I've recently finished building up a 14" Scandal frame for my partner. The only practical way I've found to route the hose for the rear brake is to run it from the lefthand lever straight down the non-driveside of the top tube where the hose guides are.
This seems fine except that the hose is pushed tightly against the side of headtube, due to the stiffness of the hose and the position of the first hose guide directly behind the headtube. Obviously I've stuck a frame patch under the hose but wondering whether this is likely to cause a problem (either to the headtube or the hose). Is isn't practical to run the hose around the front of the head, under the toptube and back out to the left side of the toptube do to the tight spacing and gear cabling.
My partners pre-built Giant has a gear cable routed the same way that's also very tight against the headtube and doesn't seem to have done any harm but obviously I want to get this right.
Anyone? Will a standard frame patch be enough or should I be looking at something a bit more substantial?
Sounds to me that you need to lengthen the hose.
Narrow bar and 'long' sideways routed brake hoses will make this worse I suppose (old shimano levers by any chance?) as the hose has a tighter curve to make to get round to the first cable guide. I think it is supposed to go that way though. Hold on... (shuffles off to have a look)
You have it the same was as my mate's (currently living in my conservatory lest his wife find out he has [i]another[/i] bike 😆 ) and he has a big bit of heli-tape over headtube/toptube junction. Spoils the anodized yummy matt-ness but at least it will stay black!
Thanks for looking. Yes the levers are sideways routed (it's a budget M445 setup) and the bars are narrowish XC one. The hose is pretty stiff and needs to bend back on itself to reach the first hose guide which sits tight behind the headtube, which is where it springs against the headtube. The small 14" size of the frame makes space tight and I don't think that there'd be space to fit a longer hose and route it around the front of the headtube and under the toptube (and it would then rub the other side of the headtube as it bent around to read the non-driveside hose guide).
I think that the same routing with a longer hose would still push the hose against the headtube whilst pushing up a longer loop in front of the bars.
I think I'll see have it goes and keep an eye of the state of the patches; I've got some 'copter tape on order.
I am sure some sort of protective patch will be fine. Lots of bikes are like this. Braided cables tend to be a bit more flexible, so work better on tight routings - although they are a bit more abrasive on the frame.