Cracking Jagwire L3 housing - red color

Equipment
1

Just wanted to get a couple of opinions/thoughts on a problem I had on my XC bike recently. While out on a ride my left derailleur stopped working suddenly. My immediate thought was a snapped cable, but it wasn’t! The red Jagwire housing between the left brifter and top tube had cracked open and would collapse on itself and suck up all the tension, thus preventing the cable from doing its job. It’s the first time that I had even seen a housing split open, but it’s not a new bike so I didn’t think much of it. I replaced the housing with a brand new one and put the bike away while I was on vacation.

The very next ride I did on the bike, the rear derailleur stopped working for the exact same reason. This time it was the red Jagwire between the right brifter and the top tube.

IMG_20250824_143744
IMG_20250824_1437441920×530 70.2 KB

So, a few questions:

  1. Has anyone ever seen this before? I’ve had bent housing or ends that prevent clean shifting, but I’ve never seen a housing split open before.

  2. Is it possible that having longer cable lines can increase the odds of this happening? This bike has more/longer housing than I’m used to seeing. By having more housing, and thus more curving, is the cable tension acting more on the side of the housing than it would if the cable was straighter?

  3. Does anyone have any thoughts on manufacturer’s defect, or a material that gets brittle as it ages? This bike has a combination of this cracking red Jagwire L3 housing and a generic black one at various places. The jagwire seems thinner and seems less flexible. What are the odds that ONLY these red Jagwire ones would crack within 1 ride of each other?

I appreciate input from any experienced / amateur bike mechanics like myself. I love learning about this stuff. I am almost happy it happened because I was getting bored of the regular mechanical failures. This was something new! :smiley:

2

It’s unusual, but old housing and sharp bends can lead to this. It’s not the length of the housing but the radius of the bends. Tight radii put much more stress on the housing (and add friction between the housing and cable). Usually, when installing a new cable/housing, the goal should be to minimize tight radii of bends and allow enough slack to not bind during movement. Too short can restrict movement and cause sharp bends. Too long usually is less detrimental but can be where it has to bend back. I have some ancient jagwire housing on a few bikes but haven’t had this happen to me.

3

Thanks so much for this feedback. There definitely weren’t any sharp bends…if anything I was thinking the opposite. The bike has very big radii compared to what I’m used to…but still not as much excess as my mountain bike. I will chalk this up to a bad batch of housing that hit it’s limit just before the 10 year mark. I still find it amazing that both sides failed at about the same time. There is still a bit more of this red housing on the bike but on the frame as opposed to the handlebars. Hopefully because these parts never move I won’t have to change those out ever.

1 Like