Test riding a true racing recumbent

[Osiris]

I was using Guerrilla Tape but got fancy with epoxy after upgrading from an 800 to a 1030 recently.

I haven't perfected hand and arm position. But. At this juncture with my current rig, very narrow hands is slower than slightly wider. I presume the legs shield the hands or it could be the elbow and forearm angle presents less surface area. Very counter intuitive. I guarantee this would be opposite for some riders. LOL

I've tried to perform some crude tests by riding without gloves and holding my hands in different positions to see how they feel in the wind. For me, the optimal placement seems to be with the hands right behind my thighs, where they're completely shielded from the wind at least 50% of the time. Phil Plath, by contrast, favored placing his hands high up directly in the air stream.

Sean Costin, Mike Mowett, John Morciglio, Larry Oslund, etc., all preferred the traditional downward pointing grips.

I find it very hard to believe that Phil's "high grip" could be the more aerodynamic of the two. I asked him about it, and his reply was that he'd never done any actual testing to determine which was best; it just seemed to him that a straighter arm position resulting from the high grip would allow the air to flow past him more smoothly.

 

[ed72]

Picture 1 shows elbows out of the air (Phil)

Picture 2 shows elbows in the air stream.

I was thinking of something like picture 1 but hands a little wider. The elbow is not only a lot of surface area but it looks like picture 2 elbow disrupts flow in the wrong place. Some turbulence of the hands at neck height might be preferable (Phil's higher hands) or at least a better tradeoff than the elbow sticking out. I could be 100% wrong.

Clearance of hands to the thighs becomes part of my "design" challenge.

We should get 4 of us and rent A2 tunnel for the day. Under $1000 each. Chung testing with sufficient replicates is probably just as good and just costs you time.

 

[ed72]

In my opinion, Phil's position in picture 1 looks very good aerodynamically. Different shoes, socks, and ditching the gloves would likely be significant gains. Helmet straps good. Skinsuit looks good at least to tired old eyes. Maybe arm sleeves.

I assume he is a pretty fast dude. Looks fit and the bike is clearly dialed.

 

[Osiris]

Picture 1 shows elbows out of the air (Phil)

Picture 2 shows elbows in the air stream.

I was thinking of something like picture 1 but hands a little wider. The elbow is not only a lot of surface area but it looks like picture 2 elbow disrupts flow in the wrong place. Some turbulence of the hands at neck height might be preferable (Phil's higher hands) or at least a better tradeoff than the elbow sticking out. I could be 100% wrong.

Clearance of hands to the thighs becomes part of my "design" challenge.

I was riding the M1 for quite some time with Phil's handlebars. It produces a LOT of turbulence at head height. By contrast, my "low" hand position results in much smoother air flow. All I hear now is a steady "swooooossshhh" at high speeds, and as a bonus I now have an unobstructed view of the road. The elbows do stick out a tad more in the low grip position, but by the time the air passes by them it has already been pushed aside by your thighs, so I'm not sure how much it matters. One other thing I noticed about the high grip is that it allows air to work its way under your arms, whereas using the low grip, I'm able to keep my arms against my torso for a tighter "envelope". Not sure what difference that really makes, but whenever I'm doing a sprint, I press my arms against my ribs to try to reduce my surface area as much as possible.

We should get 4 of us and rent A2 tunnel for the day. Under $1000 each. Chung testing with sufficient replicates is probably just as good and just costs you time.

I'd love to have access to an A2 tunnel. I'd practically live inside it, testing everything under the sun. The Chung method sounds a lot cheaper though. What does it entail?

 

[Osiris]

In my opinion, Phil's position in picture 1 looks very good aerodynamically. Different shoes, socks, and ditching the gloves would likely be significant gains. Helmet straps good. Skinsuit looks good at least to tired old eyes. Maybe arm sleeves.

I assume he is a pretty fast dude. Looks fit and the bike is clearly dialed.

Fast enough to set three WRRA records. Phil is a personal trainer by profession, so he's pretty well built. He's developed incredibly strong legs for his standing starts. I remember him telling me that he had John M. put an extra layer of carbon into the frame so that it wouldn't crack like the frame of the NoCom he was racing previously.

Here's a link to an interesting article written by Phil: http://cyclecoaching.net/portfolio/phil/

 

[ed72]

I was riding the M1 for quite some time with Phil's handlebars. It produces a LOT of turbulence at head height. By contrast, my "low" hand position results in much smoother air flow. All I hear now is a steady "swooooossshhh" at high speeds, and as a bonus I now have an unobstructed view of the road. The elbows do stick out a tad more in the low grip position, but by the time the air passes by them it has already been pushed aside by your thighs, so I'm not sure how much it matters. One other thing I noticed about the high grip is that it allows air to work its way under your arms, whereas using the low grip, I'm able to keep my arms against my torso for a tighter "envelope". Not sure what difference that really makes, but whenever I'm doing a sprint, I press my arms against my ribs to try to reduce my surface area as much as possible.



I'd love to have access to an A2 tunnel. I'd practically live inside it, testing everything under the sun. The Chung method sounds a lot cheaper though. What does it entail?

Finding a low traffic loop or a pipe that has some elevation changes.

I found an upscale neighborhood that ends at a cul-de-sac on each end of my "pipe". The middle is the low point. You basically go round and round or on a pipe, you go up and down. Maybe 5 times. This is one run. Need windless day. It gives you your Cda. The data is analysed in Golden Cheetah. I haven't read the attached in a long time but I am pretty sure it explains it all.

So, when I compared the FLO60 front wheel to the 2-Spoke, I went up and back five times. Analysed. Did the same for the 2-spoke wheel. The difference wasn't huge on a windless day....IIRC, it was 0.003. In a cross wind, the two spoke is noticeably faster. I did this with Jerseys and skinsuits and a bit with helmets but comfort also rules. It started getting cold and my last project of hands and arms hasn't progressed. Your insight is appreciated and I have no notion of what would be actually faster unless it is.

http://anonymous.coward.free.fr/wattage/cda/indirect-cda.pdf

 

[Osiris]

Finding a road that would be safe to take the M1 on is going to be difficult. This place is flat as a pancake, so I'd need to head out to Clermonte to find hills. Trouble is, I run the risk of being run over out there. I'm going to have to ask around to see if any locals can suggest a place.

Is it possible to calculate Cda from two runs in opposite directions on a flat road?

 

[Balor]

I've come up with a new tiller design for the M1. I already have most of the parts, and the mountain bike handlebar ends ($4.99 for the set) should arrive this week. I'll cut about 1.5" off the one on the right, which will be the perfect place to mount my Di2 TT shifter. This setup should be more aero than the present configuration, and allow for a more natural hand position, and allow me to brake and shift simultaneously if necessary.

Note that not all bar ends are 'equal' and having grips like you pictured would likely not be perfectly ergonomic - I've fiddled with my setup for best fit, but I mostly got lucky with a certain combination of hamster bar bend and how bar ends ended up on it...
Nothing major, but likely your wrists would feel a bit awkward. You may want some 'outward splay'.

 

[LarryOz]

Sean Costin, Mike Mowett, John Morciglio, Larry Oslund, etc., all preferred the traditional downward pointing grips.

My faster bike (Arrowhead), my gunner grips are pointed up and way up in the air compared to anything else I ride. (Very similar to the photo of Phil.)
I does make it even harder to see, since you have to look "through" the gunner and your hands to see the road. So it makes it more dangerous for any ridding except on a track where you don't have to look for potholes or other things.
It does not look as aero when compared to me on my Raptor or Vendetta, but the proof is in the speed per watts for me. I think the hands up high are cutting the wind for my head.
Note:
I wanted to post some pics, but I still am not able to upload any image files on this forum. I am getting the error: "The requested page could not be found" - not sure what is going on. It looks like someone accidentally deleted the upload page(s).
Trying to look into it, but so far no luck

 

[Osiris]

Note that not all bar ends are 'equal' and having grips like you pictured would likely not be perfectly ergonomic - I've fiddled with my setup for best fit, but I mostly got lucky with a certain combination of hamster bar bend and how bar ends ended up on it...
Nothing major, but likely your wrists would feel a bit awkward. You may want some 'outward splay'.

For me, the resulting wrist position would be ideal because this particular handlebar arrangement causes no twisting of the bones in the forearms. It's the most natural orientation for the hands to be in.

 

[Osiris]

My faster bike (Arrowhead), my gunner grips are pointed up and way up in the air compared to anything else I ride. (Very similar to the photo of Phil.)
I does make it even harder to see, since you have to look "through" the gunner and your hands to see the road. So it makes it more dangerous for any ridding except on a track where you don't have to look for potholes or other things.
It does not look as aero when compared to me on my Raptor or Vendetta, but the proof is in the speed per watts for me. I think the hands up high are cutting the wind for my head.

Have you done a comparison of hand positions on the same recumbent? The fact that you have better speed per watts on the Arrowhead than you do on the Vendetta or Raptor isn't surprising, but we can't conclude that it was your hand position on the Arrowhead that accounts for the difference.

 

[3bs]

i wonder how those compare to chimpmunks. i did make a new set of them for the tica that are a tad wider than the m5 stock to allow me to rest my elbows in tight.it really puts the whole arm behind the legs, and much more flush along the sides. but on the mid, i ended up making a narrow flat bar did the same and i was able to get a lot of the junk lowered. i fount it to be a little easier to pull back when hammering.

 

[ed72]

Finding a road that would be safe to take the M1 on is going to be difficult. This place is flat as a pancake, so I'd need to head out to Clermonte to find hills. Trouble is, I run the risk of being run over out there. I'm going to have to ask around to see if any locals can suggest a place.

Is it possible to calculate Cda from two runs in opposite directions on a flat road?

I believe that is how Andy Coggan does it but the road is extremely sheltered from the wind...IIRC.

Variability can be minimized with many or several replicates. Significance (statistically) might not be as easy to establish. I sometimes do just what you are thinking about. I have a 10 mile TT stretch along a river. On days that I am doing 8 x 20 intervals are not too high an intensity, I go up and back with one condition.....say a helmet. Swap to new helmet. Repeat twice. Fourth run is the original helmet. It really isn't going to give you your absolute CdA but does allow a relative comparison between different equipment changes or position changes. Not as precise as chung but if you can show something is better and it is as comfortable, that result is good enough for me whether it gets me 5 watts or 15 watts so to speak. Hope that makes sense. So, I might get 22 mph at say 132 watts with one setup and 22.2 watts with 138 watts with another. Which is better. Enter the numbers into Gribble to compare. The differences are often 10 watts or more especially clothing

I found circular tracks to be impossible in neighborhoods because I would be trying to corner at 30-40 mph whereas on an upright my speeds might be 23-28 mph and very doable.

Finding a suitable place to test is a lot of work. After several weeks I found a neighborhood 15 minutes by car. It is a pain to be honest....think about changing kit. I was talking to my son about that and he offered me his truck with full tint windows, so, that will make it easier. The results are very sensitive. This isn't like a 2 hour spin. Best time for my area is morning when there is low wind. The slightest wind makes testing almost useless unless the changes are huge....disc wheel vs box rims or something like that.

Lots of the big changes can be determined this way. Small changes might make sense to test in a wind tunnel for those very serious. I am not that serious but it would be fun. I know my crank, pedal, and shoes are draggy but they are comfortable. So, I am not changing

 

[LarryOz]

Have you done a comparison of hand positions on the same recumbent? The fact that you have better speed per watts on the Arrowhead than you do on the Vendetta or Raptor isn't surprising, but we can't conclude that it was your hand position on the Arrowhead that accounts for the difference.

I have done extensive testing with many different handlebars and hand position on the Vendetta. Unfortunately the Arrowheads handlebar is a one piece CF setup all the way back to the headset. I can't even change the angle. I would have to fabricate an entirely new one that lends itself to moving it around and mounting. Maybe a project for another time.

 

[LarryOz]

I found circular tracks to be impossible in neighborhoods because I would be trying to corner at 30-40 mph whereas on an upright my speeds might be 23-28 mph and very doable.

The only place I have found consistent results is on a closed loop with no vehicle traffic. I have 2 such tracks that I am lucky to have access to here where I live. Wind is always an issue no matter where you test, but if your sample is large enough and conditions are not changing it works well.
To me, doing anything "one way" is going to lead to data inconsistency, especially if you are on a road with other traffic. Plus, nothing is ever really "flat" (But a loop is always flat from start to finish). I have tried to do coast-down tests on roads, and it is amazing what just one car or truck passing you (in either direction) can do to you data.
Of course, we all just do the best with what we have available to us - such is life.

 

[Osiris]

My results on my new favorite trail have been remarkably consistent, so I was thinking I could use that to determine my Cda. Unfortunately it's perfectly flat, so it's not ideal for Chung's test. It is however very well shielded from wind, which may be the reason my results have been so consistent even on different days. If I don't find the kind of road Chung describes, it may be my best alternative for speed/power testing.

I've also been toying with the idea of building some sort of car mounted rig which I could use to compare aerodynamic drag at different speeds. It wouldn't be big enough to test anything more than individual components like handlebars, cranks, helmets, etc., but those are the very things I'm likely to swap. I've had this idea ever since I heard about a local TT racer who tested various handlebars to see which was the most aero by holding them out the passenger side window while his wife drove the car. His tests were probably too crude to reveal anything useful, but the concept sounds promising.

 

[Osiris]

I have done extensive testing with many different handlebars and hand position on the Vendetta. Unfortunately the Arrowheads handlebar is a one piece CF setup all the way back to the headset. I can't even change the angle. I would have to fabricate an entirely new one that lends itself to moving it around and mounting. Maybe a project for another time.

How did you end up with that CF handlebar on the Arrowhead? Phil told me that before John M. built his CF gunner bars, he first sent him a fully adjustable handlebar to experiment with. Once he found the geometry that suited him best, he sent it back to John to use as the guide for the CF one.

 

[LarryOz]

How did you end up with that CF handlebar on the Arrowhead? Phil told me that before John M. built his CF gunner bars, he first sent him a fully adjustable handlebar to experiment with. Once he found the geometry that suited him best, he sent it back to John to use as the guide for the CF one.

I basically bought John's prot0-type (which up until this year was the only model in existence) and it came with that handlebar and no offer to build a replacement. I think it just happens to be magic with my size and shape in the seat.

 

[ed72]

On an down and up pipeline, it is essential to make your turn around at the same place. I mark the turn point. Traffic is rare for me in this route. Once the landscaper cut me off on the SCAG Turf Tiger and yes, it showed up in the data. Even with a loop, it is essential to follow the same line at the top and bottom elevations. a foot matters. This time of year, wind is too much all the time but mornings in summer is completely still. No movement at tree tops and smoke practically just drifts away. The proof is completely consistent virtual elevations. A dog walker with 10 dogs came within 5 feet of me during one run......the VE was screwed up. I just ignored that one and did another up and back. It did show up. I would prefer a loop but most neigherhoods are more cul de sacs and those with a loop get me going way too fast. Obviously, one has to control all other variables but especially rider position.....not impossible but takes some care.

 

[ed72]

My results on my new favorite trail have been remarkably consistent, so I was thinking I could use that to determine my Cda. Unfortunately it's perfectly flat, so it's not ideal for Chung's test. It is however very well shielded from wind, which may be the reason my results have been so consistent even on different days. If I don't find the kind of road Chung describes, it may be my best alternative for speed/power testing.

I think it will work. I use it. When I was being fit to a TT frame, Dean told me he always tests gear and positions during recovery type riding days on such routes. He did win the Masters National TT championship, so, I suspect you should be fine. It is important to recognize the utility is not in establish an absolute CdA but to compare relative changes from one setup to the next on the same day.

Note: Just don't be too quick to draw a conclusion if you get small differences. Many runs and multiple days could be required to get the confidence with small improvement.

https://fitwerx.com/ask-fitwerx-article-archive/your-power-meter-is-the-best-wind-tunnel-available/