One of the biggest criticisms I've have of wind tunnel visits and bikefitters is that the prescribed riding position can't always be replicated on the road because the forces acting on the body of a bike being clamped at the axles vs those when in free space outside are completely different. The body often goes into a higher state of tension to support itself. Does anyone have any tips or advice at trying to deal with this issue. I've got to a point whereby I'm happy with my race position when I'm on a turbo but as soon as I'm outside, I can't replicate it. Any thoughts ?
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Re: Replicating your bikefit from the turbo and wind tunnel to on the road. [UK Gearmuncher]
[ In reply to ]
UK Gearmuncher wrote:
One of the biggest criticisms I've have of wind tunnel visits and bikefitters is that the prescribed riding position can't always be replicated on the road because the forces acting on the body of a bike being clamped at the axles vs those when in free space outside are completely different. The body often goes into a higher state of tension to support itself. Does anyone have any tips or advice at trying to deal with this issue. I've got to a point whereby I'm happy with my race position when I'm on a turbo but as soon as I'm outside, I can't replicate it. Any thoughts ?I can tell you what we are doing.
We have a set of sensors, IMU based, that we use on the turbo to capture a position we want to test. We take a picture so we know what position X looks like and we know it's IMU measured coordinates.
We then take them to the road, test and compare to the turbo numbers.
The purpose is to see if what we thought we were testing is what we are testing
Needless to say this isn't as trivial as it sounds. On the turbo is easy. No acceleration or inclination of the reference frame, ie the bike.
I am curious what others are doing.
I know some are using frontal image capture. That is "easier" but I think you capture much less.
Re: Replicating your bikefit from the turbo and wind tunnel to on the road. [marcag]
[ In reply to ]
marcag wrote:
UK Gearmuncher wrote:
One of the biggest criticisms I've have of wind tunnel visits and bikefitters is that the prescribed riding position can't always be replicated on the road because the forces acting on the body of a bike being clamped at the axles vs those when in free space outside are completely different. The body often goes into a higher state of tension to support itself. Does anyone have any tips or advice at trying to deal with this issue. I've got to a point whereby I'm happy with my race position when I'm on a turbo but as soon as I'm outside, I can't replicate it. Any thoughts ?I can tell you what we are doing.
We have a set of sensors, IMU based, that we use on the turbo to capture a position we want to test. We take a picture so we know what position X looks like and we know it's IMU measured coordinates.
We then take them to the road, test and compare to the turbo numbers.
The purpose is to see if what we thought we were testing is what we are testing
Needless to say this isn't as trivial as it sounds. On the turbo is easy. No acceleration or inclination of the reference frame, ie the bike.
I am curious what others are doing.
I know some are using frontal image capture. That is "easier" but I think you capture much less.
My issue isn't about nailing the coordinates or contact points, it's merely that the human body supports itself differently when a bike isn't clamped at the axles.
Re: Replicating your bikefit from the turbo and wind tunnel to on the road. [UK Gearmuncher]
[ In reply to ]
Maybe I wasn't clear or I don't quite understand what you are after
We are trying to see if for example, the head position on the turbo, that we want to test, is the same as on the road
Or if pelvic tilt is the same
Or if foot at bottom of pedal stroke is the same
Or if knee tracking is the same.....
When you say you can't replicate, what do you believe is different ?
We are trying to see if for example, the head position on the turbo, that we want to test, is the same as on the road
Or if pelvic tilt is the same
Or if foot at bottom of pedal stroke is the same
Or if knee tracking is the same.....
When you say you can't replicate, what do you believe is different ?
Re: Replicating your bikefit from the turbo and wind tunnel to on the road. [marcag]
[ In reply to ]
marcag wrote:
Maybe I wasn't clear or I don't quite understand what you are after We are trying to see if for example, the head position on the turbo, that we want to test, is the same as on the road
Or if pelvic tilt is the same
Or if foot at bottom of pedal stroke is the same
Or if knee tracking is the same.....
No, it wasn't that. It was that the muscular recruitment is different from when a rider is on the road to when they are on a bike that is clamped at the axles. It seems easier to get into a great position when on a turbo but as soon as you ride in free space, the physical forces and effort is different.
Re: Replicating your bikefit from the turbo and wind tunnel to on the road. [UK Gearmuncher]
[ In reply to ]
UK Gearmuncher wrote:
marcag wrote:
Maybe I wasn't clear or I don't quite understand what you are after We are trying to see if for example, the head position on the turbo, that we want to test, is the same as on the road
Or if pelvic tilt is the same
Or if foot at bottom of pedal stroke is the same
Or if knee tracking is the same.....
No, it wasn't that. It was that the muscular recruitment is different from when a rider is on the road to when they are on a bike that is clamped at the axles. It seems easier to get into a great position when on a turbo but as soon as you ride in free space, the physical forces and effort is different.
What about a turbo that mimicks more road conditions for fitting ?
General feedback on this was it felt really cool!!
https://www.youtube.com/shorts/xy2hYEmU2vY
Re: Replicating your bikefit from the turbo and wind tunnel to on the road. [UK Gearmuncher]
[ In reply to ]
UK Gearmuncher wrote:
One of the biggest criticisms I've have of wind tunnel visits and bikefitters is that the prescribed riding position can't always be replicated on the road because the forces acting on the body of a bike being clamped at the axles vs those when in free space outside are completely different. The body often goes into a higher state of tension to support itself. Does anyone have any tips or advice at trying to deal with this issue. I've got to a point whereby I'm happy with my race position when I'm on a turbo but as soon as I'm outside, I can't replicate it. Any thoughts ?I very rarely ride the turbo. I don’t even ride my TT bike very often.
I seem to be going faster or on a par with my peers for 10-20% less power( from Strava Stalking).
Managed to scrape a sub 20 on Levens last week on 4W/kg and I new from the off I wasn’t going well so just concentrated on staying aero so must be doing something right.
You do appear to be always making equipment tweaks.
I’m actually worried that any tweaks will make me slower.
Have a couple of helmets to test but have stuck with the Drone as I know it works for me and not that confident I can test robustly at the moment with a shoulder injury.