Before you attempt your FKT, here are some things you need to know.
FKTs have a well-established culture. Some parts of that culture aren’t explained very well. Let’s talk through what the community expects when you submit an FKT.
Fastest Known Times (FKTs) are exactly what the name describes, the fastest documented time for any given route. This holds true even for times that are not recorded on the FKT website. I can imagine some of you starting to panic right now, thinking, “how can I ever be certain?!?” You can’t, and that is perfectly ok. That’s why they are called Fastest KNOWN Times. If you want to claim an FKT, the community will expect you to make a good faith effort to identify previous fast times. They do not expect you to be the All Seeing Eye of Sauron. Many well-established members of the community have retracted their own FKTs when a faster previous time was identified. There are members of the community who know the FKTs in their own area very well and who do raise questions about accepted FKTs. This does sometimes lead to times being removed.
Despite all this, people who are not particularly fast can and do set fully legit FKTs that are recognized by the whole community. Don’t let these rules discourage you from going after an FKT. The common routes that everybody in your area runs all the time will have many pre-existing times and thus a high bar for setting even the first FKT. Routes that are remote, a little tricky logistically, combine trails in a different way, or are in some other way unique are usually not as competitive.
If there is no recorded FKT, either on an existing route with no previous time or a new route you plan to submit, here are some ways to look for previous times:
Some FKTs have Strava segments that closely match the FKT route. If so, setting a record on the Strava segment is usually pretty clear evidence that you have the FKT.
Run the full route and create a new Strava segment for the entire thing. Strava will compile the past efforts and give you a list of the fastest times on that route. While this may not be practical for long FKTs, it is a very effective way to check shorter routes. Bonus: you can do an easy familiarization run before your fast FKT attempt to both learn the route and get a file to use to look for new times.
If there is not a full Strava segment for the route, you can still look at the runs of the people who have recorded times on segments that cover part of the route. Click on their run date to see their entire effort; you may be able to find some times for the full FKT route.
For climbing routes, do a google search for the route and check websites like summitpost.org. Trip reports will oftentimes include this information.
If you poked around Strava and the web and can’t find any times faster than yours, submit your time!
If you are going to attempt to beat an existing FKT, it is considered good form to reach out to the person who holds the record to let them know you are going for the route. This is usually not required, but openness and transparency will help solidify the authenticity of your effort.
All FKTs must follow all rules from the land management agencies. This means securing necessary permits, only camping in permitted areas, respecting fire closures, and any other rules that apply. If for some reason you were not able to follow those rules during the attempt, you should not submit your FKT.