Bicycle Mechanics - Frame broke, good time to replace cables?

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waterboy
11-20-04, 03:19 PM
I had a run in with an auto and broke my carbon frame at the lower headset when the fork broke - so it’s new frame time. My LBS pulled all the components off the old frame and now I for wait the replacement frame. I am wondering if this is good time to replace/upgrade the brake and shifter cables. I have about 10 months/4000 miles of use on the existing set. One half of me say no better time than now, since it all needs to reinstall anyway. OTOH, maybe my cables are fine. I didn’t detect anything specifically wrong prior to the wreck. The existing cables are what came stock- Shimano Ultegra group on a Trek 5200. Possibly there are better quality cables that may improve shifting/braking? My riding consists of 70% commuting and longer rides on the weekends.

Appreciate any feedback/thoughts.

Thank you.


roadfix
11-20-04, 03:23 PM
Your old cables should be perfectly fine unless your LBS finds them too short when re-installing them on your new frame.
This is often the case..... what I do is use the old longer rear cables (brake & derailleur) for the fronts and get new rear cables.

waterboy
11-20-04, 03:41 PM
Thanks.

What is a typical lifespan for cables? Do I just wait until strands start braking? I have been conscious of maintaining them- cleaning/lubing frequently.

- My other question is for all the weight weenies. Why do we still use wire for the cabling? In high performance flying and sailing most uses for stranded cable have been replaced by high performance aramids (Kevlar, Vectran, and Carbon). They are lighter and stretch less. Curious if this has been tried on bikes- or if its on the way. Wouldn’t make me any faster that’s for sure but I'm curious just the same.


Berodesign
11-21-04, 09:20 AM
Maybe the use of wires instead of aramids is because of the clamps on brakes and derailleurs. Wires are strong both in the direction of the strands but also perpendicular to the strands, in other words it is difficult to cut wire. Aramids on the other hand tend to be very strong in the direction of the strands but not very strong perpendicular to the strands, in other words, easy to cut. This was shown in a GP a couple of years ago when Villeneuve's tire came off in a crash. When the suspension failed, the cable of kevlar that was supposed to hold the wheel was cut off, and the wheel went away and killed a man. The cable was engineered to stand a huge amount of stress in one direction, but perpendicular to the strands it was so weak that the failing suspension cut it of like a scissor. So, to sum this up, the clamps are probably one reason for wire instead of kevlar. The higher cost for aramids and the relative low weight saving is another, probably the real cause. :) (Sorry for my bad english but as you might know, it is not my native language.)

seely
11-21-04, 09:41 AM
While its apart I can't think of a good reason for NOT replacing a $1.99 cable.

Retro Grouch
11-21-04, 09:50 AM
Geeze, man, they're only cables and housings for crying out loud! This is a no brainer:

1. Your replacement frame is likely to have cable stops in slightly different locations than your old frame did. That's going to require slightly different cable housing lengths.
2. The area where your old cables was clamped onto your brakes and derailleurs is going to be deformed and possibly frayed.
3. Never underestimate the performance benefits that a fresh set of cables and housings makes.