Do I have to use special super-duper Shimano sti cable outer for sti gears?

[Cyclopathic]

Or will standard, off the roll gear outer be alright. Is there any significant mechanical difference that will have a bearing on performance or is it yet another way for Shimano to sell me something?

 

[compo]

I recently installed indexed gears, not STI though, and I used normal 5mm sleeving for the loop round to the derailleur. The indexing was very hit and miss. I changed it for 4mm gear cable specific outer and problem was solved. The Shimano tech-docs for your mechanism will tell you Shimano's recommended cables and outers. How critical it is I have no idea.

 

[HLaB]

Generally the more expensive stuff is smoother and more resilliant to cable rub, etc but the standard stuff will do the job

 

[migrantwing]

Jagwire FTW

 

[accountantpete]

You need the right size to prevent loss of efficiency from the cable (ie not too wide) and the big companies tell you that their stuff has special lubrication to help shifting- not too sure. I use Transfil cable and it works my Camp Quick Shifts(which rely on good cabling) very well.