If my disc brakes are rubbing and then also not grabbing hard enough on my bicycle what do I do?

Question

The problem is whenever I take off the front wheel so I can store it in my vehicle and then i put it back on when i ride it's too close to the pad on one side and I was curious how to adjust this. Do I Just adjust the break pads in and out or what? It seems like it's too close to the inside pad also.

And they are Mechanical Disc

Answer 1

If the rubbing is changing each time you mount/remove the wheel, then the problem isn't with pad adjustment.

There are lots of things to check, but it's all pretty simple. Break it down into areas and check each of them: cable/housing, rotor, hub, fork, caliper, lever.

First check is the rotor....as said above, watch it spin to see if it has a small bend in it. If so, try to fix it or replace it with a new rotor. Check to see that the rotor mounting bolts are tight and that the rotor is sitting flush on the hub. Also check your hub for proper adjustment....loose hubs will allow the rotor to wobble a little and it can change with skewer clamp pressure. Also look to see that your axle isn't bent, which will change alignment each time you mount the wheel and it's off center. With the wheel off the bike, inspect your fork to make sure the dropouts aren't twisted and that the sliders aren't loose, indicating worn or broken bushings.

If that's ok, check your cable to see that it's not binding or needs lube (or new housing). If the cable isn't proper, the pads can't return to normal position the same way every time. The bell end could be sitting crooked in the lever, too, so if that shifts when you brake hard, the cable tension will fluctuate every time it does that. Also, if your housing ends are loose in their holders or able to bind up somehow....same problem.

Next look at your caliper with the wheel removed and the cable detached. Move the arm and feel it's motion. Does it slide smoothly and is the return spring strong enough to move it all the way home when you release the arm each time? If not, you may need to overhaul/oil the caliper, or increase the return spring pressure if yours has that feature. If all is good there, remove the pads and see if the pad spring is bent or not springy enough.....sometimes they get damaged when installing the pads. Also, clean out the place where they sit in the caliper, and sand or steel wool the pad backings....this is all to be sure that the pads are not hanging up in the caliper when they move.

If none of that works, you might oil the lever pivots and adjust the spring tension there, or try a new lever with a strong return spring to see if that helps.

After all of this, install and align the caliper with a good flat rotor and then adjust the pads properly. Rotors bend easily sometimes, so be careful with it when you're storing the wheel off the bike.

EDIT: As for stopping power, clean off your pads and rotor with alcohol. A better way to do it is to make a paste with Ajax and scrub them clean. Also, if you haven't already done it, disc brakes need to be "burned in" when they're new so they'll achieve full stopping power. You need to go fast and brake hard several times, or get on a loooong downhill and drag the brakes with medium pressure, ending with a hard stop. A parking garage is great for this (you can ride the elevators back to the top), or a big hill and a friend in a car to help make it easier. Do it 5 to 10 times until the brakes start feeling grabby. When you burn the brakes in hard like this, parts of the pad material will embed themselves in the pores of the rotor surface and make a really nice mating bond between the two. Then, as long as they're both clean and free of oil or grease, you'll have good disc brakes.

Answer 2

It is tough to say without knowing what brand and model brakes you have.

Assuming you have MECHANICAL disc brakes (ones that are cable actuated) there are some quick things you can check:

1) Clean the rotors with denatured (NOT isopropyl) alcohol (available for about $2 at a drugstore);

2) Spin the wheel slowly. Is the disc bent? If so it can be straightened by carefully bending back using an adjustable wrench fitted over the disc and gently pulling or pushing the wrench until straight. Heat buildup can do this as well as damage from things getting caught in the disc;

3) When pulling the lever does the lever bottom against the handlebar? If so, the cable needs to be adjusted to remove the slack. Turn out the barrel adjuster on the brake lever until it is halfway out. Loosen the fixing bolt on the caliper, and while pushing the caliper arm closed, pull the cable and retighten the fixing bolt. Turn the barrel adjuster back in;

4) Remove the brake pads, clean them by sanding lightly with 180 grit sandpaper, then reinstall and readjust. If the pads have reached the wear marks or if they have stains from oil or lube penetration, replace them and readjust everything;

5) If these brakes are on a department store bike- like from Walmart or Target or Costco you will probably have no luck at all. They are cheap brakes designed to meet the absolute minimum safety standards... trust me, that is NOT too good.

Answer 3

With mechanical discs it somewhat is purely approximately impossible to get the brake to thoroughly quit rubbing by way of fact it somewhat is consumer-friendly that for the period of easy terms one ingredient of the caliper strikes, forcing the disc to distort extremely and forcing it into the different brake pad. So, except you may surely tell that this scraping is slowing you down, it somewhat is established.

Answer 4

I bend the disks a little by hand every once in a while so they don't rub.

You don't have to take the disks off to sand them. Just hold some sandpaper to the disk and spin the wheel! Don't forget both sides. Sanding makes a huge difference.

Answer 5

I'd suggest you rip them apart and have a look!

Can't say I know much about bike disc brakes but if I cast my mind back to my Lambretta days, I would say they are worn and sticking!

If you feel confident enough to take a look, then do it - otherwise, it's the bike shop for you!

Best of luck mate.

.

Answer 6

if you dont want to take off the pads yourself and look, then get a bike mechanic to do it for you. good luck!

Answer 7

need info,
are they hydraulic or bb/mechanical.

regardless a new pair of pads and an adjustment wont kill you. your lbs should be able to do both and diagnose any further issues.