Ambidextrous backup downtube shifter for touring?

I'm heading out on a long tour soon on a bike with Shimano STI shifters. That choice was intentional as I don't like bar-ends. However, I notice the gear cables run through stops at downtube shifters bosses and I'm curious if there's a type of cheap friction shifter that would mount on those and could be used on either side that I could carry as an emergency replacement in case an STI ever crapped out. Here is a picture of the bosses on this bike: If someone could point to one or more specific models that would fit this, that would be great. Ag...Read more

Downtube friction shifters for 11 speed

I'm planning to build a steel lugged frame and equip it with downtube friction shifting. My question is:Do Dura Ace 7900 downtube shifters come with friction mode? The left lever does not have a D-Ring for switching between SIS and friction mode according to my observation. If not, which model of Dura Ace shifters offers friction mode?Do downtube shifters have a predefined shifting cable travel so that the older DA friction shifters could not be used on 10 or 11 speed cassette simply because there is not enough cable travel?Apart from Cane Cre...Read more