Indoor Versus Outdoor FTP Numbers

By Hunter Allen, CEO Peaks Coaching Group

Do you need a FTP for indoors and a different one for outdoors?

Training on the indoor smart trainer or the dumb trainer for that matter, can really make you question your ability as a cyclist. We have all had the experience of not being able to produce the same watts indoors as we can outdoors and that just not fair! On indoor trainers, there are many factors that cause your watts to be lower and they range from the way that the load itself is generated on the trainer to the fact that you are in your basement riding beside the cat litter box!

Why is Indoor Power Lower?

-Power is measured at the rear of the bike after the drivetrain, so it will always be at least 10 watts lower than measured at your crank or pedals.

-The weight of the flywheel might not be enough to sufficiently give you the road “feel” and momentum that a true road will give and therefore you have to accelerate it in a different way.

-Electronic trainers provide resistance throughout the entire 360 degrees of the pedal stroke. Outdoors, you do not have resistance at the bottom of the stroke and across the top of the stroke. This is one of the biggest reasons your wattage is lower and it doesn’t feel like riding outside.

-You are too hot! You must use a fan or multiple fans to cool yourself while riding indoors. This is critical. Drink cold water, and do everything you can to cool off.

-You are indoors. It’s psychologically harder to ride indoors and go nowhere! It’s just not as much fun.

Hope this helps explain some of the differences between indoor and outdoor wattage.

The answer to the question is: YES!

You need an indoor FTP and an outdoor FTP. Be sure to test indoors and find your indoor FTP and use this for your indoor workouts. When you start riding outside more, then test outside and use that as your FTP outside.

Here’s a quick video I made explaining these and some other reasons about the difference between indoor and outdoor wattage.

This article was reprinted with permission from Peaks Coaching Group.