Just wondering. In an “ideal bike fit”…should your upper arm (humerus) be perpendicular to the torso or the ground?
like 10 degrees as a general aero rule
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do you mean 10 degrees in relation to the ground (perfectly perpendicular)
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yes from the origin (cartesian plane)
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I would say 90deg to the ground, because in that case, you are supporting your upper body almost entirely on a skeletal support. As soon as you start to put that arm in front of you, then you start relying on muscles to support your upper body.
From an aerodynamic perspective, there is often less drag as your arms get pushed out in front. But it comes at a very real physiological cost. A cost that many people are not able to handle.
Jordan
I just recently did a bunch of ‘ghetto testing’ on my cockpit by doing the following. I walked up to my kitchen counter and rested my elbows, then hands and so on until I was able to get in the most tension free position…basically ‘turning off’ all my other muscles. I had never been able to get a position like this on the bars so figured I would start from scratch and try to work the problem out from there.
Two big components to that were:
- Getting that 90 you talked about so I’m not fatiguing muscles in a wasteful manner…most efficient spot for my body.
- Getting my hands to the center line and having them clasped or nearly clasped.
#2 is providing some trouble, but wanted to see if you had ever worked this problem with successful mods? I have found a pair of Carbon Stryke’s and plan on doing the following…if you can follow my pathetic CAD drawing. Have not been able to get a pair in front of me to verify, but it looks to be doable and my best option. Ideas if this doesn’t work? Thanks.
BTW, hows your bod/mind? Haven’t read any new updates lately.
I figured once I reversed the extension sides, after twisting them a bit to the vertical for the tips that it would put them pretty darn close together. I tried this with ski tip extensions, but it just didn’t jive.
http://i46.tinypic.com/309rp6b.jpg
you are not supporting your body weight on the skeleton when in the aero position. the shoulder joint is not designed that way. if it was we would never have the range of motion that we have in our arms. knees and elbows are designed to support body weight on bone to bone (with cartilage in between).
so, you need to decide which muscles you want to use when in the aero position. this can depend on the legnth of the ride/race. if it’s a shorter distance you may like the arms out in front a bit more as this helps you get the torso lower with elbows closer. for a longer ride you may need them more under the body. this will also be effected by the angle of the torso and seat tube as this determines how much weight will be on the elbows v the pelvis. and on the width of the pads as this can effect the amount of stretch in the muscles being used. (if you are stretching the back muscles to get the elbows together then they may not be in a good position to hold the body weight for a long distance ride)
a general rule of thumb to get started is to drop a plumb line from the ear and it should hit the elbow joint.
you may want to pracice the ‘dolphin plank’ ( http://www.mindbodygreen.com/0-825/Dolphin-Plank-Pose-Howto-Tips-Benefits.html ) in various angles to see what your strengths are and develop the muscles. since this is an isometric exercise it is pretty specific to the purpose but it also has benefits to swimming.
good luck
I think you’ll find exactly what you need with reversed carbon strykes. I’ve seen this done fairly often, so I don’t think you’re an outlier in this regard. If not, just buy some 22.2OD titanium 3-2.5 tubing and find a good custom car shop bend it for you.
Right now…looking in a larger mirror with me in a comfy position, it looks like my ear IS directly above my elbow…and my upper arm is about 10 degree for being perfectly vertical…
NEXT QUESTION (it’s alway something!): Do you want the aero pad to be directly on the TIP (olecranon) of the elbow…NOT resting just slight distal (toward the forearm)?
I like the hand up position…like the old Profile Design Airstryke position…Im thinking of the Profile Design T1 Carbon http://www.profile-design.com/profile-design/products/aerobars/carbon-aerobars/t1--viper.html Seems to have alot of adjustment that can be made and also I can simply rotate the bars to replicate the Airstryke position
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Right now…looking in a larger mirror with me in a comfy position, it looks like my ear IS directly above my elbow…and my upper arm is about 10 degree for being perfectly vertical…
NEXT QUESTION (it’s alway something!): Do you want the aero pad to be directly on the TIP (olecranon) of the elbow…NOT resting just slight distal (toward the forearm)?
It’s personal preference. I prefer it slightly distal, because I find it to be more comfortable overall and it gives me more clearance so I don’t ever whack my knees on the pad holders. But I know plenty of people who like them in the cups. John Cobb has said at the FIST workshops that having it slightly distal engages more muscles across your upper back, giving you better postural stability, but that’s strictly anecdotal. In my own n=1 experience, I’d say I can sort of feel that. But mostly I just feel more comfortable - overall - with them placed distally. But I used to ride with my elbows right in the cups and liked that just fine too…
as rappstar said you need to try a few positions to be sure.
i also like them distal. about 1.5" of elbow overhang or more. it seems (probably in my head) that gives the arm room to move a bit and act as a ‘shock absorber spring’ and not be a rigid beam to transmit road vibration.
also, on longer rides i’ll change position a bit. if i have room to move fore and aft i have options.
for shorter rides/races you you may prefer them even more distal to allow better use of leverage. you can grip the extensions hard and leverage you arms againt the pads to stabilze the torso for more power. Lemond in his TT victory to win the Tour claimed that was the advantage of his aero bars. but probably not appropriate for long distances. you may like it for rolling courses though. …
it’s hard to see the angle of the arm in the mirror without moving the head. so, unless you have some help, take a string and tie a nut on the end, loop the string over your ear (down the back) and the nut should land right in the crook of the elbow.
also, take note of the how the arms seat in the pads. if the pads angle is adjustable (ie. T2’s have a J clamp)you might like a slight angle in to keep the arms in without having to squeeze them together.
good luck
Ok thanks Jordan that is good to know you have seen this setup run with success. Just when I thought I might be a real innovator I find out I’m a copy cat!
I would say 90deg to the ground, because in that case, you are supporting your upper body almost entirely on a skeletal support. As soon as you start to put that arm in front of you, then you start relying on muscles to support your upper body.
From an aerodynamic perspective, there is often less drag as your arms get pushed out in front. But it comes at a very real physiological cost. A cost that many people are not able to handle.
I think it finally sunk in on me. I have had 90* exactly after measuring with the goniometer last week, but still a ton of muslce fatigue. I have one of the Specialized Pro Set stems and while I can’t get my stem any lower for the time being, I did put in some negative drop with the shim kit to effectively lower the pad height. I found that as that 90* stays the same on the torso/upper arm that my stress went more skeletal…or at least less muscular in nature. Am I imagining things or is this indeed a byproduct of adding drop while maintaining the angle? I have tons of room to tweak with my 165’s now so have noticed zero issues in my hip angle/position over bb/stroke.
It certainly ‘seems’ to me that 90* with no drop vs. 90* with a fair amount of drop can feel very different in terms of how we support our bods. Am I understanding that correctly or am I still dumb as a fence post?
I would say 90deg to the ground, because in that case, you are supporting your upper body almost entirely on a skeletal support. As soon as you start to put that arm in front of you, then you start relying on muscles to support your upper body.
From an aerodynamic perspective, there is often less drag as your arms get pushed out in front. But it comes at a very real physiological cost. A cost that many people are not able to handle.
I think it finally sunk in on me. I have had 90* exactly after measuring with the goniometer last week, but still a ton of muslce fatigue. I have one of the Specialized Pro Set stems and while I can’t get my stem any lower for the time being, I did put in some negative drop with the shim kit to effectively lower the pad height. I found that as that 90* stays the same on the torso/upper arm that my stress went more skeletal…or at least less muscular in nature. Am I imagining things or is this indeed a byproduct of adding drop while maintaining the angle? I have tons of room to tweak with my 165’s now so have noticed zero issues in my hip angle/position over bb/stroke.
It certainly ‘seems’ to me that 90* with no drop vs. 90* with a fair amount of drop can feel very different in terms of how we support our bods. Am I understanding that correctly or am I still dumb as a fence post?
No, you are not dumb as a fence post. The problem is that you are mistaking 90deg with the torso with 90deg relative to the ground. 90deg from the torso is great if your torso is roughly parallel to the ground. But let’s imagine an extreme case - stand straight up. Put your upper arms at 90deg from your torso now. If you were to support your body weight with your elbows now, it would be 100% muscular. If your torso is parallel - instead of perpendicular - to the ground, supporting your upper body weight at your elbows is 100% (well, not quite) skeletal. Depending on how your torso is positioned relative to the ground will determine what % of your weight is supported skeletally. Does that make sense. I’ve obviously glossed over a lot there, but I’m trying to simplify it.
Yes, you need to consider the angle of your upper arm relative to you torso, but you also need to consider it relative to the ground - i.e. the direction of gravity. Make sense?
Ok now it makes sense…thanks for breaking that down. BIG difference.
I think the only way for me to nail this sucker down is the obvious which you have asked for previously…some really good pics of me at power. We are heading out for the afternoon while the hurricane rains seem to be at bay.
Will get those up by the end of the weekend.
Thanks again for the break down…makes perfect sense now.
Anyone have a darfish / kinovea drawing of this? I am a visual guy and trying to make sense of words/angles/planes is making my brain hurt.
Anyone have a darfish / kinovea drawing of this? I am a visual guy and trying to make sense of words/angles/planes is making my brain hurt.
I’m going to get some pics of my position up by Sunday evening and hopefully someone will use me as critique fodder…I’m sure it will be ugly, but at least you and I can learn from it.
I’m going to propose a slightly different idea.
I think that your upper arm angle should be **perpendicular to the angle of your bodies rotation **at your current body angle.
Let me explain.
Your butt is a fixed point, that you body rotates around. The goal of here is to provide support against that rotation. Thus, the angle for your upper arms is determined by the angle which your body will move from your “fit point”.
On a mountain bike, you might be upright and thus your upper arms will be nearly parallel to the ground.
On a medium aggressive tri fit, if your aerobars magically disappeared, your body would rotate downwards at approximately a 10 degree angle. Thus 10 degrees off vertical is the right angle.
On an aggressive tri fit, your body would move from it’s fit point down at a 90 degree angle, and thus 90 degrees is the right forearm angle.
I hope that makes at least some sense.