Cajer wrote:
Slowman wrote:
Cajer wrote:
Hookless rims is due to cost though most of those savings really aren’t being passed down to the consumer. It’s either a much simpler mold or you get to skip a few machining steps by going hookless. It most likely also results in higher yields.
They also maybe able to save a low single digit number of grams by either betting better compaction and using less material (if they aren’t machining the hooks) and by not having hooks. But that’s nearly inconsequential
i think you're half-right. the parts you omitted are:
- you can make the wheel a lot stronger if you omit the bead, because of manufacturing processes now available to you;
- the bead pinches the tire, and as the tire moves around the bead it balloons out. a tire made for a hookless bead can be made to fit better, and the contour of the rim/tire makes good aerodynamics easier to achieve. example:
but you're right, it's also cheaper and easier to make this rim. as to the price reduction that should follow, we'll see about that. i don't know that this is determined yet. zipp's 303 S is a lot of wheel for the price. a lot of wheels pass through the workshop here, and i don't think i've seen a $1,300 wheelset made this well. but this is a fake economy. it's very hard to get wheels. it's hard to get both wheels and tires. it's going to take a couple of years before we see what hookless means in terms of price.
I would say the wheel strength bit is moot for road as I already accounted for it by saying they could take out a few grams of weight. As unlike mountain we don’t see rim strikes due to drops/jumps/gnar. So it makes more sense to just remove weight to break strength back down to that of a hooked rim.
On the aero front, I do agree that you can have a smoother transition than with a hooked rim. However due to the lower pressure limits of hookless rims/tires, you’re forced to run a wider tires at best negating the benefits of a smoother transition. But more likely resulting in an overall less aero package.
Before the 105 rule of thumb is mentioned, even on the wide knot 64 wheels (32mm external) they and other wheels tested faster with 23mm tires than 25mm (found in their white paper). The same is found on clx 64 wheels (30mm external) with 22/24/26mm s-works tubros in the bike blather blog. This difference is just going to get larger with larger tires.
i'm fine just stipulating to what it is you write. if i can ride a wheel with a fatter tire, and be only as fast, with a much more comfortable ride and much less likelihood of a flat, i'll take it! every year at kona i hear bombs going off during the swim. it's the latex tires blowing up in the transition area. or, i get a flat and put in a new tube and it immediately goes flat, and it's because of something (a spoke hole is peaking out behind the rim tape; something's in the tire i didn't find). i'm just done with all of that.
now, for sure, you can get relief just by going tubeless, with today's newer wheels and tires, what you might call a second generation of road tubeless that started to flow around 2019, that all conform to the ETRTO's 2019 first-ever road tubeless specs. i've got really nice wheels here, from Bontrager, DT Swiss, Shimano, Reserve, and i'm very high on the Vision wheels, and most or all of those have hooked beads. they still are made, mostly, with 22mm or inner bead width and up, so the narrative in tire pressures still applies.
but i also have a lot of wheels and tires made for hookless, new generation product, and having ridden all of this stuff i think what we're hearing now is kind of - to my ears - a repeat of just the discussion on road tubeless 2 or 3 years ago. everybody was talking about how road tubeless was a bad idea. now we know that was just the typical reticence-to-change that we got with disc brakes on road bikes, disc brakes on tri bikes. there's only so many times you can cry wolf. i'm convinced, for reasons i'm happy to describe to anybody who wants to know - why hookless is at least a muscular alternative to hooked. but i'm pretty sure there is just going to be the typical naysaying, and one of the hurdles you have to overcome is the long list of naysayers who've just been wrong. you are saddled with that. demonstrating that you're just not another naysayer is kind of your gap to close, as unfair as that might be.
Dan Empfield
aka Slowman