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I own a hybrid Trek bike that uses V-brakes. When I apply the brake, the brake pads make contact with the wheel's rim, but don't apply enough pressure to actually brake the wheel. (No matter the level of pressure I apply, there isn't a substantial difference in the level of braking.) My immediate response was that the brake pads might be worn or too thin — so I installed a new pair. Unfortunately, the same problem persists.

I would appreciate any guidance on what might cause the problem. Do I need to find a better or thicker pair of brake pads? I apologize if this problem appears straight-forward; I am a newbie to both bike repair and the bicycle StackExchange community.

The question should be addressable based on the description above, but I have linked a very brief video here that demonstrates the problem.

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  • What is that funny gizmo on the cable, preventing the two levers from being drawn closer together?
    – Daniel R Hicks
    Commented Dec 29, 2020 at 3:58
  • @DanielRHicks Unfortunately not sure what you are referring to, but I was able to get the problem resolved. All is fine now.
    – Anshul Pattoo
    Commented Dec 29, 2020 at 4:03
  • @DanielRHicks I think you're referring to what I know as the "worm", a flexible rubber accordion that locks over the end of the aluminum noodle and is intended to protect the modesty of the bare cable. It should be quite flexible and so not interfere with the arm closing.
    – Armand
    Commented Dec 29, 2020 at 4:44
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    @Armand - In the video it appears to be a solid metal tube -- it seems to be what is causing the clacking sound. And if it is the "worm" it's misplaced -- should be attached to the end of the "noodle".
    – Daniel R Hicks
    Commented Dec 29, 2020 at 12:47
  • I see no metal tube, only the rubber noodle.
    – Michael
    Commented Dec 29, 2020 at 18:02

3 Answers 3

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From your recording, it looks like the left side arm is the only one moving. The right-side arm is not really moving at all when the lever is actuated.

I would adjust the small screw at the bottom of each V brake arm to equalise the tension of the retraction spring, so that both arms move away from the rim with about the same amount of force.

Adjust the barrel adjusters in the levers so they're 2/3 fully screwed in. This allows some adjust in either direction without bottoming out or risking the lever falling out.

Then back off the cable's pinch bolt at the top of the left side arm, and pull some inner cable through, maybe 3~5mm. Enough so both brake pads are barely clearing the rim. Tighten the pinch bolt.

When you squeeze the brake lever, the pads should touch the rim well before the lever runs out of travel. That's why you have minimal pressure on the rim.

Also check the housing is fully seated at both ends, and you may need to fiddle with barrel adjusters in the levers to get it dialled in.

This assumes your rims are running "true" with no side-to-side wobble. You need to just-barely avoid brake rub when the brake is open.

You can do this - just take your time. Do one brake completely and test it before you move onto the other brake.

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    Heartfelt thanks — I was able to successfully resolve the issue with your answer (don't know why your answer is downvoted).
    – Anshul Pattoo
    Commented Dec 29, 2020 at 3:58
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    @AnshulPattoo if you can see that Criggie's answer is downvoted, it is presumably your own vote that you can see, perhaps an accidental click when you were selecting the green tick for accepted answer. clicking the downvote, or even adding an upvote should remove it. I'll make a small edit to reset the timeout in case that has llocked your vote in
    – Swifty
    Commented Dec 29, 2020 at 14:01
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    It could also be excessive friction. There is a strand of the cable sticking out and the movement of the brake arms looks a bit jerky (not smooth and frictionless). New brake cable or cable+housing is probably a good idea. Or at least some lube/grease.
    – Michael
    Commented Dec 29, 2020 at 18:06
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I find it useful to narrow down which part(s) of the braking system are having issues.

  1. It looks like you've got a partially-frayed cable with a strand sticking out just past the "noodle" tube, and a long tail past the clamp bolt. I'd trim off the strand and cut the tail to be maybe 1.5" long. Use a crimp cap, solder or even strong tape on the end to prevent it from fraying. Also, the flexible rubber "worm" between the noodle end and the clamp bolt should snap over the lip on the end of the noodle so it stays fixed relative to the noodle.\

  2. Can the brake arms stop the wheel? Just grab the tops of the two arms and squeeze using your hand. If that won't stop the wheel then the pads need to be adjusted to be closer in or there's something blocking the linkage from fully closing.

  3. Another factor is whether the wheel is true or not. If not, the rim will "wobble" from side to side inside the brake pads when it is spinning and you won't be able to adjust the pads to be properly close to the rim.

  4. If you've got issues re: 2 or 3 above, fix them by e.g. following the instructions at parktool.com

AA makes good points about the other end of the system.

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If the force you are applying to the lever isn’t being transferred to the caliper so that the pads are not being pressed against the rim, there must be some flex in the cable housing.

Without more detail or pictures it’s not possible to determine exactly what the exact problem is. You can try tracing the cable from the lever to the caliper looking for issues.

You do not specific if the front, rear or both brakes are affected. If they both are there is a chance the bike was not built or adjusted properly. If you are not familiar with bike repair or maintenance having a local bike repair shop take a look may be a good idea.

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  • Thanks for the response! Both brakes are affected. It is actually difficult to get it looked at a repair store given that my region is on lockdown due to the pandemic (but I will further look into the possibility). I just attached a video — perhaps that may be of help.
    – Anshul Pattoo
    Commented Dec 29, 2020 at 3:17

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