I think about inner bead width a lot when looking at wheels. But where I'm significantly different from Dan is that I'm racing at 205-215lbs. Maybe one day I can get back to 190lbs, but sitting at a whopping 230lbs right now I don't know where that is. I think I've had only one person actually reply to me about hookless with a real answer. (larger inner bead width allows me to use a bigger tire at good pressures, take HED Ardennes, 90ish PSI, the only time I'm running less pressure than that is what going full gravel and 32mm tire?) Either Fredly or Rappstar, and their answer was...yeah you're pretty much effed. This might be the first wheel that is rated for big guys in the hookless development. Think about how many wheels have hit the market that will effectively explode if the rider is 185lbs? And not so much as a reply to this concern when I've asked Dan. I'm not being a dick, but I am trying to make a point. We have wheel companies trying to mass market, through Dan and other reviewers, wheels with limited markets and use cases. Unlike super shoes, the market for this wheel is like two people at IMAZ. And both of those dudes are brain surgeons and weight 165lbs.

But hey, let's keep pumping out the orthodoxy that hookless is somehow better and cheaper...when in fact all we've done here is toss millions(?) in RND costs that could have gone to making better hooked wheels? Hooked wheels that would obviously still work for the 195-215lbers?

Thanks for the post, it made a significant point for me.

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Washed up footy player turned Triathlete.

You know, if you're going to do something, do it right -

"Let's go back to 23c Tubular Tires with Latex tubes, and disc brakes."

Tubs were wonderful! Track, Road, TT, Cross - all great! I had always hoped the early switch to disc brakes would have caused a resurgence in their popularity by removing the rim heating/glue melting issue of rim brakes, but clinchers were already too entrenched. That, plus they have always been (for all practical purposes) unrepairable - somebody should have figured out how to put a zipper in them! I sure do miss them.

Let's all remember Management 101 - NO personal attacks. This is not brain surgery, and ultimately the success or failure of hookless will be determined by the marketplace. What we discuss here will have very little (or no) effect on that outcome vs. (for example) a YouTube video that will have thousands and thousands of views in as little as 24 hrs.. My $20.

if you look at the discs people are riding these days i'd say it's the toroidal ones are better than either. this is - again - something that HED pioneered.

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Dan Empfield
aka Slowman

<<"Let's go back to 23c Tubular Tires with Latex tubes, and disc brakes.">>

this!
I love having disc brakes and wider tires on my road bike, haven't and don't plan anytime soon jumping to tubeless on it.
My Tri bike is a different story, 2nd Gen Trek Speed Concept. Too much invested in wheels to change there. Race set up is a HED Stinger 6 on front, and choice of HED Stinger 9 or Zipp Sub 9 disc both with Powertap hub, all sew ups (tubulars), then training is a set of HED Ardennes with a Powertap hub that are clinchers.


Interesting note, at Toughman LC a couple of years ago in NY, I hit a pot hole so hard that I got a front flat, surprised it didn't kill the rim. It would have also surely flattened a tubeless as well. In comparing my bike computer time (that stopped when I stopped to fix the flat) to the official results, I was down for 2 minutes even changing the tubular. Doubt I could changed a clincher or fixed a tubeless in that time.

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Mike Plumb, TriPower MultiSports
Professional Running, Cycling and Multisport Coaching, F.I.S.T. Certified
http://www.tripower.org

completely understandable. but i don't think that's the point. the truck i'm driving is 6 years old and i have no plans to buy a new one any time in the future. my wife and i are celebrating 18 years of marriage today and i don't think she intends to upgrade to new tech. but that doesn't mean i would prefer that my next truck and my wife's next husband (if it came to that) wouldn't benefit from technical upgrades. the question is: if you bought a new bike now would you buy it with rim or disc brakes? tubed or tubeless? electric or mechanical shifting?


perhaps. i still ride quite a few miles. i haven't gotten a flat, road or offroad, since 2019. that is coincidentally when i move to tubeless across every platform (road and gravel).

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Dan Empfield
aka Slowman

<<my wife and i are celebrating 18 years of marriage today>>

congrats! I still remember being there on day one in the compound amphi-theater

<<if you bought a new bike now would you buy it with rim or disc brakes? tubed or tubeless? electric or mechanical shifting?

good question and I think about it often after we upgraded my wife's bike to a new SC.
Definitely would go with disc brakes and electronic shifting (both my bikes have Campy SR 12 EPS), not sure if I would go tubeless though. Getting ready to build a new road bike once I decide on a frame and might try tubeless on that first. BTW new road bike will be hydraulics in lol

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Mike Plumb, TriPower MultiSports
Professional Running, Cycling and Multisport Coaching, F.I.S.T. Certified
http://www.tripower.org

IIRC the toroidal ones were meant to mimic the trailing edge effects of lenticular discs that weren't possible because of the width of the cassette.

Jumping down a light conspiracy theory hole here. Are we convinced that teams are actually running hookless, and not just running hooked versions with stickers put on to match the consumer facing hookless pairs? Less out there, are we convinced that teams are actually abiding by pressure limits? It wouldn't take them more than 10 tires and an hour of time to do blow-off tests with a specific tire and get their own data set. Maybe 28mm GP5000's are actually safe on certain Zipp wheels up to 100psi.

TBH if I was Dygert (or anyone in that position) and a 5-10w loss is the difference between winning Worlds or finishing off the podium I'd be taking the risk 100% of the time. The difference between finishing 12th because of inefficient tires and 12th because of a blow-out induced bike change is immaterial. Bike racers aren't known for being risk-averse.

We know very few teams are using them for TT at the WT.

I know one team for sure is using Zipp and does acknowledge 5 bar is low. Lots of teams make compromises. It's part of the sponsorship game.

As for Chloe at Worlds. Sure. It was a pretty bad road. I was there doing tests a few days earlier and we dropped pressure on a hooked wheel.

I am sure her weight, that road, she left nothing running those wheels.

Does that one team using Zipp acknowledge and adhere to the 5 bar limit though? I didn't see the details of the road for WCTT but that makes sense. Not a use case I'd design a race wheel for tho.

It's ironic that the fastest riders are the only ones without the true freedom of choice to pick the fastest equipment. It's why the argument "WT Pros run hookless so they must be fast" is such hogwash.

I'm curious if you've ever done testing between wider/thinner tires at the same casing tension (lower pressures with wider tires) or more simply the optimal pressures for that width to see if wider tires are actually any faster. I'm curious as I've never seen that data, and all the data people cite for wider tires being faster is with the same pressure used for both the narrower and wider tires.

For all this move to larger tyres, one naturally thinks you are increasing A in CdA but with an improved tyre/rim interface, does anyone try and calculate the potential aero benefits of a deeper wheel due to increased tyre size. The radius of the wheel is bigger and adds to the wheel depth. I don't know how many mm a 28mm tyre would add to the wheel radius compared to a 23mm tyre, but wondering if this would have much of an impact?

We were more interested in optimal pressure for a given wheel/tire/ride/surface. Each test set was 10 runs at 5 different pressures. The only thing that varied run to run was pressure. Each test set (10 runs) was a different combination of tire width/inner width, rider weight, surface.

There were two test sets where the only thing that changed was tire width. Optimal for 28 was slightly different than optimal for 30 but they tested very close at their optimal pressure. This is a combination of rr and aero. I am not sure just those 2 tests (of 10 runs each) is enough to make a conclusion

GCN did this, although I am not sure how precise it is. They corrected pressure for different widths using Silca.

In theory we could take our "optimal" tire pressure results and use them to feed a fastest tire width test.

i've been digging in the new vanquishes and have been spending some time in a back-and-forth with the designers of those wheels. there are 4 depths, from shallow to full disc. HED has generated data in the tunnel on them all, with 25mm and 28mm tires. this is the takeaway. the aero penalty is so small, and in some cases no penalty and even with 28mm better in some runs, that Crr gains appear to me to overwhelm the very slight aero penalty.

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Dan Empfield
aka Slowman

Where does the "Crr gains" data come from ?

I don't know the specifics but I doubt it has a large impact. You're basically noticing that the chord length of the tire/rim increases with tire size. If it increased linearly you'd see a 60rim +25mm tire / 25mm (3.4x deeper) go to 60+28 /28 (3.14x deeper). Keep in mind also that the tire height does no scale linearly with the the tire width. It's constrained at the bottom by the internal rim width. It's ~75% of width increase goes to height.

Intuitively I doubt that extra height is enough to make a difference. There is probably some speed/depth/width/shape combos where the airflow stalls out or has some weird vortex shedding that is obviated by changing tire size, but this is likely a special case that is unlikely to show differences outside specific wind tunnel tests.

Yes the chord length is what I was trying to get at (just didn't know the term) and if it was making much of a difference. Thanks for your reply.

HED didn't test Crr. don't you think it's generally accepted that wider tires offer less rolling resistance than narrower tires - up to a certain width, with that width being probably 30mm to 32mm - and the limiting factor is aero? that is, at the high end of Crr gains you get diminishing returns, as in, 32mm isn't much if any faster than 30mm, but 30mm is faster than 28mm, and 28mm is faster than 25mm by a yet larger margin. and the smaller the tire the greater the incremental Crr penalty. i take it you don't stipulate to this. i know how it feels to be at odds with the bulk of the illuminati ;-)

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Dan Empfield
aka Slowman

While it does seem there's truth to larger tires being faster, I think the biggest issue is that the effect is extremely surface/pressure dependent, and therefore it's very hard to quantify the actual rolling resistance benefit.

why do you think the world tour pros are switching to 28c for road stages? why are the manufacturers now making their bikes optimized for the 28c size? what's your theory?

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Dan Empfield
aka Slowman

I really don't know.

One one hand, it's a common belief.

On the other, why do they not go wider than 25 when they do the hour record ? They certainly could have.

I have seen data that shows a 30 faster than a 28 both at the same tire pressure. But never a 28 vs 30 at the optimal tire pressure for each on real roads ? Never

BRR showed on their test drums, which are real road that the delta between a 32 and a 23 (huge difference in width) went down significantly as pressure increased.

I believe that if a road is bad enough, even at optimal pressure for each the 30 will be faster. Between the track and the bad road there is a spectrum and I haven't seen anyone show what happens in between.

I do believe you can make a wider wheel as fast as a narrower wheel. But faster ? I'd love to see data.

I don't have enough of my own data (yet) but it certainly isn't obvious, so before I fork out lots of money for a new wheel and a new fork to accomodate my new wheel, I'd love to see some data other than manufacturers claims with no data to back it up. Right now those performance gains are theoretical.

Of all the people in the world that should be able to get such data, you're the man and you don't seem to be able to get it. This puzzles me. The manufacturers certainly have the means to get that data.

I guess I am not a member of the "illuminati" nor a member of the "because the marketing dept told me so". I am more on team "doubting Thomas".....show me the data.

It's obviously because the roads are in worse shape now than they were 20 years ago. Only like 90% joking

With how hard companies are pushing for hookless you have to believe they'd be shouting this data from the rooftops if they had it. Every company tweaks wind tunnel tests to find the one yaw angle and speed where their product is fastest. But on their 'game changing' hookless tech there is nothing. The silence speaks louder than data.

i can only speculate, but i think it's 2 reasons: first, 25 is as good as 28 on glass-smooth resin-covered wood and it's marginally more aero. second, that marginal aero difference at, say, 28mph becomes not so marginal at 35mph.

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Dan Empfield
aka Slowman