I need the advice of the eyball wind tunnel experts regarding two positions.
I raced with these two positions on back to back weeks. I averaged about 15 Watts less in the more aggressive position. Not sure if it was a bad day or limitation of the position. The two courses were very different so I can’t really make any judgements as to which was better from the two results.
I made an attempt Saturday to gather some data for Aerolab. I don’t think my data is going to be useful due to wind changes and strange elevation readings. I have some runs where there is a significant speed difference for almost identical power output. The elevation also makes sudden jumps that don’t look right and they won’t match.
My goal was to quantify the savings in the more aggressive position. I flipped a 35 degree high rise stem to get lower. Frame may be too short for me but that’s another topic.
The first position is more powerful, more comfortable and easier to breathe. I have thought about shorter cranks to make the more aggressive position a little more comfortable. I’ve also leveled the base bars since they look jacked in the picture.
So, eyeball wind tunnel experts, how many watts gained/lost going to the more agressive position at say 25 mph or 30 mph ( not that I’m going that fast) ? In other words, any reason to not go with the more aggressive position even with lower power output?
Get an adjustable stem and start in the more aggressive position. Then raise slightly (like 1-2 mm at a time) until you can generate the same power as position 1. There was a very distinct point for me where I was still able to comfortably generate power in what is still a fairly aggressive time trialing position (see profile pic). Then again, you may just need more time in position 2 to adapt or you may need to consider shorter cranks if you feel like your hips are getting pinched over the dead spot in your pedal stroke.
I’m no aero expert but I would keep training in the more aggressive position and flip between the two positions a few more races to see if you still lose 15 watts.
So, for a stab in the dark on time savings… 1 min 30 sec for a 25 mile bike.
I think I like the idea of the adjustable stem. How did you find that point where you were still able to comfortably generate power. Did you do a max power test like 5, 10 or 20 or just go by feel?
I’m due up for another FTP test this week and I race again in 2 weeks. I’ll give the more aggressive position another shot just for the hell of it and I’ll get an adjustable stem ordered.
If you can find an adjustable Ergostem, they are the bomb for aero testing. You can change positions in less than two minutes and repeat stuff over and over on the same course. IMO, the more aggresive position is always better for tri as long as it does not adversely affect your run. You never have to generate your best/highest wattage while racing because you always have to run afterwards. You have power, so go out and find a nice out and back or loop course and just test it enough times to be confident of your results.
Food for thought, I found that between 18-22 cm of drop (I have long arms) was equally aero. Below 18 and above 22 was slower. So from this I would recommend you start out with a reasonable amount of drop and then go lower in front until it doesn’t make you any faster. You want to find the confluence of speed and (relative) comfort, which was at 18cm in my above example.
Chad
I think I like the idea of the adjustable stem. How did you find that point where you were still able to comfortably generate power. Did you do a max power test like 5, 10 or 20 or just go by feel?
I’m due up for another FTP test this week and I race again in 2 weeks. I’ll give the more aggressive position another shot just for the hell of it and I’ll get an adjustable stem ordered.
I basically did what you’re doing and used video side shots to get in the most aggressive position I could. Then I rode that position a few times and it was very obvious that I was not able to generate the same power, and also my handling was horrendous. What’s funny is my current position is only ~.5 cm higher than the most aggressive position I tried. There was just a little bit of binding at my hip flexors that I had to open up and that did the trick.
I never do formal FTP tests, but I think it’s pretty easy to gauge the effects of position changes during your longer interval sessions. You should be able tell easily at the end of a 2x20 if your position is more or less powerful based on feel and your avg power for your intervals.
Edit: Remember too that if you’re going significantly lower in the front from your previous position, it can also help to move your saddle forward to keep your hips from getting too closed. Small changes can have a big impact on comfort and power.
That first, less aggressive, position looks pretty good really. My guess is that due to the increased power output that position is closer to your ideal than the 2nd one.
The 2nd one is crazy awesome.
The secret weapon for the crazy positions are short cranks. How long are your cranks and how tall are you?
** IMO, the more aggresive position is always better for tri as long as it does not adversely affect your run. You never have to generate your best/highest wattage while racing because you always have to run afterwards. You have power, so go out and find a nice out and back or loop course and just test it enough times to be confident of your results. **
This was my thought as well. As long as the more aggressive position is 15 watts better, then it seems that would be the obvious choice.
I have a loop around a mall I tried to test this weekend. However, it got really windy and I don’t think it’s worth even trying to do something with the numbers…
** So, for a stab in the dark on time savings… 1 min 30 sec for a 25 mile bike.**
Hell I would take that. Hopefully, I get a chance to redo my Aero tests and get something I can use.
The secret weapon for the crazy positions are short cranks. How long are your cranks and how tall are you?
I’m 6’1". Currently on 172.5 mm cranks.
When I ride in the second position, it really seems to be a breathing issue. I’ve only rode in the lower position a couple of times. Once in the race and a week intervals on the trainer. After 15 minutes or so into my 2x20 set, I have a strong urge to sit up in order to catch a better breath. In my race, I just let off the throttle a little instead of sitting up. My thought was that shorter cranks may help with the breathing. It seems like I don’t have enough reach on the bike to move the seat up/forward but I could be wrong.
Would losing weight help any with the thigh/gut breathing issue?
Just trying to see what will work in the meantime until I get a chance to go in and pay for a good fit.
It is a good idea to have a readily accessible area you can use consistently. Then you have 30-40 runs on the course you will know exactly what is going on and can detect changes. Somedays you just toss out, but enough consistency will help you nail stuff down.
When you are doing this, the more data the merrier. I’ve made incorrect conclusions in the past that were caused by having too little data to work from when I was making decisions.
Shorter cranks and position number 2, or somewhere in between. John Cobb always says that having the point of your lat above the point of your shoulder is a key aero position. BUT, you need to be comfortable and breathe. shorter cranks will NOT DECREASE your power. They might even increase it, or at least your top speed. Borrow some 165s. Whoa? Too short? Maybe not.
If you think reach will be an issue just get a longer stem. Your hip angle is what’s making it feel like you can’t breath. And losing weight will help, but that’s not your problem. I have a nice little gut and I’m in a far more aggressive position than your first picture. Getting in an aggressive position and maintaining power is all about hip angle.
my $0.02: get the 165 cranks, that’ll help with yout hip angle and breathing,; I also think your bike is too small but if you got a longer stem and moved your aerobars\pads forward and stretched out your arms a wee bit, that would open your chest up too
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I’m 6’ but almost certainly have longer legs than you. I switched to 165 cranks and it solved my breathing issue due to leg interference.
You really need to try short cranks. borrow some 165s or buy a cheap square taper set to test with. I’m 90% sure you will be very happy with them.
I have what seems to be a relatively long torso. I’m going to get some 165s ordered since I don’t know where I can borrow any.
Thanks for all the tips. I’m going to try to lengthen thins up as much as possible and also see if shorter cranks help with the breathing. I probably won’t end up as aggressive as the second picture but going to try to get as low as possible while still being able to breathe.
I went with a position somewhere between the two posted above. Less compact and more comfortable.
I violated the “don’t change anything before the race rule”. Yesterday, I stumbled across a 120mm adjustable stem at the LBS and bought it. I locked it at a negative 20 degree angle. However, during the race I hit a bump and the damn stem loosened up so I was nervous about half of the ride. I felt much less compacted and comfortable with the longer stem. I think this is proof that I don’t have enough reach on my bike.
My power was about 10 Watts higher than I’ve ever raced … even getting blocked some and having to ease off what seemed like quite a bit. Speed was surprisingly faster than I would have expected at the same venue I raced two months ago. However, the course was slightly different and it was less windy.
Put the bike in the shop today after the race for shorter cranks and I’ll give the really aggressive position a shot for a couple weeks on the trainer and maybe some outdoor testing.