@KWalker, sorry I'm having a hard time believing that.
I'm with you @ryanH. My baseline on my DA was .225....now that's a good way off from .25, but i'd love to see the guys on road bikes that are getting that close to my baseline position.....
Moderator: robbosmans
RyanH wrote:@KWalker, sorry I'm having a hard time believing that. Attached is a screen shot of Chris @ Specialized in the wind tunnel in the drops position which netted him a CdA of around 0.32. He looks pretty aero to me. Would you care to share some data to substantiate that?
If I remember, I'll have someone take a picture of me riding on the weekend but I'm 5'9 on a small frame (S/M in Fuji, 51 in Cervelo and 52 in Scott). I normally run a slammed 110mm -17 stem but tested a 125mm -17 on the Fuji today. Bars are 38cm CTC at the hoods. Not exactly a cafe cruiser position, but hey, if there's room to optimize my position and get it down to 0.25 to 0.27 on the hoods then I'm all ears. At 0.25 with a FTP of 300w, I could hold, theoretically, 26.7 mph on the hoods!
Grill wrote:A really good road bike position is in the range of .260m^2. The best bike positions are <.180m^2 (I know of a few below .170m^2)
KWalker wrote:RyanH wrote:My biggest issue is getting motivated to ride early in the morning. Training in the afternoon is hit or miss since I can be zapped by work and zero desire to push myself on the bike. Through fall and winter, I'll begin the same training plan as last year which will overlap with the testing. I think Chung method model should be flexible enough to accommodate non sprinting intervals.
Kwalker, curious what CdA numbers you have seen with people riding on the hoods? I thought the low 0.3's was a fairly good number considering non optimized TT positions begin around 0.27. Specialized did their WIN tunnel testing on positions and the faux aero was 0.27 and drops were 0.32 so me posting up 0.31 to 0.32 on the hoods, not sure how you're coming to the conclusion I'm giving up a lot on position. I am going to test a longer stem and see what the effects are as well as see if I can cope with the extra length.
I do agree with others that so far the results are not very comparable as my position is changing between bikes. Even slight changes are showing notable differences. That's the big take away so far. It's a learning process.
I have seen quite a few people with road positions around .25-.3. Mine was .26 last time I tested, the .25 might have been due to some testing protocol error, but that same rider is .24 on his TT rig! It might be fairly good for dudes on the interwebs who tend to document their testing publicly. .3 was for a rider who clearly had a high/ugly position. Many of the low numbers were final- we adjusted the bike fit for power and efficiency. In most cases the seat height was slightly lower than predicted by just fitting and riding on a trainer, reach was a tad longer and bars almost always a bit higher. There is a ton of room for road bike improvements through fit, but that alone is going to result in MUCH higher reductions than this frame testing stuff.
From what I've seen, allowing more forward pelvic rotation usually aligns the spine and drops the shoulders and head typically. Optimizing spinal extension and pelvic rotation can dramatically reduce rider height and usually a better bar/hood position can further allow the rider to drop their head and bring their elbows in closer.
Considering you said you were dropped at Winters on the climb, I'd look internally for more motivation to train since you could hide in the pack with whatever aero and sprint/attack near the end, which is how almost every cat 3 race goes anyways.
Stalkan wrote:Grill wrote:A really good road bike position is in the range of .260m^2. The best bike positions are <.180m^2 (I know of a few below .170m^2)
I am assuming these are all at 0º? If so, I'd love it if I could hit those numbers on my Time Trial rig let alone my road bike. I'm curious, though, as to the size of the individual that is .260 and more so of those that are sub .180.
RyanH wrote:@cyclespeed, when covering a fixed distance, aero differences are more pronounced the slower you go (time wise).
In example:
40K@200w
Speed @ CdA of 0.32: 34.072402
Time: 70.438 minutes
Speed @ CdA of 0.31: 34.412557
Time: 69.742 minutes
Time Difference: 0.696 minutes
40K@400w
Speed @ CdA of 0.32: 43.864276
Time: 54.714 minutes
Speed @ CdA of 0.31: 44.312922
Time: 54.16 minutes
Time Difference: 0.554 minutes
So, I think it's a generally incorrect statement to say that aero benefits kick in at X speed. If you're racing an Iron Man for the first time and expecting to average 15-16 mph on the cycling leg, a very aero setup is going to net you a lot more time saving (in absolute terms) than the top contenders. I'm too tired to calculate the percentage differences, which may be the inverse. But, moral of the story is that aero benefits everyone regardless of speed traveled.
Grill wrote:Stalkan wrote:Grill wrote:A really good road bike position is in the range of .260m^2. The best bike positions are <.180m^2 (I know of a few below .170m^2)
I am assuming these are all at 0º? If so, I'd love it if I could hit those numbers on my Time Trial rig let alone my road bike. I'm curious, though, as to the size of the individual that is .260 and more so of those that are sub .180.
Between 0 and 5 degrees (velodrome tested). I don't really see much higher than that unless it's a long race. The guy at .260 on a road bike is 85kg. Although I don't know their exact numbers, here are a couple that are easily below .180.
And here is me at 78kg who is not as aero as the two above, but not far off either (although not on the wheels show, fast ones were getting new tubs at the time).