Thanks, but I was hoping for a little more of a breakdown and explanation. David K
Triathlon Forum
Login required to started new threads
Login required to post replies
Re: Am I low/aero enough? (pic) [The Oracle]
[ In reply to ]
Re: Am I low/aero enough? (pic) [Gary Tingley]
[ In reply to ]
hi Gary,
Sounds like you're on a similar quest to mine: get as aero as possible w/o benefit of a wind-tunnel.
I'm sure you take the shot's that Kraig recommends that he be able to give some good advice.
http://biketechreview.com/...d807dc36fc3682aa4861
FWIW, my take on CdA is that 'Cd' is very elusive w/o wind tunnel data but 'A' (frontal area) can be adjusted pretty darned by well by eye. Lower AND narrower are better in general - although after a certain point 'A' doesn't get any smaller.
Kraig's site has plenty of interesting info on there too.
rmur
Sounds like you're on a similar quest to mine: get as aero as possible w/o benefit of a wind-tunnel.
I'm sure you take the shot's that Kraig recommends that he be able to give some good advice.
http://biketechreview.com/...d807dc36fc3682aa4861
FWIW, my take on CdA is that 'Cd' is very elusive w/o wind tunnel data but 'A' (frontal area) can be adjusted pretty darned by well by eye. Lower AND narrower are better in general - although after a certain point 'A' doesn't get any smaller.
Kraig's site has plenty of interesting info on there too.
rmur
Re: Am I low/aero enough? (pic) [Gary Tingley]
[ In reply to ]
You're a windbag Gary. And I mean that it the most correct, nicest possible way. ;-)
(and the side pic makes you look even higher, and you probably are since side pics are best)
Try this:
Eric Wohlberg at Athens. It just doesn't get any better than this under UCI rules. Also, here are some guidelines posted over at G-World by Andy Coggan (a guy who can go 40 kph on only 215 watts and does 40k in under 54 minutes at the age of 48). These notes describe how low to get your torso.
1) at the highest, your scapula should dead-level, i.e., parallel to the ground. Wohlberg's is lower than flat.
2) at the lowest, a line drawn forward and parallel to the ground from the center of the knee joint when the leg is at the top of the pedal stroke would intersect the mid-point of your upper arm. If you imagine his knee coming around the circle, it's pretty clear that the knee is higher than the elbow, but not higher than the middle of the arm.
3) between these extremes, look for (a) the front of your chest to be parallel to the ground, or ( b ) your entire back to be generally parallel to the ground. His chest is parallel to the ground.
Another, somewhat more quantitative way of evaluating the "aggressiveness" of somebody's position is to draw a line connecting the hip joint to the shoulder joint (acromion process)...a difference of 4-5 cm and/or an angle of <10 degrees would likely result in close to minimal drag. His shoulder joint is no more than 4-5 cm above his hip joint.
One thing disciples of the so-called slam position will learn is that, to get your shoulders as low as Wohlberg, your knees are going to be in your chest. You either move down and forward or you stay slow. The choice is a simple one. BTW -- this is the model for my goal setup on the tri bike. Time will tell if I can stay that low for 112 miles, but I've got 9 months to figure it out.
(and the side pic makes you look even higher, and you probably are since side pics are best)
Try this:
Eric Wohlberg at Athens. It just doesn't get any better than this under UCI rules. Also, here are some guidelines posted over at G-World by Andy Coggan (a guy who can go 40 kph on only 215 watts and does 40k in under 54 minutes at the age of 48). These notes describe how low to get your torso.
1) at the highest, your scapula should dead-level, i.e., parallel to the ground. Wohlberg's is lower than flat.
2) at the lowest, a line drawn forward and parallel to the ground from the center of the knee joint when the leg is at the top of the pedal stroke would intersect the mid-point of your upper arm. If you imagine his knee coming around the circle, it's pretty clear that the knee is higher than the elbow, but not higher than the middle of the arm.
3) between these extremes, look for (a) the front of your chest to be parallel to the ground, or ( b ) your entire back to be generally parallel to the ground. His chest is parallel to the ground.
Another, somewhat more quantitative way of evaluating the "aggressiveness" of somebody's position is to draw a line connecting the hip joint to the shoulder joint (acromion process)...a difference of 4-5 cm and/or an angle of <10 degrees would likely result in close to minimal drag. His shoulder joint is no more than 4-5 cm above his hip joint.
One thing disciples of the so-called slam position will learn is that, to get your shoulders as low as Wohlberg, your knees are going to be in your chest. You either move down and forward or you stay slow. The choice is a simple one. BTW -- this is the model for my goal setup on the tri bike. Time will tell if I can stay that low for 112 miles, but I've got 9 months to figure it out.
Re: Am I low/aero enough? (pic) [Gary Tingley]
[ In reply to ]
Gary, might I suggest that if you are willing to spend $$$ in a panic at the drop of a hat, that you should maybe be willing to get an appointment at a windtunnel to refine your position. As Rotorcrank-USA guy and TT.org guy, surely you could find some sponsorship for this endeavor.
.02 $
Dave
------------------------------------------------------------
.02 $
Dave
------------------------------------------------------------
I just purchased a set of HED aerobars and disliked the bends of the extensions. I have a simple, and more importantly, a strong and safe way of getting the hands lower and pointed more forward by cutting the extensions. From the looks of the picture, I think go lower and a little wider with the elbows (not quite to the width of your hips). I've found that as long as you move gradually, keep going lower and lower and your back will be ok. If you would like a picture of the extensions give me your email address and I'll forward them to you - Ernie