Is Colombia safe for cycle touring?

You should be fine. Roads are challenging at times, both when it comes to traffic and varied terrain.
I met a couple who cycled around Colombia for five weeks. I still have a map they gave me on their last day, edited by mapascartur.com, which you might like to check, as as they said getting a good map was a problem.

Colombians are crazy about competitive bicycling, and the highways in many parts of the country stream with cyclists riding in packs. Motorists generally seem to go out of their way to accommodate cyclists. The bad news is that once you leave the coffee country, much of your itinerary is two-lane roads through two different mountain ranges. On much of that trip you'll spent a lot of time cycling at the edge of one 4,000-foot cliff or another, which offsets the utility of rear-view mirrors, and you'll lack the visibility conveyed by numbers. Also, be prepared for the heavy rains that fall in complicated seasons pretty much all along your route. To the extent you value arriving at your intended destination, good maps are not only indispensable, but for all intents and purposes impossible to find in most parts of the country. Many Colombians seem constitutionally honor-bound to provide travelers with directions, and the light of brotherhood will shine in their eyes as they provide those directions, sometimes invented on the spot. For those interested in wealth creation, there is an informal market in Colombia for highline bicycle paraphernalia that rivals any US university town and often at much higher prices.

getting a good map was a problem

Try ITMB who have a good map (we took the photo on the front, and provide updates to them periodically).

Their maps are available online/by mail, and also in major bookstores in Europe (FNAC etc.).

Alternatively go to IGAC in Bogotá once you arrive - their maps are excellent.

Buenaventura is very dangerous. We went there a few years ago to go to Juanchaco and just got the taxi to the boat and did not walk around at all. You can go there but do NOT sight see.

I would take strong note of all safety advice and try to be entirely vigilant at all times, as ever avoid travel at night unless entirely necessary. That said I would upmost advise to take the trip on as its a wonderful landscape and from what I've seen the roads are in good shape.

Here's my horror story June 2016
I was robbed of everything in broad day light in Zipaquira, 50k north of bogota on an intended cycle tour of Colombia. I was greeted during an inconspicuous 2 minute pause in a cafe by two fake cyclists ( evil greedy thieves posing as fellow enthusiasts. Professional robbers). Having traveled in multiple continents these two didn't ring any major alarm bells as was there friendly embrace of my endeavour. Clean well dressed guys with their own nice bikes. This was a planned event, I was clearly followed. I was not harmed but this event has completly ruined my trip. My advice sadly is you really cannot trust anyone. It's well documented that if you are robbed you should not expect help from other people in the area. That was exactly my experience, the local folk didn't really care at all what had just happened and the police didn't convince me they were making much of an effort. Once you get out of the main suburban districts there I think is less reason for concern and given the opportunity to try my trip again I certainly would do so and So should you.

Josh

Firstly, I fell awful about what happened to you having read your story. How exactly were you robbed? I just arrived in Bogota a few nights ago, I plan on taking off on my tour in the next week, but your story has me really worrying.

One of The two cyclists acted to be impressed and interested in my bike & wanted to try it out as it had quite a bit of weight on. I politely refused twice purely out of an appetite to get back on my way ( I'll admit I didn't foresee in such a short time any major suspicion of his interest) I was handed some papers for a local biking trip company ( of no interest but didn't wish to be rude) he jumped on my bike the next second and they both made an immediate get away. There is a rule amongst Colombians you purely CAN NOT trust someone you do not know, the trickle down of crime in the country is a long way from over. If you keep your guard up and only give trust to those whom you have had an introduction to or previous Acquaintance you should be fine. I'd been in south east Asia too long where events & organised crime are far less common. Get out into the countryside, be vigilant and enjoy the beauty of what could have been for me. I'll return at some point. You can't let the buggers win x

If you leave very early in the mornings you will see many ciclists on roads, especially in central Colombia. It is very common for people to bike outside town prior to work. I have Friends who bike at around 4 or 5 a.m. On the other hand scenary makes it worth biking in the day. Slopes can be very steep in many places around central-south Colombia.