No, they are just very high quality. The Shimano ones in particular are made of very fine wires (smaller gauge) very tightly woven and then polished to round. The bulk ones that many bike shops use are not nearly as well made; although the bike shop can buy the higher quality Jagwire ones in bulk. If I need housing, I generally try to buy the DuraAce sets on the net, but I also have the Jagwire ones if I am just redoing one for whatever reason. I tried teflon coated one time years ago and they did not work very well for me, but they might have gotten better over the years, I don't know.

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For certain parts stiffer is more important than lighter.

Do Power Cordz cope better or worse?

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r o y g b i v

I have no personal experience with power cords but have read of issues with the way certain brakes clamp them. You should probably search the forums.

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For certain parts stiffer is more important than lighter.

Hi yourdaguy, thanks, I you had this issue at all ... where any of the fine wires (1 or 2) have broken where they run through the BB cable guide?

I haven't had any issues. I generally replace cables between 2-3 years which means on some of my bikes they get up to about 5,000 miles. Cables are a maintenance item like tires and brake pads. They wear out and you have to replace them. I have had no issues using the high quality ones so if you are having issues and using the low quality ones, that might be the problem.

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For certain parts stiffer is more important than lighter.

Changing cables and housing should be part of a yearly or every other year maintenance depending on how often you ride and how much effort you put into maintenance. I strongly insist that you include brake cables as well - these are the last thing you want to break.

Cleaning and lubing your cables DOES NOT extend the life of a cable system, it only keeps it feeling smooth during its use-life.

It is a pain in the ass for the less mechanically inclined to do a full cable swap, but it is worth learning how to do for the cost saving alone, not to mention the care you will (hopefully) put into wrenching your own ride. In a bike shop context, a full-cable replacement is generally part of every extended tune-up and/or full-overhaul. I could do a full cable replacement (brakes and derailleur) in 10 minutes, including wrapping the bar with new tape, and quickly add $50-75 to for parts and labor on the repair bill. This gave the customer's bike that "new bike" feel and ensured reliable shifting and braking for the season.

Also remember: Traumatic loss of either braking or shifting functions while riding a bike has been known to cause face-to-tarmac problems...

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1984 Ciocc Aquila 84 - SLX frame and full Campy Super Record
2006 Orbea Lobular - Aluminum and Carbon frame with Ultegra

I've experienced this going all the way back to 7400 (8-speed !). Reckon I've just revealed my advanced age!

What I've found over time is a couple of issues; from time-to-time I've tried to shift up when I'm already on the big cog stressing the cable, and over time, that'll start the fraying at the head inside the shifter; the other I've experienced is setting the upper limit a little too tight causing me to have to shift "a little too hard" to get onto the big cog in the rear. Either or both of those will excelerate wear at the head of the cable with fraying being the result.

As others have stated, when you have to start making adjustments to cable tension that's your sign ..... change the shift wire soon !!!

careful with the jagwire cables. most of their stainless shift cables are 1.1mm thick. i like 1.1 cables. however, shimano designed and tested their stuff for 1.2mm cables (the standard shift cable thickness). their tech guys seem to attribute very short shift cable life with using 1.1mm cables. ive seen plenty of frayed/broken cables of all brands, but i still believe there's likely a longer life with a 1.2 cable in these circumstances.
slightly OT, with current generation shifters, occasionally a cable head will get stuck in the shifter. shimano will not warranty that if the cable head does not belong to a shimano-branded cable. kinda crappy, but i see that they cant control what other companies do with their cable head size tolerances...