Focus bikes are designed and assembled in Germany - Hamburg to be precise - and brought into the UK by mail order giant, Wiggle. There are advantages and disadvantages to mail order. The most obvious advantage is that Wiggle miss the independent bike shop link in the selling chain and pass on some of the cost bonus of that to you.
The most obvious disadvantage is that if something goes wrong you have to box the bike up and send it back to Wiggle, or pay your independent local dealer to sort out a problem that isn't theirs. This bike comes fully assembled, almost ready to ride.
The chassis: conservative but bang up-to-date
The Fat Boy frame is made from butted 6061 aluminium. The tubes are mainly straight and round, almost a pleasant change at a time when so many other manufacturers feel a need to flare, curve or square taper everything in sight. But the fat biaxially-ovalised and gusset-reinforced down tube and low weight of the Fat Boy make it obvious that this is a bang-up-to-date frame that would be worth upgrading with even better componentry at a future date.
The frame's thoroughly practical finishing details include a tough powder coat and mounting bosses for a bottle, a rack and even a Euro-style frame mounted rear wheel lock. There's lots of mud room around the tyres but standover room is less generous than on the other bikes.
A RockShox Dart 2 fork is a good choice for a £450 bike. We found it impossible to achieve more than 80mm (3.2in) of the stated 100mm (3.9in) travel, but it has a lockout facility that doesn't knock in use (like on the SR Suntour forks) as well as preload adjustment and adjustable rebound damping.
The detail: good gear, great wheels
The only obvious concession to price on the Fat Boy is the low budget, square taper axle Shimano crankset and bottom bracket. Other similarly-priced bikes boast more upmarket Octalink spline-axled offerings. The Focus and the identically priced Cube have the same gears, Deore shifters and front mech with an XT rear mech, and both have Shimano hubs. With the gears perfectly adjusted, the chain on the Focus jumped from time to time in the middle ring on the first ride, but calmed down as everything settled in... this seems to happen a lot with new chains and chainrings, especially on bumpy climbs, and we can't work out why.
The Magura Julie hydraulic disc brakes on the Fat Boy are great - crisper in lever feel than Shimano offerings (some like this, some don't) and reliably powerful in all conditions.
The wheels and tyres are a bit of a highlight too - Alex DP17 rims shod with Continental's grippy but fast rolling Mountain King tyres make for light, high-performance wheels; probably the best we've seen on a sub-£500 bike. The Concept own-brand seat post, saddle, stem and bar are all good quality offerings but we suspect many riders will upgrade the flat bar to a riser.
The ride: confident and lively
Because most bikes come with riser bars these days, it feels odd to get back on a bike with a flat bar, even when it's 23.5in wide. There's nowt wrong with flat bars, but the backsweep on a riser bar helps a little with control when the terrain gets technical.
Despite this, the Focus Fat Boy offers confident but lively handling and noticably faster acceleration and climbing than other bikes in its class. At 12.9kg (28.5lb) it's the among lightest. It also has the lowest bottom bracket of the four, which means you need to take a little more care when tackling steps and awkward twisty/rocky/rooty stuff. On the other hand, the advantage of a low bottom bracket is a bit more stability when travelling at speed.
The Fat Boy's steep-angled geometry creates a personality that may take beginners a couple of rides to get used to. But we like it. It sits you slightly forward and helps you to get the best from the fork. There's no two ways about it, it's a superb £449-worth.