Gearchange problem - bottom bracket shield?

[Fastpedaller]

Yesterday (despite cleaning the bike recently), the muddy Norfolk roads did their worst - When I changed to a higher gear it didn't happen until further shifter movement, which then put me in an even higher gear than I wanted! Time for maintenance, and a clean of the cable guide on the underside of the bottom bracket, followed by a little silicone grease had it all working again. It made me wonder about making a 'shield' to fit over the guide and could be clamped in place between the BB and the cable guide, with an access hole for the allen key to hold everything in place and act as a drain hole for any water that enters. An issue would be the difficulty of inserting the cables, unless this is done before the cover is added, or a clip-on cover. Any creative 3D printer users on here?

 

[Sharky]

You could try with a short section of cable outer.

 

[Shearwater Missile]

Yesterday (despite cleaning the bike recently), the muddy Norfolk roads did their worst - When I changed to a higher gear it didn't happen until further shifter movement, which then put me in an even higher gear than I wanted! Time for maintenance, and a clean of the cable guide on the underside of the bottom bracket, followed by a little silicone grease had it all working again. It made me wonder about making a 'shield' to fit over the guide and could be clamped in place between the BB and the cable guide, with an access hole for the allen key to hold everything in place and act as a drain hole for any water that enters. An issue would be the difficulty of inserting the cables, unless this is done before the cover is added, or a clip-on cover. Any creative 3D printer users on here?

I had thought about that too and tried it, attaching a piece of plastic over the cables. I attached it via the bolt that holds the btm bracket guide in place. It was kind of all right but crud still went underneath it. In the ideal world the cables under the btm bracket would still be in their outers. Anyway, I ditched my effort, but check and clean the guides more frequently.

 

[MichaelW2]

Cable outers gather water unless the run the whole way.

 

[Ajax Bay]

Frankly you're better off keeping the arrangement as designed. Any kind of 'shield' would function as a crud gatherer, potentially generate crud friction, and deter a simple clean and with it any early detection of a strand of the cable parted.
Include as frequent maintenance a simple clean and a quick wipe with a GT85 paper towel followed by application of grease to both cable 'channels'.
Ride on.

 

[Ian H]

A longish flap on the front mudguard would keep it clean. Assuming you have mudguards.