CLARKS CMD22 DUAL PISTON MECHANICAL DISC BRAKE SYSTEM
The Clarks CMD22 Dual Piston Mechanical Disc Brake System is a cable operated design aimed at road, cyclo-cross, and gravel audiences. Progressive, powerful racers will still find hydraulics have a definite edge. However, if you were looking to upgrade from a single piston cable system (such as Avid BB5 or 7), the CMD22 are well worth a closer look.
Pros: Inexpensive, Powerful, with good modulation and feel, readily available spares.
Cons: Can be trickier to set up than some systems.
Each set comprises of, surprise, surprise, two ready assembled callipers, ISO mounts, 160mm disc rotors and fasteners. I should point out these are the traditional 6bolt drillings, not Shimano pattern.
Since we're here, the callipers accept assorted Shimano pad patterns, so replacements shouldn't be a problem, even on tour. Callipers are machined aluminium with a satin black powder coated finish, which should ward off the salt monster and other nasties convincingly.
As the title suggests, dual piston designs ensure both pads move, and ultimately, strike the disc rotors equally. The most obvious benefits over single-piston models, is easier setup/adjustment and even, consumer able wear. So, you'll get your money's worth from pads, rotors etc.
Now, if you're new to discs and wondered why I suggested hydraulics for competitive riding, such as cyclo-cross, or cross-country mountain biking, its simply because most are open systems.
Fade/wooden braking is last thing you'd want, on a 1in 4 with
a trailer and 20 kilos of kit, let alone young protege and tagalong en tow. Cables aren't included, which isn't surprising. It’s worth noting that decent cable sets make all the difference. My preference errs towards those with compressionless housings and coated stainless inners. Jagwire Pro Road . Those needing a fully sealed hell 'n' high water system might be better with Jagwire's Road Elite Sealed Cableset.
Set Up 3/5
This is straightforward, and though the printed instructions were a little faint, there's little difference between these and TRP Spyre. Ensure you have 5 and 3mm Allen keys, and a Torx 25 driver.
Start by donning disposable examination gloves and mounting the disc rotors to your hubs. Snug these down to 6/8nms tops.
Assuming the frame threads have been cleaned and are in good health, simply offer the callipers and correct mount (e.g. IS/POST) to the frame/fork and bolt aboard with your 5mm Allen key, leaving them slightly loose for the time being.
Cut and attach cables to suit, feeding them through and again, snugging bolts to 6nms. Now reintroduce your wheels and centralise the callipers by pulling the brake lever fully home, while tightening the mounting bolts to 6nms.
Spin the wheels, pump the brakes ten times, taking up any minor slack using the barrel adjuster. Allow for some minor cable stretch during this phase. Need to align the pads slightly? Introduce your 3mm Allen key to the corresponding side and turn in/out. Standard MO I hear you cry. Yes indeed, and it was that plug 'n' play simple when introduced to a tourer that had been running single piston Avid BB5 commanded by Sora brifters.
Things got more interesting when I switched to my fixed gear winter/trainer. Being my bike, and one that racks up big mileages, it’s a quirky though reciprocal mix. Cutting to the chase, so the CMD-22 calliper wouldn't foul the spokes, I needed to switch to its TRP post mount.
I use a single Cane Creek SC5 lever, which has greater mechanical advantage. The sort needed for Linear pull (V) brakes. Getting this configuration to play nicely required quite a bit of time and painstaking adjustment. Nonetheless, these proved a reciprocal mix.
Satisfied with performance on the stand, I took both bikes out and gave everything a seriously good bedding in, repeatedly belting along long descents at 30mph and hauling the levers home. Save for some minor brake squeal, coinciding with wet, greasy roads and detritus coating the rotas, that's as involved as things got.
Perhaps unsurprisingly, the greatest difference was felt with the tourer. Modulation feel and stopping prowess were all greatly improved. I only recall adjusting our's once, during the first 50 miles. Unladen, there was sufficient power to lift the rear wheel a few inches off the ground.
That said, there was ample warning beforehand and, for the most part, I simply relaxed and enjoyed the hills, freshly refurbished trailer trundling obediently behind, hauling various payloads.
This improved prowess worked a treat through town, inspiring greater confidence when negotiating rush hour traffic and jaywalking pedestrians.
A bit of grit on the rotor and pads certainly helped bed things in, and the slight squeal was neither annoying, nor indicative of anything wrong.
Switched to my 'cross inspired fixed gear winter/trainer, which usually sports a TRP Spyre, performance was similarly
impressive, although modulation and feel lacked the absolute precision of the TRP Spyre. (Mind you, a single TRP calliper costs almost as much as the complete Clarks ensemble, so I'll wind my neck in!). Something I attribute to the otherwise excellent Cane Creek CR5 lever's greater mechanical advantage. Nonetheless, as with the tourer, braking was very progressive and lever pulled in anger, raising the rear wheel was not a hardship. I've also run ours with other brand's disc rotors. 160mm Shimano and TRP have all played nicely, with only a quick turn of the barrel adjuster.
Though I've tested these through a relatively arid late summer, a mix of wet, dung strewn lanes and flooded coastal causeways have made little impression on the fasteners, pads, or indeed finish. I've put a drop of light ceramic lube on cables to keep them happy, but that's been the extent of their care, during this period.
For £69.99 and given the overall spec, the Clarks CMD-22 represent superb value for money. Half the rrp of Avid BB7's (which are a single piston design), they are obvious upgrade for a lower mid-range tourer, hybrid or gravel bike Especially those needing to earn their keep during the week.
Ultimately, the CMD22 are a lot of brake, for very modest buck and an ideal upgrade, for an older cable operated, single piston model. That said (this goes for cable operated models per se) for best results, go for a compression less cable set. True that might bung another £30 on top but it’s still cheaper than Avid's BB7 pairing. Though not worlds apart, the CMD22 are also a bit lighter than the Avids, which is another, obvious draw.