GT produce some amazing bikes featuring their i-Drive suspension system, which eliminates pedal feedback. One of their latest is the 2007 DHi. This rig is designed as a downhill race bike - in fact, it's one of the lightest off-the-peg downhillers out there - and it wants to do just one thing: go flat-out all the time.
The DHi's i-Drive suspension system is clean and simple. It works by isolating the chain tension by countering the bottom bracket movement against the suspension movement. This is done by mounting the bottom bracket on a link under the main pivot, which moves backwards as the suspension compresses, and so stops chain growth.
A huge monocoque mainframe and swingarm combo makes the bike outstandingly stiff and light (complete weight is 18kg/39.6lb). A carbon fibre seatmast houses the shock, protecting it from the elements, and helps to keep the weight down. With its 150mm effective chainstay length, 66-degree head angle, low 14in bottom bracket height, Fox DHX 5.0 shock and Maxle (20mm boltthrough quick release) rear end, the DHi has the latest gadgets and great geometry. It has 215mm (8.5in) rear travel and, in keeping with the futuristic feel, the frame is finished in bare carbon and NASA white.
GT have specced nothing but the best on the DHi. Up front is the amazing RockShox Boxxer World Cup fork, giving 200mm (8in) travel and spinning in an FSA Pig Pro headset. Easton provide a Vice stem and carbon MonkeyLite DH bar. Brakes are Avid Juicy Sevens with a 203mm rotor up front, 160mm out back.
Kenda tyres, Sun MTX rims and DT Swiss FR 440 hubs make a light, strong wheelset. This, combined with the Shimano Saint cranks, Shimano Dura-Ace cassette and chain and SRAM X.0 shifters and rear mech, means you can propel the rig to cruising speed with ease.
The DHi's geometry feels spot-on, although with only small and medium frames in production, larger riders are left out. One of our test riders is 6ft 3in tall and he found the medium size a bit short.
The light weight means dialling in the rear end takes a little longer than usual as there's nothing to it - too much rebound and it feels dead, too little and it becomes skippy. However, once sorted, the DHi sticks to the ground well and becomes a planted, agile ride.
Tight turns in particular are a breeze - you can throw it into switchbacks with good speed and explode out. The low weight also really helps you out of turns. We would fit Maxxis tyres but, all in all, the DHi is an awesome World Cup level rig.