Handlebar adjuster - brake sensor

[Peter Woodier]

I have a Powacycle Salisbury, and I am aware that when brakes are applied, the power cuts out. There is an adjuster nut by the back brake on the handlebar, but under what circumstances would I need to turn the adjuster? What happens if I tighten it or loosen? I have the occasional problem where when I squeeze the brake lever, the power doesn't kick in again on release. Any advice appreciated. Thanks.

 

[Ian Spencer]

The adjuster on the handlebar brakes are there to compensate for wear of the brakes. V-brakes (the brakes which have two separate levers either side of the frame pulled together with the cable between them) have a very short amount of travel so as the pad wears, the brake lever will tend to come closer and closer to the handlebars. Rather than adjusting the cable on the brake, there is this system for adjustment. The brakes should be "just off" and you unscrew the adjuster until that is the case - reducing the lever travel. Don't overdo it though, as if you extend it right out there is not enough thread and the adjuster gets pulled out when knocked, damaging it or the lever. On a cycle service, I'd expect a cycle repairer to reset the brakes so that the adjuster is fully screwed in.

The power cut-out is a switch inside the lever. If you apply the brake, you should be able to see a little lump.

If the power doesn't kick in, then there are two possibilities - firstly that the brake handle itself is not returning to its home position so is not pressing the switch. You sometimes get that if the cable is a bit loose or the lever has had a knock and then is not moving smoothly. The other possibility is that the switch itself is not being pressed home due to wear. Try sticking something in and working the button and see if it pops in and out freely. It's not a serviceable part if the switch is sticking, but the brake levers are not that hard to fit (getting the rubber grip off and on is a skill though!).

 

[Deleted member 4366]

If it's the thing I'm thinking of on the back of the switch where the wire comes out on the inboard side of the brake lever, it's not an adjuster. It's a retaining nut that holds the switch in place, so should be done up as far as it goes to hold the switch right back. If it were loose, it would make the switch less sensitive, but yours is over-sensitive, so isn't the problem.

There's additional adjusters for the brake cable. One is where the cable comes out of the lever and the other is at the brake caliper. These take up the slack in the cable to make the lever operate the brake at the right point, but as the brakes wear, they usually max-out, so you have to shorten the cable where it clamps to the caliper. A properly adjusted cable should help.

The brake lever should have a spring in it that makes it return regardless of brake adjustment, so if it isn't fully returning, you have a stiff cable or lever, or even possibly a broken spring. If you haven't already done it, make sure that the cable and lever pivot are well lubricated. Check that the cable hasn't frayed a bit. A new cable is only £1.50 in Wilkinsons, so try one of those if all else fails.

 

[Peter Woodier]

Many thanks for the replies. It is an adjuster for the switch, not the brake cable tension. I will adjust it as suggested, and do a trial and error test. The problem I have is that I have to literally stop the bike and restart for the power to kick in again. Not a big problem, it happens once in every trip, but when in busy traffic and you need to get cracking it causes problems as the bike is heavy. Cheers.