Trek Superfly 9.9 SL XTR Project One review

Custom finished version of a flexible and well proven rig

Our rating 
4.0 out of 5 star rating 4.0
GBP £6,555.00 RRP

Our review

Obviously flexy but uniquely customisable, inspiringly agile and seriously fun ultralight race day flier
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We put Trek’s off the peg Superfly FS 9.8SL through its paces a few months ago, and were mighty impressed with what we found. But this custom iteration of the bike takes performance and personalisation to another level.


Frame and equipment: featherlight full-susser, meet kit box of delights

The 9.9 series frame has not only the carbon seatstays of the 9.8, but chainstays too, saving 100g and making this one of the lightest full suspension frames available. It’s just 1650g without the Fox rear shock.

While there’s a stock 9.9 XTR option, Trek offered us the chance to try its Project One custom program to create our ultimate Superfly. The process starts with choosing a huge range of paint finishes including the ultralight subtle sheen ‘Rainforest Vapor Coat’ we opted for.

We picked a ‘rainforest vapor coat’ for our project one superfly. looks nice, anyhow:
Russell Burton

We picked a ‘Rainforest Vapor Coat’ for our Project One Superfly. Looks nice, anyhow

You can then run through various transmission options from XT to 2×11 Di2 XTR, Fox or RockShox rear shock and fork options complete with colour coded decals and wheel, cockpit, saddle and seatpost choices from Trek sub brand Bontrager. We chose superlight alloy Race XXX Lite CL wheels but shod with fat 2.35in XR2 treads and a 750mm wide carbon riser and light but cost conscious alloy finishing kit.

That still brought the complete bike in marginally under 10kg, but with more carbon trim and skinny race tyres a hardtail-challenging 9kg is certainly possible.

Ride and handling: a flexible friend, once you get the frame’s measure

Despite the fact that it could have been lighter still, our build translated into blistering acceleration and as close to effortless altitude gain as you’ll get with full suspension.

However, the ultralight frame and wheels are flexy under sideways loads. That means the front and rear wheels can follow different lines through random rock and root sections, and things get out of shape if you brake or accelerate hard when you’re still turning. Learn to accept this and the whip from the frame as it unloads can fire you out of corners. Its snake hipped shimmy will often save it from the biggest speed-eating impacts too.

There’s appreciable flex when you snap the superfly through corners, but it’s no handicap once you’ve got things figured out:
Russell Burton

There’s appreciable flex when you snap the Superfly through corners

The twang never exceeded the extra leverage and traction of our bigger bar and rubber choice either, keeping it more planted and technical trail proof than the stock 9.8.

Unlike the Cannondale Scalpel Carbon Team we tested alongside it, you can really feel the shock working to get the wheel out of the way so you’re definitely getting a benefit from the rear damper. Pedal and impact response is also controlled enough to leave the rear shock in Trail mode 90 percent of the time, only flicking to Climb or Descend mode for extended climbs or descents.


The fork is easy to sync with the rest of the bike too, keeping it buoyantly balanced rather than a random ricocheting mess.

Product Specifications


Name Superfly 9.9 SL XTR Project One (15)
Brand Trek

Available Sizes 15.5in 17.5in 19in 21in 23in
Rear Tyre Bontrager XR2 Team Issue TLR 29x2.35in
Wheelbase (in) 45.24
Top Tube (in) 23.86
Standover Height (in) 30.04
Seat Tube (in) 19.02
Chainstays (in) 17.8
Bottom Bracket Height (in) 13
Weight (kg) 9.95
Stem Bontrager Race X lite 80mm
Shifters Shimano XTR
Seatpost Bontrager Rhythm Pro
Seat Angle 73.8
Saddle Bontrager Evoke RL
Rims Bontrager XXX-Lite TLR Disc 29
Rear Wheel Weight 1990
Rear Shock Fox Float CTD Factory 100mm travel
Bottom Bracket Shimano PF
Front Hub Bontrager XXX-Lite TLR Disc 29
Brakes XTR Race 180/160mm IceTec
Cassette Shimano XTR 11-40T
Chain Shimano XTR
Cranks Shimano XTR 32T
Fork Fox 32 Float CTD Adj FIT Factory Stealth 100mm
Frame Material Full OCLV Mountain Carbon
Front Tyre Bontrager XR2 Team Issue TLR 29x2.35in
Rear Hub Bontrager XXX-Lite TLR Disc 29
Front Wheel Weight 1630
Grips/Tape Bontrager Race Lite single lock
Handlebar Bontrager Rhythm Pro carbon 750mm
Head Angle 70
Headset Type Cane Creek IS40
Rear Derailleur Shimano XTR
Frame size tested 19in