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Resurface bike rims for up to 300% stopping power, even in wet conditions. Makes some bike brakes impervious to water, even submerged....
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Signing UpStep 1Get some slate first
get a sample piece of slate used in construction....Slate is a grindable and fileable sedimentary stone, and is almost as hard as granite....an ideal chioce for a resurfacing stone on aluminum up to cast iron....
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Thanks.
Yes they are. Caliper brakes are weak and flexible, and rubber and steel are easily parted by a layer of water. Some will even tell you that they are downright dangerous in the rain, and to them I agree. The first way to make sure your brakes are working at their peak potential is to keep your wheels "true" (straight), and set your brakes properly on the rim (I think there's an Instructable on how do do this on this site somewhere). When squeezing the brakes, the front part of the pad should touch the rim first, and the pad should "land" squarely on the rim under hard pressure while the wheel is rotating. Maximum braking power should be achieved without the brake lever coming close to touching the handlebar-grip. For caliper brakes, the calipers shouldn't wobble, but also shouldn't be "sticky" (it's a terrible design, really).
Something you can try is to roughen the rim a little. What you need is a portable drill and a grinding stone (gray-wheel) on it. Using the same method as with the wire-wheel, hold the wheel at a 45-degree angle relative to the braking surface (when looking at the wheel from the side) and use the drill to spin the rim, like the pic below. Don't put too much pressure or you may grind too deep and weaken the rim. As the wheel turns, the grinding stone will draw a line around the rim. It doesn't have to look pretty, it's more effective when it isn't.
The idea is to scuff the rim diagonally so the pads have a little more to bite into. Be careful not to grind too much, you just wanna ugly that mirror-finish so your brakes will work. Wet performance will almost exist, and dry performance will improve.
If for some reason above is not an option, an even quicker and dirtier way is to cut some durable and coarse sandpaper to cover the pads like little booties, and ride the bike while holding the brakes down lightly (be sure you aren't sanding the tires!) to score the rim surface. This is even less effective, but it's better than leaving them the way they are. Be careful as your braking power will be dramatically increased while doing this, so don't honk on the brakes hard or go too fast. This can be a good thing, but using this for a fix would eventually cause a blowout by grinding the rim away.
Above all, NEVER wax the rims, and try to keep them clean, because oil from car exhaust and just on the road can gather on the rim surface, and eventually the pads themselves. Don't use the pads that were on the back wheel on the front, because they are likely already contaminated with oil from the chain (not to worry though, any more braking power and the rear wheel locks anyway). If your pads are glazed, use a file to take some material away and get rid of that shine. Using a hacksaw to cut 2 or 3 shallow slots diagonally in the pad should give water someplace else to go. Observe wheel rotation and cut the slots so that when installed, they angle opposite the angle of the front forks so that they sling water outward from the rim.
Don't cut too deep (maybe about 2mm or so), and don't cut too much. Too deep, and the pads will deform under braking. Too much and you won't have enough surface-contact for braking.
If you can afford it or are otherwise willing, replacing them with aluminum rims would be best (or at least the front, where 85% of your braking is). They are lighter, faster ("an ounce off the wheel is worth two off the frame"), and more durable than steel wheels.