Brakes... The video I haven't made
What I would put in the video:
(When energy allows, maybe I will - let us know if you want to see it happen)
What causes brakes NOT to work?
1. Pad Wear
2. Worn or warped rotors
3. Cable Stretch (for mechanical brakes)
4. Low fluid or air bubbles (hydraulic brakes)
6. Dirt, dust, oil, or other contaminates on the pads or rotors.
The basics are simple. Two pads squeeze each side of the brake rotor (aka disc), causing enough friction to slow you down. When the pads wear down too far, your braking performance decreases. Pads also lose friction as a result of extreme heat. This is common when braking down a long hill, especially with the extra weight of typical electric bikes. (A dragging brake will heat up too) Most brakes simply were not designed for electric bikes and will wear prematurely.
What can be done?
Proper Break-in procedure - With any new bike, or new set of pads, make sure to properly "bed in" the brakes. Soft, light braking will cause the pads to glaze over. This creates a smooth, somewhat slick surface that does NOT stop well. I always recommend a few dozen firm, hard stops on any new bike or new pads to ensure this doesn't happen.
Higher quality pads - Pads come in many different compounds which result in different performance. Stock brake pads are just average at everything. They're a balance between wear, friction and cost. In my experience they are not designed to handle the occasional high temperatures ebike braking can cause. High performance "racing" pads would stop excellent! But they would wear down after a single hard ride and are basically disposable. Galfer is one of few companies that has "ebike" rated pads. This is not a marketing gimmick, the pads are designed to withstand longer periods of high temperatures, and will last longer.
Adjustment - Improper adjustment can cause uneven wear (one pad wears more than the opposite side, or both pads wear at an angle).
Most mechanical brakes only pull from on side, causing a slight warp of the brake rotor until both pads squeeze onto the disc. As the pads wear down the pull becomes more and more offset. If your rotor visibly moves side to side under braking, adjustment is needed. This warp to one side can also cause some loud squeaking! There are 2 adjustments for pads, one being the cable leading to the pad that moves (typically on the outside). A second knob or adjustment screw is typically reached from the inner side to bring the inboard pad closer to the rotor.
Pro tip! This is why I like our Juintech hydraulic calipers so much (as do tens of thousands that have installed them, just read the reviews! Although they are mechanically actuated from the brake lever to the caliper. The caliper is hydraulic and pulls the pads in evenly from both sides. Even wear means they stay adjusted long, and are easier to adjust when needed. Since your existing brake switches are not replaced, motor cutoff functions still work as they would with your stock brakes.
Hydraulic brakes both pads move in unison. There is a side to side adjustment with the 2 mounting bolts on the top of your caliper however. Loosening these two and re-centering the caliper over the rotor will ensure even wear on both sides.
Pads clearly wear down and are replaceable. Rotors are made from thick steel and don't wear out, right? Wrong! Rotors are just as susceptible to wear as brake pads, but sometimes seeing the wear is a little bit more difficult. Rotors wear down from the pads themselves, dirt or dust, and again heat!
The typical recommendation is to replace when they fall under 1.5mm thickness. It depends on the use case, but I think a bit more margin for error should be taken into consideration for ebikes. As rotors get thinner they dissipate less heat, which causes your pads to heat faster, decreasing braking performance.
Pro Tip! Galfer offers thicker rotors to combat this problem. By having a thicker rotor there is more mass to dissipate heat - the enemy of good braking. Most brakes are 1.8mm thick, Galfer rotors come in 2mm in both 180mm and 203mm rotor diameters, and 2.3mm in 246mm diameter!
Most affordable ebikes come with mechanical brakes. The steel cable runs from your lever on the bars down to the caliper. As mentioned above the cable typically only pulls one brake pad closer to the rotor. This cable will stretch over time, making it longer and looser. There may be up to 3 places to increase cable tension on a mechanical disc brake. For a large adjustment (such as new installation, or perhaps with new pads) there's a bolt or nut holding the cable crimped into place on the caliper. For fine tuning, there's a barrel adjuster which will increase or decrease tension in small amounts, allowing you to get the brake action just right. One barrel adjuster is found on the caliper, one is found on the brake lever itself.
Low fluid or air bubbles
Hydraulic brakes (or hybrids such as the Juintech calipers) have fluid to actuate the caliper. A full hydraulic system, such as the Area 13 4 Piston Brakes have a reservoir next to the brake lever, then a line with fluid that runs all the way into the caliper. Why do most large, heavy vehicles use fluid? It doesn't compress! Even steel cables stretch, which means that some of your effort to pull the brake lever is wasted due to cable stretch, or friction in the cable guide. This is not a problem with fluid. The lever pull feels much easier and smoother on a fully hydraulic system. Unfortunately they're not all perfect. Small leaks can introduce air bubbles, which most certainly DO compress. If your brakes feel "spongy" or soft you may have air in the lines. Pumping your brakes several times may alleviate this problem temporarily, but the brakes should be bled with new fluid. Most ebike brakes use mineral fluid. Do NOT use DOT brake fluid unless your brakes are specifically labeled for it. (Few are)
This is the enemy of all brakes, no matter what type. Excess heat can wear pads, warp rotors, and even boil fluids in extreme cases. Higher quality pads, larger diameter rotors, thicker rotors, or a combination of all 3 will help reduce heat buildup and keep your brakes working better, longer.
Dirt, Dust, and Oil
Dirt and dust is all but guaranteed to wear your pads and rotors down. Make sure to give your brakes a good cleaning on occasion. Standard brake cleaner found at the auto parts store is perfectly good for bicycle brakes too. Don't use other cleaners or solvents as they may soak into your pads and ruin them permanently.
As a thank you for being an Area 13 Customer, here are some deals to keep you moving on your bike, and stopping on a dime!
(Or at least a quarter - that's enough to make me stop)
Area 13 Hydraulic Brakes in stock and ready to ship! High quality 4 piston hydraulic brakes for just $199.
NEW! Area 13 Hydraulic Brakes for Cargo bikes - We finally have an option for the long tail bikes that need great brakes too. These are the same as our brakes above, but with a rear hydraulic line that's 78 inches long!
Galfer brake products 10% off - Use Coupon Code GALFER10 Includes ebike pads, 180, 203 and 246mm rotors!
Discounts end Friday, September 9th at midnight, or until supply runs out.