So, I think most of us here have some sense of the nuances of what works and doesn’t with deep wheels and road tires.
And it’s pretty clear that having a road tire even slightly oversized or badly shaped can delaminate flow from a deep wheel and especially in off-axis winds negate some or all of the benefits.
And there are a few “deep” – in this case meaning 40-50mm – gravel oriented wheelsets out there. But I haven’t seen any data anywhere that would suggest whether they are helpful even a little with real gravel tires on, and if so under what conditions…
You can see that even 4-5 watts of help would be much appreciated at, say, Kanza if you’re looking at a hundred miles of 20mph headwinds solo. But if they really have no chance of helping much, I just see extra weight.
For reference, I’m talking specifically about 40-43mm tires with some tread/knob and for wheels Reynolds 700ATR, which are 40mm deep and ENVE 4.5 AR, which are even deeper, but there are a couple others out there in 40mm range and all are pretty wide.
Seems like if there is any benefit its like to be a couple watts straight on, but that’s just a WAG.
There’s a small benefit because the rim is more aero than the spokes - even if it’s only rotational drag that’s being reduced. Wouldn’t put it over 1-2W though.
Seen a few cases of people cracking carbon rims at Kanza, not sure it’s worth the risk on a 200 mi race.
That sounds like a reasonable guess but maybe a little more benefit under certain wind speeds/angles.
I ran the Reynolds ones at Kanza last year with no issues but … sample size of 1.
My sense is there is a fair amount of luck involved with that and flats, but that in both cases it helps substantially to go big and soft with the tires rather than 36mm-38mm and more pressure.
There’s a small benefit because the rim is more aero than the spokes - even if it’s only rotational drag that’s being reduced. Wouldn’t put it over 1-2W though.
There’s a reason I prefer bladed spokes over round…even on wheels with large tires and/or low profile rims…especially if they’re naturally higher spoke count wheels such as disc brake wheels…
Tom, I figured you’d be one of the two or three people most likely to know if there was data that might be art least helpful on this. Am guessing there probably isn’t…
Good tip. They must have totally run out of types of body hair etc … not a ton of time – 1 sec/kilometer with wind off axis, any the speed and with the 50mm road wheel they were using …but apparently still measurable.
Good tip. They must have totally run out of types of body hair etc … not a ton of time – 1 sec/kilometer with wind off axis, any the speed and with the 50mm road wheel they were using …but apparently still measurable.
Aaah…but their fixture doesn’t include “power to rotate”, which can be quite a non-insignificant number, especially with higher spoke count wheels
Also…1s/km is nothing to sneeze at…that’s ~10W at decent road speeds.
ENVE tech support indicated that they were absolutely certain that the G23 was a better wheel for Kanza than the 4.5 AR because of its weight advantage and because “there was no aerodynamic advantage to deep wheels with gravel tires.”
I was skeptical, especially off-axis a bit when the side of the wheel is presented to the wind.
The 4.5 AR or the similar Reynolds seem even more likely to give some help with gravel tires than the Rovals your friends in the Win Tunnel used.
ENVE tech support indicated that they were absolutely certain that the G23 was a better wheel for Kanza than the 4.5 AR because of its weight advantage and because “there was no aerodynamic advantage to deep wheels with gravel tires.”
I was skeptical, especially off-axis a bit when the side of the wheel is presented to the wind.
The 4.5 AR or the similar Reynolds seem even more likely to give some help with gravel tires than the Rovals your friends in the Win Tunnel used.
I tend to be skeptical of many technical claims made by ENVE…FWTW.
ENVE tech support indicated that they were absolutely certain that the G23 was a better wheel for Kanza than the 4.5 AR because of its weight advantage and because “there was no aerodynamic advantage to deep wheels with gravel tires.”
I was skeptical, especially off-axis a bit when the side of the wheel is presented to the wind.
The 4.5 AR or the similar Reynolds seem even more likely to give some help with gravel tires than the Rovals your friends in the Win Tunnel used.
I tend to be skeptical of many technical claims made by ENVE…FWTW.
Yes, for a long time I have felt that the retail dollar-to-tunnel time ratio on their wheels was heavily skewed to the left.
Which is not to say they’re some sort of bizarre semi-fraud like lightweight wheels.
