Too little cable tension or is it fine?

[fair weather cyclist]

Hi folks. I am building my bike and yesterday night I installed the rim brakes.

I'm a complete newbie, never done it before so I watched a fair amount of youtube videos and followed their steps. I learned a lot about how brakes work, what the barrel adjuster does, and so on. I've reached a point where I am almost 100% happy with what I've done; the brake pads make contact with the rims when and how I want them (I don't like the levers to be too loose and I've achieved that, the pads touch the rims and the wheels stop when the levers are midway to the bars. Happy with it).

I was expecting for the brake cable to have much more tension, although this could be completely unjustified as all my other bikes have got internal cable routing. Therefore I don't have anything to compare my work with.

So here is a photo of the rear brake cable, that is routed underneath the top tube. I'm pulling it so you can see the slack. Do you think it's fine or does it need more tension?

 

[fossyant]

It's fine, especially with SLR brakes as there are springs in the caliper and lever, reducing the need for 'stronger' springs.

 

[fair weather cyclist]

It's fine, especially with SLR brakes as there are springs in the caliper and lever, reducing the need for 'stronger' springs.

Thanks. That's reassuring.

Can't wait to finish it up and take the baby on the road. I'll still try the brakes from slow first and progressively increase my speed

 

[cyberknight]

depends on how much lever movement you want before the brakes bite, for me i would say to slack but its a preference.Test your brakes to see how effective they feel.

 

[fair weather cyclist]

depends on how much lever movement you want before the brakes bite, for me i would say to slack but its a preference.Test your brakes to see how effective they feel.

yeah, I don't know. Maybe I'm not doing it right. I've tried an option where I increased the tension using the barrel adjuster up to a point where the levers were super responsive and the brakes would bite immediately with barely any movement. Even in that configuration, the cable had the same slack as the one of the photo.

 

[Bike Tyson]

If its rattling the frame then you can put some brake cable donuts on it.

 

[figbat]

The only thing pulling on the cable when in a 'relaxed' state is the springs in the caliper; the tension in the cable will be a combination of the spring tension and the friction in the caliper pivot(s) and cable outer. So long as this tension is enough to move the pads clear of the rims with no sluggishness, and you are happy with the brake lever travel then I'd say you're good.

 

[Dogtrousers]

I happen to be sitting next to my bike so I just pulled the cable. It came out about the same amount as your picture.

But to be honest I've never thought to test that. As long as the brakes feel right and work properly ....

 

[fair weather cyclist]

Lol okay thanks. Maybe I was just being paranoid

Maybe it's just cables look much more tense on youtube videos

 

[Cycleops]

You really need to test it at the lever. The pads should sit just off the rims which should give an almost instantaneous haul on the rim.
You'll have rather more slack with MTB levers than STi drop bars.
Which do you have?

 

[Ming the Merciless]

As the above a ride on a safe flat bit of road will tell you whether the brakes are set right.

 

[fair weather cyclist]

You'll have rather more slack with MTB levers than STi drop bars.
Which do you have?

Neither. It's a tt bike.

 

[Cycleops]

Not familiar with those but you should aim for as little free play as possible at the lever before they bite without dragging. You'll know when you've got it right from feel.