Forgive me if this has been covered…
How do the power numbers compare on a home trainer vs. the road?
I’ll be using either Ergomo or SRM on a Kurt Kinetic. Are the numbers comparable? Or do you have to adjust? Any other concerns?
The numbers should be pretty close to what you would see outside. It can be a little more difficult mentally since the terrain/scenery don’t change at all. That’s my experience at least.
The same watts generally “feel” easier when put forth outdoors vs. indoors. You have the cooling effect of actual motion and/or wind, possibly some actual terrain and scenery, and time seems to move more quickly. All good reasons to make time on the trainer as efficient as possible.
Some people track an indoor FTP vs. an outdoor FTP because outdoors you might be able to go 10-15 watts higher just because.
I may be way off, but it would seem to me that power is power. My PT measures power at the rear hub. It doesn’t care whether I’m on the road or not.
Mentally, it’s a completely different story. Doing 30 minutes or whatever at some particular wattage on the trainer is likely to seem harder than that same average wattage on the road because it is constant (and boring). On the road, even on seemingly flat terrain, changes in pitch, wind speed, and wind direction are going to create small fluctuations in the power your applying. On the trainer, if you’re doing 90 rpm, you’re wattage won’t vary by much more than probably 5 watts either direction.
I typically see indoor watts that are 15-20+ lower than what the athlete can do outside as the same PE and HR. A few athletes have very little to no difference between inside/outside watts. People with Computrainers seem to have a narrower spread, particularly if they are racing against past performances.
During the winter, if you’re stuck on a trainer, this effect is what it is. It can become confusing in the spring, when you’re training with a mix of indoor and outdoor riding and therefore different FTP’s.
out side my MP20 is around 280watts but inside on the trainer it’s 250watt’s i think my trainer is draging a lot of my power away?
Dan…
I don’t have power yet. What is FTP? Normalized watts? Etc.
Or - where can I go to learn about this (for free)
I don’t have power yet. What is FTP? Normalized watts? Etc.
Or - where can I go to learn about this (for free)
http://www.cyclingpeakssoftware.com/power411
I don’t have power yet. What is FTP? Normalized watts? Etc.
Or - where can I go to learn about this (for free)
See the Classifieds. I’m selling copies of Training and Racing with a Powermeter for $13.50. Just less than Amazon and I can promise you I’m loosing money on this.
I’m selling copies of Training and Racing with a Powermeter for $13.50. Just less than Amazon and I can promise you I’m loosing money on this.
You’re not the only one.
my watts are a bit lower on the trainer, i think it has to do with the fact that on the bike you’ve got a lot of momentum with the wheels spinning and all of your weight going down the road. it makes it easier to keep up your cadence, whereas on the trainer you’ve got the overtightened little flywheel resistance unit really trying to slow the wheel down and provide resistance. since power is basically cadence multiplied by torque (basically) if it is harder to maintain momentum of your pedalling then the watts are a bit harder to get up. this is basically why kurt just came out with the trainers with the much larger and heavier flywheels. this is in addition to the fact as others have pointed out that it is more mind numbing (your 300 watts of effort inside don’t result in you flying up mountains or cruising the flats at 28mph like outside) as well as the whole body temp thing (even with a good fan). still very valuable as a guage, i just am more likely to compare trainer sessions to trainer sessions and outdoor sessions/races to other outdoor riding.
i think it has to do with the fact that on the bike you’ve got a lot of momentum with the wheels spinning and all of your weight going down the road
Well look at it this way: if you stop pedaling on the road you come to a stop (on a flat) over a reasonably long period of time. If you stop pedaling on the trainer you come to a stop (well, your rear wheel) in a matter of seconds. That deceleration is happening every pedal stroke so the effect will be reduced while you’re cranking, especially if you are at a high cadence or you’re pedaling your perfect little circles.
So to me, the trainer is like riding up a grade that would cause you to stop in a matter of seconds if you stopped pedaling.