Ultra Wide gravel wheelset

[bastianb]

Hi,

Maybe some have seen my posts here. Maybe not. So I am introducing myself first: my name is Bastian, I am 26yo, cycling enthusiasts mainly on the road, also having a strida folding bike and riding my hardtail occasionally. I am a composite engineer from Germany.
Soon I start with my first product from my own business. I don’t want to tell too much but it will be triathlon related.

Other topics I see kinda underrepresented are new gravel wheels for wide mtb tires. With the new clearances of 55mm, wouldn’t it be interesting having a 48 to 50mm outer width wheelset which is 50 to 60mm deep? Inner width of around 38 to 40mm?
Any gravel racers here, what is your opinion, where would it need to be weight wise and 24 steel spokes?

Btw I can have access to a small wind tunnel with 60cm diameter of test surface area, enough for half a wheel and I can do some aero development there in the future.

Kind regards,
Bastian

[Chiyou]

From a commercial (and hence liability) perspective you'd have to take a look at ETRTO - 38 to 40mm internal width seems to be on the very limits of what they recommend.

This WTB page (see the Mountain tire table) lists optimal inner rim width from 25 to 35mm for a 55mm tire, with anything above 40mm as not suggested.
https://www.wtb.com/pages/tire-rim-fit-chart

Continental and Vittoria go for the skinny look, 17 to 30mm inner rim width.
https://www.continental-tires.com/tire-knowledge/tire-rim-combinations-etrto-standards/
https://vittoria.com/blogs/magazine/vittoria-is-a-member-of-etrto

This note on the Vittoria page also requires some attention:
When fitting a tire to a rim with a width different from its design rim width, the actual tire section width will vary. As a general rule, the tire width changes by ±0.4 mm for every 1 mm difference from the design rim width.

The design rim width for a 55mm tire is 25mm (according to Vittoria), so your tire is now ~0.4mm * (38 - 25) = 5.2mm wider, possibly exceeding the tire clearance of your frame.

Further to the commercial aspect, the demand for wider rims is rising, no question, but my guess is that most buyers will want a rim that is compatible with a range of tire options (say, 40mm for my fast/smooth event and then 55mm for the next rocky-road-not-sponsored-by-dreyer's-grand-ice-cream event). Maybe a dedicated gravel racer will want to invest in a such a wide rim but it seems to be a very narrow market segment. (Disclaimer: I am not an anything racer.)

From an aerodynamic perspective, I have no idea whether 48/50mm outer width and 50/60mm depth is particularly interesting - on the surface, they're just numbers. You have very wide, knobby tires; my hunch is that you'd want to test a variety of rim shapes before settling on something that comes close to optimal.

[DrDanger]

Enve released their new ultra wide gravel rims which come close to what you were describing albeit with premium price tag. Carbonal also has some rims similar in profile, with 35/36mm internal width and up to 60mm deep for a fraction of the price

[hubba]

Light Bicycle has 35mm internal 48mm external rims.

https://www.lightbicycle.com/ag48-disc-ultra-wide-aero-gravel-wheelset.html

[FlorianS]

Light Bicycle has 35mm internal 48mm external rims.

https://www.lightbicycle.com/ag48-disc-ultra-wide-aero-gravel-wheelset.html

They‘re 48mm at the widest part of the rim but ‚only‘ 40mm at the hook, where it meets the tire. That‘s probably not what OP is asking for.

[Tijoe]

Regarding wide rimmed gravel bikes with larger tires.  This is the newer category called "Monster Gravel".  Just another niche between Rigid forked 29er hardtails that run gravel bars/components and traditional gravel bike frames that can run larger tires.  This trend started gaining traction around 2022.  Monster Cross started around 2010 and is being blended with Monster Gravel over the past few years.

What I want to see are more gravel frame geometries with a Boost/148 rear ends so that I can standardize all of my wheels with 148 hubs.   Then, one could run wide rimmed FS wheels, XC, or narrower width rimmed wheels on any frame you own. 

Just like roadies are concerned with Aerodynamics and associated rim depths and widths, dirt/gravel riders are concerned with wheel weight, wheel durability, and the correct width rim that fits the optimum tire for their riding/trail conditions.

[Rolle2k]

Look the Zen wheels thread, they recently posted these new wheels which seems like what you were asking for:
 https://chinertown.com/index.php/topic,6093.msg112956.html#msg112956