line means both pads will touch only the braking track once the brakes are applied. Parallel means the entire surface area of the pads are in contact with the braking track once the brakes are applied. Centered means both pads show uniform distance to the braking track once the brakes are not being applied.
To adjust the pads position we will loosen the pad mounting bolt or nut making sure we don’t remove it completely, so the pads can be moved freely in the calliper. With one of your hands align the pads with the braking track, while you apply the brake with the other hand. While we do this we want to play with the pads position to ensure we cover all the points we’ve previously gone through, while maintaining pressure on the brake. Once we’re happy with the pad position we can tighten the pad mounting bolts to approximately 5 to 7Nm.
At this point the pads should be in line and parallel to the braking track on the rims, but they may still not be centered. To address that we need to adjust the spring load on each brake calliper arm. This adjustment can often be done with a 2mm hex wrench or a phillips head screwdriver. Locate the adjuster bolts on the sides of the calliper arm, clockwise will increase the spring load on that particular side, increasing the distance between the pad and the rim. Anti-clockwise will release the spring load, consequently decreasing the distance between pad and rim. Sometimes you can get both pads centered by adjusting only one side, sometimes you’ll need to adjust both sides to obtain the desired outcome.
CABLE TENSION ADJUSTMENT
Now we have our pads position dialled, it's time to move on to the cable tension adjustment. This is important as it will define the amount of bite your brakes will offer. If the cable tension is not set correctly you might not have any braking force.
Adjusting the cable tension is simple. We’ll use a similar method we used to align the pads, by holding your brake calliper with one hand and engaging the brake. Then, release the cable clamp bolt using a 4mm or a 5mm hex key. Pull the brake cable all the way with the other hand and retighten the cable clamp bolt to 5-7Nm. This should give you a good bite. If your pads end up being too close and touching the rim, back off a little bit, using the same method.
What we’re looking for here is to have around 25-30mm between the brake lever and the handlebar after engaging the brakes. This will give you enough room to effectively control and modulate your brakes on harder braking scenarios.
And this is how to adjust your rim brakes. Make sure to do a few test runs and progressively experiment harder braking to ensure you’re happy with the adjustments and most importantly, safe to go on riding your bike under normal conditions.
For more fine adjustments guides, check out our Workshop Series. Make sure to enjoy your time maintaining your bike as much as you do riding it, and happy riding!
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