Did you know that you don't need a power meter to get value out of Best Bike Split? All you need is a reasonable estimate of your FTP number to feed the model, and a way to execute the plan on race day without watts staring back at you. Both of those are solvable.
Step 1: Get an FTP Number Without a Power Meter
You don't have to guess, and you don't have to buy a power meter just to run a 20-minute test. If you've got a finish time from a course you've already ridden, a gran fondo, a local time trial, a gravel race you've done before, that's information you can work backward from.
First you will need to create your Athlete Profile and enter 200w as your FTP to start, then build out your bike to match the one you rode for that ride or race. Upload the course file, add a new Race Plan, and fill in your bike, course, and the weather from that day (the closer you match the real conditions, the more accurate your result will be). Use the Adjust Weight option to account for anything extra you were carrying (water bottles, food, or a spare tube). Then select the Goal Time Model (a premium feature) and enter your actual finish time (not moving time). From there, Best Bike Split takes the course, the time, and the weight, and works backward through the terrain, the climbing, and the wind to calculate the normalized power, intensity factor, and variability index for that ride.
That normalized power number is your effort for that day. To know if your FTP (functional threshold power) guess is in the right neighborhood, take a look at the intensity factor and variability index Best Bike Split calculated for you, and compare them to the ranges below based on the type of effort you did.
Intensity factor is your normalized power shown as a percentage of your FTP. Shorter efforts allow a higher IF, while longer efforts push that number down. Here's what's typical for different types of efforts:
| Effort Type | Intensity Factor (IF) |
|---|---|
| 40k time trial or hard hour-long crit | 0.95 – 1.05 |
| 2 to 3 hour road race or hard group ride | 0.85 – 0.95 |
| Century or gran fondo | 0.75 – 0.85 |
| Half-iron bike leg | 0.83 – 0.87 |
| Full-iron bike leg | 0.70 – 0.75 |
| Long gravel race or 100+ mile ultra effort | 0.65 – 0.75 |
| 12 or 24 hour event | 0.55 – 0.65 |
Variability index compares your normalized power to your average power. A flat, steady effort will sit close to 1.0. The more a course makes you surge and recover, the higher that number climbs:
| Course Type | Variability Index (VI) |
|---|---|
| Flat time trial or pancake-flat course | 1.02 – 1.08 |
| Rolling road/gravel race with some punchy climbs | 1.15 – 1.25 |
| Hilly or technical gravel course | 1.2 – 1.35 |
| Mountain bike or highly technical terrain | 1.2 – 1.5 |
If your IF or VI look off for the type of effort you did, adjust your FTP in your profile and rebuild the race plan; raise your FTP value to lower your IF, and lower your FTP to raise it. Once the numbers land in a realistic range for your effort, you have your estimated FTP!
If you want to double check things, you can divide your normalized power by the intensity factor and that should give you the same estimated FTP value that you set in your profile.
NP ÷ IF = FTP
Step 2: Let Best Bike Split Build the Plan
Feed that FTP estimate into the model along with your upcoming course, and Best Bike Split will generate a segment-by-segment pacing plan: where to hold back, where to spend it, where the terrain lets you coast. All of it is expressed in watts, which is a problem if you don't have a power meter to read on race day. But with our Rate of Perceived Exertion "RPE" Based "cheat sheet" we’ll translate those watts into RPE which you can use to guide your pacing on the day. Take a look at the "cheat sheets" from our demo race plan.
Got a course you've ridden before? Use it to get your number, build the plan, and go race it by feel.
Dave Schell / Kaizen Endurance
Dave Schell is the Founder and Head Coach of Kaizen Endurance coaching based out of Boulder, Colorado, where he works with off-road cyclists of all abilities. Dave is the former director of coach education at TrainingPeaks where he traveled the world teaching coaches how to better use training software with their athletes.
Read more about Dave Schell at Kaizen Endurance.
