I would guess his sponsor doesn’t or that if he put his Race Kings on a 25mm ID there wouldn’t be enough clearance on his Felt. Reynolds is his wheel sponsor. The 3T Discus is wider than the Reynolds road wheels but expect the 29mm internal would make the Race Kings blow up too large, they are also not as deep so maybe wouldn’t be as much of an aero benefit as the deep road wheels.
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In theory 60mm deep 40mm external and 30id would be best?
But if windy that wheel would be a handle full and that’s why it’s made in a 45mm
On the Marginal Gains podcast Josh Portner talked about testing with DJ ahead of Unbound. They said the RaceKing 2.2 had unaccountably excellent aero characteristics; while most tires followed the expected narrower-is-faster rules, the RaceKing 2.2 had similar drag (wheel alone) to most 40mm tires despite being like a 57mm tire. They didn’t know why; something about the casing shape, tread pattern, or the weave/scale pattern of the sidewall, they speculated?
Likewise the Lauf suspension fork; it was actually a few watts faster than the stock Felt fork, though they noted that the Felt fork was not really aero optimized to start with.
Point being I think DJ actually tested his gear and found the combo he used to be the best blend of comfort, rolling resistance and aero, but this would not have been predicted by him, Josh or anyone just using the “eyeball wind tunnel.” For the rest of us, unless we have access to a tunnel or are willing to do a ton of Chung method laps, we’re doing a lot of guessing in choosing wheel/tire combos for performance.
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I’ve mentioned this before, but they need to do more testing based on their results. When you get an outlier result like that, you need to dig deeper into it and test more in order to confirm the results.
It may well be that the results are correct (lord knows Poertner knows his way around a wind tunnel), but as a one-off test that seems to defy all accepted “rules” of aerodynamics, more testing is necessary to confirm the results, IMO.
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I run René Herse 44mm slicks, and I was surprised to see them measure 45.5mm WAM after putting them on new 29ID wheels recently. I expected them to blow up wider, but not really.
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They did do multiple runs of DJ’s tests to verify, but they’ve also said results don’t always carry over to other people and other bikes. It can be very specific to that setup.
One example they gave was the USWE pack - tested faster for DJ, slower for Ben Delaney because of riding position.
I know they did multiple runs….i am talking about additional test sets, not just runs during a singular test session.
It was also only tested against the stock Felt fork….so all we know is that it is a faster than that fork. How does it test against other forks? Is it truly a faster option or just faster than a Felt fork?
That is why you need more testing, not just multiple runs in a single test.
You could say that about everything aerodynamics. There are always combinations that aren’t tested that should or could be. And it’s not that easy or cheap because of the logistics.
And they addressed that subjectively - Josh’s guess / opinion was that it was exactly that, the Felt Fork not being particularly aero optimized.
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Which is exactly my point…when you get an outlier result, you need to do additional testing to understand why you got the result.
When DJ tested the USWE pack and it was faster, everyone ran out and bought the same pack. But no one said “Hmmm…that is an odd result…maybe we should dig into it more.” Now, a year later, with more testing, we know more about the situation.
So it should be with the Lauf fork…instead of “A Lauf fork is faster than a regular fork”, which was pretty much what most people was saying, it should have been “Man…that doesn’t particularly line up with what we hold to be true re” aerodynamics. Let’s dig into that a bit more."
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Been on Thundero 40s since last fall. Can’t really imagine running anything else. Worked great at Unbound (though I went with the new HD version), crushes mud season in VT, eats up hero gravel, and rolls fast on pavement. Durable enough, too.
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I just got a set of Thundero 48’s and am really impressed by the suppleness of the casing. Have a set of ENVE 3-4 wheels on the way and looking forward to mounting them up to see how they ride!
How wide do they measure out and what are your rim width numbers?
Measures out to 41.1 mm at the absolute widest part of the tread on a 22mm ID.
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Not to single you out, because this is becoming very common, but it is not ID, which is Internal Diameter. It is Internal Width.
Sorry, pet peeve. 
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Thank you! It’s also one of my pet peeves and seems to be far too common recently.
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I just put some vittoria mezcal 2.1 on my lauf. I’ll need to do a few rides on them. First ride they felt a little sluggish compared to my pathfinder pro 47s but for descending they were super nice feeling very stable. I may have to try the race kings or thunder burts which both are rated as having better rolling resistance than the mezcals.
Anyone got a real measured width after the Mezcal Gravels stretch out with a little use? Preferably on wider rims.
Been riding the tires / wheels for about a week now…love the combo, overall. Tires are very supple and roll fast / hook up well on our “kitty litter” gravel.
That said, I just measured them and was surprised by the endresult width…47.5mm. Figured on the 3.4 wheels they would come closer to 50mm, and certainly not under 48.
(oh, and according to my buddies riding behind me, they do have a “Gravel Fling” characteristic to them, as well. 
)
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They measured 48mm on my 29mm internal wheels once mounted but ended up at 50mm after a few hundred miles.
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