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ENVE definitively explains the hookless tubeless rim for road, gravel & MTB

Written by Cory Benson
ENVE Behind The Product - Why hookless beads are the future!
18 Comments
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You can say that road tubeless is one of the most hotly debated concepts in cycling these days. And the hookless bead even more controversial. ENVE makes rims both with and without bead hooks, so they wanted to explain…

Why hookless beads are the future!

ENVE Behind The Product - Why hookless beads are the future!
images c. ENVE

The latest in the ENVE Journal’s ‘Behind The Product‘ series tries to set the record straight on hookless beads, especially for road and gravel. Most performance mountain bikers settled on tubeless many years ago, and the tubeless-ready mountain bike tire & rim markets have stabilized in the year’s since with near-universal fits, and more-and-more hookless adoption.

ENVE Behind The Product - Why hookless beads are the future!

With less of a legacy to overcome than pure road, All-road and Gravel are quickly adopting tubeless. And many of those wheels are already hookless. But like Road Tubeless, still in its teething stage, there is fear and ambiguity over the safety & security of hookless rims, especially at higher pressures.

A big stumbling block is the number of cobbled together road tubeless solutions, significant variance in tolerances from one rim or tire to the next, and anecdotal failures muddying the water.

So, ENVE decided to go deep on what a hookless bead is, how it works, and what type of rider it is for. It isn’t an issue unique to their rims, and helps clear up why the entire cycling industry is moving (at times, slowly) in the direction of hookless beads for almost all tubeless rims.

TL;DR – How do hookless beads work?

Here’s the nutshell version: First, just know that motorcycle and automotive tires have been using hookless beads forever. Those work because the tires can use ultra-strong wire beads that won’t stretch. They get away with that because a few extra grams don’t matter on motorized vehicles.

For bicycles, where every gram counts, the key is having the tire’s bead be designed within a certain diameter tolerance (standards are coming soon, but there’s a general consensus among most of the good manufacturers) and not stretching out of that tolerance over time.

Rims’ bead seats must also be within that tolerance. This creates a rim-tire system where both parts match each others’ shapes perfectly and don’t change during use. So, they’re able to provide a strong, airtight seal that also keeps everything in place even during hard cornering.

If these conditions are met, which they increasingly are as both rim and tire brands improve their manufacturing techniques and standards come online, then your hookless tubeless setup is as safe as any hooked setup.

Want the whole rabbit hole? Read the full blog post on ENVE’s website.
Cory Benson
4,157 articles

Cory Benson is the EU Tech Editor of Bikerumor.com.

Cory has been writing about mountain bikes, enduro, cyclocross, all-road, gravel bikes & bikepacking for over 25 years, even before the industry created some of these names. Prior to Bikerumor, Cory was a practicing Architect specializing in environmental sustainability, has designed bike shops & bike components, and worked as a bike shop mechanic.

Based in the Czech Republic for 15+ years, he is a technical mountain biker, adventurous gravel rider, and short & medium-haul bikepacker. Cory travels extensively across Europe riding bikes, meeting with key European product developers, industry experts & tastemakers for an in-depth review of what’s new, and what’s coming next.

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Mark
Mark
4 years ago

Until the road and gravel wheel industry gets its act together (looking to you for guidance, ETRTO) and we don’t need to look for a rim manufacturer’s list of approved tires, tubeless in general is stifled.

And what’s this about an 83psi maximum tire pressure for their rims that fit 700x23c? Okay, maybe some people will want to stay with tubes.
https://www.enve.com/en/tirepressure/

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ENVE
ENVE
4 years ago
Reply to  Mark

Mark,

There is something up with the data being pulled for the tire pressure calculation on the Road tire pressures. Our Hooked rims have a max PSI or 120psi w/ a 23mm tire.

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OriginalMV
OriginalMV
4 years ago

ENVE’s newer tubeless-ready SES3.5, 7.8, and 5.6 work well for tubeless…and are reasonable when using conventional clinchers with tubes in terms of consumer ease of mounting and unmounting. The SES4.5A-R, which has the ENVE hookless rim design, is a complete nightmare for use with tubes. This is partially because one MUST use a tubeless-type clincher on the hookless rim to prevent blow-off. The stiffer, bulkier bead of a tubeless tyre always complicates mounting with a tube, and the SES4.5 A-R is particularly difficult to break the bead (ie dislodge from fully mounted position).

I get that tubeless might very well be the way to go in the future, but I have plenty of customers who don’t want to run tubeless tyres. For them, tubeless just isn’t a good fit for the way they want to ride and maintain their bike. I can’t sell them on an ENVE hookless road rim if they are not fully committed to tubeless. If the rest of the ENVE road line goes hookless, I’ll be selling something else.

Even if hookless makes for a marginally stronger rim, that doesn’t sufficiently compensate for the lack of versatility with respects to tyre types. Also, I get why ENVE says that hookless carbon rims have better manufacturing efficiency, but why would consumers care?

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blahblahblah
blahblahblah
4 years ago

hookless is only in their favor not the consumer

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Bryin
Bryin
4 years ago

ENVE wants everyone to move to lower pressures. They have been on this kick for a long time. The problem is rolling resistance goes up when pressure goes down. Do a roll down test and you will be surprised how much difference 20psi makes. Holding all other factors constant, MORE PRESSURE MEANS LOWER RESISTANCE. I challenge anyone to prove otherwise- WITH A REAL WORLD ROLL DOWN TEST, NOT CALCULATIONS. You have use exactly the same equipment, only varying the pressure in the tires. Go ahead, I dare you.

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ENVE
ENVE
4 years ago
Reply to  Bryin

The idea of lower tire pressure is well beyond a theory and ENVE isn’t the only brand on this kick. Here are a couple good articles. Also, the beauty of all this is that you can run whatever tire pressure you want.

https://blog.silca.cc/asymmetric-effects-of-tire-pressure-optimization
https://blog.silca.cc/part-4a-rolling-resistance-the-history-and-previous-works

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jon
jon
4 years ago
Reply to  Bryin

Bryin is wrong in the real world, see the excellent explanation by Silca.

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Lyford
Lyford
4 years ago
Reply to  Bryin

Since you mentioned a roll-down test, see the second part of this article:
https://www.velonews.com/2018/06/from-the-mag/optimal-tire-pressure-gravel_468329

If your real world has perfectly smooth roads, I envy you, and higher pressures probably will work better for you. But as the Silca articles explain, lower pressures can be faster as the surface gets rougher.

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JBikes
JBikes
4 years ago
Reply to  Lyford

Even the silca blog posts linked show that by and large lowest resistance on a 25 mm tire is around 100-110 psi. This is pretty standard practice learned over decades of actual riding. Up to 115 on 23mm (load dependent but it seems like something for 180 lbs). Key, however, is that it seems its better to err on the low side than high.

Lower pressure, lower resistance, wider tires, these are being conflated. Wider tires deflect less, and hysteresis is reduced, at the same pressure. The flip side is that they can run lower for improved comfort with only small losses. For most people that’s okay. But “small loss” is not the same a “lower resistance”. Its opposite in fact and there is no reason to sell it otherwise.

Cobbles are very different. So is gravel.

There does seem to be a marketing drive on selling how low one can go.

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Joshua Poertner
Joshua Poertner
4 years ago
Reply to  JBikes

If you read the whole blog series you see that the breakpoint pressure decreases as tire width increases OR as road surface becomes more rough. The 25mm at 110psi breakpoint you mention was for a 25mm tire that measured 25mm, tested on a brand new road surface. That same tire in a rim like this would measure ~28-29mm and probably have been optimal at ~98psi on that same perfect road. Of course, perfect roads are pretty rare and as you add roughness the optimal pressures decreases, you can see that in the same study where the optimal pressure for that tire on the new surface paved with larger fill stones was 10psi lower and for the machined roughened surface the fastest pressure was around 40psi lower..

I think that the thing that is getting confused here is that a lot of the product development that is happening now is so that you CAN ride lower pressures and/or larger tires in situations where they are faster.. which is slightly different then what people are hearing, which is ‘lower pressures are faster’..

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Stephen Cuomo
Stephen Cuomo
4 years ago
Reply to  Bryin

Bryin is not wrong. Tubeless road is being pushed down our throats with big $ and loads of disinformation. The only tests I believe (other than my own) are from the independent Finnish lab Wheel Energy, which show lower pressure is clearly slower under normal road conditions. If pro’s could go even a tiny bit faster on normal roads using bigger, heavier, flatter, or stiffer tires, don’t you think they would? Any fool knows it’s not actually possible.

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Joshua Poertner
Joshua Poertner
4 years ago
Reply to  Stephen Cuomo

Wheel Energy and other labs are ONLY measuring casing losses, so yes, higher pressures are always faster in those tests, however, those tests are very specifically meant to isolate and measure casing losses, so that makes sense. These tests are exceptional at finding which tire will roll with the least losses, but they tell us nothing about optimal tire pressure.

Unfortunately, the bike/rider system has complexity well beyond just casing losses. I can assure you that impedance losses are very real and must be balanced with casing losses for optimal speed when looking at the bike rider system. In a nutshell you want to pick the tire with the most supple casing and lowest internal losses possible, then run it as hard as you can before impedance losses take over.

You can find this effect quite easily using the Chung Method, we do it throughout the year at key events for some of the top teams and athletes in the world, it is a bit of a hassle, but can save considerable watts while also optimizing comfort and handling for a given course. https://blog.silca.cc/part-4b-rolling-resistance-and-impedance

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Velo Kitty
Velo Kitty
4 years ago

> why the entire cycling industry is moving (at times, slowly)
> in the direction of hookless beads for almost all tubeless rims

180 degrees from the truth. The upcoming ISO 5775 rim and ETRTO tyre standards have hooked beads!

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P. Molinar
P. Molinar
4 years ago
Reply to  Velo Kitty

You are wright. The new ETRTO standard is with hooked beads. From what I understand, ETRTO are also considering a hookless standard at Stan’s no Tube request. But the later are very slow at releasing their technical details.

Back to the new ETRTO UST standard, there seems to be some confusion on the dimensions, in particular the bead height. i.e I am not sure ETRTO mandates all the rim dimensions.

I have not been abble to find any confirmation of this, either on the rim side or on the tyre side. For example, none of tyre manufacturers that make MTB UST models specifies the beads sizes,

Woul anybody know ? In particular, would a present WTB TCS tyre (TCS is there name for UST) fit an old Mavic UST rim ? Neither Mavic or WTB has answered me on that …

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Fraser Cunningham
Fraser Cunningham
4 years ago

Alright, I often don’t bother to post on Bikerumor articles because the comments section is usually so full of snark you don’t need mine too. But I gotta say that those cross sections are, lets say, out of scale to a very unrealistic level. Add to that the fact that the hook makes the rim much more damage tolerant, especially with carbon rims. That’s all.

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voodoobike
voodoobike
4 years ago

Hook beads require higher tooling and labor cost for carbon rims. Think about what it takes to make the hook bead: the mold has to be make to be assembled and disassembled to release the rim from the hook shape. It’s a less complicated process with a straight bead.

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Velo Kitty
Velo Kitty
4 years ago
Reply to  voodoobike

> Hook beads require higher tooling and labor cost for carbon rims.

Maybe, but so what. More of ENVE’s cost is for marketing.

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Caveman
Caveman
4 years ago

Interesting… Really convincing from Enve but the keyboard heroes have some solid points!

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