The widget says to use measured tire width so it accounts for rim inner width.
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I’ve done my share of arguing for today, and I think this particular discussion has run its course as well. I’m going to take your advice and head outside.
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I know you didn’t say it because everything I’ve told you is correct. That’s my point. Clear advantage for 28’s on that wheelset, just like I said. Even your own post agreed with my points. ;-D You’re just upset because somewhere you saw 28 and you thought some other numbers should be there & that’s the end of it. Maybe you should go for a ride on your real roads and calm down a little. Ha!
" He also shows the breakpoint where “…we learned that Tom Anhalt’s data was repeatable, and impedance does in fact dominate the rolling resistance beyond the breakpoint pressure”"
Negative. You are showing theoretical data. Impedance losses start at over 100 PSI. This is actual data from Silca. Not theoretical. Here is the Conti grand prix on asphalt:
So who is cherry picking charts, my friend? Heh.
“I very clearly do NOT see any mention of impedance in the initial arguments by @Brennus and the “I’m not ignoring it, I just know what it is” response clearly indicates a dismissal of its importance.”
Again, negative. I didn’t bring impedance into this thread. Another poster did by posting over and over again that BRR data is on a metal roller. I didn’t bring that up, somebody else did. I’m just saying I didn’t bring it up because I actually know what the data look like. You start to see impedance losses at higher pressures. I’m not talking about higher pressures. I showed you the pressures I’m talking about.
Did I say that? I don’t see anywhere in this thread where I said that. Are you making things up now?
Yes that’s a great video! However, two critical things. First, the internal width on the wheelset in that video is very different from the OP wheelset. And the wheel depth. So not apples-to-apples.
Second, and here is where the average person who is into cycling gets thrown off…watch the video again…what do you not see? What do you not hear? Wind. No wind. Without seeing the yaw distribution of those rides it seems like it was mostly less than 5% for the whole ride.
Now, look at the 28 vs 30 comparison. It’s less than 2%. Which is just about the error of an orthogonal strain gauge array power meter. 
In fact, they even say that in the commentary…oh, maybe the difference is about the same on a percentage basis.
So, yeah, like I said AT YAW there is an aerodynamic disadvantage to running the foundation 45s with larger-than-manufacturer-recommended tires. Most rides are going to have a yaw distribution with negative kurtosis compared to the day shown in that video. And, of course, we can’t hold race day off until the wind dies down.
Agreed.
I must have missed it, where did we get the evidence that 28 was clearly better than 30?
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Best. Post. #ThreadOver.
@AgingCannon im not arguing with @Brennus because that guy is a multi-sport beast.
Maybe on a cheap hotel bike, but I just hiked 3 miles thru palm oasis in SoCal and it was so windy on this ridge, in the shadow of an almost 11,000 foot mountain
That I had every yaw angle imaginable! My world for a bike and some 28 and 30 tires to test!
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One of the things I love about cycling is the relentless debates you can witness over 2 mm of tire width.
But here’s a thought – what if you do both: 28 mm in the front and 30 mm in the back?
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Wonder why I don’t bother posting a lot anymore
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That’s why I try and post ridiculous sh*t, to break up the monotony of debating endless variations of “how many angles can dance on the end of a pin?”
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And make the front wheel hooked for safety and the rear wheel hookless for … … make the rear wheel hookless for … for … oh nevermind.
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Above your post there is a bunch of text. You’ll find what you’re looking for up there.
Ha! Yeah. The forum has come full circle on Rule of 105 stuff, though. I remember getting yelled at back in the day when I said Rule of 105 doesn’t really matter at 0 yaw. These days I get yelled at for saying Rule of 105 does matter at yaw. Everybody is so different. I haven’t changed. ;-D
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Life has been good, right? Love me a good musical reference.
Bringing this back to me, as my bike is the only one that matters, I will say this about my current fast wheels:
- front rim: 35mm external width
- front tire: around 31mm measured width after 1600 miles (GP5000 All Season TR in 32x622)
Measured earlier this week, thought it was 30.5mm but maybe it was 31.5mm. Either way I think it meets the rule of 105? I dunno. Does it matter? Haven’t tested it in any meaningful way. I absolutely run a 32 on rear wheel as it greatly reduces probability of punctures.
Will say this, at the edge of the San Francisco Bay Delta region we ride at a lot of yaw angles, including some high yaw. These wheels feel like they pick up speed at 45 degrees and echeloning at 22-28 mph on fast group rides - the fast guys are doing 28-30mph and 350W, I can only hang on at 22ish mph in cross winds.
Anyways, the NorCal cycling video results don’t surprise, the front wheel is pretty wide. To my eye it looks like Los Gatos or Los Altos (maybe Cupertino? I dunno) roads near the base of the coastal mountain range that separate the South Bay from Santa Cruz. It can be windy there too, just like we experienced last night in Palm Desert the closer we got to the mountains. Just not ‘under the flight path for SFO’ on the peninsula windy, or delta breeze windy.
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