Lelandjt wrote: ↑Tue Jun 22, 2021 2:58 pm
I'm a MTBer, not a gravel rider, so forgive my ignorance.
On road side, the pinnacle of wide rim narrow tire is now about 25mm tire on 23mm internal width rim and 28mm tire on 25mm internal width rim. In fact, I use this very same combo on my road bike (25mm front tire on 23mm ID front rim and 28mm rear tire on 25mm ID rear rim).
Why wide rim+ narrow tire on road:
1) wide base support for the tire:
tire stability is higher, so handling is sharper at lower pressure without feeling the tire flop when cornering hard
2) straighter tire side wall: more aerodynamically efficient.
3) coincedentally, internal width also imply external rim width. A tire this narrow on a rim this wide means the rim external width is wider than the tire. So again, it is more aerodynamically efficient.
why it wouldn't work on mtb:
1) unlike slick smooth road tires, mtb tires have knobs and tread patterns. Flatten it can spoil intended handling geometry of the treads.
2) most benefits on road are aerodynamic, which mtb don't care. So why bother.
On gravel, well, it's borderline. I saw people use slick 35mm tire on 50mm deep rim on gravel. So aerodynamic is still a focus for some. Handling stability might still be better on wider rim. But you risk rolling on cornering knobs in straight line too.
Fat slick tires might work well. Maybe 35-40mm slick tires on 30mm ID rim make sense.
But I'd avoid tires with inconsistent tread patterns, like smooth center with tall sidewall knobs.
To OP:
forget aero at this depth. If your rim is going to be this wide the only way to make it aero is to make it deep too. 45mm+ deep might be the minimum for reasonably aero rim curve.
3t make one at 45mm depth, 29mm internal.
https://www.3t.bike/en/products/wheels/ ... 0-732.html
