This bike will be doing dual duty - a drop bar geared "gravel" bike and a flat bar single speed, it's replacing two bikes I currently own. The drop bar has mechanical discs and the single speed has hydros, ideally I'd like to be able to swap between the two within about an hour. I'm sure you have the best intentions with your advice, but I would much rather have the brakes externally routed and am just wondering if anyone else has any experience putting guides on a frame. Bleeding is time consuming and my braided stainless Hope brake lines look pretty cool so having them exposed is a plus. Internal routing doesn't offer much advantage other than aesthetics and external is much more practical for my application. Thanks for the advice, I appreciate the time taken to respond.

Hi everyone, first post on the site. I've been getting a lot of great info here but have some questions.

Has anyone installed external cable guides on their frame that only has internal routing? I'd like to be able to easily swap brakes and drivetrains and internal routing would make that time consuming, especially with hydraulic brake lines. I'm looking at getting a CS-057 which only has internal routing. It seems like my options are-

1) Zipties, the least elegant solution and could potentially mar the frame but quick and easy. One of the drivetrains is singlespeed and not having the guides when I don't need them would be nice.

2) Jagwire stick on guides, I'll probably have to replace them every so often but the reviews say they do a decent job as long as they stick. They're made from aluminum so I can shape them to the frame. http://jagwire.com/products/v/Stick-On_Guides

3) Install bolt on guides. Invasive installation and could potentially ruin the frame! but also the most professional looking. I'd have to install Nutserts into the frame which means drilling some 7.1 mm holes. Then I would be able to use bolt on Ragley cable guides, I have some similar on my Yeti and they're great.
http://www.mcmaster.com/#stainless-steel-rivet-nuts/=zs3w7k
http://ragleybikes.com/products/cable-guides/

Does anyone else have any experience with running external cables on a frame with out guides?