Super tight brakes don't work

Question

My son is at an age where I could be buying him a new bike each year because he is growing, but instead I managed to pick up a free bike from someone who put it out for trash collection.

Only problem is the brake pads were worn to the end.

I have replaced the brake cable, tried two different sets of different brand brake pads and tightened everything until it can't be tightened anymore.

You can see from the pics that the brake pads are right up against the rims, but those @&$@#%s just don't stop the bike.

The pictures show the pads right up against the rims when the brakes aren't even engaged.

The only thing I can think is the rims. Any suggestions?

Answer 1

Reading the comments I am going to presume the problem lies with the rim/pad interface not generating enough friction rather than pressure from the brake lever getting to the pad/rim interface.

First step - Presume the rim is contaminated with something slippery. Clean the rim presuming its either oil or silicon based. Use an degreaser/solvent first to attack an oil based contamination, the use an abrasive cleaner and scrub well with a steel wool or aggregative nylon scrubber and plenty of soapy water to remove non-oil based contaminants. Don't worry too much about damaging the rim - if you can't get the brakes working do you want you son riding on it?

Now the pads - presume these, even if new, have been contaminated by the rims. Ideally buy new ones (Come to that later), second best and worth a try is to clean them with degreaser, soapy water then file or sand the top layer off.

Assemble them with a bit of toe in (front of pad hits rim first). Put them together. (Look here for good instructions). Now the brakes need to bed in. Go for a ride, and give them a dozen of so max effort stops from high speed (careful you don't do anything silly)

Couple of points: Are the pads good quality one like Koolstop? Cheap pads are often made of hard compound, take a long time to bed in and have low friction. If possible, get softer pads with more grip (and shorter life). The brakes are calliper brakes typical of road bikes, that offer poorer braking compared to V brakes and discs. Better callipers may help, but they do have a limit of how good they can get.

Answer 2

Surprised no one mentioned this: lever is not positioned well. It must not be clamped to the curved part of the bar. It should be moved closer to the handle. That will move the lever away from the handlebars, and give it and the cable more travel.

Also, the cable should be replaced and the cable housing straightened at the point it enters the lever.

Answer 3

Did you try the following sequence?:

1. Move the tension adjustor on the brake lever to the lowest (original) position. The tension adjustor is that little screw next to the brake lever.
2. Unscrew the screw which locks the cable on the brakes.
3. Press the brakes (the brakes, no the lever) using your hands to the rims and keep them in this position while...
4. While still pressing the brakes tighten the screw. Do not overtighten.
5. Release brakes.
6. Check if the problem is gone.

Also, using cable caps on the cable ends to avoid separate threads wandering all around is good.

• Tip: when installing brake pads install them at a very little angle, so that the front is slightly above the back. The brakes must remain on rims. This will make brakes less noisy.

Answer 4

I couldn't add this as a simple comment: use rubbing alcohol on clean paper towels on the rims and the pads until most of the black crud comes off. Also take pride in your work and wrap the loose wire strands with black tape or ideally crimp in a short section of brass tube.

Answer 5

1. Make sure that the cable is tight enough so that the brake levers do not "bottom out" when you squeeze them. When squeezed as tightly as possible the levers should still not bottom out.
2. Clean the brake pads and the rim face. Use soap and water, then wipe with rubbing alcohol. Get some fine sandpaper, slide it between rim and pad, facing the pad, squeeze the brakes gently, and work the sandpaper (turning the wheel slightly) to sand any glaze/grease off the pads.
3. Double check that the brake levers and the brake arms are "made for each other". If someone replaced the caliper brake levers with V brake levers, eg, then the force ratios would be way off.

Answer 6

No-one's pointed out that the ferrule on the lever end is not sitting flat. Could be that the pressure is being taken to distort that rather than pulling cable. Screw the adjuster in, and then pull the slack out.

While its disconnected, check that the inner moves through the outer easily. You would benefit from new inner wire and outers if they don't slide nicely.

The Brake pads look cheap, hard and nasty. Buy "koolstop" ones - you should be able to put a dent in the surface of the pad using your fingernail.

Answer 7

Some of these points have already been made, but you are at a serious disadvantage in your effort in that this type of long-reach sidepull brake system will barely work under ideal conditions. It's only positive attributes are that it is cheap and easy to install.

1. Disconnect the cable and adjust the center pivot nuts so that there is as little play in the arms as possible while still moving smoothly after oiling both arms at the pivot. Put a drop of oil on each end of the spring where it contacts the arms, as well.
2. Check the cable while it is disconnected. Is it moving smoothly in the casing? It is easy to pull the lever back to it's relaxed position by pulling the inner wire at the caliper? It's frayed enough that I would replace it, anyway. Lube the new wire. If the bike has a fair amount of wear, or looks like it's spent a lot of time in the rain, or if the casing is kinked at all, replace it as well. Make sure the ends of the cable housing are ground square. Be sure to open the end of the liner with a suitable tool (I use tapered steel scribes). Put some light oil or silicon lube on the cable wire before threading it through. Definitely replace the casing if it is not lined.
3. Move that lever so that it butts right against the grip. It needs to be on the flat area of the bar. This will give a slightly longer pull. Make sure the lever moves freely when the cable is not connected. Put a drop of oil on the pivot.
4. Check the brake pads. There's nothing you can do to improve the performance if the pads are hard and some inexpensive pads were lousy when brand new. Don't bother to clean them. Sanding the surface that meets the rim will be more productive, but good pads can make all the difference. On the other hand, those are better pads than the originals, so check them before replacement.
5. Lightly sanding the braking surface of aluminum rims isn't a bad idea, but it won't last very long, either.
6. Be sure to put an end cap on that new cable wire. Those frayed cables are a safety hazard.

Answer 8

The others have answered the lack of braking, so let me answer this

The pictures show the pads right up against the rims when the brakes aren't even engaged.

You mean they are rubbing? You should try disconnecting the cable and seeing if they move away. Else it could be that the previous owner replaced the wheels to ones that were too big for the brake system. You can try remove the pads and move some washers to the outside of the arms to move the pads a little away from the rim.

If the cable disconnect causes the arms to move away inspect the cable line and connect it to the arms taut but not under too much tension.