rationale for tubeless: you don't get flats. now, some folks beg to differ per their experience. but i pay a lot of attention to who is really making good tubeless tires, who is really making good tubeless rims, which rims work best with which tires, and of course i put sealant in them. famous last words. knock on wood. i just don't... flats... on... tubeless. this being road tubeless i'm talking about. road or tri. i'm not riding slow tires. and i ride exclusively 28mm or larger.

this is why at least 2/3, probably 3/4, or maybe more, of all the top IM pros - men and women - are riding tubeless. low rolling resistance, no flats.

---

Dan Empfield
aka Slowman

Yeah. 30 Schwalbe Ones were my jam. I think I have their gravel tire on the new TPC bike that came to the house (a 3T). It looks aero enough. It's comfortable. And ultimately as long as it's comfortable enough, I'll be able to ride it faster than if I've got something that's too harsh -- especially given how frost heave ridden we are this year.

It's gonna be a *rough* summer of riding in New England on older pavement.

---

----------------------------------
Editor-in-Chief, Slowtwitch.com | Twitter

None. If you're happy with narrow tires and latex tubes and only ride on bike-tire-friendly roads, no need to pay attention to this thread. You can be very fast with what you've got.

you are clearly not hip to my jive, bro, and it's harshing my high. i should know what you're riding these days, but i don't and i'm too lazy to go back through your posts to find out. and, let's just leave it at what you're riding for your road bike, because those are the wheels that are out right now that you could be riding if you had them.

---

Dan Empfield
aka Slowman

No, I'm 100% on board with you. Been 100% road tubeless for ~5 years now, and never going back.

I was being facetious. I'm just tired of defending tubeless with people whom I sense aren't yet ready to join the cult.

I would really like to hear you're reasoning for tubeless. As it doesn't seem to make any sense from a road/tri racing perspective if you're already running latex on decent roads and don't flat.

As I've never understood it for either of those applications. If you're during all road/gravel/mountain sure it makes sense, but on road it just seems to be something the companies are pushing to make more money.

does hookless rim play the same/well with any tubeless tire?
if the sidewalls are straighter with hookless (is this always true) does this mean there is a sweet spot rim width that ticks the rule of 105 (or slightly more?) box.
are some wheels optimized for 28 tubeless and others for different widths?

my trusty enve 5/6 with gp 5000 25 width and latex have served me well for group rides but the older man in me who hasn't even ridden the road bike (just gravel) since late Sept, is ready for more plush (plusher?) ride and not losing (maybe gaining?) any aero speed.
just let me sell the enve 5/6 before the masses know what i'm up to....

ahh. okay. i'm too dense today.

---

Dan Empfield
aka Slowman

no. i'm writing a series, first article up today, and in that series i'll be covering the following:

- every time there's a new hookless bead wheel that's out in the aero market, i'll review it or provide some form of commentary describing it.
- every time there's a hookless compatible tire that you may want to ride, the same.
- i'll also write about hook-bead wheels that you need to know about.
- interviews with some of the important people who understand this tech.
- i expect to produce an evergreen chart that i can update and point you all to that show which tires - make, model, size - go on which of these wheels that are coming out this year.
- in that document will be recommended pressures, and i'll cover that in articles you'll see on the site.
- whatever else it is i notice as i mount these various tires on various wheels i'll share with you. for example, in certain cases you might be able to mount a 25mm tire in a wheel with a 23mm inner bead width, but this is a narrow tire on a wide rim and sometimes particular models make for a bad match. this is the case regardless of hook or hookless.

and yes, we'll talk about aerodynamics, and how hooked, hookless, wider rims, wider tires, rule of 105 pertain to this.

---

Dan Empfield
aka Slowman

It's a long answer, because I feel that tubeless is better as an overall system. Not just because of an isolated reason.

But if I had to pick one: flatting. Around 10 years ago I moved to HED C2 rims, that initiated the wider-is-better trend. And started learning on this forum about lower pressures being better in various ways - the progression of knowledge that's led to the article on the main page right now. This was with latex and 23mm tires.

And I started pinch flatting a lot in road races when I went below about 90PSI (I'm about 170lbs.). This was on rough Southern CA roads that we tend to use for time trials and road races (Slowman knows about these roads, some of them are downhill from his compound).

It really annoyed me. So I experimented with tubeless, and the pinch flats stopped cold. All flats stopped, really. It was a relief. So much less stress. The lower pressures were sooo much more comfortable. Life was just better. That's when I became a believer.

So yes, if you never ride on anything but pristine blacktop, I could see latex and 23mm tires being just fine. But that's a pretty narrow set of conditions. For almost anything else, I think tubeless starts to justify the extra setup and maintenance.

I might be helped by the fact that I’m under 130 lbs at race weight so I can run low pressures and not pinch (<70 psi on 23mm). But I’ve been fortunate enough to get few than 1 flat a year even when racing road weekly up in the northeast.

I do wonder how much of the tubeless benefits go away with lighter riders.

You didn’t really answer his question. Is your 28 mm tubeless tire @ 65-70 psi faster than a 23mm tire w/ latex @90 psi? Or a 25mm tire w/ latex @85 psi? Let’s ignore aero for this exercise and assume same wheels (eg; enve 7.8), same tire (just different sizes), and no flats.

Quick edit: let’s assume the same course… Kona or the queen k.

---

blog

A - thanks. If there is an old school slowtwitch vibe - i think your enthusiasm around this kind of tech and how it could benefit our riding experience personifies it. I appreciate the info and the let's improve our enjoyment of the ride ethos.
B - in the pretty long, lost focus on the details bad habits of my feeble mind - i'm definitely looking forward to the do a,b,c and the results will be can't miss.
sincerely, rick

good question. i'm going to let the data speak for itself. just, i think there are facts not in evidence. up higher in this thread is a filtered result from BRR. but i think BRR is about as bad as it gets for the platforms i think we'll see more of (22mm to 25mm inner beads, 28mm to 30mm tires, certainly tubeless, often hookless). i hope to interview josh poertner again and talk more about this. i don't want to speak for him, but i think he'd say that the testing rig that captures everything that goes into this equation is rarely found in the labs testing rolling resistance. and this doesn't begin to touch on what biomechanical or physiological losses there might be associated with muscle vibration. i'll probably spend some time with bio_mcgeek on questions like that (if he's interested in engaging on this), tho i don't know if he's ever studied that in particular.

so the answer is, i don't know the answer. authoritatively. yet. but i expect that you and i will by mid-year.

---

Dan Empfield
aka Slowman

I will be very very curious to hear information about the bio-physiological losses of vibration and if the difference in vibration has been quantified between say 28mm tires at lower pressures vs 23mm at higher pressures along with just raw rolling resistance. People have been alluding to physiological losses due to vibration however most examples are with something extreme like cobbles riding. In the case of the Zipp TSE white paper they were riding over a dirt road in real world testing and "rough roads" which has ~15 dB/hz (32x more vibrational energy)! higher PSD values than their new condition roads. Which is not at all applicable to tri or the vast majority or road racing. I would this to fade into irrelevance on good roads which is why Zipp was cherry picking dirt roads for their numbers, and they didn't even mention that those numbers were for dirt in the press releases to mislead people!

Also talking to a friend who was a former McLaren engineer with regards to rolling resistance of tires, he was really surprised at how tires have been tested for cycling. As the rollers/drums that are used completely ignore microtexture which was found to be a big contributor to how formula tires behaved.

Irrelevant to tubeless/tubed but as a suggestion I would avoid GP5000s (maybe the tubeless ones are better??) but they wear out quickly, the sidewalls go and they shed threads from around the beaded area which end up caught in derailleur pulleys.. went through 2 sets this way and swapped to Pirelli PZeros.. much better, just as light and roll well.. Just a suggestion from my bit of experience with the Contis..

Just jumping in on someone else's conversation here with an opinion and no data to back it up.. just a bit of experience.. There is no frigging way a lower pressure 28mm tyre will be quicker than a 23mm tyre.. especially if the tyre is wider than the rim.. Lighter is faster when it comes to rotating weight! I do believe however, that your tyre can't be wider than the rim.. they need to be the same width when all mounted and inflated.. I found (very noticeably) in this situation you are more stable and when you have accelerated and are trying to hold speed (over about 35-40km/h) you can do it with much less effort than with the narrow rim/wider tyre (old style).

Rotating weight is no different than static weight. The weight difference between a 23mm race tire and a 28mm race tire is negligible for every person on this forum, and I strongly suspect that while the 28mm tire may not be faster, it will also not be meaningfully slower, and it will also be more comfortable and handle better when each is on the appropriate wheel for the tire size.

Hi imswimmer328,
I get the comfort part and agree with you there.. Im a cyclist not a triathlete (I joined here for info re the tubeless/hookless bit). I would however respectfully disagree with you on the rotating weight vs static weight.. and I do concede we are talking small watts here.. Inertia principles back up what I'm saying in that its harder to get a heavy rim rolling (and to keep it rolling) than a lighter rim .. I believe this not just because physics backs it up but from a noticeable practical example from my own experience-- I replaced my butyl tubes a while back with the PZero Smartubes (I wasn't expecting much but I did want to see what the hype was about- at worst I had wasted 100 bucks on tubes) and saved about 140 grams for the wheel set.. My average speed increased by about 1.5 to 2km/h over 50km as a result and I didn't get that much fitter overnight.. I reckon 140grams in static weight wouldn't make a difference like that.. All on the same rims BTW- Campy BORA WTO 45s.. Again, respectfully disagreeing- not picking a fight here but I really was surprised how noticeable the difference was.
I would however love to know the theory behind the Hookless rims? Why???
Cheers
Brendan

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

Thanks Cajer.. Thats what I suspected.. My LBS complains about them from a practical point of view but I just wondered if there was actually some benefit there.. It seems not..

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.

---

Dan Empfield
aka Slowman

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, on clx 64 wheels (30mm external) with 22/24/26/28mm s-works turbos tested much faster with 22mm tires in the bike blather blog. 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). 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

I guess I'm one of those people that still prefer latex tubes over tubeless. I haven't had a flat in ~2 years and I also ride on smooth pavement so there's also no reason to go wide/super low pressures. To me dealing with sealant and additional difficulty mounting tires is just additional faff.

Like with almost all technologies, there are regimes where they operate best. If you're looking at doing gravel/all-road/ride on shitty roads, I have no doubt that tubeless makes sense and there are no downsides to hookless rims. However I am much more skeptical of it for racing/riding on good roads.

My issue with the tubeless/hookless/super wide rim marketing material is they advertise it as a benefit for all conditions and don't state the test conditions (while only testing in the most favorable conditions), when it is no improvement or a regression for some use cases. I marketing is marketing, but it still drives me crazy as most people listen to marketing/allot of articles aren't fully informed about the topics involved (not yours).

Either way I am super interested to hear about the bio-physiological effects of vibration on performance in normal/good not poor road conditions, even if I have a hunch it's going to be small or insignificant.