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.

Kai Winters

Smooth but not excessive lines are best for a smooth shift.
Use the new housing to measure from point A to B then cut. Better to cut a bit longer then trim to fit than to short and waste housing.
Make sure to use a proper housing cutter tool or you may be very sorry. Same for the cables.

Bike Gremlin

For me, it's easiest to just measure - from housing stop to housing stop.
With handlebars, I make sure to measure when they are turned so the longest possible housing length is required (not sure if I've explained this clearly).
I go for the shortest possible, without having extremely sharp bends (though, despite the popular belief, it's the total angle change, not the curve radius that causes more friction).

For more details I wrote this article (with pictures, explanation, and Mr Mark Barrilleaux's friction test results):
Routing brake and shifter housing and cables

Relja

potosr

I would be grateful if you could tell me more precisely where A and B are located on the front brake.

andrewclaus

The front's easy. You don't have to allow for wrap around the head tube when you turn. Measure a smooth arc from the lever to the noodle. For the rear, turn the bars all the way to the right and leave a few cm around the front of the head tube.

Read Sheldon Brown's article on this in his website.

JohnDThompson 

The housing should be long enough to allow turning the handlebars without tugging the cables, without any abrupt bends or angles, and not so long to leave big loops of housing at the levers, derailleurs, and calipers. The housing ends should be dressed with a grinder or file after trimming, to remove any burrs and allow the housing to seat properly in the ferrule or housing stop. Use a pointed object (I use an old spoke, ground to a point) to open the plastic housing liner. Compressionless derailleur housing needs ferrules on each end to prevent the housing from splaying in use.

smd4

Those aren’t bike-specific terms. They just refer to the starting and end point of the housing, which in this case is the brake lever and the brake itself. For the front brake, this should be the absolute easiest length to measure.

As mentioned above, do you possess appropriate cable cutters? This tool is crucial.

Schweinhund

A bit long in the housing is better than a bit short. A little long won't apply brakes or cause shifting when you turn tight like too short will.

Gresp15C

In addition to the advice given here, I suggest actually looking at a bunch of bikes, to get an idea of what the right amount of curvature looks like in front.

My habit when cabling a bike (often because I've thrown it together from parts) is to route the housing from the rear brake through its guides, up to where it departs from the frame in front. Then I hold it in what looks like the correct position, more or less, cut it off, and prep it for use. Done.

"Looks about right" will get you into the ballpark.

veganbikes

Also not as an install point but just in general get the best cables and housing you can don't go for cheap stuff go for nice polished uncoated stainless cables and good stiff compressionless housing. It will greatly improve your braking for little money spent and this is true for linear pull brakes, road caliper brakes, cantilevers, mechanical disc brakes and with some different housing mechanical shifting as well (you would also need a different cable but the actual style of cable would be the same). Also good stiff brake shoes and really high quality pads (the two should be separate for better braking) will help out a huge amount again with low costs associated with them.

Everyone looks like they have given good install pointers and tips but I like to mention the above because it really improves things in a really cost effective way that actual brakes and levers may not do to the same level.

etherhuffer 

Excellent advice. Also, some kits come with a fitting on each end of the cable. You cut the cable appropriately. But even with good cutters the end often frays and won’t go down the housing. Better to buy the specific cable needed

smd4

Never once had that problem.

etherhuffer 

Specific to Jagwire coated cables mostly. Park Tool cutter. Good quick cut but still frayed out.

smd4

I'm using Alligator cables now, and I use an ancient Shimano cable cutter. Even if the cable frays, it's pretty easy to just twist the individual wires back.

veganbikes

Jagwire doesn't do coated cables. The Park Tool Cutter is fine but it isn't the greatest of tools, Felco or Knipex is the way to go on that front. You should have issues with a decent cutter that is properly sharp and using good pressure and an even cut.
'
However agreed that the kits are nice, it comes with everything and plenty left over for future repairs.

etherhuffer 

Jagwire makes a Teflon coated wire

veganbikes

Which one do they make that is coated? I don't see it on their website and haven't seen it in real life. Shimano and others make some coated stuff but not Jagwire as far I know and can tell from their own website. They make cheap or slick stainless and galvanized, polished or ultra polished stainless but nothing coated that I can see.

etherhuffer 

I think this was one I got long ago. It had a dark Teflon coating. https://cambriabike.com/products/jag...kaAmt6EALw_wcB

veganbikes

Well shiver me timbers, that must be an older legacy product. Alrighty then I guess I was totally wrong here.

etherhuffer 

No worries. Like I said earlier, it cut poorly and frayed easier. Having thought about it a bit, the world doesn’t need more fluorocarbons in circulation either. Sure they are more slick, but for vintage use I am not sure they are needed. I silicone lubes are plenty good and don’t attract dirt like oil lubes. Anyway, just my 2 cents

smd4

Agreed. I didn’t find the Shimano Teflon coated cable did anything except get fuzzy. I’ll stick with the Alligators.

veganbikes

Yeah that is probably why the don't make it anymore. Their polished cables are so much better than any coated cables and yeah no added flourocarbons.

Shimano should learn from them and get rid of the coatings but they are who they are and do what they do.

potosr

I'm glad that my post has generated so many discussions from which everyone can definitely learn something, especially those less knowledgeable like me. Thank you very much.