Rock Shox SID Carbon
£699
2.68lb or 1.2kg (Ours was sightly heavier but it had a starfangled nut and
long steerer so we’re not going to quibble).
www.MadisonBrandInformation.com or www.rockshox.com

Test Logbook: We’ve had these rare forks plugged in the front of Scoop’s scooter for a couple of weeks now (since we clocked 100 miles with the Pace’s), hacking them round the local singletrack trails as well as some bigger raids out into the Dales. They’ve met all the usual sets of steps, off camber sections, stutter bumps, rubble-strewn corners and other sorted grimness that we normally put forks through, as well as more than their fair share of snow, ice, slush, grit and general winter nastiness.

SID

The ‘Superlight Integrated Design’ family have been Rock Shox lightest race babies since 1997. They’re based around minimalist magnesium lower legs controlled by positive and negative air springs that let you control the actual spring rate as well as initial stiction. Over the years seals have been improved and the new ‘Pure’ damping system has been introduced, complete with ‘Climb-it’ lockout control on the compression damping.

The 2002 family line up is SID SL, SID Titanium Race (titanium nitrided stanchions and titanium hardware) and SID Carbon straight from the Black Box race development programme.

Carbon fibre has been used for the crowns and steerer tubes of road bike forks for several years now. It was adopted for its light weight and also its reduction of high frequency road ‘buzz’ that can otherwise turn hands and wrists numb. Pace have been using carbon fibre lower legs for years, and Marzocchi have used a carbon upper leg and crown assembly on their very expensive RAC forks, but Rock Shox are the first company to use a one piece carbon steerer and crown.

Ride

Rather than some stripped down race special, the Carbon still has all the same features as the SL and Race forks. Pure damping uses a two piston (one floating) oil chamber to provide impressively smooth heat compensating rebound and compression. The handily “hare and tortoise” marked rebound control at the bottom of the right-hand leg offers wide adjustment for all riding styles and air pressures. It’s also building up a good reputation for reliability. At the top of the fork is the clear plastic “Climb-It Control” knob which allows gradual adjustment from free flowing to total lockout of the compression damping. As it’s on top of the fork it’s not as handy as the Pace handlebar lockout, but it offers more damping options than either that or Marzocchi’s ECC control. In short it’s a quality unit that handled stutter bumps or big wallops alike, with no unpleasant spikes or kickback.

The “Dual Air” system of positive and negative springs is well proven now. It runs at a medium pressure (around 50-80-psi) compared to the curious very low (30psi) positive, very high negative (150psi) pressure of the Marzocchi Dopio Air system. It also scores points for using a standard Schraeder shock valve rather than needing an adaptor. The spring rates can be set to move only on the big strikes or flow happily along the trail over chatter depending on your tastes, but either way it’s a smooth progressive stroke with no bottom out thump.

Travel can also be changed from 63mm to 80mm by moving internal “All Travel” spacers, and to their credit even the 63mm setting delivered the full stroke (actually a whopping 66mm) rather than the disappointing actual travel figures from some forks.

We can’t comment on breaking-in periods as I wasn’t the first to ride this set of forks, but they were running smoothly with no slop, thanks in part to elongated lower bushings on 2002 models.

So far very good, but won’t a 2.7lb carbon fibre crowned fork be a twangy, skippy nightmare? Rock Shox claim increased stiffness for their carbon crown and having ridden them they certainly don’t seem to be any flexier than normal SIDs or other lightweight forks. They’re not as pinpoint accurate as bigger forks like the Fox Float and given the chance they will wander slightly round the far side of round rocks and roots rather than tracking over the top. Snatched braking on rocky sections will also flex them back and forwards, and there’s some brake rub when locked out and sprinting hard, but none of this is unusual in forks of this weight or even a fair bit heavier. We can’t see racers or those willing to go lightweight elsewhere on the bike having a problem with that. They certainly matched the geometry of the STP superbly, with very predictable and accurate enough responses to keep us out of trouble even when we were asking for it by shoving it sideways across frozen tractor ruts.

What really sets these forks apart is the eerily smooth sensation on high-speed, completely frozen moorland track sections. The carbon really does seem to soak up the small stuff in a way unlike any other fork apart from the carbon legged Pace RC31 rigid fork. This ‘micro-suspension’ action also completely stabilised the front end of the STP which is otherwise a notorious tank slapper.

Verdict: OK, so they are madly expensive and offer a mere ounce or two in weight saving compared to other SIDs, but they do have some genuine advantages that we weren’t expecting. Limited edition race bred Black Box stuff is never going to be cheap, but the carbon is certainly more than a gimmick, with a superb small bump wrist soothing action.
If you’ve got the money and are wanting a very smooth, full feature race fork that also happens to be the lightest in the world then get one on order. The rest of you whippets will just have to wait until carbon becomes as widespread as it is on the road scene.

In a sentence: The best race fork in the world, but that costs.