Cable housings

[potosr]

Hi. I want to install new v-brakes but I don't have the old cable housings. How to determine their correct length?
I have seen many videos about this, but I think your explanations will help me more.
If there are general rules on how to determine the correct length of cable housings (brake cables, gear cables), I would be very happy if you could tell me them or where I can find out about it.
PS. If this problem has already been discussed on the forum, I apologize and please indicate where I can read.

 

[Cycleops]

Just take the cable from the lever bring it down to where the top of the ‘noodle’ sits, after having first installed the V arms, holding the noodle in place. Then move the fork from side to side to make sure the cable clears the head tube without too much rubbing (rear brake) and there’s no tight spots using sufficient cable housing to making sure the cable runs in a smooth arc, mark the position. If you’re worried about the cable rubbing you can buy rubber tubes that slip over or make your own.
Use a cable cutter if you can, or a good scissors cutter and clean up the cut with a file.

 

[Ajax Bay]

Adding to @Cycleops advice:
Then move the fork from side to side to their fullest extent . . .
If you’re worried about the cable rubbing you can buy rubber tubes that slip over or make your own or apply some 'helicopter tape' to the frame.
. . . clean up the cut with a file and use a nappy pin (or similar) to ensure a clear 'ole.

 

[potosr]

Thanks for your advices, they were helpful for me.