Strange brake binding problem

[Femto]

I've just picked up a new bike which has Tektro R538 brakes. I thought I was getting tired as I cycled to work today as it was getting increasingly more difficult to maintain a constant speed.

It turns out that, as I rode along, the rear brake was slowly getting tighter and tighter onto the rim!
I adjusted the brake out as much as I could but couldn't quite sort the problem out. The only way I could continue on to work without blowing a lung was to flip the cam open which is for when you need to get the wheel off and then to readjust the nut on the top of the brake. This left me with no rear brake to speak of but at least it wasn't permanently on.

What on earth could be causing this? It only seems to happen as I'm riding along and bumps in the road seem to make it happen more quickly.

Please save my sanity!

 

[mickle]

It aint built right - take it back to the shop.

 

[Femto]

Do they get closer to the rim when you pull the brakes (ok, obviously) and let go again, like they don't go back to their normal position?

Well, they seem to return okay when I operate the lever so they seem to be set up correctly as far as pad clearance etc but when riding, they seem to tighten up.
I found when it did tighten up, that if I gave the brake lever a firm squeeze, the brake returned to the normal position. It's almost as though the cable is getting a bit stuck on its way from the lever. I think I'll whip it into the shop and ask them to have a look at it.
Also, as I climbed the hill home yesterday, as it's a singlespeed, I had to get out of the saddle and pull on the bars. When I did, I could feel the rear (left) brake hood moving around as though it needs tignening up onto the bars. I'm not sure if it's possible to do that job without first removing the bar tape; something I'd rather not have to do.

The entire problem could be due to the slack lever/hood assembly. Reckon?

 

[Amanda P]

It does sound as if both problems are caused by the rear brake lever not being properly secured to the handlebars. As you ride, your weight is pushing the lever down the bar, which would pull more cable through and cause the brake to bind up.

When you climb, you're pulling on the lever, hauling it back up to where it started, freeing off the brake.

Mickle's right - that's not acceptable in a bike straight out of the shop. It's easy to fix, and shouldn't involve removing the bar tape. Take it back, make a fuss if necessary, and get them to fix it while you wait.

I reckon letting a bike leave the shop in that state is worth quite a bit of goodwill. Need any water bottles, spare tubes, stuff like that...?

 

[Femto]

Sorted it. It was the loose brake lever. Commuted 26 miles in total today and no dragging back brake. :-)

 

[mickle]

Kewl.

 

[Femto]

Yeah, I'm quite surprised such a small thing had such a dramatic effect on the operation of the brake. I've been mucking about around Manchester for a couple of hours this morning and it was totally fine. Slack brake levers eh. Every day's a day at school. :-)