Osiris
Zen MBB Master
With a difference that small, how much aerodynamic difference do you think wearing a different style of eyewear might make? I assume you're wearing the typical sleek cyclist eyewear, not some clunky pair of sun glasses?
Helmet field testing? CdA impact
- Thread starter ed72
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With a difference that small, how much aerodynamic difference do you think wearing a different style of eyewear might make? I assume you're wearing the typical sleek cyclist eyewear, not some clunky pair of sun glasses?
DavidCH
In thought; expanding the paradigm of traversity
Well I haven't done it yet but my intention is to get a full uvex face visor and try and fit it over the giro air attack. The big issue with that is the visor will mist up but I think it's worth a go. Many of us cycle with our heads at an angle.
Osiris
Zen MBB Master
At 285 watts, a reduction of 0.003 should take me from around 29.6 mph to 29.8 mph. Taking my mirror, headlamp, and tail light off the seat stay is probably another 0.003. Losing that last 15 pounds is probably the remainder. LOL. Sounds trivial but it isn't. I remember playing golf at Winged Foot with a very wealthy member who would go looking for golf balls if he was out of a hole, which seemed silly considering his wealth. He looks at me and says, would you pick up a $5 bill if were on the ground? In terms of power, it is like finding a free 5-7 watts on the floor (at 30.25 mph).
Getting the whole 0.010 improvement desired (in CdA aero) would get me to around 30.25 mph. Best estimate. CdA with face shield was 0.1572 vs 0.1542 with with glasses (now, I forgot if I was in a skinsuit but highly doubt it). I don't think I am going to get to my goals but we'll see. I am trying. Certain things could be quickly determined in a wind tunnel but this isn't THAT important, besides it would take all the fun away. I am certain a Magic bike would get me there.
There should be error bars around all those numbers. I had two objectives. A sub 20 minute 10 mile TT and around 140-150 watts to go 24 mph. A second uncertainty is my use of 0.0045 for Crr, this was my measured value for the Conti GP4000 tires on that pavement. I have not repeated the test for GP5000 that I am now using. So, the absolute CdA values are not of interest or necessarily accurate but since I am only interested in relative improvement and therefore actual performance, good enough for the Russians. I have not done an FTP test since early May. I suspect it is around 285 watts now, which means I should be able to hold closer to 300 watts on a 10 mile TT. Not sure. I am currently needing 160 watts to go 24 mph and 178 watts to go 25 mph (full fastest gear) in perfect conditions. Not bad.
I have several pairs of cycling eyewear. Smiths are a favorite. I was wearing the Shimano S-Phyre R1.
Osiris
Zen MBB Master
My SH+ Eolus helmet just arrived!
My initial impressions:
1. The first thing I noticed when taking it out of the box was how light it felt; it seems no heavier than a conventional Styrofoam road helmet. Whereas the old model has a thick outer shell and relatively little padding inside, this one has much thicker padding and the outer shell is just a thin layer of plastic. Weight savings are evident even in the visor, which is made of much thinner material than before.
2. It comes with two visors; one in clear plastic, the other featuring a dark reflective tint. The shape of the visor is much improved as well. It covers more of the rider's face, shielding everything above the tip of the rider's nose, and the downward curvature of the lens is greater, making for a better air seal at the edges. The greater outward "buldge" of the visor should allow ample room for a pair of glasses to be worn underneath, which was not the case before. The visor is held in place by tabs that fit into slots in the outer shell, and can be easily detached, unlike the old one.
3. The shape of the helmet is different in more ways than I expected. The rider's ears are now fully enclosed for improved aerodynamics, and the overall shape of the helmet isn't round any longer, but more of an egg shape. Gone are the top and side vents. The only openings in the shell are two slots in back and four small cutouts in the top of the visor. No doubt this makes it more aero, but the lack of adequate ventilation could be a problem in hot weather. While the old model had lots of air space at the base, the new design comes with an inner "fairing" that seals up the gap between the rider's neck and the edge of the helmet.
It's really too hot and humid to ride the M1 low racer, which sits mere inches above the searing pavement, but I'll at least have the opportunity to test the helmet for fit once the M1 is back on the trainer, and I'll probably do some test rides with it on the M5 high racer and Cruzbike V20.
My initial impressions:
1. The first thing I noticed when taking it out of the box was how light it felt; it seems no heavier than a conventional Styrofoam road helmet. Whereas the old model has a thick outer shell and relatively little padding inside, this one has much thicker padding and the outer shell is just a thin layer of plastic. Weight savings are evident even in the visor, which is made of much thinner material than before.
2. It comes with two visors; one in clear plastic, the other featuring a dark reflective tint. The shape of the visor is much improved as well. It covers more of the rider's face, shielding everything above the tip of the rider's nose, and the downward curvature of the lens is greater, making for a better air seal at the edges. The greater outward "buldge" of the visor should allow ample room for a pair of glasses to be worn underneath, which was not the case before. The visor is held in place by tabs that fit into slots in the outer shell, and can be easily detached, unlike the old one.
3. The shape of the helmet is different in more ways than I expected. The rider's ears are now fully enclosed for improved aerodynamics, and the overall shape of the helmet isn't round any longer, but more of an egg shape. Gone are the top and side vents. The only openings in the shell are two slots in back and four small cutouts in the top of the visor. No doubt this makes it more aero, but the lack of adequate ventilation could be a problem in hot weather. While the old model had lots of air space at the base, the new design comes with an inner "fairing" that seals up the gap between the rider's neck and the edge of the helmet.
It's really too hot and humid to ride the M1 low racer, which sits mere inches above the searing pavement, but I'll at least have the opportunity to test the helmet for fit once the M1 is back on the trainer, and I'll probably do some test rides with it on the M5 high racer and Cruzbike V20.
Osiris
Zen MBB Master
Doesn't sound trivial to me at all! 5-7 watts adds up over long distances, like my anticipated 30 mile TT. Remember when bike manufacturers managed to find ways to hide all the cables inside the frame? The claimed aero benefit, IIRC, was only 4 watts, but that was enough inducement for people to upgrade their $10,000 bikes for the newest model. If I could find a way to shave 5-7 watts worth of drag off my M1, I would consider it money well spent.
If I had access to a wind tunnel, I'd probably live in it for a month, testing everything under the sun. I love that kind of stuff. I'm already thinking about doing more coast down tests, but this time I'm going to prevail on someone to drive me back up so that my data gathering won't be limited by the number of times I can climb that hill. I want to do more helmet testing, tire testing, as well as test my skin suit, and that's going to require a LOT of runs.
I'm not getting numbers that good on my M5. Maybe I need a deep section front wheel and an aero-tail box. Not sure what more I can do with it at this point. I want to see if I can average 24 mph on the M5 for 60 miles, but the hard part is finding a road where I don't need to stop or slow down for the duration of the test. Aside from the interstate highway, I don't know of one.
So, I loaded all the gear into the car along with the bike. It was calm at my house. Although only 15 minutes away, I get to my half pipe and it is windy. I decide to head to the other side of the ridge and go North South along the tree sheltered river road. Four laps for each helmet config. Large Vanquish with shield, Medium with shield, and medium with glasses. The wind was around 507 mph and the bike seemed unstable. Low and behold, I had a slow leak. Ruined my testing. Put a new tube in and decided to run 30 minutes of Large Vanquish with shield and 30 minutes of Medium Vanquish with shield to compare just those two configs.
Not great data but it appears the primary reason the Large Vanquish with shield was much slower than when run without the shield and with cycling glasses? The large has a huge gap between the bottom of the shield and my face, aside from just being much larger overall. Of course, it is also larger. This difference was very apparent swapping helmets back and forth. I could actually feel the speed difference riding and the numbers showed it. Medium to Large comparison, both with shield. Now, the wind is certainly a factor but out of maybe 20 Strava segments, the large was more aero only once using pencil, paper, and Gribble. The size of the gap is a bit more than the width of my finger whereas the shield on the medium helmet just touches my cheek at one point. I could not get the large helmet shield to get closer to my face. It is what it is. Not sure why. To give an actual number would be incorrect of me but it is more than the 0.003 figure. I have a feeling it is going to be 10-20 watts at 30 mph. I'd have to get a calm day and do proper Chunk testing. My mind is pretty blown by the apparent differences and the fact I spend 4 hours for only somewhat useful information.
I normally wear a large helmet, my head diameter is 59.3 cm, which is usually just beyond a medium unless I do some surgery. The Vanquish helmets run large or at least on my head. I suspect the medium could fit close to a 60 cm head.
Not great data but it appears the primary reason the Large Vanquish with shield was much slower than when run without the shield and with cycling glasses? The large has a huge gap between the bottom of the shield and my face, aside from just being much larger overall. Of course, it is also larger. This difference was very apparent swapping helmets back and forth. I could actually feel the speed difference riding and the numbers showed it. Medium to Large comparison, both with shield. Now, the wind is certainly a factor but out of maybe 20 Strava segments, the large was more aero only once using pencil, paper, and Gribble. The size of the gap is a bit more than the width of my finger whereas the shield on the medium helmet just touches my cheek at one point. I could not get the large helmet shield to get closer to my face. It is what it is. Not sure why. To give an actual number would be incorrect of me but it is more than the 0.003 figure. I have a feeling it is going to be 10-20 watts at 30 mph. I'd have to get a calm day and do proper Chunk testing. My mind is pretty blown by the apparent differences and the fact I spend 4 hours for only somewhat useful information.
I normally wear a large helmet, my head diameter is 59.3 cm, which is usually just beyond a medium unless I do some surgery. The Vanquish helmets run large or at least on my head. I suspect the medium could fit close to a 60 cm head.
The M5 2 spoke is what I use up front.
The tailbox helps except in a cross wind. Mixed bag. Overall, it helps.
I am using the shortest seat post and the front of the seat is elevated 1/2 inch. I suppose my seat angle is 17-18 degrees. My eyes are in line with the front derailleur.
Try closing off the gaps between the seat and frame. It is very helpful in the rain, too. My cockpit is much more tidy or at least from your old photos.
If you are not using sun sleeves on your arms, try those. Def faster
Osiris
Zen MBB Master
I'd love to have one of those, but every time I look at the price tag, the room starts spinning and I feel nauseous.
I've got Kent's RailGun seat on mine, so there's no space under the seat. Not much I can do to change the seat angle on that thing, ether. But if I use a thinner seat pad, I'll sit further down "in" the frame. Maybe that will make me a bit more aero. I'm still peeved over the fact that I can't position my arms the way Aurelian Bonneteau's are. That's got to be worth at least an extra mile per hour.
You're the second person to have mentioned that. I just tried on my skin suit for the second time and it still looks ridiculous on me, so sun sleeves it is. One bit of good news is that my new Eolus helmet fits the M5 perfectly. I thought I might have to modify the headrest to position the helmet properly, but it fits like a glove just the way it is. Time for some speed testing this weekend, methinks.
I've made a concious effort to all but eliminate any unwanted body movement when pedaling, and the new handlebars have completely done away with front wheel waggle, except when I'm climbing steep hills. I'm pretty sure that thick spongy seat pad is absorbing some of my power, though. Another reason to get rid of it.
DavidCH
In thought; expanding the paradigm of traversity
Snap
I was pretty sure that was the case, some riders are all over their bike. Such movement disrupts airflow. Look at how stable pursuiters are even laying down massive power, the slight side movement is probably partly the frame bending.
Another difference. I measure my power at the hub. Yours is at the pedal. There is at least 10 watts difference there.
I also shave legs.
I am also tall. Tall and slender like a missile.
Truth is .......absolute values mean nothing because conditions change so rapidly from day to day or even during a single ride AND, I do not doubt that I could have systematic error in my measurement; however, my results are consistent and therefore relative changes are useful in terms of identifying improvements. I tend to look for a consistent relative improvement. I am confident the medium helmet with shield is much faster than the large with visor. I don't know if the medium is faster still with cycling glasses sans shield. The reason I liked the large is because I could wear cycling glasses underneath and in the rain, the shield tended to keep my glasses relatively dry with decent road visibility.
I am considering coating my Giro Shield uber expensive Zeiss shield with Rain-X but somehow I think this is a very bad idea from a materials standpoint. (weaken or clouds it up....??)
A Zipp 808 is 50% more cash and the latest stupid 858 is almost double the 2-spoke per wheel. I would like to have a set of Zipp 808 NSW tubeless but I don't want to spend $3500 on a set of wheels. If speed were THAT important, I would fly over to England to have a custom skinsuit made to remove the wrinkles and pocket the $2k difference while still being faster.
Osiris
Zen MBB Master
I never thought about that. The reason I try to keep my upper body as motionless as possible is to limit power loss. I see some riders out there bending and twisting in their seats like a weak spring, and I always wonder how much of that is just wasted energy.
It would have been even worse if I hadn't eliminated the second idler wheel up front and put another spacer between the under-seat idler and frame to straighten out the chain as much as possible. It still rubs against the inside of the idler wheel, but it's better than before. Not sure how much power all of that is saving me, but it's got to be worth something. When I push on my pedals with the tip of my finger, I still notice more resistance than on any of my bicycles, though. I might have to try ceramic bearings.
Fortunately I don't need to. The hair on my legs is so thin and sparse that other cyclists always assume I've shaved them.
I am also tall. Tall and slender like a missile.
It works for racing kayaks too. The longer they are, the faster they go.
Even with a visor keeping the rain off, my glasses quickly fog over until I can't seen anything. Fortunately my nearsightedness has actually gotten better with age, so I can now safely ride without corrective eye wear. I still can't read street signs from far away, but as long as I know the roads, it's not a problem.
I've been told that Rain-X deteriorates plastic. People in my motorcycling group warned me never to use it on my visor or plastic gauge covers. If there's a scuba diving shop in your area, they'll have a spray on anti-fog solution that does a better job than Rain-X but does no damage to plastic or rubber.
Osiris
Zen MBB Master
My Zipp 808's cost me around $2400 back in 2014. Isn't that close to what just one of those M5 double spoked wheels costs?
I think $1300 for the front? I just checked, front and rear are 2066 euro or about 2300 USD. Front alone is 1177 euro.
Thanks for the tip. I'll check it out.
Osiris
Zen MBB Master
Hmmm. That's about half what I thought it was. If I sell both my Zip 808's, I should get at least that much for the set. How much extra speed do you think the double spoked wheel might give me?
I don't know. The 808 wheels are already fast. I Chung tested the 2 spoke front against the FLO60 carbon in dead calm conditions, I was expecting a bit more improvement than I got. I reported it somewhere, I think it was 0.005 with both having the recommended tire width (flo60 25 mm gp4k at 95 psi and the 2 spoke had a 23 mm supersonic at the time but gp5000 now)
I've gotten some crazy results in crosswinds. Like only needing like 80 watts to go 21 mph over 5 miles in strong crosswinds, switching to the Flo60 and needing the normal power, say 110-120 watts. These are just example numbers, I have them written down somewhere. In calm conditions at modest speeds, the difference isn't so much and isn't really noticeable. It does have a sail effect like a disc wheel but more controllable. The claimed effect or tested effect is more than a disc. The English description is sort of hard to follow. I have to be very honest, I can't say bad or good about them because they are so different that my brain can't wrap its head around them. I am also not good at feeling wind direction riding and assessing performance in a crosswind is also not easy to measure. I tried.
Osiris
Zen MBB Master
I found lots of stuff online about the two spoke M5 wheels. I couldn't find any published test results that put the matter to rest (all are from biased sources so far), but there's plenty more reading to do. Odd that so many people think they look ugly. I find them rather appealing.
One thing that has always bugged me about all carbon rims is how long the braking surface will last. I've never worn out an aluminum rim, but you can clearly see where some material has been rubbed off from repeated braking. You probably ride as many miles in a month as most people do in a year, so what has your experience been in this regard?
One thing that has always bugged me about all carbon rims is how long the braking surface will last. I've never worn out an aluminum rim, but you can clearly see where some material has been rubbed off from repeated braking. You probably ride as many miles in a month as most people do in a year, so what has your experience been in this regard?
