https://flocycling.com/collections/inflation/products/flo-air-gage
this looks interesting, and apparently works with disk wheels too.
what are your thoughts on this vs the silca one? i like that it’s inline, so i don’t have to faff around bleeding/checking/topping off.
Just get a $20 pressure gauge from anywhere on the internet. Pump to higher psi, use the bleed valve on the gauge. $179.99 saved.
I’m not sure what $20 gage would replicate what we’re doing with this product. “Any gage†will not have the accuracy this gage has. $20 is a small fraction of the production cost of this product.
I get your point, it’s not the cheapest option but cheap gages are why this product exists in the first place.
Just get a $20 pressure gauge from anywhere on the internet.
i think the whole point is to have accurate and precise measurements. if the wattage penalty for over-inflation is correct, considering the amount of money that gets spent around here to save fewer watts, it seems like a good idea.
orthogonally, i’ve always wondered about the accuracy of the <100 digital guages, esp those ordered online. silca’s looks nice, but its not inline (or whatever the term is) so you still have to faff around.
Here’s one for 27.50GBP, or about $30USD, only because I don’t feel like going past the first page of Google.
“An easy to read 45mm dial displays 2% accuracy between 40 psi and 120 psi and 3% accuracy across the rest of its range.”
https://www.accu-gagecycling.com/products/accu-gage-road-bike-tyre-pressure-gauge
Okay so it’s approximately 1psi less accurate than Flo, although Flo doesn’t state through what range their started accuracy apples.
Also, Flo’s statement that 1psi =1watt is an absolute travesty of data. Using 4 data points and connecting them linearly to imply that there’s is a magical peak of minimal resistance is at best completely dishonest or at worst shows a negligent approach to days and testing. Testing data for optimal tire inflation doesn’t come out in a V-shape, it comes out in a curve. From right here on Slowtwitch
https://www.slowtwitch.com/...lling_Resistance.jpg
Yes, there is a 1 watt/1psi increase above absolute optimal. There’s also a 20 psi range below this value that only loses 1 watt over 20psi, and then a continued range that loses about 5watts over 30psi. I have to question if $200 could be saved by just erring 10 watts under the optimal and sacrificing 0.5watts. Or if $170 could be saved by purchasing a +/-2% gauge and sacrificing. 1/10th of a watt.
Lastly, the entire optimal rolling resistance test is based on a conceptualized road surface. A good concept, for sure, but there are hundreds of thousands of different qualities of road surfaces, dozens encountered on an average ride. This further reinforces that one should err down on psi, unless the surface of the race in question has already been tested in the rider’s race setups at various psi’s.
Meh, I’ve spent a lot of money on less useful things.
I’ve bought a nice floor pump to have certainty around PSI, and if I had a small travel pump I carried w me when I traveled - I’d buy this for sure
i kinda want to buy it anyways, just to test how accurate my Silca pump is
I respect your opinion. The truth is there are many things I agree with and it seems there are a few things you’ve missed about FLO, our R&D, how we test. You’ve raised good points which I am sure some of the readers here will want answers to so I will address your points below for the sake of those readers. I understand your opinion is your opinion and this product may not be for you, which again I respect.
Here’s one for 27.50GBP, or about $30USD, only because I don’t feel like going past the first page of Google.
“An easy to read 45mm dial displays 2% accuracy between 40 psi and 120 psi and 3% accuracy across the rest of its range.”
https://www.accu-gagecycling.com/…-tyre-pressure-gauge
I’ve spent a lot of time looking at gages. As I stated in the video, podcast, and blog most are in the 2% to 3% range that you’ve found on the first page of Google. I’ve looked beyond the first page and I can tell you they aren’t on those pages either.
Additionally, this is a different product. If I stripped out all of the additional components then the cost would drop. We’re making something different.
Okay so it’s approximately 1psi less accurate than Flo, although Flo doesn’t state through what range they’re started accuracy apples.
Our accuracy is over the full span of the gage which we state on the site, blog, podcast, and video. This results in a +/- 1.2psi accuracy.
Also, Flo’s statement that 1psi =1watt is an absolute travesty of data. Using 4 data points and connecting them linearly to imply that there’s is a magical peak of minimal resistance is at best completely dishonest or at worst shows a negligent approach to days and testing. Testing data for optimal tire inflation doesn’t come out in a V-shape, it comes out in a curve. From right here on Slowtwitch
https://www.slowtwitch.com/...lling_Resistance.jpg
Yes, there is a 1 watt/1psi increase above absolute optimal. There’s also a 20 psi range below this value that only loses 1 watt over 20psi, and then a continued range that loses about 5watts over 30psi. I have to question if $200 could be saved by just erring 10 watts under the optimal and sacrificing 0.5watts. Or if $170 could be saved by purchasing a +/-2% gauge and sacrificing. 1/10th of a watt.
I’m sure you don’t know me all that well but what I can tell you is that I’ve spent the last 14 years of my life conducting R&D in the cycling space and then sharing and educating the cycling community about how it works and why it matters. For some reason there’s always a small percentage of the population that feels we are dishonest or negligent as you’ve stated.
I’m confused by what you’ve written. You state that our claim that 1psi = 1 watt is an “absolute travesty” but you later state "Yes, there is a 1 watt/1psi increase above absolute optimal. I’m not sure how it’s a travesty if you agree with it.
I did use four points on a graph to show a trend. We spent 18 months collecting on-road data performing hundreds of tests with multiple riders, tires, rims etc. In this testing we actually found new information about the impedance break point not collected on road. I can tell you that measuring on-road rolling resistance is the most complex measurement I’ve ever taken and we went through dozens of protocol attempts to get it right.
I know the graph you’ve shared. I’ve studied it and talked with the creators at length. I’ve had many conversations with many folks about Crr and tire pressure. Not unlike aerodynamics, rolling resistance has countless parameters that all greatly impact the results. It’s why we create rules of thumbs like 1 watt/1 psi. It’s not to fool people it’s to make complex topics digestible. I’ve spoken and written at length about our protocols and I’m happy to do so. The truth is most people want rules to follow so they can improve. We show one graph with a few data points that shows a trend. Again it’s there to be digestible.
I also agree that the impact of being under inflated vs. over inflated is asymmetric. This is stated in our blog on the FLO Air Gage. I repeat to athletes time and time again that being lower is better. In general most athletes are over inflated and I work to break the idea that 120psi if faster. Yes, it feels faster due to the brains perception of vibration but we know it’s not. A rule of thumb like 1 watt/1 psi helps cement the learning. However, a rule of thumb is only a rule of thumb. We can find scenarios where they results would be less than 1 watt/1 psi and scenarios where the result would be greater than 1 watt/1 psi. Most people don’t want to or can’t perform the tests to get their exact number. Companies like our spend time and resources to discover thing like this so athletes don’t have to. Regardless, there is proof that being over inflated leads to a loss of time for athletes. When tire pressure is too low you can cause additional issues outside of watts lost especially when you move into gravel. A tire pressure that is too low can result in rim impact.
Lastly, the entire optimal rolling resistance test is based on a conceptualized road surface. A good concept, for sure, but there are hundreds of thousands of different qualities of road surfaces, dozens encountered on an average ride. This further reinforces that one should err down on psi, unless the surface of the race in question has already been tested in the rider’s race setups at various psi’s.
True, and this is why we don’t use a conceptualized surface. We test on multiple road surfaces. Our original tests were done using an AeroLab sensor and protocol I developed with Dr. John Mercer at UNLV. Like most research you are often left with more questions. John and I then set out to study the characteristics of road surfaces using vibration analysis. We found the natural frequency of wheel and tire combinations and then monitored the energy produced in a wheel over road surfaces as the tire pressure changed. When you break down the frequencies with FFT you learn a lot of interesting things about road surfaces. To be honest more are similar than you would think.
Ideally you want to know as much about your road surface as possible when racing. Then you have to understand what the percentages of sections breaks down to. If you have one section that is 5% of the race but really rough then you do not want to set pressures for this surface type. You have to take everything into consideration.
Finally, I think it’s important to state that we’re simply offering a product that is solving a problem for some people. It may not be a fit for someone like you. Over the years I’ve worked to help people perform their best and for some people a watt or two matters. They same data I share, and the advice I give has helped set a world record and has helped an 80 a year old make a cut off to qualify for Kona. For these athletes, our efforts made a difference. I have the same joy for both of these athletes and it’s why I do what I do.
I and I am sure others would be very interested in seeing the FFT data if you wish to post up.
Just get a $20 pressure gauge from anywhere on the internet.
i think the whole point is to have accurate and precise measurements. if the wattage penalty for over-inflation is correct, considering the amount of money that gets spent around here to save fewer watts, it seems like a good idea.
orthogonally, i’ve always wondered about the accuracy of the <100 digital guages, esp those ordered online. silca’s looks nice, but its not inline (or whatever the term is) so you still have to faff around.
Between the three gauges I have (digital BBB gauge, digital Ryobi inflator and analog BBB pump) all of which were under $40, there’s no more than 1psi discrepancy. So they’re either all wrong in exactly the same way or they’re all pretty accurate.
Meh, I’ve spent a lot of money on less useful things.
I’ve bought a nice floor pump to have certainty around PSI, and if I had a small travel pump I carried w me when I traveled - I’d buy this for sure
i kinda want to buy it anyways, just to test how accurate my Silca pump is
if you have a silca floor pump the standard gauge is 1% with 1 psi resolution, per the site and guaranteed to maintain that accuracy for 2 years. (https://silca.cc/collections/service-parts/products/super-pista-ultimate-replacement-gauge-kit) price $86.
I have a Silca Ultimate and I trust the gauge but have checked my other gauges using a device I built very similar to the one Flo has. The other bits and pieces of the flow design can be had for 30$ ish. The rest of the cost is their time/overhead and a reasonable profit margin… so it may not be out of line though I assume they can purchase usages at a discount in certain quantities so pricing is a dilemma though their price seems in line if you try to build a single unit yourself and value your time etc. My own truth trials seem to say that gauges I have are within 1 psi of my reference gauge, which in most cases is the base resolution of the measurement anyhow.
“Why We Made This:
For every 1 psi you over-inflate your tires, you lose 1 watt to rolling resistance. Most pumps are +/- 9psi, so setting an accurate pressure is nearly impossible.”
Are you suggesting that “most pumps” have an error of 10%. Where are these data from?
FLO https://blog.flocycling.com/news/introducing-flo-air-gage-set-accurate-tire-pressures/#Why_Does_Accurate_Tire_Pressure_Even_Matter
“. . . the rule of thumb is that for every 1 psi your tire pressure is over the impedance break point, you lose 1 watt. So, if your tire pressure is reading 80psi but your actual tire pressure is 89psi, you are giving up 9 watts! That is a big deal to any competitive cyclist.”
From the graph the rule of thumb is that for every 4 psi your tire pressure is under the impedance break point, you lose 1 watt. So, if your tire pressure is reading 80psi but your actual tire pressure is 72psi, you are giving up 2 watts. That’s no big deal to a competitive cyclist."
As you say: lower is better than higher. So unless you are very sure of your guage, drop a few psi.
Great post, Jon.
To the person who mentioned Accugage, i was STOKED when i got mine. It looks cool and feels solid, especially for the price. But, it didn’t last long. I haven’t dropped it or done anything else that would hurt it, but it reads a few psi off from my Silca Digital pump now. I don’t think i’d buy one again. At rest, the needle doesn’t go back down to zero.
I had a couple SKS digital gauges and they were pretty cool too, but i think my sealant destroyed them.
If anyone wants a gage checked they can send it to me, Just take care of the shipping each way,
.
Here are a couple plots from a blog I posted a while back. The first is at 60psi and the second at 120psi.
The spike in seen in the 120psi chart occurs at the natural frequency of the wheel and tire combo.
