Training to power indoors

tdougan

Hi All,

I've been having an issue getting the power numbers out indoors. I'm struggling to hold numbers that are 20-35% less than my FTP on the trainer.

When I'm out on the road I can hold for arguments sake, 275w for 24min up a local climb, in the house if I go for a 15min effort im struggling to hold 210w.

I use a stages power meter that I calibrate before every ride and I've checked the tension with a torque wrench and i've checked for firmware updates too. I use this with a elite fluid trainer. I used to think, its just because i'm indoors whatever, I'm still getting a good workout ect, but I recently got to ride a watt bike and my numbers were comparable to the road. I last night rode for the first time a Tacx Neo and I noticed the stages was showing a lower number to that of the tacx output.

does anyone have anythoughts on training indoor and outdoor with power? do you think i struggle because it's a cheap trainer?

many thanks,

Tony

Allza

I have the same trainer and the same power meter as you. I definitely find it harder to do the same power indoors but not to the same extent as you. My power is about 20w down for 20 mins indoors. I have found the the more I am using the trainer the easier it is getting to hold the same power as outside. You might just need longer to adapt to it. Have you made sure it is level at the front?

tdougan

intresting to hear, cheers!
Yeah Ive played with different heights I've got one of the cyclops climbing blocks that you can turn around for different heights. I've had the trainer about two years, I'd just accepted it was different until I rode the watt bike. I plan to compare the Tacx neo power file to the stages power file over the next week or too.

birdy247

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19745218#p19745218]tdougan[/url] wrote:

intresting to hear, cheers!
Yeah Ive played with different heights I've got one of the cyclops climbing blocks that you can turn around for different heights. I've had the trainer about two years, I'd just accepted it was different until I rode the watt bike. I plan to compare the Tacx neo power file to the stages power file over the next week or too.

Have a read of the first few paragraphs here http://turbotraining.co.uk/turbo-trainer-setup (inertia could be the culprit).

supermurph09

I have a Tacx Flow and Stages PM.

You say you calibrate the Stages every time, do you calibrate the Tacx? I say this because I calibrate both every time, then I decided to use the turbo without calibrating it and 200W felt more like 280W, I stopped, calibrated the Flow and hey presto everything was ok.

tdougan

interesting reading. I'm not sure inertia is the reason for the difference - surely 200w up a hill is 200w and on fluid trainer it's the same?

*turns out you cant calibrate a Tacx Neo.

amaferanga

Pedalling asymmetry on the turbo?

sloppyschleckonds

Tailwind?

UnaBomber

Ive experienced the very same thing today, I put it down to the resistance on the turbo being different than that of the road. Its sort of like pedaling through treacle in comparison, i have a fluid kurt kinetic turbo.

Alex_Simmons/RST

See this:
http://alex-cycle.blogspot.com.au/2009/01/turbocharged-training.html

buckmulligan

Firstly, I would say that the inertia of the roller on the turbo is a significant factor and could well be affecting your power output. You don't mention exactly which model of Elite turbo you've got (they have about 20 or so models on the market at the moment, let alone historical models) but if the trainer you're using is anything like my Elite Crono Fluid Elastogel, the roller inertia could be very low and your pedal stroke could be having a micro-stall at the top/bottom of each revolution. The difference between the pedaling mechanics on this and outdoors is pretty significant.

Another major factor could be cooling. Do you have a massive fan going full blast right in your face on the trainer? If not, do so, the significance of this should not be underestimated. Often, relative perceived effort (RPE) is going to be more closely correlated with heart rate than power output and overheating will send your heart rate through the roof and ultimately limit the amount of power you're capable of putting out. Doing everything you can to cool yourself down will close the gap between indoor and outdoor conditions. Remember that riding outdoors, most of the time you're going to have a constant 20-40 kph wind in your face so try to replicate this indoors.

I don't know how the Tacx Neo works, but presumably if it has an actual power meter in it then you must be able to do a zero offset. As amaferanga says, the Stages left-leg only thing could be contributing too, either or both of your indoors/outdoors numbers could be affected by pedaling asymmetry, but I'd be surprised if that is causing a 20-35% drop on its own.