Old Shimano 105 external cable routing.

[giverdada]

Hey Friends:

So I've been burning through the pleasure of building up my buddy's frankencross bike, and it's a bit new to me with the old school Shimano shifters. How loopy do those housings go before entering the downtube stops? I have it pretty loopy/uncut right now, so the guy can do a full 90˚ bar turn x-up and the brakes won't activate accidentally, but it may be a bit much. Anyone got a picture of 'The Perfect Housing Length'? I'm game. Thanks in advance for the help.

N.

[Louis]

Maybe some TDF pics from back when they were using that routing would help.

[oldpotatoe]

Originally Posted by giverdada

Hey Friends:

So I've been burning through the pleasure of building up my buddy's frankencross bike, and it's a bit new to me with the old school Shimano shifters. How loopy do those housings go before entering the downtube stops? I have it pretty loopy/uncut right now, so the guy can do a full 90˚ bar turn x-up and the brakes won't activate accidentally, but it may be a bit much. Anyone got a picture of 'The Perfect Housing Length'? I'm game. Thanks in advance for the help.

N.

Housing out of the levers, overlap where they cross with about a 1 inch gap.

Better to have the housing a wee bit too long than a wee bit too short.

[David Tollefson]

If it's not internally routed in the frame, I'd let the loops be long, but route them to the opposite frame stop. Then cross the cables under the down tube.

Otherwise, I like a loop that's a single arc from lever to stop, where the housing doesn't touch or cross.

[benb]

It depends on where the cable stops are.. if they are on the downtube I prefer to cross them in front of the head tube, and then if necessary just cross them again as they run down to the BB.

If you don't cross them in front of the Headtube and the cable stops are on the DT as you ride the housing will rub the paint off the HT. Crossing them in front with a little slack will prevent this. Some frame manufacturers actually specify to do this if you read the fine print. (E.x. my BH G5 specifically said to route this way in the frame instructions, although the shop never read the instructions and it took me a while to find the instructions too. But when I redid the cables this way I no longer had rub & the bike was quieter because the housing didn't slap against the frame when hitting bumps)

If the cable stops are on the HT it doesn't really matter. IIRC my Serotta Concours had the stops way up by the HT so the housing didn't slap/rub against the HT.

The only other thing is whether crossing them or not allows the shift cables to clear the front brake cable so there is no interference. But if this is a cross bike with cantis that won't be an issue.

I have never found how you route them to actually affect performance as long as you keep the housing long enough though.. this is all just aesthetics and hopefully not messing up the paint/finish.