Some of you guys want to talk about hookless for tri/TT, so here's your thread

Triathlon Forum
1

i started a thread a few days ago and i did so because - as it has been for the past 35 years or so of my time in the industry - shade gets thrown on a new tech paradigm until it gets proved valid and safe. (then people still complain.) carbon as a frame material (steel is real!), aero bars, riding steep on those aerobars, whether wetsuits actually make you faster in the swim, disc brakes on road bikes, the same on tri bikes, road tubeless tires. now it’s the idea of tires getting wider, along with the other current contentious tech idea: rims with hookless beads.

big brouhaha over the winter about hookless rims because 1 rider fell in an early season race and it was assumed - very likely wrongly - that the culprit was the tire blowing off that style of wheel. what i think i know from the springs classics plus the first 2 grand tours is that there were no blow-offs in the pro peloton. also, the teams riding these wheels fared quite well in racing, so there should be no question about whether wheels of this type are fast. in road racing.

hookless wheel makers were overly ambitious in my opinion. it took them 3 or 4 years to admit that 25c was just too narrow for this tech, and that a 2mm delta between tire and rim width was too small. since i started riding these wheels (in 2020) i made 2 rules for myself, because at my age i don’t bounce as well as i used to and i wanted to be ultra safe. (A) i don’t ride hookless with any tires narrower than 28c and (B) the nominal (named) size on the tire has to be at least 5mm larger than the inner bead width of the rim, so, if i ride a rim with a 23mm internal bead width the tires have to be 28c tires or wider. pogacar rode on most stages of his recent TdF a rim with a 25mm internal width and he rode a conti tubeless tire in a 30c size (that measured 31.5mm in width).

to the best of my knowledge 4 teams were on wheels like these made by 3 different manufacturers in the recent TdF, with no misadventure. but…! these were on road stages. what about the TTs? that’s a valid question and i’m not convinced this tech is a clear winner in timed race or triathlon. a number of people wanted to talk only about this in the thread to which i linked, and while that is a separate topic from the thread i started it’s worth discussing so i’m creating that thread here for this purpose.

the reason hookless is fine in road race is that the width of tires has expanded with breathtaking speed. what i hear from the pro peloton nowadays is that 28c is now considered borderline skinny. all road racing is now done on tires ranging from 28c to 32c, and 25c - the dominant size just 2 years ago - is now an almost unused tire size in mass start racing. this means the pressure limitations that attach to hookless are pretty much a non-issue in road because the tires got bigger and the pressures got lower. but that’s not the case in TT and tri. at least, not yet.

so, for those who have all kinds of problems with hookless in tri and TT and you want to express that view, this thread’s for you.

2

what worked for your wife to make the switch to hookless.

3

An influencer with a mission?

4

what worked for your wife to make the switch to hookless.

i assume this is a snarky remark because i already wrote that she’s on a set of shimano wheels for her road bike. that’s a pretty tasteless remark.

5

New member but have been reading in the background before signing up.

New to tri, started training last November, completed first 70.3 in July and my first full is IMAZ in November. Been a roadie for 20+ years.

This topic convinced me to register as I’m interested in purchasing the Zipp 858 (rear) and Zipp 454 (front) for my Tri bike. I have a 3rd gen Treek Speed Concept and a set of bontrager wheels with tubes and a set of bontrager wheels tubeless, both on 25c tires. The min reccomended pressure per the tire is 90 on both sets of tires and it can be a little rough on the road. I have been hesitant on hookless wheels based on YouTube etc… but I’m interested in running 28s on the zipps with approved tires of course at lower tire pressure to make the ride a bit more compliant.

I curious what the responses will be in this thread as far as running 28 tubeless on the 23 inner width zipp hookless wheels. Is 25 still the dominant tire size in tri or has tri moved onto 28 plus like road?

6

i [url what about the TTs? that’s a valid question and i’m not convinced this tech is a clear winner in timed race or triathlon. a number of people wanted to talk only about this in the thread to which i linked, and while that is a separate topic from the thread i started it’s worth discussing so i’m creating that thread here for this purpose.

I will bite. I think this is the first time I’ve seen you write or acknowledge the above. I don’t understand or follow your road argument (strictly smooth roads) but that’s another conversation.

I don’t think there is a clear winner for tri or TT. We need more data and studies or maybe the data isn’t clear enough so maybe the testing isn’t there yet. My personal opinion has been that a hooked wheel is faster than its hookless counterpart at their breakpoint pressures w/ the 5 bar hookless limit with everything else equal (tire, wheel width, etc). If we remove the 5 bar limit on a hookless wheel, my hypothesis is that for a course like kona, the breakpoint pressure is higher than 5 bar. So I could run the hooked wheel at its breakpoint pressure at kona but giving up the small aero penalty that hookless provides. Is the aero penalty on the hooked wheel greater or less than the crr penalty on the hookless wheel for not being to run at the breakpoint pressure? I believe it’s less.

So to summarize:
Hooked - Crr optimized, Aero penalty
Hookless - Aero optimized, Crr penalty

I also question whether a hookless wheel (23mm internal width) can be faster with a 28 mm vs a hooked wheel (19-21 mm internal width) with a 25 mm tire. Zipp’s data flirts at this but the rolling road surface isn’t exactly what you see in kona or a road triathlon.

7

An influencer with a mission?

i don’t know what you mean.

8

I also question whether a hookless wheel (23mm internal width) can be faster with a 28 mm vs a hooked wheel (19-21 mm internal width) with a 25 mm tire. Zipp’s data flirts at this but the rolling road surface isn’t exactly what you see in kona or a road triathlon.
This is really what must be answered first - what’s fastest on a typical Tri or TT course? Does the decreased rolling resistance of a 28mm tire outweigh it’s aero penalty? If 25mm is fastest, end of discussion, since at this time hookless is NG <28mm.

Note I said “typical Tri or TT course”. Highly Technical courses, or courses where some riders are switching to road bikes, are not “typical courses”.

9

New member but have been reading in the background before signing up.

New to tri, started training last November, completed first 70.3 in July and my first full is IMAZ in November. Been a roadie for 20+ years.

This topic convinced me to register as I’m interested in purchasing the Zipp 858 (rear) and Zipp 454 (front) for my Tri bike. I have a 3rd gen Treek Speed Concept and a set of bontrager wheels with tubes and a set of bontrager wheels tubeless, both on 25c tires. The min reccomended pressure per the tire is 90 on both sets of tires and it can be a little rough on the road. I have been hesitant on hookless wheels based on YouTube etc… but I’m interested in running 28s on the zipps with approved tires of course at lower tire pressure to make the ride a bit more compliant.

I curious what the responses will be in this thread as far as running 28 tubeless on the 23 inner width zipp hookless wheels. Is 25 still the dominant tire size in tri or has tri moved onto 28 plus like road?

in my opinion you would not run a tire narrower than 28c on this (or any) hookless system for multiple reasons. but you’re already looking at 28c. a number of riders in the olympic TT were riding 30c, but that’s partly because of rain and partly (i suspect) because of cobbles. i think 28c is going to be the dominant TT width but i’m probably still in the minority. but then i was in the minority a couple of years ago when i said 28c and 30c would become the dominant road race tire size :wink:

what 28c needs is for systems to grow up around them. wheels built for that tire, and frames built for those wheels. i think we’re there on wheels and we’re largely there on the new tri bikes. you’re certainly there already with the wheels you’re considering.

which take us to pressures and the main disagreements that i have with some knowledgeable folks here are:

  1. what’s the optimal tire size?
  2. does that tire, whatever it is, allow for a low enough pressure suitable for hookless use?

so let’s take 28c as an example. depending on your weight you’re pressure would be 60psi, 65psi, 70psi (the more you weigh the more pressure). so, you’re fine. but…

in my opinion the pressure you choose depends on the road conditions you choose and i think this is the major point of departure between me and, say, marcag here, who’s one of the very few people who can speak with authority on this because of his technical knowledge and experience. i don’t want to speak for marcag and i hope he clarifies my statement by saying, “dan, you ignorant slut .” i suspect marcag takes a look at the road conditions you see during most of the course, or the great majority of the course, and chooses a pressure to suit.

i am less likely to do that. i’m likely to look at the worst parts of a course, look at how often i’ll see those conditions, and choose my pressure accordingly, largely favoring those worse conditions. my premise is:

  1. the amount of power you lose by riding 5psi to 10psi slower on good road surfaces is very slight; but the amount of power you lose by riding 5psi to 10psi higher in rough conditions is huge. the cobbles in paris roubaix are a small fraction of the course, but everybody chooses tires and pressures them for the cobbles.

  2. riding too high a pressure on rough surfaces takes a biomechanical toll we don’t even know.

10

i think my reply to Rushca01 speaks to why i don’t think break point pressures are an issue with 28c tires for most races.

as to which is the optimal tire width, 25c or 28c, i look at this as pretty much a replay of the disc brake in tri arguments. what i wrote 5 or 6 years ago - and most of the forum thought i was stupid or crazy or writing for secret financial reasons (that’s always an accusation, as predictable as godwin’s law and i think it was made here a few posts up) - is that you can’t look at just slapping a disc brake on a tri bike. you have to look at how the wheel would be made, and the frame would be made, if you didn’t have to contemplate a rim caliper. it’s not the disc brake itself that’s the question. it’s the entire system. now what you see are entire systems and the reason there’s terrific differences now in the way that forks look on both road and tri/tt bikes is because of the lack of the rim caliper.

same with 28c. when frames and wheels are optimized for 28c then we can look at whether the 28c is as good or better than 25c. i think what you see what frame and frame coming out now is they’re optimized or 28c (the new introductions). why? what is it these frame makers know that the folks here on this forum don’t know?

11

i think my reply to Rushca01 speaks to why i don’t think break point pressures are an issue with 28c tires for most races.

I think we just fundamentally disagree on our approach to choosing the right tire pressure for a given triathlon course. And that’s ok.

12

i think my reply to Rushca01 speaks to why i don’t think break point pressures are an issue with 28c tires for most races.

I think we just fundamentally disagree on our approach to choosing the right tire pressure for a given triathlon course. And that’s ok.

we might not be on the same page and you’re right, that’s fine. but i might not’ve been clear. i don’t necessarily identify the worse part of a course and pressure my tires for that, but i weight the worst parts of the course much more heavily than i weight the majority of the course. this means i may be slightly underpressured versus the pressure i’d choose for a field trial over a representative smooth section. i would never calculate the ideal pressure for a field trial (say, a mile, or two miles) of smooth road and call that the right pressure for 56 or 112 miles that also had rougher sections.

13

i think my reply to Rushca01 speaks to why i don’t think break point pressures are an issue with 28c tires for most races.

as to which is the optimal tire width, 25c or 28c, i look at this as pretty much a replay of the disc brake in tri arguments. what i wrote 5 or 6 years ago - and most of the forum thought i was stupid or crazy or writing for secret financial reasons (that’s always an accusation, as predictable as godwin’s law and i think it was made here a few posts up) - is that you can’t look at just slapping a disc brake on a tri bike. you have to look at how the wheel would be made, and the frame would be made, if you didn’t have to contemplate a rim caliper. it’s not the disc brake itself that’s the question. it’s the entire system. now what you see are entire systems and the reason there’s terrific differences now in the way that forks look on both road and tri/tt bikes is because of the lack of the rim caliper.

same with 28c. when frames and wheels are optimized for 28c then we can look at whether the 28c is as good or better than 25c. i think what you see what frame and frame coming out now is they’re optimized or 28c (the new introductions). why? what is it these frame makers know that the folks here on this forum don’t know?

I wonder if the answer to that is as simple as the marketing/sales department telling the engineers to design the frames to allow for 28c clearance because all the road bike are going to 28, 30, even 32 clearance and that’s what the consumer wants.

14

i think my reply to Rushca01 speaks to why i don’t think break point pressures are an issue with 28c tires for most races.

as to which is the optimal tire width, 25c or 28c, i look at this as pretty much a replay of the disc brake in tri arguments. what i wrote 5 or 6 years ago - and most of the forum thought i was stupid or crazy or writing for secret financial reasons (that’s always an accusation, as predictable as godwin’s law and i think it was made here a few posts up) - is that you can’t look at just slapping a disc brake on a tri bike. you have to look at how the wheel would be made, and the frame would be made, if you didn’t have to contemplate a rim caliper. it’s not the disc brake itself that’s the question. it’s the entire system. now what you see are entire systems and the reason there’s terrific differences now in the way that forks look on both road and tri/tt bikes is because of the lack of the rim caliper.

same with 28c. when frames and wheels are optimized for 28c then we can look at whether the 28c is as good or better than 25c. i think what you see what frame and frame coming out now is they’re optimized or 28c (the new introductions). why? what is it these frame makers know that the folks here on this forum don’t know?

I wonder if the answer to that is as simple as the marketing/sales department telling the engineers to design the frames to allow for 28c clearance because all the road bike are going to 28, 30, even 32 clearance and that’s what the consumer wants.

clearance: yes, bike companies engineer for clearance because they can’t anticipate what tire the customer might use, including if the bike might be used for light gravel.

optimization: in the case of bikes that have come out in the last year optimized for a wider tire (like 28c) keep in mind that bike project is probably 4 years old. it’s the opposite of what you suppose. a road bike project designed to work with a 28c tire was in the works well before 28c became an important road tire. remember, just 2 years ago the dominant road tire was 25c. marketing is shitting as the product managers and engineers are explaining why they’re making the bike they’re making.

15

Can someone please break all this down in a tyre size for dummy’s?

My understanding is a wider tyre has lower rolling resistance at the same pressure. But a wider tyre also less aero. But the two tyres at the same pressure the skinnier tyre wins?

So why the push to wider tyres, is it all just comfort? If my 25 mm at 90psi gives the same rolling resistance as a 28 at 60 psi then what’s the point of going to a 28, is it all just lower pressure hence better comfort?

16

When running a narrower tire and a wider tire with the same casing tension, so the wider tire will have lower pressure, they have the same rolling resistance on a drum. However, on rougher roads a larger tire will absorb the roughness better and result in reduced rolling resistance, and therefore be more comfortable.

A larger tire also has an increased area and is likely an aero penalty.

The problem is, despite manufacturer claims, ideal tire pressure even for these bigger tires is likely a little higher than the max pressure hookless will allow on smooth roads.

Additionally, there is a trade off between aero and rolling resistance that may not favor the wide tires hookless rims with 25mm internal widths require, particularly at pro athlete speeds.

17

At the risk of looking dumb (I know I know). For the neophytes who exited the sport a number of years ago (but were afraid to ride anything but “clinchers”) and may be returning to the road.

Is there an article posted on the main page previously about how hookless “works” vs. the old way? Or an outside review you could point me to.

thanks

18

When running a narrower tire and a wider tire with the same casing tension, so the wider tire will have lower pressure, they have the same rolling resistance on a drum. However, on rougher roads a larger tire will absorb the roughness better and result in reduced rolling resistance, and therefore be more comfortable.

A larger tire also has an increased area and is likely an aero penalty.

The problem is, despite manufacturer claims, ideal tire pressure even for these bigger tires is likely a little higher than the max pressure hookless will allow on smooth roads.

Additionally, there is a trade off between aero and rolling resistance that may not favor the wide tires hookless rims with 25mm internal widths require, particularly at pro athlete speeds.

Thanks, so this whole hook less stuff aside are there any studies showing what is quicker, a 25 or 28? What is the aero penalty?

Also, aero as side is a 28 faster than a 25?

Or put it this way, people are told to put a 28 at the rear because it’s in ‘dirty air’ so aero isn’t as important, are there any studies showing how many watts you loose aero for a 25 versus 28?

19

Dan perhaps you can offer some insight-why is wider better?

https://www.bicyclerollingresistance.com/specials/grand-prix-5000-comparison

Is it all down to comfort? Seems wider is slower?

“We feel the ultimate test is adjusting all tires to the same comfort level. When all tires are adjusted to the same comfort level, rolling resistance is nearly the same (0.2 watts max) for all sizes of the GP 5000.
We now feel picking the right size tire is more a matter of looking at what level of comfort (and grip) is required. At some point, a smaller tire isn’t able to provide the same comfort level (and grip) as its bigger counterpart because it will start bottoming out.
If you want to go as fast as possible, choose your required comfort level and pick the smallest tire that can provide that comfort for you.”

20

For TTs on reasonably smooth roads both Josh Portne and Marc Graveline’s data put the optimal pressures for many athletes above the max for hookless, so there is a Crr loss. JP Ballard likes to say that physics hasn’t changed, so going 10-20% wider is going increase CdA by a similar amount. I know JP is in the business of selling wheels, but he also sees no aero advantage in hookless rims and his designs (SwissSide and DT Swiss) are typically some of the fastest wheels.

For World Tour TTs, cornering grip and handling are much more important than for your average point and shoot TT or Tri us amateurs ride, so maybe there a wider tire overcomes the loss of CdA and Crr.

So on decent pavement and a course that us punters would ride, a hookless setup is almost certainly slower than an optimized hooked wheel.

Whether you agree with my argument or not, my final point would be “why not ride that 30mm tire on a hooked rim? “. My guess is a 23mm internal width hooked rim mounts a tire almost exactly like a 25mm hookless rim because the hook is about 1mm on each side. For example, the new HED. Vanquish is 22.6mm and is designed for 28s. I haven’t put a 30 on mine yet, but I am guessing there would be very little aero penalty.