Problems Measuring Power on Trainer?
09-17-12, 06:55 AM
#1
Junior Member
Thread Starter
Join Date: Sep 2012
Posts: 141
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Liked 0 Times
in
0 Posts
Problems Measuring Power on Trainer?
Yesterday I did my first hard workout on my new trainer with my powertap wheels.
I have a SuperMagetoPro Trainer and G3 Powertap Wheelset by CycloOps.
On the road, pushing 320Watts is hard, but not that hard. On the trainer, pushing 320W seemed SO HARD!
I was on the Hill climb setting of the trainer. Has anyone else wondered if there is a difference the wheels capability to register power on and off the trainer. Does the trainer misread when on the road (I hope not) or on the trainer?
Just inquiring. Prob just going to have to suffer!
DP
I have a SuperMagetoPro Trainer and G3 Powertap Wheelset by CycloOps.
On the road, pushing 320Watts is hard, but not that hard. On the trainer, pushing 320W seemed SO HARD!
I was on the Hill climb setting of the trainer. Has anyone else wondered if there is a difference the wheels capability to register power on and off the trainer. Does the trainer misread when on the road (I hope not) or on the trainer?
Just inquiring. Prob just going to have to suffer!
DP
09-17-12, 08:36 AM
#2
Senior Member
Join Date: May 2007
Location: Santa Cruz Mountains
Posts: 6,169
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
It's not your power meter, it's you. Most people find that riding the trainer has a higher perceived exertion for the same power. Some of that is due to overheating. You need good fans to stay cool.
09-17-12, 09:00 AM
#3
Junior Member
Thread Starter
Join Date: Sep 2012
Posts: 141
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Liked 0 Times
in
0 Posts
So by this understanding perceived exertion goes up but the actual work does not? It felt as though my legs were in more pain that they would be on the road. More LT buildup.
Noted - need good fan.
Noted - need good fan.
09-17-12, 10:48 AM
#4
Senior Member
Join Date: Jun 2008
Location: Vancouver, BC
Posts: 9,201
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 1186 Post(s)
Liked 289 Times
in
177 Posts
I've experienced your pain on the trainer as well. I agree the heating is an issue, but I also believe the resistance provided by the trainer is a factor as well. The inertial load presented by most trainers is significantly different than what you will experience riding outdoors. I think this takes some time to get used to. On the occasions when I've ridden on the trainer consistently over a 2 week period it does seem to get easier, or at least my legs get used to it and don't experience the same soreness I get when starting out.
09-17-12, 12:20 PM
#5
Junior Member
Thread Starter
Join Date: Sep 2012
Posts: 141
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Liked 0 Times
in
0 Posts
I'm just wondering if there's a rolling resistance (created inside trainer) that the powertap wheels are unable to pickup. Probably not!
09-17-12, 01:46 PM
#6
Senior Member
Join Date: Jun 2008
Location: Vancouver, BC
Posts: 9,201
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 1186 Post(s)
Liked 289 Times
in
177 Posts
No, the powertap will detect any change in rolling resistance. The only possible effect the trainer could have would be from clamping the hub in the trainer. But I believe similar experiences to yours are reported by those with crank based powermeters.
09-17-12, 07:08 PM
#7
just another gosling
Join Date: Feb 2007
Location: Everett, WA
Posts: 19,534
Bikes: CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004
Mentioned: 115 Post(s)
Tagged: 0 Thread(s)
Quoted: 3889 Post(s)
Liked 1,938 Times
in
1,383 Posts
Yes, it's the change in inertial loading. Every different sort of cycling or cycling simulation has a different inertial loading. Fixies, spin bikes, rollers, trainers, outdoor road, they're all different. Each requires a period of adaptation to the differing pedaling mechanics which are encouraged by the amount and location of inertia in the system. Many people also find outdoor riding easier because of the arousal produced by the kinetic sensations.
09-18-12, 12:33 PM
#8
Junior Member
Thread Starter
Join Date: Sep 2012
Posts: 141
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Liked 0 Times
in
0 Posts
So there may be a difference in inertial loading which my body needs to adapt too... yes? Is it a difference in inertial loading that is harder to get moving and keep moving which I'm feeling - i.e. more power is needed to move.
09-18-12, 09:28 PM
#9
just another gosling
Join Date: Feb 2007
Location: Everett, WA
Posts: 19,534
Bikes: CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004
Mentioned: 115 Post(s)
Tagged: 0 Thread(s)
Quoted: 3889 Post(s)
Liked 1,938 Times
in
1,383 Posts
Well yes, but it's micro in the pedal stroke. The flywheel in the trainer isn't doing as much for you as the inertia in you and your bike going up the road. That's my theory, anyway. In that regard, another thing to think about is why do we pedal higher cadences on the flat than we use climbing?
09-19-12, 08:14 AM
#10
Junior Member
Thread Starter
Join Date: Sep 2012
Posts: 141
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Liked 0 Times
in
0 Posts
It just dawned on me - I hope these questions have been studied by doctors and scientists.... I was told (by a doctor) recently that there are physiological differences between people and that some people actually perform better as higher cadences and others at lower. I'm guessing that it's how the body responses. I have noticed a more dramatic response at lower cadences than at higher while in my body while producing constant power. (i.e. my heart rate is higher). THis was a pretty cool discovery.
