Hookless rims, what's the value proposition?

[Miller]

Hookless rims seem to be becoming a thing in the gravel world. Is this a trend worth paying attention to, what's the deal exactly, when and why would I select a hookless rim for a wheel build?

[NovemberDave]

They have several compelling benefits.

First, they're easier to build. The techniques for building hooked carbon rims are complex, and there is almost always some amount of patching done at the hook. The hooks themselves are vulnerable to damage simply because you have some material levered out over the rim sidewall with no support under it, but it's also difficult to get proper resin flow in extremities like that. It's also very easy to get voids in the hook area. Taking away the hooks provides a lot of benefit along those lines.

Second, there's more mass of material at the sidewall. You can trade the material from the hook, where it's vulnerable, and put that at the sidewall, where it will work to prevent damage from strikes.

When you make something easier to build, you reduce the incidence of construction errors and you also over time bring the cost down from fewer rejected parts and fewer downstream failures that need to be made good. When you combine that dynamic with making something stronger, all to the good.

The downside is that there is no hook to prevent the tire coming off. With properly sized tires (rim needs to squeeze the beads in a bit) and gravel-type tire pressure, the risk from that is severely mitigated. People are also by and large using tubeless with these types of rims (some of the rims mandate tubeless tires) and tubeless tires have stronger beads that don't stretch. But even road tires can be used successfully, like with Enve 4.5AR. They mandate use of tubeless tires, but they work great for road.

For what it's worth, I'd neither build nor sell a hooked carbon gravel or mountain rim, but hookless gravel and mountain rims convinced us to begin working with carbon again. This has a lot of caveats, very prominent among them that the rim needs to be disc specific from the ground up. Laminate schedules and more importantly resin systems used without need for the heat resistant requirements that rim brakes necessitate allow much more durable and resilient rims. From the fairly extensive survey that I've made of what's on the market, these are few and far between.

[Hexsense]

Whoa, that's great news that November is back on carbon disc specific wheel soon.
Hopefully it'll be wide... very wide.

[NovemberDave]

Whoa, that's great news that November is back on carbon disc specific wheel soon.
Hopefully it'll be wide... very wide.

Not with our own product, just with reputable branded components that are already out there. There's more or less 0% chance of us sourcing our own rim again, and less chance of branding an open mold. There are good rim products in the market, and more coming over time. Stan's just announced carbon versions of Crest and Arch rims yesterday, which are very competitively priced.

[Miller]

Thanks for a thoughtful reply, NovemberDave.

You've described some advatages from the construction and quality assurance point of view, and certainly tubeless and disc specific is where I'm coming from, but are there any benefits directly to the riding experience?

[NovemberDave]

Thanks for a thoughtful reply, NovemberDave.

You've described some advatages from the construction and quality assurance point of view, and certainly tubeless and disc specific is where I'm coming from, but are there any benefits directly to the riding experience?

My pleasure.

Apart from the better ownership perspective of buying a product that's able to be better engineered and constructed and last longer and cost less (although some are expensive - no one's calling an Enve 4.5AR anything other than expensive), no there is not ever likely to be any instantaneous "oh the lack of hooks make these ride better!" component.

There's evidence developing that shows a lower likelihood of pinch flats with a good hookless design. PinkBike (?) did a video about it with an Enve rim, at Enve.

[bikesrdangerousmmk]

They have several compelling benefits.

First, they're easier to build. The techniques for building hooked carbon rims are complex, and there is almost always some amount of patching done at the hook. The hooks themselves are vulnerable to damage simply because you have some material levered out over the rim sidewall with no support under it, but it's also difficult to get proper resin flow in extremities like that. It's also very easy to get voids in the hook area. Taking away the hooks provides a lot of benefit along those lines.

Second, there's more mass of material at the sidewall. You can trade the material from the hook, where it's vulnerable, and put that at the sidewall, where it will work to prevent damage from strikes.

When you make something easier to build, you reduce the incidence of construction errors and you also over time bring the cost down from fewer rejected parts and fewer downstream failures that need to be made good. When you combine that dynamic with making something stronger, all to the good.

The downside is that there is no hook to prevent the tire coming off. With properly sized tires (rim needs to squeeze the beads in a bit) and gravel-type tire pressure, the risk from that is severely mitigated. People are also by and large using tubeless with these types of rims (some of the rims mandate tubeless tires) and tubeless tires have stronger beads that don't stretch. But even road tires can be used successfully, like with Enve 4.5AR. They mandate use of tubeless tires, but they work great for road.

For what it's worth, I'd neither build nor sell a hooked carbon gravel or mountain rim, but hookless gravel and mountain rims convinced us to begin working with carbon again. This has a lot of caveats, very prominent among them that the rim needs to be disc specific from the ground up. Laminate schedules and more importantly resin systems used without need for the heat resistant requirements that rim brakes necessitate allow much more durable and resilient rims. From the fairly extensive survey that I've made of what's on the market, these are few and far between.

Resurrection, but why do you say you would not build or sell hookless rims? Is it the tire blowing off risk? Do you generally find the concept safe for gravel or fatter 28-30mm road tires at lower pressures (Im thinking 70 or less)?

[bm0p700f]

he said he does not do hooked carbon rim for gravel or MTB because of the risk of bead damage in impact. Same reason why the MTB carbon rim I will be using at some point is hookless.

[bikesrdangerousmmk]

he said he does not do hooked carbon rim for gravel or MTB because of the risk of bead damage in impact. Same reason why the MTB carbon rim I will be using at some point is hookless.

Thanks. Totally misread that, but I primarily did so because I thought November Was building and selling a number of carbon, hooked rims right now and saying they’re suitable for gravel. Are these not hooked rims ? https://novemberbicycles.com/blogs/blog ... -explained



What am I missing? I’m by no means well-schooled in this terminology. I think some other pages refer to hooked rims too, like for the GOAT rim.

[NovemberDave]

Hookless is great for mountain bike. For other uses, hooked beads are more practical at present. The use of non-heat resistant resins has a lot to do with the efficacy of hooked beads for gravel/road/cross. We used to see, across a wide array of hooked bead rims for rim brakes, a lot of voids and vulnerabilities in the bead hook area. We never saw these prior to when resins started to actually have some heat resistance. Heat resistant resins are more finicky to mold, and thus easier to screw up. In testing out rims to decide if and what we were going to sell for carbon rims, we found that the problems we saw with heat resistant resins were back to more or less a non-issue with non-heat resistant resins.

Hookless beads have shown some promise and, as stated, they're great for big tires at low pressure. Basically zero blowoff threat. With narrower tires, you have a blowoff risk except with very specific tires and even then we're not totally sure how it plays out over time. Any of you who've owned Schwalbe Pro One tubeless know that the bead even on those very good tires does stretch. So for a road rim or a rim that's going to see mixed use, which defines the vast majority of what our customers are doing, the hooked bead is more practical. So long as it can be manufactured well, which it very much can be with disc specific construction.

[jlok]

I think tires mounted on hookless rims will gain a bit more volume, if that's an advantage.

[bikesrdangerousmmk]

Hookless is great for mountain bike. For other uses, hooked beads are more practical at present. The use of non-heat resistant resins has a lot to do with the efficacy of hooked beads for gravel/road/cross. We used to see, across a wide array of hooked bead rims for rim brakes, a lot of voids and vulnerabilities in the bead hook area. We never saw these prior to when resins started to actually have some heat resistance. Heat resistant resins are more finicky to mold, and thus easier to screw up. In testing out rims to decide if and what we were going to sell for carbon rims, we found that the problems we saw with heat resistant resins were back to more or less a non-issue with non-heat resistant resins.

Hookless beads have shown some promise and, as stated, they're great for big tires at low pressure. Basically zero blowoff threat. With narrower tires, you have a blowoff risk except with very specific tires and even then we're not totally sure how it plays out over time. Any of you who've owned Schwalbe Pro One tubeless know that the bead even on those very good tires does stretch. So for a road rim or a rim that's going to see mixed use, which defines the vast majority of what our customers are doing, the hooked bead is more practical. So long as it can be manufactured well, which it very much can be with disc specific construction.

Thanks for the reply, Dave.

[Patto]

https://www.velonews.com/2018/10/podcas ... ims_480080

[bikesrdangerousmmk]

https://www.velonews.com/2018/10/podcas ... ims_480080

Enjoyed that. THanks.

[Bordcla]

Enve seems to have great confidence in their hookless 4.5 ARs at road pressures (for 28 and above road tire pressures that is).

Even if their beads stretch (haven't experienced it 1st hand), Enve recommends them with no reservations. They also approved of the use of the Conti GP4k in 28mm with tubes at pressures not exceeding 80 psi. That's the set up I've run for the last 5000 km or so with zero problems so far.