Haven't heard back yet, no biggie. Put on the speed sensor and it works. Shows laps automatically in GC. One feature in GC notio that would be nice is a lap trim feature where you can tell it to trim the first and last XX seconds of a lap for the accel and decel.

Either way, got some usable data yesterday on a out/back close to my house in town. Little down at start and turn around, so natural decel versus brakes. I can pickout some consistent lap CdA from it, which is what I wanted.

So, for hands positions. Is it reasonable to see a delta of 0.020 from worst to best? Cocked writs fully gripping extensions side by side was consistent 0.207 and the Ganna type hands but maybe a little more overlap than he does I was seeing consistent 0.195. Also, I tried a wedge hand hold where I wasn't gripping the bars at all just out of curiosity and it was about 0.196 consistently........but super unsafe. I'm guessing the two good results due to how it moved air around my face better than the more traditional grip. Or did so in a more organized manner of moving the flow of air.

But, is 0.020 to 0.021 improvement reasonable for something that simple? Seems like a lot. Delta for same hands for runs was only like 0.001 or 0.002 per run.

I had the same result for 3 runs on each grip done twice in two different lap locations. Lap data was a bit noisier on the first lap location I tried but gave the same finishing order of the three hand holds. So I trust it.

As for seeing the 0.195. I don't care too much for overall true CdA, just the gains or losses trying stuff. The CRR was set at 0.0037 I think for some gp5000's. No skinsuit, just a Giro aero road helmet. No disc or 90 front. I thought the gp5000 with latex on BRR was about 0.0035 in a 25mm?

Makes me happy now to have lap data from the Garmin and able to actually see things.

This was an important first test as it determines purchase decisions for extensions now as to which ones have which default grips or changeable grip styles. Unfortunately cost wise the ones it looks like works better for that grip and result are the pricier ones.

Ninja edit: if I zoom in only on the data parts with lowest accel/decel figures then the improvement is 0.005. Which seems more reasonable.

Ninja ninja edit: GC still does the thing where the average for a selection doesn't seem to match the individual points it has displayed for the selection.

A 0.01 difference sounds a bit high, but the hands are the leading edge of the system and they set up the flow around the helmet and down the back. If hand position affects reach, it can also reduce shoulder width. I guess the short answer is that changes that large are possible.

The best way to know would be to repeat the testing and see how close the changes are when repeating the experiment. If you get the same results on different days, the improvements are likely the real deal.

This is what 'may' be going on.

The chart you are showing is a rolling 60s window.

Let's say your lap starts at T=60seconds.
Let's say at T=0 you are sitting up, noddling around, your CDA is 0.5, at T=30s you slowly get into aero, your CDA is 0.35, at T=60s your are comfortably in aero and your CDA is now 0.20 and your lap starts.

But the 60s rolling average at T=60s will be something like 0.35. At T=70s, it will have gone down a bit, slowly going down...and finally at T=120s your rolling chart will be 0.20.

You would have to see what's to the left of what's displayed on that chart but I suspect it's making the first part of your chart inflated. You interval is 45s so all of it will be inflated.

Notice how the chart comes down at about 2/3 ? That is a sign....

The "average" shown on the left will not use this rolling window. It will use from T=60s (start) to whenever you press end (45s later).

IMO, there are better ways to get the rolling CDA number but if you understand the way they are doing it you can make sense of the data.

Ahhhh, gotcha. Since it is like that it will always likely on the window be showing a big contribution of the u-turn part of an out/back unless the out/back is long enough. Whereas the average is the average of the time x to time x+y.

Is there a way to adjust the averaging duration in GC for that chart like you have in the Notio sensor settings? Other than plotting it myself in Excel? In excel I could do some formulas to look at only the lap I want, then setup an average for during the "rolling" part just before any u-turns. I may try that.

Next phase of the project is try the down east pan flat 1/3 mile loop in that neighborhood. I could then get lap data without any interference of start/stop of out/back. I just need to find smallest backpack or a fanny pack I can find to hold a couple tools and fit parts to ride over to it from parking so I don't randomly park the side of the road in their street.

The arena in the city has a huge parking lot also that is almost pan flat at the top, I may be able to do a circle in it "at speed" faster than a 400m run track.

I know knowing what I'm looking at I can make decisions on the data I have. But making both the workout laps easier owning the sensor AND the post data look-see faster will make the iterative process of gains searching better. Like, if I can just see laps of a loop where the laps after the first one become "the CdA of the lap" instead of "the CdA of the u-turns and the lap" then there's no zooming in or farting around. Just look.

So I went to the upper parking lot of our local arena. I can do a circle of right at 0.25mi. It was windy so didn't feel comfy pushing the limits of speed, but looking at the Notio data after.........it will work. I think laps were like 23mph. So well shy of TT pace, but I can practice and learn.

So what I didn't like about the whole out/back thing is that I wasn't getting what I wanted. I wanted to be able to trust just doing the lap function, get laps, then check out the results. Not hyper analyze out/back laps to see if I could use them. Out/back I kept getting lap to lap differences in CdA I didn't like, even when selecting far enough after u-turns.

So, this arena parking lot does "tilt" a little. So imagine the lap is a perfect circle just tilted a hair. So, this introduces the little rises and falls in CdA in the results due to the accel and decel. Fine. I still was seeing a little variability lap to lap if I wasn't perfect on the pedals with minimizing the accel/decel. I find this whole process depends a lot on minimizing accel/decel. The results seem to hate it. IMO.

So, knowing I'm covering the exact terrain a dozen times for a run......I just set the elevation in GC to velodrome. Ignoring the fact that the laps do have elevation. Just to see. Suddenly...........the laps are perfect mirrors, as they should be if I'm not moving around or doing stupid stuff.

So, if you can get a "flat enough" loop that isn't a total nightmare of a hill or something..........I think there's a lot to the velo "ignore elevation" function.

I mean, I was shocked the difference.

I am in the process of buying fancy extensions with adjustable tilt and such, so will wait to schedule an "aero day" for that.

I still think it would be fun to schedule a "guys weekend" to go climb near Asheville but go do an "aero camp" afternoon also at the Mellowdrome.

I'm a Jeep guy. I have had 8 or so Wranglers since 1997. I have a place up in the country so am often hauling trees, climbing up hills.....I am in Canada with lots of snow.....The ultimate car. Tops off in the summer, no need to shovel, just crash through the snow banks in the winter.

I bought my wife a Jeep (4 door Wrangler). But she doesn't like driving in the snow, she doesn't like driving on dirt road (mostly because the car gets dirty), she doesn't like putting it in 4WD because she thinks it uses more gas.....

You use your aerometer like my wife uses her Jeep :-) No altitude change, no acceleration/decelerations. Do you take it out in the wind ?

I am pulling your leg.

For fit stuff and some helmet/skinsuit stuff you want to test at speed.

For stuff like a front wheel/tire, if the yaw is in the intended window for your test........does the airspeed matter too much?

Like if supposedly a trispoke is better at low yaw and you have a low yaw day (limp flags on the flagpoles), then do you really need to crank it up to high speed? Or would something more tame do?

Testing speed is an interesting consideration.

Personally I always test at multiple speeds but most of my testing is at speeds that I can do a lot of. If I do too much testing at 15km TT speed, I will be wiped after 30minutes of testing. I think number of tests trumps everything. So I tend to test at 70 to 80% of threshold most of the time but do check at, 90 and 100%. I very rarely see differences at the 70% and 100% threshold.

I also like to see if I get similar CDA numbers at different speeds. If I do, I have more confidence in my CRR number. If you over or under estimate CRR you will have a hard time getting consistent CDA numbers at varying speeds.

Yaw is tough for most. I never have a no wind day but I have the luxury of measuring yaw. My favorite test course is 4km, with a West-East 2km then a North-South 2km. I can measure CDA for each segment, see changing yaw and making comparisons. But most of the time, my apparent yaw is in the -10 to 10 range (or less) and things are relatively consistent. Several times I had inconsistencies and with big yaw numbers I attributed it to that.

If you have a very low wind day, yaw should be negligeable. If you have a bit of wind, high speeds will make yaw negligeable.

If you are comparing different wheels with different tires you probably want to test at different speeds to work out CDA/CRR.

I am not sure I answered your question .....

What are you using to test ? If VE on a windy day it will probably be difficult to differentiate yaw different from air speed.

Revolver replica against HED 9+. It finally arrived from China or wherever it is made.

Identical tire, tube, pressure.

I'm guessing if wind is low, I can go in Z2. If wind is higher, I'll crank it up to sweetspot.

I was going to test it today, but forgot I can't wrap a speed sensor on my rear disc OR on a front trispoke. So couldn't test. Doh!!!

But, in process I did google maps a new neighborhood I haven't tried yet right next to a public park. Google maps looks promising for 25mph laps on the neighborhoood loop laps.

Will try very soon.


Edit: are there some accepted known for Notio CRR's of some tires like the Michelin TT or the GP5000 or the TLR Corsa Speeds?

I personally would use bicycle rolling resistance numbers and would correct for temperature if much below/above 20C.
But if you are doing your tests at constant temperature no real need to adjust.

So far that's precisely what I've done, but haven't adjusted for temp and not seen any issues.

I am getting impatient with the weather. Been in the low 40's recently finally for winter. Ice storm this weekend.

I guess I'll build up the track bike with the old TT bits and get back to Zwift/Rouvy this weekend. Sigh....

Can't wait to see how a modern 3 spoke compares. Is a 3 spoke any easier to handle than a spoked deep front wheel? Following a similar thread on TrainerRoad and there's preliminary results. https://www.trainerroad.com/...ing-thread/46868/824 (I think this link should work.)

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I have a Slowtwitch private message from Andy at HED that the gt3 and 3+ modern width trispokes need about 28mph minimum to beat the 9+ spoked wheel.

I TT a 10mi just over 28mph excluding the u turn. So am trying a Revolver copy Notio test soon at that speed.

Handling isn’t too bad but I would go 9+ or 6+ if really cross winded badly.

FWIW my GT3 tested favorably at low yaw compared to a Zipp 808 Firecrest in the tunnel.

E

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Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”

What kind of difference did you see ?
Did you ever try confirming the result on the road ?

I’ll have to dig up the numbers but it was faster at low yaw IIRC and I have not tested it on the road yet.

Basically, the numbers indicated that with a weighted distribution at Kona I’d go with the firecrest if that makes sense.

E

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Eric Reid AeroFit | Instagram Portfolio
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“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”

Didn't feel like starting a whole topic for this, but anyone know where you can buy the TT extension finger loops? Or are folks making their own?

I can probably make something. Not the ones replacing bar plugs on track bikes. But ones that seem to clamp the extension end and have a little protrusion that fits between perhaps your 2nd and 3rd finger up on the extension grip area.

The way I'm going to trim my bars for a one button TT shifter, the ergonomics would be really nice for one. I like stuffing my thumb down inside my fist then pushing it down for a gear change. That moves the button/bar a tad shorter. I would have 3 fingers on carbon and 4th on the button side.

I'm going this way as I am finally fed up with the ergonomics of the two button tt shifters on the extensions. I have synchro shift so may as well use it. Races would be 1x anyway.

Are you UCI limited?

E

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Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”

No, and yes, more on that in a minute.

It's really the ergo of how they're made and not wanting a bunch of pole sticking past my hands. They make them with extra grip length so you can cut to desired. People's hands are different sizes. To hold my thumb inside my fist and have the base of my hand against the extension as designed, you can't have a mile of grip sticking up. If you do, thumb goes around or to one side or another, probably inside. They really provided a lot of grip, like a whole inch or two more than a Wattshop Anemoi does.

But, even with my thumb not tucked in my fist and resting on top of the button......a solid bit needs cut shorter.

Since the single buttons plug at the button instead of the stupid integral cable like the two button, I can try the one button as-is length of the grip first. Then cut later. As it's as easy as pull the button, unplug, cut, put button back. Right now it's a royal PIA to pull the cable out of the basebar/fork and put it back.

No on UCI, I won't be winning/record at any USAC nationals anytime soon. As for otherwise, I picked up a track bike. I broke the spare basebar I have drilling out some stuck screws. Otherwise, I was going 1-button also on the TT bike so I cold easily pull the shifter/unplug and put the entire thing onto the track bike in the same position. I thought for track I may need to abide. That's a big IF riding it I like the bike first locally to then go do the class and try a few races. So easy swapping over the bars.

In this photo, with my hands on that grip.......there is still about 1" proud above my hand of carbon left before you get to that 2 button shifter. Issue with the 2 button shifter is the ergo is ruined on the button design when hands are really close without rotating the buttons so you have to rotate your thumb and reach on top. So single button, right now, I wouldn't be able to reach the top of the button easily to shift.

There’s your trouble… don’t use the extensions “as designed”, use them as you need to. The bike works for you.

E

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Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”

Bringing this over from the other thread so as to not pollute the other thread

Found them, both Amazon and Aliexpress have them.

On Amazon it's called a "drop bar thumb grip". Like $8.

Say I want to test with the rear disc and trispoke on the bike. I have to have a speed sensor.

Who makes something that could fit on the subby little bit of left of the disc’s hub? A Garmin is too wide. Spoke magnet stuff, it’s a disc, so no.

I swear I see pics of Notios on bikes with both, how is the speed picked up?

Tape it around one of the trispoke blades? A couple passes of electrical tape ought to hold up for a few dozen out-and- backs

I paste a bit of tape on the disc and than paste one of these tiny super magnets on the tape with a superglue.