Bicycle Mechanics - Derailleur Housing/Ferrule Problem

FD was not shifting to smaller ring. I thought it might be the spring in the derailleur; however, upon inspecting the housing at the shifter, I found that the housing wire strands had burst through the ferrule.

Causes and fixes very much appreciated.

Is it just bad quality ferrule, housing, install?

http://cache.nebula.phx3.secureserver.net/obj/OTc1ODU1N0RDRTZDRTk5MDBDQ0Q6ZDRjMGU3MDg2NmZjN2I0ZWQzZDYyNTEyYWM5YTMxMTQ=?u=54dd0024-d2aa-49ed-b52b-1c151d6175a4

http://cache.nebula.phx3.secureserver.net/obj/OTc1ODU1N0RDRTZDRTk5MDBDQ0Q6ZjhmYzExODc5YTA0ZTQwN2U0MDEwY2JlMDZjYjIwNTM=?u=c9a8138a-44eb-4cf9-b805-b17e426a33c1

Cause could be a thin ferrule not able to with stand the force by the end of the cable. I'd start by simply replacing the ferrule but would certainly make sure the exixting cable and sheath are in good shape. Maybe replace cable and sheath to be sure. If it is indexed shifting you cannot tolerate any give in the cable terminations.

are you using a brake ferule? they are different

Got new housing and ferrules....I think they were in fact for brakes.

Followup question.....with Tiagra shifters, could I go 105 FD instead of the current Tiagra?......I want to think yes, but making sure.

Thanks!

Got new housing and ferrules....I think they were in fact for brakes.

I've had "real" derailler housing ferrules do the same thing after lots of miles. Best way to prevent this is to use the right ferrules and replace the housing every 5000 miles give or take a few depending on your riding conditions.


Followup question.....with Tiagra shifters, could I go 105 FD instead of the current Tiagra?......I want to think yes, but making sure.

Thanks!

If you have Tiagra now that means your bike is 9 speed. A new 105 derailler will be ten speed. The cable pull will be correct but the wider 9 speed chain will rub on the derailler cage more than you'd probably like. Unless your current FD is broken, you won't gain anything by replacing it.

Thanks for the follow up....

I found an old-stock FSA 9 speed derailleur. Shop is letting me try it out. Not so much looking for an upgrade, but the Tiagra FD doesn't spring back to position (won't shift to smaller ring). I have tried cleaning spring and pivot points as best as I can figure but still no luck.

There are t basic types of ferrules, pressed or machined.

Pressed ferrules are made the same way as beer cans, have thin bottoms and zero structural strength. They're OK, (barely) for brake housing if the fittings are well made, but not at all suited for index housing. Their only virtue is that they're dirt cheap.

Machined ferrules come in many varieties but generally have thicker bottoms and greater structural strength. Brake ferrules usually have conical bottoms (inside) because it's easier to leave the shape of the drill point in place, but that can cause index housing wire to pinch closed binding the wire. Good quality index specific ferrules have flat or reverse conical bottoms so the housing doesn't get squeezed closed.

Whoever set up the OPs bike used whatever ferrule he grabbed first, ending up using the worst possible choice. A pressed ferrule, probably with a conical bottom.

I've always found the snug fitting plastic ferrules Shimano supplies with it's brifter and cable sets to be very durable and work extremely well. Most LBS's will have a box full of spares and extras.

Campy supplies excellent quality metal ones, which I suppose are theoretically better, but don't seem to work any better.

i always give my ferules the squeeze test. if i can crush it with my 2 fingers then it goes in the trash. the good quality derailer type ferules have thicker walls and bottom