Ergo cable housing burst

Alan said:

Yesterday, I was well into a long ride with lots of climbing, headed
up a steep hill, when my drive train started going bonkers. Would not
stay in a gear; kept upshifting. I was afraid the chain would break,
so I dismounted and could not find anything wrong with the
derailleur. I put it into a middle gear and forced my way up to flat
spot. As I dismounted, I saw the right der cable housing and nearly
choked.

The housing where it enters the trim control on the frame lug was
burst above the ferrule. Just shreds of split black plastic and wires
sticking out everywhere. The only resistance to shift against was the
inner housing, which was quickly collapsing.

With 50 miles and several thousand climbing feet to get home, I was
lucky to be able to apply a temp fix with duct tape (gather and wrap
the wires, and splint the whole thing against the frame) enough to
finish the ride.

This is a relatively new build (< 1 year) with only a few thousand
miles of use. My first Campy setup. I believe this problem developed
on this ride and was not the result of any trauma to the cable
housing. The black plastic housing seems quite thin and brittle
compared to gray Shimano housing, which seems tough and flexible.

Is this at all common? Should I not replace with Ergo housing?

Thanks,
Alan

What Andy said and make sure it's long enough. Sometimes too short der
housing can split like that.

Alan said:

Yesterday, I was well into a long ride with lots of climbing, headed
up a steep hill, when my drive train started going bonkers. Would not
stay in a gear; kept upshifting. I was afraid the chain would break,
so I dismounted and could not find anything wrong with the
derailleur. I put it into a middle gear and forced my way up to flat
spot. As I dismounted, I saw the right der cable housing and nearly
choked.

The housing where it enters the trim control on the frame lug was
burst above the ferrule. Just shreds of split black plastic and wires
sticking out everywhere. The only resistance to shift against was the
inner housing, which was quickly collapsing.

With 50 miles and several thousand climbing feet to get home, I was
lucky to be able to apply a temp fix with duct tape (gather and wrap
the wires, and splint the whole thing against the frame) enough to
finish the ride.

This is a relatively new build (< 1 year) with only a few thousand
miles of use. My first Campy setup. I believe this problem developed
on this ride and was not the result of any trauma to the cable
housing. The black plastic housing seems quite thin and brittle
compared to gray Shimano housing, which seems tough and flexible.

Is this at all common? Should I not replace with Ergo housing?

Thanks,
Alan

On last year's Hell Week a friend burst the shift cables on his STI
bike. Both cables on the same day. He had about 50 miles of hills to
get back to Fredricksburg to get to a bike shop and get new cables. I
think he was left with 42x14 as the single gear. These were old and
well used STI cables.

Let's see... you didn't mention it, but there WAS a metal ferrul in
use, right? This is rare, and it was either a defective piece or (most
likely) too short a piece making too sharp a bend.

FWIW, I've had Shimano housing burst that way as well.

Alan said:

Yesterday, I was well into a long ride with lots of climbing, headed
up a steep hill, when my drive train started going bonkers. Would not
stay in a gear; kept upshifting. I was afraid the chain would break,
so I dismounted and could not find anything wrong with the
derailleur. I put it into a middle gear and forced my way up to flat
spot. As I dismounted, I saw the right der cable housing and nearly
choked.

The housing where it enters the trim control on the frame lug was
burst above the ferrule. Just shreds of split black plastic and wires
sticking out everywhere. The only resistance to shift against was the
inner housing, which was quickly collapsing.

With 50 miles and several thousand climbing feet to get home, I was
lucky to be able to apply a temp fix with duct tape (gather and wrap
the wires, and splint the whole thing against the frame) enough to
finish the ride.

This is a relatively new build (< 1 year) with only a few thousand
miles of use. My first Campy setup. I believe this problem developed
on this ride and was not the result of any trauma to the cable
housing. The black plastic housing seems quite thin and brittle
compared to gray Shimano housing, which seems tough and flexible.

Is this at all common? Should I not replace with Ergo housing?

Thanks,
Alan