Fit for the purpose

I raced on Saturday at the Quabbin Road Race, which is thoroughly unremarkable and would have been more so if it hadn't been my first road race in over a year and just my second in almost three years. Almost replaying one of my favorite moves, I nearly missed the start gabbing with a friend. A bunch of kids on development teams like Hot Tubes, CCB, and CCAP quickly put paid to any delusions I may have had that generally being kind of fit is enough to do better than hang on for dear life in a very hilly and aggressive race. After the 90th time we had to find out who could do 500 watts for a minute, my legs finally told my will to go do anatomically improbable things to itself, and I took the last half mile climb at gentlemen's pace and staked my claim at mid field. 

Still life with Dave's legs in a wood chipper

Nonetheless, it was very very fun, about as good a result as I could have hoped for, and it was great to see so many people in shape and psyched to race. Rumors of road racing's death turn out to be greatly exaggerated. One thing about which I was very curious was how many disc brake bikes I'd see, the answer to which was one. And this is not because people haven't bought new bikes. No, there were plenty of this year's model (also one of the best records ever) on hand, it's just that the (overwhelming) majority are still racing rim brake bikes. 

Which leads me to the next topic that came up out of the weekend, as I got to have a bunch of conversations with people about wheels, rims, materials, fried chicken, and life in general. Rail customers generally understand where we've come from in the decision there. Note that our decision process wasn't "oh my gosh, we were totally wrong with our old wheels and now you have to buy our new ones which are so much better" and I have no idea how the guys who did that didn't have people with torches and pitchforks outside their front door. Rails are still great wheels, but there's so much to the story of the right material for the purpose. Who'd have thought that after all this time, I'd be recommending HED Jets to people who have a use for really deep road clinchers? But this review makes crystal clear every reason why I do - so much so that I'm half tempted to sell them on our site. For that purpose, they make the most sense.

In a roundabout way, this is to say that we do - and have - thought that there are applications where carbon is a great fit for purpose in bike wheels. In road tubulars, carbon's wert braking still more or less sucks but you can make a nice tubular that's giving you zero aerodynamic handicap and have it come in reliably under 400g per rim. The nature of the structure of carbon tubulars means that you can take away a lot of material compared to a clincher, plus you have that big gigantic air cavity to sink and dissipate the brake heat, and the relatively easy molding process for tubulars gives them less of a cost premium to aluminum. We're somewhat more than idly looking for a product to use there. 

For disc brake rims, carbon has an application for sure. The cost will for sure be higher than comparable aluminum, but you're getting a couple of real benefits: resilience and weight. There are two caveats there, though. The first is that all these disc rims that you see advertising themselves as being made with high temp resins? That's the opposite of what you want to do. High heat resins are more difficult to mold and are way more brittle than low temp resins. Unless you need to mold with high temp resins, you don't. And bead hooks are always going to be problematic in carbon wheels, so we've got no interest in using carbon rims with bead hooks. 

Believe it or not, there is more than one carbon rim I have in mind as an ideal product for a purpose. The Enve 4.5 AR is pretty attractive, so long as you're willing to shell hard for wheels. If that describes you, we're happy to build you a set. But beyond that, I haven't yet seen the product that I think is the right one. Maybe it will turn up, and if it's from a very reliable supplier, and we can make it work with the byzantine insurance stuff, there's no reason we wouldn't do it. It's just all about having the right tool for the job at hand. 

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Ike – As with basically everything, there's no one blanket answer. The hooks have nothing to do with tubeless performance so far as I can imagine or make out in any way. They are purely for keeping the tire from blowing off, whereas burping is purely a matter of the tire going "in" on the rim. So hooks are incidental at most but almost certainly irrelevant. Tubeless mtb performance, from a burping perspective, is wicked easy – there's so much volume there that you're not asking a lot of a rim to have it not burp. As a class, the mountain bike rims I've heard of being used for tubeless cross haven't been up to our standard, which as you know is basically "it won't burp except in a situation where a well glued tubie would have rolled." So if the dent resistance of carbon comes without the burp resistance we've known in the best alloy tubeless rims, then it's not a good trade. There are a number of "sorta popular" carbon rims out there which are to some degree or another designed for tubeless cross, and at least most of them have a rep for burping in cross use. They may work great for gravel and adventure riding with bigger tires at less aggressive pressures, but cross tubeless is a special beast. Simply multiply pressure and volume to figure out how demanding any tubeless use will be. For example, road tubeless = low volume x very high pressure = easy tubeless. Mountain bike = very high volume x low pressure = easy tubeless. Gravel = medium volume x medium pressure = easy tubeless. Cross = low pressure x low volume = ruh roh, rorge (thanks to my buddy Astro for the assist there). There's neither the time nor the budget to search through the whole haystack to find the needle. Don't really know what the answer is there.Salvatore and Greg – You two may be the only ones, but I guess we'll have to find out.

Dave Kirkpatrick

Tubular . Yup peaked my interest as well .


You had me at "tubular." Now you're speaking my language.


You bring up carbon and bead hooks, or lack thereof…I know there are a good number of MTB rims out there without bead hooks, how well do you think that design would translate to CX rims/tires? I've destroyed a handful of tubeless aluminum rims over the past couple of years, so hookless carbon is enticing. I'm a willing guinea pig if you haven't explored it much yet…


Yes, we're certainly a dying breed.


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