The last Diamondback I owned was way back in 1999 as a kid – admittedly, maybe not so long ago for some of us. In the years since I hadn’t given much thought to the brand. Similar to many brands of their time the company went through a rough patch in the early 2000s with acquisitions and big-box store sales. Diamondback has since been working to reclaim its previous position as one of the world’s top brands, and the Release C4 is a strong sign that they’re moving in the right direction.

Frame check-in

The Release C4 has a full carbon asymmetric frame and rear triangle. Its short 1.5″ tapered headtube keeps riders low and in an aggressive position. While internal cable routing for the shifting offers a clean look – though the brake is still run externally. The slacked out front end helps hold lines through technical downhills without being a handful in tight sections. The C4 has Boost spacing with 110x15mm up front and 148x12mm in the rear. The carbon layup helps keep the weight down, but maybe more importantly offers a latterly stiff ride that prevents understeer adding confidence in corners.

One of its strongest attributes is Diamondback’s take on the virtual pivot point (VPP) linkage system. It felt responsive and plush through small and large hits and tracked well over rooted sections and rock gardens. The back end simply felt planted. But over time, the exposed pivot points did collect dirt and debris which required a thorough cleaning. With great pivots comes great responsibility (to keeping them clean and happy). The included front fender is a good idea, but it would benefit from a slightly thicker grade of plastic.

Spec overview

Getting the bike moving is a Shimano SLX 1×11 drivetrain with an 11-46T cassette and 30T chainring. A Raceface AEffect Cinch crank is held by a threaded bottom bracket, and the frame includes ISCG-05 tabs. An integrated downtube guard adds protection on the lower half and slightly wraps around the bb.

For the front, Diamondback chose a Fox Float Performance fork with 150mm of travel, tapered steerer tube and, as mentioned, Boosted 110x15mm hub spacing. In the back is a Fox Float DPS shock with 130mm of travel. Together, they perform as expected with plush action and great responsiveness.

The cockpit is complete with Ergon GE10 grips locked onto Diamondback’s DB35 780mm handlebar. Holding the bars is a 40mm stem. The pair offers good leverage over the front end which helps on downhills but are still comfortable during long days in the saddle. At the back is a LEV SI dropper post with 150mm of travel (size L), and it’s actuated with a Southpaw remote. A WTB Volt Race saddle gets the job done offering plenty of space to maneuver and good contact points.

Diamondback’s Blanchard 27.5 tubeless ready wheels held true through some crazy trails in Pisgah, NC and only needed a minor tweak over months of riding. Maxxis Minion DHF 2.3″ TR tires are almost always a good choice, and offer great traction in corners, on climbs, and confidence in wet conditions. As a 180lb rider, I was running 20-24psi as tubeless and getting great results. In particular, they were solid in rock gardens where sidewall strikes were prevalent. With a tubeless setup, the bike’s total weight with stock pedals is under 31lbs.

Riding the Release C4

If the Release C4’s low price of $3,300 and unboxing doesn’t get your attention, its ride quality will. The suspension and geometry just work well together. The tires stay planted in technical sections while maintaining a playful willingness to get airborne off lips. I can’t say climbing is its strength, but it certainly isn’t a hindrance either. The C4’s geometry kept my 6’3″ body over the front end just enough to naturally prevent wheelies. Getting up steep climbs – rooted or slick rock – just took cranking into an easy gear and spinning it out. I did consider going to a 50mm stem to add some space in climbs and flats, but its performance was so well rounded as is there was no real need to.

Overall, the Diamondback C4 is one of the best trail bikes I’ve ridden. It’s not the lightest option available and the exposed rear pivots will likely need more cleaning and care. But I can overlook all of that considering how well it manages to tackle everything thrown at it.

Diamondback.com