I had to turn it off pretty quick, I’ve been hoping someone here would post a summary.
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Ditto. I’m sure he’s a good guy, but he needs to dial down the shtick-o-meter.
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I wouldn’t read into it, they’ve been on each others YT channels before.
He did a 300w avg over 3 different sections of gravel climb, road climb and gravel flat, and the 40mm Pathfinders were a bunch faster on all except the gravel flat, where the 50mm RS One was faster. 2.2 Race Kings were last on all 3. Road climb was the largest margin of difference, 14 seconds over 6 mins. Gravel flat put the RS One ahead by 10 seconds over 6 mins, Pathfinders in the middle.
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I saw the video (bicycle station I think?) that had some coverage of the testing. I’ll just say it didn’t come across as the most controlled approach. Not saying the results aren’t valid, just saying I personally wouldn’t put much stock into them. Maybe Drew’s video provides some info that would instill some confidence.
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Nope. He’s just another YouTube slapdick trying to use a thumbnail of his “buddy” to get some clicks by trying to prove him wrong. He frequently makes Bonk Bros unwatchable, but his schticky quasi-religious rant in the beginning was just grating and annoying.
Dylan has own schtick for sure, but he’s actually pretty meticulous in his testing and seems to take presenting the data pretty seriously.
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Drew’s testing was better than the bicycle station guys, but anyone testing still needs way more runs to weed out the outliers. He at least did three on each tire and surface though instead of one.
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I thought it was all the same testing. But I couldn’t watch Drew’s video. He was front and center in their video and said he’d be releasing full results on his channel.
No. He started his testing with them, but was doing a different protocol. Then he finished up and re-tested some of it at home afterwards. Totally separate. But I totally understand if one wouldn’t want to watch it or care. I only watched it for fun, not to learn a whole lot. When the tester starts out wanting to prove his own theory rather than collecting data and then reporting the results, you have to take it with a major grain of salt.
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Agreed, and Dylan acts like a normal human most of the time and then works in “backwards hat Dylan” in small doses. That works (at least for me).
And I struggle with the Bonk Bros podcast. They hit on some good things from time to time, but it’s a hot mess most of the time. If I’m stuck driving for 10 hours and have exhausted all other content, it might make the playlist.
But more power to these guys for building a following. Way better than I could do.
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Haven’t watched the video but I think the take away from reading commentary here is that tire choice still depends on the course profile. MTB is not faster all the time. This was brought up a lot by the pros at Sea Otter. With fairly smooth gravel & a decent amount of pavement, a narrower tire (42-47mm) seemed to be the best choice. But on a course like unbound… probably not!
To me that’s what makes it fun. Kinda like in car races in adverse conditions. You going with the fast tire or the slower one with better grip? Makes things interesting.
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Do you mind refreshing me on how CdA fits into Chung testing? Is it one of the inputs that the algorithm cancels out in order to get CRR, or is it baked into the process somehow?
If I understand correctly, I think you’re estimating CdA at the front end and so it’s not part of your results for CRR. But then are you putting it back in for your ‘watts to ride at 18mph’ charts (and similar)?
I’m trying to work out how much we should/shouldn’t be considering aerodynamics separately from your results.
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This guy is the king of bro science and doesn’t deserve any views. Kinda sucks that hes gonna make money on U-tube off of crappy testing
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Yes, you need to have a CdA in order to get CRR from Chung testing.
I have been doing this a few years so had a good idea what my old gravel bike was CdA wise. I also had seen a few wind tunnel tests so knew my ballpark numbers.
From there, you can zero in tighter with shallow grade climbing tests with a big spread of speed and power. This makes it where only one match of CdA and CRR makes any sense for all the runs.
This actually gets even easier if you test on different areas and with different tires over time.
This gets pure absolute rolling resistance and you can throw total aero back in whenever to give a full view of system performance when needed.
This photo shows an example of this with uphill sections alternating between like… 150 and 375 watts per lap.
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Ok thanks. Really helpful. So, in terms of interpreting the data you’re reporting, it sounds like what we need to know is that it’s pretty reliably removed from your CRR numbers (not just based on your own historical experience but also refined/confirmed within the algorithm itself to a degree).
And when you’re adding it back in for the ‘watts at XXmph’ charts, you’re using the same estimates that got checked and refined in the algorithm, so again it’s an estimate but based on far more than just historical reference points?
Yeah, correct on the first part. If you want really accurate rolling resistance values, variation in aero drag is really important. For example, in colder weather I know how much extra drag my winter kit has vs summer.
On the second part, if I added it back in to give a total wattage for a rider and bike system at a speed I would often just pick an average gravel setup CdA like 0.380
In the case of more specific wheel testing or something I would use the exact value from me on my bike during the test.
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After reading through half the thread (which is around 700 posts or 1.5 hours of Zone 2) I am still not sure if my next ~40mm gravel tire should be a Schwalbe G-One RS Pro or again a Specialized Pathfinder Pro. 
I ride 50% asphalt, the 42mm Pathfinders are a great all-rounder, though a bit „washy“ on multi-layer gravel, especially on descents. Also not the fastest on pavement, that doesn‘t matter that much but a bit faster would be nice. The rear tire held up for 6k km and I had one flat only which is decent.
The Schwalbe G-One RS Pro is regarded as kind a “modern version” version of the Pathfinder Pro, right? (grippier + a tad faster) Sadly I don’t have more clearance.
Tufo Thundero
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So unbound in 2 weeks. I have two wheel sets and currently have on front a 47mm pathfinder and 2.1 thunder Burt. I can’t fit any larger than the TB. I’m very reluctant to run the TB at unbound due to puncture risk.
With that in mind, I still want a backup front tire to the pathfinder 47. Preferably something that measures 52mm or less. With the new offerings this year, suggestions on a 50ish-mm puncture resistant, reasonably fast rolling tire? I’m thinking about the Schwalbe G-One RX, but not sure how puncture resistant it is. I think that Dilman? Ran it (and I may have been part of the discussion in a thread and can’t find it) and he flatted a few times, but unsure if that had to do with his set up, more info surrounding the flat, etc.
Thoughts?
The new Specialized Tracers are excellent
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how many watts does your cold weather kit cost you vs summer?