Following on from the introduction last year of the Fuel EX, for 2009 Trek has launched an all-new Top Fuel race bike. Bringing it into line with the rest of Trek's full suspension bikes, the Top Fuel's back end features all of the current Trek gizmos. The shock is driven from both ends, which gives more scope for tuning the rate curves. The top end of the shock is driven by a new one-piece magnesium EVO link, and at the back you'll find the Active Braking Pivot coaxial with the rear axle. In this incarnation Trek's suspension layout delivers a race-ready 100mm of travel, matched up front on this 9.9 SSL (presumably "Super, Super Light") model by a RockShox SID World Cup fork.
Nothing too unfamiliar at the back half of the frame, then. But the front half has a bunch of interesting features. It is, of course, carbon fibre, but in this case it's all carbon fibre without a hint of aluminium to be seen. Most carbon frames feature alu inserts in the headtube and bottom bracket, but the Top Fuel has net-moulded carbon shapes ready to take drop-in bearings.
This is most interesting at the BB, where Trek has introduced the BB90 bottom bracket. The shell is 90mm wide (hence the name) and takes a custom twin-ring 29/42 FSA chainset. This is designed to offer an extra-low Q-factor, which is the daft name given to the distance between the outer crank faces and hence the pedals. The theory goes that the narrower this is, the better, as your legs go straight up and down rather than pushing out to the side. The Top Fuel's BB90 setup has a Q-factor 11mm wider than a Dura-Ace crank on a road bike, quite impressive given that the frame has to accommodate MTB tyres.
There's more innovation at the top of the frame, with Trek's "No-Cut" seat mast. This is intended to deliver the low weight and stiffness benefits of integrated seat masts without the hassles of lack of adjustability and while avoiding that whole "having to cut off bits of frame" scenario. The system uses a stubby 34mm diameter seatpost with just enough length to accommodate the range of heights for a given frame size.
The cantilevered seat mast looks faintly precarious, but it feels solid when you're in the saddle. In fact, so does the bike as a whole, an impression reinforced by the impressively stout SID fork and quite conservative geometry - this isn't the kind of race bike that'll try to kill you if you look at it a bit funny. The 2x9 transmission setup feels very appropriate, although the narrow Q-factor isn't something that leaps out at you when you climb aboard.
It's certainly a very fast bike, but very well-behaved with it. No surprises, no weird behaviour. It looks good, too...
www.trekbikes.com
