Routing the rear mech cable

[cycle tramp]

Renewing the rear deraillure cable on my self build - I could go along the top tube and down the seat stay, or along the down tube and then the chain stay - which route has less friction?

[Eyebrox]

Depends on the angles. The angle at the seat post is sure to be more acute than the one at the bottom bracket. The cable will work better on the route with less of a bend.

[Samuel D]

Friction with a new cable is proportional to the total angle through which the cable bends.

However, cables will wear a groove into the lined insides of housings faster on sharper bends and perhaps disproportionately increase friction there as they wear. Imagine a vee-belt in a pulley.

[pwa]

That area near the seat post is problematic for rear brakes, so for a rear mech I would avoid it. It is a problem you don't need.

[reohn2]

Either way works well,but top/seat tube route keeps the cable out of road muck etc.

[hamster]

Either way works well,but top/seat tube route keeps the cable out of road muck etc.

I agree, but the muck and water then seems to run down the seatstay part of the cable and into the outer for the last bit.

It's the Law of Conservation of Misery. It works nicely with sealed cable setups though.

[reohn2]

Either way works well,but top/seat tube route keeps the cable out of road muck etc.

I agree, but the muck and water then seems to run down the seatstay part of the cable and into the outer for the last bit.

It's the Law of Conservation of Misery. It works nicely with sealed cable setups though.

I thought it would be a straight through out,my mistake.