Great episode.

Obviously John's a guy that "gets it".

He has participated in this thread, so maybe we'll get him to participate in the future.

Nice interview. Thanks for pointing it out.

I hadn't seen that before. Very nice. Thanks Marc and Ryan.

Hi Jon...I was curious...does that bolded statement above hold when the data is normalized for measured tire width? I'm not sure if I've ever seen that proven before. Thanks!

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http://bikeblather.blogspot.com/

Great question Tom. To be honest we didn't look at the problem that way but now I am wondering what it would show. We looked at the same tire over different rim widths which creates a wider casing width.

In theory, the same casing width would be achieved with a smaller tire on a wider rim. In order to match casing width you'd likely need a custom tire.

I do know height does not really change as rims get wider. We've taken thousands of measurements of different tires over the years looking at the relationship between casing width on different internal rim widths along with tire height. Casing width is almost linear with each tire having unique slope equation and height is generally a flat line. There are exceptions but the data is random.

Knowing that height generally stays the same a rim with a wider internal rim width would have a lower height than a larger tire on a rim with a smaller internal rim width. Stretching the width could in theory create a wider contact patch which may slightly lower the Crr. Likely negligible but possible. Would be fun to test if I could make custom tires.

Then there is the aerodynamic component. Many things to consider.

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Jon Thornham
Co-Founder FLO Cycling

d, I saw something pop up today regarding another aero sensor: https://aerosensor.tech/about/
it says it has Dr. Barney Garrood PhD as the person behind it later mentions John Buckley, they also sell a body position sensor so it is the same stuff in 2 locations or company names.

The aerosensor has an idiegogo page as a start up and Chris Hoy is a backer.... https://www.indiegogo.com/...mic-cycling-system#/ their indigogo is not going crazy that is for sure.

Is it just me or was John a little more conservative on offering dates for delivery?

Yes that was my take away as well, but maybe to get onto Indiegogo they had to advertise a ship date? Seems that on the Aerosensor page John is sort of secondary person whereas he seems a bit more prominent on the Streamlines web page... seems a bit strange, but the podcast interview was fairly recent so that makes one wonder about deliveries. They still have a substantial way to go on their Indiegogo, I assume if they don't make it to 100% funding it might impact delivery? and even project success. The ask is not small so you had better have money to burn.

These devices need to go way way way down in price, not up.

One part I found interesting was he said (or I understood), they sold some of the tech to the F1 companies.

IMHO, they wind/yaw sensing technology is way overkill for this application, but not if you are selling to an F1 team at the same time.

I presumed Streamlines and Aerosensor are sharing or licensing tech, but have separated into two companies?

It sure looks schizophrenic. Sort of like one guy is the front for one company and the other the front for the other... That would cause me concern with longevity if they are already splitting but using the same technology, that could get messy.

for those interested in this sort of thing here is their patent:
https://patents.google.com/...nventor=John+Buckley

Hello,

Yes, it is confusing. We have tried to give some explanation on the Streamlines website - https://www.streamlinesaero.com/company
But I will elaborate further here.

The founder of Aerosensor, Barney Garrood and I both started Velosense in 2016. I am very proud of what Barney, and I achieved with Velosense. With a two-person company, we managed to patent and build a very accurate airspeed and yaw sensor, as well as develop world class aerodynamic and body sensing technology which has been used by Mercedes and Ferrari F1, as well as by Jumbo Visma in their TDF preparations.

At the end of 2021, we decided to license the Velosense technology to two separate companies, Aerosensor (Barney) and Streamlines (myself), as we had different views on how to bring the cycling technology to market. It is worth mentioning that we are still on amicable terms :)

To explain the difference in view, a brief bit of history is helpful. The Velosense aero device was originally intended to use the ANT+ Aero profile. The aero device would provide real time (or lap) CdA calculated in the embedded code. It would be a mass market device and work with all the main bicycle computers.

By 2021, the main difference in views were:

1. Cloud Computing and Post Event Software
As you many of you know, indoor aero testing on a Velodrome is complicated, outdoor testing on roads is many times more difficult.
Our work with Jumbo Visma and other successful outdoor tests all relied on cloud computing and/or post event analysis. So, for me, when the Velosense cycling probe is used to calculate drag outdoors, it needs this additional software. With Streamlines, we have invested further into the cloud computing and post analysis software. We have hired software developers and are looking to hire more.

2. Aero Sensors are not yet ready for the mass market
Aero sensors are a great engineering tool, but even with our cloud analysis software, they require more understanding than is suitable for a typical consumer product. For this reason, our initial AEROS product will be aimed at coaches, bike fitters, and industry professionals. We believe we can provide a great product to this market a pricing structure that will allow them to economically test clients. We will work closely with each customer to refine our software and training material. As the product becomes easier to use and understand, we will expand our target market.

3. Customer Support
Aero sensors are complicated products and currently require some knowledge and training to use. Streamlines plans to properly support customers with training materials, suitable bike mounting solutions, and any other troubleshooting. This requires dedicated in-house customer support staff with specialised knowledge.

4. The value of the Body Sensor
The body sensor was developed initially to improve repeatability of the aero sensor, but I personally always felt that it had the potential to be a great stand-alone product, and just needed some further attention and development. With Streamlines, we have added a lot of setup, adjustment, and general usability features to our FORMA body sensor, and this will be our first customer product.

5. Velodrome Capability
We know from experience that our FORMA body sensor can be an invaluable in testing and training in the Velodrome. However, with aerodynamic drag calculation in the Velodrome, we believe that there are several companies that provide an accurate Velodrome system with a good user experience. In addition, apart from some specific applications, an aero sensor in the Velodrome can sometimes bring more complication than benefit. For these reasons Streamlines is not providing any Velodrome specific technology.

Velosense was far from profit making and put us both under serious financial strain. For the reasons above, I felt the aero sensor system needed considerable further development to be commercially viable. Barney held a different view and felt that the existing Velosense technology could be crowdfunded into a consumer product.

With Streamlines, we have recently acquired funding, which we plan to announce soon, that will allow us to grow the company to the vision above and deliver products that will give long term customer satisfaction.

Feel free to ask further questions. I saw the previous posts about the podcasts and I was preparing to post a bit about Crr, but this obviously needed addressing.

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John Buckley
https://streamlines.aero

I enjoyed your interview.

Having experienced all the pains of developing in this space, I am a very skeptical listener.

My BS meter didn't go off once, which is rare.

Thanks.

Yeah, aero sensors are not an easy space technically or commercially. Michael Liberazon from the podcast is so knowledgeable, interested and passionate about this technology, it makes speaking about them a lot easier.

For people who are not in the pointy end of the TT / Triathlon scene, technical expectations can be a bit too high, which makes things difficult.

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John Buckley
https://streamlines.aero

Thank you John for your cogent explanation. It did look schizophrenic when I looked at each web site and how they were laid out and the story each told, the details you have put forward explain that schism. I was very impressed by the podcast interview and how you were very up front and quite transparent. This is very refreshing. I hope your endeavour works out well. There are some really knowledgeable people on this thread. I am constantly learning something new from their posts. Please post your CRR info I am now really curious to hear your thoughts on that.

  
Here is my analogy of the aero sensor space. Let's pretend an aero sensor is a derailleur

A few years back someone came out with an Ultegra. It was ok. The problem was it wouldn't go into certain gears. That's OK, ride it on a flat course, make sure the wind isn't too strong......you won't need those gears, besides it's better than no derailleur at all. It was innovative with lot of room for improvement.

Since then, people have been working on a DurAce. They made it lighter, way lighter, they keep shaving off a gram here, a gram there. Problem is the "it doesn't go into these 3 gears" is not resolved. But it's lighter. Unfortunately it is getting more expensive.

If someone comes along and fixes the gear shifting, the DurAce and the Ultegra are now more useful than ever. You can ride them anywhere. Maybe the DurAce price point makes sense then.

But what if someone fixes the gear shifting, even if it's a bit clunky at first and comes in at a 105 price point, what happens ?

There will always be a market for DurAce. But your best shot at the seaside home you talk about in the podcast is in 105.

Sometimes I get the impression the market doesn't see the value of a derailleur, they think a fixie is just fine :-)

Thanks for the clarification, John. I could tell the products were slightly different in their emphasis, and I'm glad you guys are amicable. That's always important.

I liked the podcast with Michael a lot.

Best of luck with Streamlines.

This.

If you're not gifted as a problem solver or using things like GC, then a lot of this stuff simply doesn't "work" still. Almost nobody lives within distance of a velodrome or super pan flat circular lap. And out/backs even on a windless day often have little dips or rises that elevation detection do not pickup.

I know it was explained me earlier, but still.........if we freaking know for a lap you're "in position" and the CdA won't change "that much" why do all the damn calcs attribute accel/decel to aero changes instead of undetected elevation? I did a ride yesterday with my cross bike at work. There is a super standard "bridge clearance height for railroad crossings". Meaning this bridge crossing is at least 30 feet per crossing. It's on a loop at lunch I cross this same bridge 12x. 12x30 alone is 360 feet. The ride only registered 348, excluding all the other small lumps around the ride. With the aero sensors, this accel/decel for those wrongly detected elevation changes fucks the CdA reading.

For me if they during a lap allowed you to say "attribute accel/decel to an elevation change the sensor didn't register" I bet the CdA goes stone cold solid for the lap.

For now, I've designed laps well enough the "fuck ups" by these sensors/software are repeatable enough for all laps that I can assume each lap gets the same little elevation blip screwup that causes the CdA to go up and down.

My holy grail is a trip to the Asheville mellowdrome for a weekend personal "aero camp".

Mine don't.

I do have to clarify, looking at my data post-ride it looks to the non expert's eye that when CdA flatlines but suddenly rises by .050 or more then falls back.......I can directly point to a bump in the road that briefly caused more power to hold speed or less speed to hold power (doesn't matter I get same bump in CdA either way).

This is in GC-Notio that I see this. Where I do my out/backs I do my best to pick roads, but there's always that one or two little 5 foot tall humps in the road.

The 1st Crr question isn't too contraversial:

In the podcast Micheal mentions a really steep relationship between Crr and Temperature. At the time, I was a bit dismissive as a 1% change in Crr would be less than 0.1 to 0.15% change in energy expended at at speed. At the time I was thinking that 5% would take 20 - 30°C change or something like that.

I have done very little Crr testing, but I have this very low speed data set from last summer. See attached pic.



The test protocol involved traversing a 130m stretch with a 1% gradient.
A powertap power meter is used as the time based signal copes much better with very low power and cadence.
All the runs had a ground speed between 2.3 to 2.7m/s.
Wind was negligible
Dynamic pressure and elevation are recorded, and CdA was fixed at 0.35 for all runs. Crr was then computed from an energy balance.

The test was around sundown and the air temperature dropped by about 1.5° and the Crr increased by 3-5%, which was a shocking amount!

After looking at this test here - https://www.bicyclerollingresistance.com/...crr-temperature-test
and this one
https://docs.google.com/.../edit#gid=1567734751
I calmed down a bit, as all values are within 0.5 to 2% Crr / °C.
Which suggests to me that in the set above the tires had possibly cooled off a lot quicker than the air. Maybe the sun was shining on them to start with?

Has anyone used a thermal gauge to record external tire temps?
How much hotter do the tires ever get than the air temperature?
Do they change temperature at speed?
I would have thought that at a stationary tire in the sun could get quite hot (even with UK sun), but at speed the convection should cool them off. But then on the other hand there can be about 20W of energy per tire which should be dissipated as heat? I have a fuzzy memory of an infrared gun in a velodrome and the tires were never more than a few degrees above air temperature. Does anyone have any experience or numbers for this?
I am not trying to model it right now, just get an idea of the magnitude change.

Thanks

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John Buckley
https://streamlines.aero

I think Tom Anhalt has used both and ambient temp and an IR sensor on outdoor Crr tests.

Long ago some of us who did outdoor field testing noticed temperature dependence in Crr. It seems to vary with tire but generally we could see around a 1% change with each deg C. When Al Morrison was doing indoor roller tests, he used Tom's spreadsheet to adjust his measurements to a standard temp for his basement testing area.

We discussed (and argued) the magnitude of temp dependence in a series of epic threads on the late lamented and sadly missed wattagetraining site.

I think I understand your analogy. My thoughts would be this -

Right now, if money is not an object, the most reliable way to improve a cyclists CdA is a wind tunnel. A wind tunnel cannot be beaten in precision, but road testing can give a more realistic condition. I imagine everyone has heard the pros and cons.

The metric that I think provides real utility is meaningful tests over time. A meaningful test is being where the effect of something can be quantified to a reasonable degree of certainty.
When road tests can be shown to consistently get 4 to 8 meaningful tests in a two hour period, I think the utility becomes undeniable.
It my belief that a 'gold standard device' that shows this utility is needed to establish the technology as a performance tool, rather than a science project / novelty item.

Once this gold standard or "Dura Ace" is accepted, I believe that cheaper less accurate products become viable, a "105" in this example.
I don't think we would have had single sided power meters if SRM and Quarq had not arrived before.
I think the same can be said for optical heart rate versus chest straps. Optical heart rate was quickly adopted despite it being quite unreliable, I believe that this could only happen because chest heart rate straps had proven the utility.

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John Buckley
https://streamlines.aero

Okay, I will start digging into Tom's site to find it.

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John Buckley
https://streamlines.aero

Taking an IR thermometer out on the road I found a lot less temperature rise than indoors (that's not surprising of course) and never more than a few degrees over air or road temperature
That wasn't for CRR testing - just trying to understand what was happening.
Given it was 10yrs ago I don't recall whether I observed the same higher temperatures in worse CRR tyres as I did indoors. I have some recollection that the differentials were suppressed