What is the point of gear outers?

gt-arrowhead

On my first ever build, i bought gear and brake cable outers separately. Then the second time round i decided that id just use brake outers on the gears. Since that time i never ever used gear outers again. I have never ever had any sort of issue by using brake outers on my gears.

I was fixing a friends bike yesterday, and it involved taking off the gear cables. Then it made me think. What is the actual point of having a different outer for a gear cable, and a different outer for a brake cable. If anything, using brake outers on gears are better, surely. As they are larger, so technically are less likely to produce friction with the gear inner.

Am i missing something? Why isnt it a usual thing to just use brake outers for gears too. Its easier, especially if you get a bit of flaring, and as far as i can see, the only difference is that you are going to have less friction by using a brake outer due to the larger diameter.

njee20

Brake outers have a coil of metal running through them to make them strong in compression. Gear outers have wires running lengthways through the cable to make them stiffer.

Monty Dog

Cut open the outers and you'll see they're constructed differently - gear outers use a wire reinforcement along the length whereas brakes are spiral reinforced - years ago we got away with spiral for both, but Shimano messed it up for everyone. Modern gear systems rely on the outer not compressing to maintain accurate shifting - keep using brake outers and you'll find you can change gears when you turn your bars!

gt-arrowhead

Thanks for the replies.

That does make sense now. I totally forgot about the different reinforcements they had. I still get accurate and reliable shifting even with brake outers though. And shifting while turning? Thats never happened!