So about those brakess...HELP!!

[mrbiff]

OK, so seeing as how I've never built or worked on a bike before, it appears that cutting, welding and assembling the frame is the easy part. The brakes really have me scratching my head. I understand how they work and I understand all of the adjustments. (I am using side pull caliper brakes) My problem is this: I have to pull WAY to hard on the brake lever to get the brakes to even CONSIDER slowing the bike down. I set them up by using a clamp to hold the pads to the wheel rims and then pulled the cable taut with a pair of pliers and then tightened the cable-holder-nut-thingy. When i released the clamp, the pads stayed about 2mm away from the rims. This seemed quite normal to me. But when I pull that lever, the brakes contact the rims, but with not nearly enough force to slow the bike down, even if I'm just standing next to the bike and pushing it. (I have big, long brake pads. The entire braking surface is contacting the rim.)

Help!???

[trikeman]

Sometimes bike manufacturers put brake levers and caliper arms on bikes that are way too small and often times they flex too much. I have never liked adjusting brakes, but I find that even the good side pull brakes on my road bike (Shimano 105s) work really well when adjusted, but the ones I get off cheap bikes don't. The caliper arms I saw on some cheap walmart bikes recently are so thin that they are not worth having and are downright dangerous. Old 10 speeds, including one of my old Schwinns had brake levers that came around to the front of the handlebars. They were very convenient because you could brake with your hands on the front of the bars. They were so long and spindly that you could barely stop with them, since most of the force was taken up bending the levers. Modern bikers call them "suicide levers" for that reason. They could have made the levers thicker, but it would have been heavier and cost more.

It is also important to have good cables, as short as possible and with as few bends as necessary. You don't want all the force taken up in moving the wire through the cable, as opposed to applying force to the brake.

One other thing to consider is that side pull brakes are about the worst design you can have. Next up would be center pull and then the linear pull and cantilever brakes found on most mountain bikes. Many of us put disc brakes on our DWs but its probably overkill. A good rim brake is as good or better (it actually can exert more stopping torque on the wheel) than a disc brake when its clean and dry and you are not going down a lot of hills. In order to work a brake must have good cables, and parts that don't flex like rubber when you squeeze them.

It sounds like you have been snugging the cables up tight, so I suspect you may have some inadequate caliper arms and/or levers.

Sheldon (RIP) has a lot of good info on his website at

http://sheldonbrown.com/brakes/index.html

[mrbiff]

Thanks! Sounds like a brake upgrade is in order!

[TheKid]

Another thing to consider is stretch. According to my LWB owner, new cables often have to be stretched before assembly, especially the cheaper ones. He said he gets a lot of Wallyworld bikes that are just a few weeks old that need brake and gear adjustments, and most times they went out of whack because the cables stretched. Some need readjustment several times before they are totally stretched out, so he suggested stretching new cables a few times before assembling the brake and gearing assemblies. The way to do it, is to assemble the cables, and slide the crimp ferrule on. With one hand, pull the cable as tight as you can, and use a pair of pliers to slide the ferrule tight to the stop. Clamp down on the ferrule, and pull as tight as you can. you'll start to see a small gap between the ferrule and the stop. Keep pulling and relaxing the cable until the gap stops getting larger.

[AtomicZombie]

Two things I have found that make brakes inefficient...

1) Chrome rims. Avoid these on all but choppers or fun bikes. Only an aluminum rim will provide enough grip to the pads.

2) Crappy cables and levers. If you can't slide the cable through the housing with ease, then it needs to be replaced. Good levers also make a huge difference.

Brad

[trikeman]

I second that chrome rim thing, especialy when they are wet. I won't even buy a thrift store bike that doesn't have alloy wheels.

[TheKid]

The levers also have to be the right ones. If you use cantilever brakes, you need cantilever levers, which give more leverage. The old brake levers don't work well with them, if at all.

[mrbiff]

WOW! What a difference decent cable makes! i went to Big Shark Bicycles here in St. Louis and paid $60 for new brake and derailer cable. I can stop now!! Thanks, all for your advice. i expect I will upgrade my brakes when I've got and extra hundred or so lying around, but until then, I can stop!!

[n9viw]

When I worked at a LBS, my method of pre-stretching cables was the same for derailleurs as for brakes: route the cable, slide it through the clamp, and take out ALL slack. Then, for brakes, just sit there and squeeze the levers as hard as I could for a few minutes, I could often generate as much as 1/4" of slack! For derailleurs, attempt to shift without rotating the drive (so it doesn't actually change gears). Have to be a bit more gentle with that one, but the effect is usually about the same.

+1 on the quality cables and housing... I always use teflon-lined housings and good quality cable. That ensures the cable stays 'slippery' much longer... the brake cables on my Cannondale are 12 years old, and the derailleur cables are 2 years old in the 12-year-old housings... the old ones started fraying at the cast ends! I should probably replace them anyway, but they still work well.