Diamondback, originally a BMX brand, has been around for nearly 30 years. Its current incarnation is distributed in the UK by Raleigh, and a close look at the bikes shows that the UK link is not just superficial: a set of Crud Catcher bosses under the down tube symbolises UK designer input, while the excellent UK-designed Quad hydraulic brakes are more than welcome, too.
The 6061 heat-treated aluminium frame is a very nicely put together offering for the price. Its simple single-pivot swingarm design pivots level with the middle chainring, which is an efficient compromise that exhibits very little pedal feedback into the suspension. The shock is a simple coil/oil affair that sinks halfway through its travel almost as soon as you sit on the bike.
The remainder of the travel ramps up quickly, so you never feel as though you're getting the claimed 100mm travel. Still, the adjustable rebound damping is not bad and there's none of the tail wag effect that often afflicts low budget full sussers.
The tube structures are simple, effective and strengthened where necessary - most notably via hydroformed shaping and ovalising on the big down tube and by bridge gussetting across to the extended seat tube from the dropped top tube. The head tube is reinforced around the cups too, and the swingarm is kinked in for maximum foot clearance. Cable routing is over the top tube and there's one set of bottle bosses.
The fork, an SR Suntour 100mm travel unit, comes without a lockout dial and with a very limited effect from the leg-top preload dials but with reasonably effective compression and rebound damping.
The Coil EX has a full Shimano Alivio 24-speed gearset, driven by a Truvativ steel-ringed Isoflow crankset, so the shifts remained smooth throughout the test.
2.24in treads add comfort to an already comfy bike, but inevitably the wide-spaced tread pattern is slow going
The brakes, Quad QHD-SP (Single Piston) hydraulic discs, are powerful in all conditions and with a much better modulated lever feel than the cable-pull Tektros on the other three bikes. Not everyone appreciated the manual pad clearance adjustment dial, but we like the fact that it allows fine adjustments to rotor clearance on the fly.
The wheels are simply average in quality and weight, but Quando hubs have a good durability reputation and the double-wall rims and 36 spokes create a tough build. The WTB Motoraptor 2.24in treads are very grippy and big enough to add plenty of extra comfort to an already comfy bike, but inevitably the wide-spaced tread pattern is slow going.
The handlebar, stem and seatpost are all Diamondback branded offerings. The seatpost allows the 18in bike to fit riders up to about 6ft and the WTB saddle is comfy enough.
With its long top tube, generous bottom bracket height and a geometry that rewards a fairly aggressive riding approach, the Coil EX initially feels like a more costly full susser.
It can deal with lumpy trails with confidence in handling terms but the clunks when you're off the saddle are off-putting
Unfortunately, both the fork and the shock showed their limitations fairly quickly. The fork was not that well controlled in rebound and the rear shock starts to get clunky if you hover over the saddle, no matter how you set up the coil spring. It performs a lot better if you remain sitting, but that's not always practical. It can deal with lumpy trails with confidence in handling terms but the clunks when you're off the saddle are off-putting.
On a positive note, the rear suspension adds a lot of comfort on bumpy trails and gives you the confidence to hit stuff far harder and faster than you would on a hardtail. In pedalling terms, the Coil EX's simple single-pivot frame set-up is efficient enough to allow you to pedal hard along bumpy trails without pedal-to-shock feedback becoming an issue. Against most other sub-£500 full sussers, the Coil EX would have done fine, but everyone thought the £300 Decathlon was more fun to ride.