Unpopular opinion: Stop putting new cables on bikes with rusty housing

I see it all the time at the shop, people swap out frayed shift cables but leave the old housing on. Did a tune up on a Trek hybrid last Tuesday and the owner said he just had new cables put on last month. I pulled the housing off and it was rusted inside, making the shifting feel gritty and slow. You're basically wasting your money if you don't replace both, right? Has anyone else had customers argue about this after you show them the rust?

3 comments

3 Comments

stellat463d ago

lol I mean yeah ideally you replace both but is it really that deep? I've thrown new cables on old housing before and it worked fine for months. Maybe I just got lucky but it feels like overkill sometimes.

flores.emma3d ago

Saw a mechanic on YouTube explain how rust flakes act like sandpaper on new cables.

grantw413d ago

Nah, it's not just about luck... rust flakes are tiny but they're basically grit. When you slide a new cable through old rusty housing, those flakes grind into the cable liner and create drag over time. Even if it feels smooth at first, that drag builds up fast with normal use. I've seen cables snap at the bend points because of that hidden wear... it's not a maybe thing, it's physics. You're adding friction where there shouldn't be any, and that causes the cable to stretch and fatigue way faster. It's one of those things where it works till it doesn't, and then you're stuck on the roadside.