On Friday, March 10, 2017 at 2:04:12 PM UTC-8, ixiz wrote:
I only recently found out that there were 2 diameters and about to buy a box (100). I hate to buy the wrong diameter - most of my bikes are campy 9 and 10 speeds and eventually 11.

I am about to purchase a box and split with a friend but unsure which diameter to purchase.

IS there any guides as to which cables are for what models or just get the 1.2mm and call it a day.

I don't get what everyone is talking about Ixix = there are two different cable diameters because shifters use the smaller and brakes the larger. As Al pointed out the end caps on Campagnolo are different from those on everyone else but Campy will work properly on everyone else. Though in older brifters it's possible to stick the smaller Campy ends though usually it isn't any problem to free them.

The BRAKE cable ends are two different sizes for road bike brifters and mountain bike levers.

So there are TWO different diameters of outer cables as well.

The newer levers from Campy and Shimano are very similar cable-wise. but Campy is easy to thread and Shimano decided to make them the hard SOB's possible where you have to pull off doors etc. and then remember to reinstall them.

Modern carbon fiber integrated handlebars/stems often have the outer cables threaded through tubes. And frames also often have the rear brake cable threaded through the top tube. Setting the outer cables up properly the first time is a great pain in the ass on these. Though once installed they are neater and cleaner. Cyclocross bikes often use a top pull front derailleur so you may have a second cable to contend with on the top tube.

There are also cheap inner cables made of steel and higher prices made out of stainless with almost an infinite lifespan. Some of the steel cables have a teflon coating so that even if they rust a small amount they still pull OK.

I prefer buying the top grade Shimano or Campagnolo cables for the specific purposes.