Hidden wire brake sensor - too tight?

[pajtaz]

Hello,

I bought 2 hidden wire brake sensors (HWBS) from pswpower (part number MS-BK-1R) and I tried installing them last night. I tried installing them at the end of the brake cable, just before the caliper. I have disc brakes, if it helps. Anyway, it was difficult to insert the brake cables. After installation the sensors worked (initially I installed them the wrong way around) but it is obvious that the HWBS is installed too tight since the calipers get stuck after pressing the brake levers. Calipers do not return.

During installation of the cables several times I had single wires on the cable get snagged and start pulling away from the brake cable. Then I had to unwind them and cut them all the way back to the outer housing of the brake cable. Then try installing the HWBS again. I should have known HWBS are too tight. Now after removing the HWBS from both brakes, both calipers still do not return because I obviously damaged the brake cables too much during installation. Now I need to get new brake cables and probably new outer housings. I will do that today.

But I would like to try installing HWBS one more time. Can anyone tell me have they had the same problem as me? Am I correct to assume that the HWBS were too tight and the cables were never going to be able to move freely inside the HWBS to allow calipers to return? I do not know how "free" should the HWBS "feel" on the cables. Should the cables be able to easily slide through or should there be some tension? If cables should slide freely, what is the maximum diameter of the cable? I found some diagrams that say diameter of cable should be between 1.5 mm - 1.8 mm.

I am about to go buy new cables. I will take one of the sensors with me to test it. Thanks to anyone who can help answer questions above.

 

[Woosh]

you may have accidentally introduced a kink on the innercable. A new set of inner and outer cable will fix that.

Should the cables be able to easily slide through or should there be some tension?

it's normal that the innercable feels stuck when you try to feed it through. The gap for the cable is magnetically closed. Think of how you separate two magnets.

Push it quite firmly the first time.
The cable will go straight through without causing trouble.

By the way, install it always at the lever side unless you have a brand new innercable. The section that goes through the sensor needs to be straight. Once the inner cable is used, it will have a kink at the pinch bolt. Adding a sensor will move the kink inside the sheathing.

 

[pajtaz]

Thank you. I just bought new cables and before I did, I asked if I can test the cable from the shop with the sensor. Cable is 1.5 mm in diameter and it went in fine and it was able to move fairly well up and down. As you said, I definitely kinked the old cable plus the cables are at least 5 years old. It was time for new cables anyway.

I have dropped handlebars so I don't know how I would install them at the levers. Actually, the ones pswpower sells are the ones that should be installed at the lever side. Arrow on the sensors points to where the cable should be inserted but the wire is on the opposite side. So installing them at caliper side makes the wire come out from the bottom side, which is not optimal.

I will go install the new brake cables, outer and inner, and see what I can do.

 

[Woosh]

if you have dropbars, then consider installing it a few inches from the lever, like this (it's not my picture, check the arrow first):

 

[pajtaz]

I thought about that but after I was worried about again having problems with cable getting stuck due to the sensor. Also, in case I want to get rid off the sensors, it is easier to access them at the calipers.

I successfully installed the sensors after installing new brake cables. The old cables were terrible. It was clearly the cables because now calipers return without a problem and I had none of the problems with pushing the cable through. I also used the little plastic ends to assure sensor is not bending the cable. The plastic ends are inserted into the tensioner (is that what it’s called?) and then into the sensor.

I will take a few photos and add them later for anyone who might need help in the future.

 

[Benjahmin]

I installed those on two folders I did for my neighbour. Put them on the chainstay at the rear, near the brake, they work fine.

 

[Nealh]

Adding two brake cut offs adds to issues should one arise, on a bike only one is really needed on the rear brake.

 

[pajtaz]

Here are the photos of how I installed front and rear HWBS. They work perfectly so far.