Disc CX bikes…not going away.


Mr. Tweedie of Roscoe Village Bikes on a Humble Frameworks Sextant disc.

Disc CX bikes are gaining ground. First, Tim Johnson won a UCI race with a Cannondale Super-X disc. Now, ENVE and 3T have made disc forks. So, there a real options for real racers. I’m even considering having Spooky retrofit a disc tab on my Supertouch.

My TRP CX-9’s are great in the dry, but when it’s really wet, they have trouble (just like any other rim brake). They do alright in the snow, but take a little dragging to get some heat into them. So, they have downsides in performance. Discs have one definite downside: weight. But like any bicycle product, they’re getting lighter. They also have one conditional downside: cost. Depending on your rim brake of choice, you could end up paying more for discs.

I’ll do some actual research (read: simple googling) and compare the two possibilities in two types of price ranges.

Claimed weight per wheel:

Comp:
430 grams – Avid BB5 road mechanical caliper with 160mm Avid G2cs rotor. $49. Cheap! 95 grams of rotating weight (rotor).

157 grams – Avid Shorty 4 cantilevers. $35. I won’t even speak to their performance, but they come stock on “comp” level cyclocross bikes.

Pro:
451 grams – TRP Parabox ‘cross specific parabox disc brakes. $469 for the setup (rotors, calipers, and hydraulic box). And you still have to buy mechanical cables. Such a weird, odd-looking setup for such a high cost. But it probably works incredibly well…I hope. I may drop coin on

128 grams – TRP CX-9 ‘cross specific v-brake (my favorite). $149.

For the “pro” setup, that’s a crazy difference in price and weight. Even if you pop for a set of TRP CR959’s at $349 (and anybody who does is getting the “least braking performance for their money” item on the market), that is still $110 difference in price, and 323 grams per wheel. Still not easily swallowed.

And just as I thought I should not overlook the other possible weight differences between rim and disc, I checked the weights of ENVE’s ‘cross forks…460 grams for both. Nice…but unnerving. Wheels can be lighter with disc setups, but that would be a whole different topic.

In the midst of this wad of info, the economy and sense comes in the shape of the Avid mechanical setup: greatly improved wet-weather braking, without a huge difference in price, and a weight you could overlook.

Without testing the two disc setups, unless you’re doing some crazy hilly races, the mechanical setup should be plenty.

Another upside of discs: ease of use. In pleasant weather, their pads last a good duration of use, as opposed to soft rim-brake pads that would offer close to comparable braking. With pad changes, no alignment is needed. Rim brake adjustments take a mechanical finesse that most people do not possess. With proper setup, quick wheel changes are a breeze, and can be quicker than with canti’s and v-brakes.

Many other topic can be ground out, like rotating weight relocation, carbon rim braking, etc…but those are for another time.

Short story, expect to see some more disc ‘cross bikes in your hood next season.

The enabling forks from ENVE and 3T:

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One thought on “Disc CX bikes…not going away.

  1. Last months Bicycling magazine had an article about the coming wave of road-disc wheels and frames. The authors made it seem like a middle school dance with bicycle manufacturers on one wall and component manufacturers on the other wall. Everybody knows it’s going to happen, but no one wants to be the first couple on the dance floor.

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