Wil reviews the Scott Spark RC

Totally redesigned and reimagined for 2022, the 4th generation Scott Spark has made headlines with its striking frame design, hidden shock, dual bottle capability and adjustable head angle. We’ve been testing the stealthy Spark 910 for the past six months, which has impressed us with its new-school geometry, supple suspension and clever TwinLoc system. For the full story, check out our Scott Spark review.

Turning the Spark into a Spark RC

As with the previous generation Scott Spark, the latest model is offered in two distinct versions; the Spark and the Spark RC. Both models feature 120mm of rear wheel travel, but there are some key differences between them.

The regular Spark features a more trail-oriented build kit, with a 130mm travel fork and chunkier tyres that turn it into a lightweight trail bike. In comparison, the Spark RC gets a lighter build kit with a 120mm travel fork and faster-rolling tyres to make it more suited to XC racing.

In terms of the geometry and suspension design however, the chassis is identical between the two models. And thanks to the use of adjustable headset cups, you’ve essentially got two-bikes-in-one.

With this in mind, instead of getting in a whole new test bike, we decided to take our existing Spark 910 and turn it into a Spark RC. Here we’ll be taking you through all of those changes, how they play out on the trail, and why you would choose the Spark RC over the Spark.

Faster-rolling tyres

The first step for our Scott Spark RC project, and the easiest way to add speed to any bike, was to fit faster-rolling tyres.

The Spark 910 comes stock with 2.4in wide Schwalbe Wicked Wills, which are brilliant tyres for rapid trail riding. They’re a bit chunky for XC racing though, so we fitted a pair of Maxxis tyres in their place.

Up front is a Rekon Race, and on the rear is an Aspen. Using the 2.4in ‘Wide Trail’ casing, these are a perfect match for 30mm wide rims, providing a nice high volume profile with fantastic damping qualities and noticeably more grip than the skinnier versions. The Spark frame comfortably accommodates these new-school 2.4in tyres, with plenty of mud room through the compact swingarm.

Compared to the Wicked Wills, the Maxxis tyre combo is much quicker off the mark, with significantly lower rolling resistance. They’re also over 100g lighter per wheel, resulting in a 219g reduction in rotational weight.

Lightweight race wheels

Following tyres, wheels are typically the biggest upgrade you can make to any mountain bike. And while the stock Syncros Silverton 2.0 wheelset on our Spark 910 has performed pretty well, with a confirmed weight of 1,956g there was plenty of scope to go lighter.

In their place we’ve fitted a DT Swiss XRC 1501 wheelset. Weighing in at just 1,589g, the XRC 1501 wheels have made another big improvement in rotational mass. With a taut build and low-profile carbon rims, they’re significantly more responsive too, boosting acceleration and sharpening up the Spark’s handling. Important attributes for XC racing duties. The faster-engaging freehub is a welcome upgrade over the stock Syncros wheelset too.

For an in-depth look at these high-zoot hoops, check out our DT Swiss XRC 1501 review.

A one-piece Syncros cockpit

Another key difference between the Scott Spark RC and the regular Spark can be found up at the cockpit.

The Spark 910 comes fitted with a 760mm wide riser bar, along with a 60mm zero-rise stem. To emulate the Spark RC models, I’ve fitted a Syncros Fraser iC SL XC one-piece carbon cockpit. The virtual stem length is the same, but it features a hefty 12-degree drop, and the overall bar width is narrower at 740mm.

As subtle as it might sound, the cockpit switch-up has resulted in a noticeably more aggressive riding position that feels particularly powerful on the climbs. The narrower width has also been appreciated during fast-paced bunch riding at the beginning of a mass-start race. There is less leverage and stability though, and the lower bar position puts more of your weight over the front wheel too.

In addition to altering the Spark’s riding position, the Syncros Fraser iC SL XC is literally half the weight of the alloy bar and stem that came off the bike (271g vs 553g). That’s weight that sits high up on the bike too.

I’m also digging the profile and overall ride quality, with the carbon layup delivering a surprising level of vibration-absorption that isn’t typically present in oversized carbon cockpits. Of course the whole structure is beautifully integrated into the Spark’s headset too, providing a very clean and stealthy look to the front of the bike — as it should do for the $699 AUD asking price.

120mm Fox 34 Step-Cast fork

The shorter 120mm fork is easily the most obvious difference between the Scott Spark RC and the regular Spark.

The Spark 910 comes fitted with a 130mm travel Fox 34 Performance Elite fork, which weighed in at 1,720g with a chopped steerer tube and the Kabolt thru-axle. It is possible to fit a shorter 120mm air spring to this fork, which Fox sells for $89.99 AUD. That’s a relatively inexpensive option for existing Spark owners, who might not want to shell out for a whole new fork.

In our case we received a Fox 34 Step-Cast for testing, which would prove to be a useful piece of of our Spark RC puzzle.

This fork still uses 34mm diameter stanchions, but features a narrower chassis that is optimised for its 100-120mm travel range. Along with its hollowed and stepped lowers, the result is a weight reduction of over 200g. Our test fork tips the scales at a lick over 1,500g, making this a seriously lightweight 120mm fork. For more info on how it rides, check out our Fox 34 SC review.

Adjusting the head angle

In addition to running a shorter fork on the Scott Spark RC, it’s also possible to adjust the bike’s head angle via the modular headset cups.

Made from reinforced plastic, the top and lower headset cups can be removed from the head tube by hand and rotated 180° to steepen or slacken the head angle by 1.2°. Included in the box with the bike is an extra set of cups that offer a neutral position, delivering you three different head angles from the one frame. However, once you add in the two different fork options, there are actually six possible head angles with the Spark.

Here’s how the complete bikes come set up from the factory;

• Spark – 130mm fork & slack headset position = 65.8° head angle
• Spark RC – 120mm fork & steep headset position = 67.2° head angle

Regardless of which model you have, changing the head angle is a pretty straightforward process. And unlike traditional geometry flip chips, this adjustment is done independently of the seat angle and BB height.

Locating pins help to secure the cups in the head tube, though the markings on the cups are somewhat vague as to which position you’re in. There’s a small notch in the top headset cup, and this is meant to face forwards in the steep position, or rearwards for the slack position. There’s also a notch on the lower headset cup, and (perhaps confusingly) this has to be set opposite to the upper cup. So the notch needs to be at the back for the steep position, and at the front for the slack position.

Along with fitting a 120mm fork to our Spark RC test bike, switching the headset cups into the steep position brought the head angle up by 1.4° in total. That is a very big change – about twice as much as what you’d expect from a traditional flip chip, whilst maintaining the rest of the bike’s geometry.

There are two Nude shocks

Of course the heart of the Scott Spark RC and Spark is its proprietary Nude shock. Well, technically there are five different Nude shocks across the Spark lineup, but to keep things simple there are two different styles that I’ll be discussing here.

The shocks themselves are manufactured in partnership with Fox or RockShox, and feature a twin-chamber design for the positive air spring. A valve sits between these two chambers and is activated by the TwinLoc remote up at the handlebar. In the Descend position the valve is open, creating a large air volume for maximum plushness for the 120mm of rear travel.

In the middle Traction Control position the valve shuts off the secondary air chamber, radically shrinking the total volume. This change in spring rate makes the shock so progressive that it physically limits the rear travel to 80mm, providing a much firmer feel to the suspension and lifting the bike’s overall ride height in the process. Damping is also increased, providing further support to improve pedalling response.

The result is a superb climbing mode that offers better efficiency, more pedal clearance and a steeper effective seat angle for laying the power down. It’s very effective and has been the Spark’s party trick ever since it was launched back in 2007. Though it’s been around for 15 years, it still manages to impress us today with its clever engineering.

While the functionality of the Nude shock is shared across the lineup, our Spark 910 test bike came equipped with the Fox Nude 5T shock. This features an extra large air can that provides the plushest performance possible for maximum grip and control.

To get the full race bike experience, Scott sent us the Fox Nude 5 shock that comes on the Spark RC. The eye-to-eye length and 45mm stroke are identical, so it still produces 120mm of rear travel. However, it utilises a smaller air can, which does result in it being a little lighter (295g vs 376g). More importantly though, it’s claimed to alter the spring rate and change the suspension performance — more on that in a bit.

What else can you change?

Those are the six major differences between the Scott Spark RC and the regular Spark, though there are some further areas for tweaking if you’re searching out the raciest possible setup.

Most of the Spark RC models come fitted with a 100mm stroke Fox Transfer SL dropper post, which is nearly 200g lighter than the 125mm stroke Fox Transfer that comes on our Spark 910 test bike (353g vs 542g). That’s a decent weight reduction, and I’ve typically found a 100mm dropper to be fine for XC racing.

All Spark models are spec’d with lock-on grips, though foam grips will save a few more grams while offering a little more squishiness to help fight long-distance fatigue. It’s also possible to fit a smaller 160mm rear rotor, though you’ll need a new adapter, which is a Scott-specific item for this frame.

And while 32T chainrings are standard across the Spark lineup, this frame is ready to take a Nino-worthy 38T chainring should the Watts be flowing freely through your Thunder Thighs.

Scott Spark RC weight

With all the upgrades to our Scott Spark RC project bike, it’s no surprise that the number on the scales has come down. And not by a small margin either.

Confirmed weight for our custom Scott Spark RC is 11.24kg, without pedals and with the tyres set up tubeless. Compared to the Spark 910 we began with, that’s a weight reduction of around 1.2kg.

The savings have been spread pretty evenly across the wheels, fork and cockpit. As mentioned above, a lighter dropper post would help shed more weight. Along with a carbon-railed saddle, we’d be looking at sub-11kg. Not bad for a bike with 120mm of travel at both ends.

It’s worth noting that all of this is based around the Spark HMF frame, which is the heaviest carbon frame in the Spark lineup with a claimed weight of 2,150g including the rear shock and hardware. There are two lighter carbon frames that are featured on the higher-end models; the HMX and the HMX-SL. You can see all the frame weights, specs and pricing of the full 2022 lineup in our Scott Spark overview.

What’s the Scott Spark RC like to ride?

Compared to the bike we started with, the personality of our Scott Spark RC project bike has evolved significantly.

Of course the faster-rolling tyres and carbon wheels have made a huge difference. This is definitely the place to start for anyone wanting to add speed and efficiency to their XC or trail bike.

The 1.2kg overall weight reduction is plenty noticeable. And anyone who says weight doesn’t matter on a mountain bike has never redlined while racing a dirt crit or XCM event. Our souped-up Spark RC accelerates faster, both off the start line and during mid-race overtaking manoeuvres. The steeper head angle has quickened up steering response, while the lowered cockpit delivers a noticeably more powerful pedalling position on the climbs.

Having changed to the 120mm travel fork, the seat angle does get a lick steeper, going from 75.9° to 76.1°. That’s the static seat angle by the way. The dynamic seat angle feels even steeper when you select the Traction Control mode, putting your hips further over the BB when you’re heading uphill.

Re-learning the TwinLoc

While the TwinLoc system itself remains just as versatile, my approach to it has changed along with the bike. With the stock Spark 910, I found I would ride most of the time in the Descend mode, and would only flick into Traction Control when I was facing a climb or meandering along smoother trails. It was probably a 70/30 split.

With the Spark RC, that ratio has flipped to 30/70. I’m now mostly riding in the Traction Control mode, and only flicking into Descend for, well, the descents, or any time the trail is particularly gnarly.

It’s worth stipulating that the Spark RC is very plush in Descend mode. In fact, it’s plusher than any other XC bike I’ve tested. The extra 20mm of travel over a conventional full suspension XC bike is noticeable, and it gives you a much bigger margin for error when sending it down choose-your-own-adventure rock gardens. Along with the sensitive Fox 34 SC fork, the Spark RC offers terrific comfort over rough terrain, packing plenty of reserves for when things inevitably go awry.

This plush performance means that pedalling efficiency isn’t great in the Descend mode. The Spark features an anti-squat level well under 100%, which is quite uncommon for an XC bike. It feels soft under power, and there’s a reasonable amount of bob if you’re not pedalling smoothly.

You can increase the shock pressure and run less sag, but that kinda defeats the purpose of the TwinLoc system. That’s because the whole bike is designed around you utilising the middle Traction Control mode to provide the snappy pedalling response needed for XC racing duties. And a snappy pedaller it is. With the smaller volume Nude 5 shock installed on our Spark RC, the Descend mode doesn’t feel all that different. However, the Traction Control mode does. The rear end is much firmer and more responsive, giving the Spark RC a similarly tight and energetic feel as the short travel Trek Supercaliber.

The downsides

While it provides a terrifically stable platform for sprinting uphill, I have found that the Traction Control mode can be a little harsh on really rough and technical climbs. The suspension stays active enough to allow the tyres to drive for grip, but because it also increases compression damping on both the shock and fork, there’s noticeably more feedback on square-edge hits. The high volume 2.4in rubber does add a good deal of compliance to help in these situations, but if things are especially choppy and I’m not riding as aggressively, I’ll sometimes climb in the Descend mode. Each ride I seem to be getting better at predicting which mode is best for which trail scenarios.

Needless to say, your left thumb gets a total workout on this bike. While the TwinLoc remote is about as well designed as a three-lever system can be, it’d be nice if the suspension levers were able to sit a little further outboard, as it’s currently a bit more of a reach than I’d like.

Ergonomics aside, it’s the TwinLoc concept itself that will be the main downside of the Scott Spark RC for certain riders. It is totally reliant on the remote, and you need to make regular use of it to get the full performance out of the bike.

This is what separates the Spark from the Live Valve-equipped Giant Anthem and the Specialized Epic. Those two bikes feature automated systems that open and close the suspension for you, leaving you to concentrate on the trail ahead. While that certainly has its advantages, it’s worth noting that automated suspension doesn’t always perform how you expect it to. Sometimes the suspension stays locked-out in situations where you want to be open, and vice versa.

In the case of the manually controlled TwinLoc system, the suspension behaviour is predictable and reliable, and you choose how you want the bike to ride. I’ve found this particularly advantageous during some longer XCM races, where fatigue starts to kick in around the halfway mark. At that point there are sections of trail where I’d rather the suspension to be open and as comfortable as possible, rather than worrying about efficiency. In these moments I’ve been glad to have access to that plush Descend setting on the Spark RC.

How’s long-term durability been?

We’ve now put over six months of testing into our Scott Spark RC project bike, and thankfully no glaring durability issues have emerged in that time.

The hidden shock might seem like a bit of an industrial design gimmick, but the compact arrangement provides clearance to run two bottles, and I like that the shock is tucked away from dirt, dust and degreasers. In theory, this should keep the lubrication oil and seals in better condition, so it requires less maintenance in the long run.

When it does come time to servicing, the shock itself is surprisingly easy to remove. I’ve done it a couple of times now, and it takes me less than five minutes. The pivot system is nicely engineered with sealed bearings throughout, external bearing shields, and clever colour-coded spacers. There’s a beefy splined axle to increase stiffness through the rocker link, while a locking collet head is used to secure the main pivot.

As well engineered as it is though, the Spark is still a noisy bike. I like that the rear axle lever hides integrated Torx and hex keys, but unfortunately it rattles around while riding. The noise annoyed me enough that I removed it entirely.

There are also a lot of cables to manage inside the downtube, and while foam insulating tubes do quieten down rattling, for some reason the tube for the brake hose seems to migrate upwards during every ride. It eventually ends up at the headset, where the polystyrene foam causes an annoying squeak on every hard compression. I suspect this could be solved with some zip ties and a replacement foam tube made of a different material, but it’d be nice if it was quiet to begin with.

While the internal routing no doubt contributes to the Spark’s clean lines, sending the cables and rear brake hose through the headset also adds time and complexity to servicing. Thankfully the Acros bearings are still running smooth, and it’s worth noting that they’re further protected by tight-fitting external shields. I’ve had no issues with the plastic headset cups either, and admittedly the whole system is really well designed and put together. I still can’t help but wish the cables didn’t go through the headset though.

Scott Spark vs Spark RC

Having experienced our test bike as both a Spark and a Spark RC, which bike would we recommend? The answer to that question simply boils down to how much racing you’re doing, and how seriously you’re taking it.

The Scott Spark RC is, obviously, the race bike. It’s lighter, offers a more aggressive riding position, and comes with faster-rolling tyres. The smaller volume shock also provides a more supportive platform in the Traction Control mode, bolstering its pedalling response and overall climbing speed. If you’re hunting for podiums across XCO and XCM race formats, the Spark RC is the pick, as it’s totally race-ready out of the box.

The lighter build and lower front end does mean it loses some of the planted descending performance of the regular Spark. The 34 SC fork isn’t as stout, and while the steeper head angle delivers sharp steering on tight and twisty singletrack, it comes at the expense of outright high-speed stability. Of course you can slacken out the head angle, and you could also beef up the build if you were simply riding for fun versus competition. However, you’d have to make bigger and potentially more expensive upgrades to the Spark RC to make it more trail-friendly.

Personally, I’d come at it the other way. The standard Spark will tick the box for a lot of folks who are after a comfortable and capable bike for long-distance XC riding, while its progressive geometry and supple suspension also makes it terrific fun for light-footed trail ripping on more technical terrain. If you found you were doing a few races and multi-day events each year, then a lighter wheelset and faster tyres would be a great upgrade to inject a bit of extra speed to up your competitiveness. And if you wanted to sharpen up its performance on the race track a little further, the head angle and cockpit setup would be the next logical step to consider.

Flow’s Verdict

In its race bike form, the Scott Spark RC is perfectly suited to the demands of modern XC riding. The stiff carbon frame and progressive geometry deliver superb handling, and the 120mm suspension package offers maximum grip and comfort for riding the most hectic of race courses.

The TwinLoc system continues to offer useful fingertip control of the suspension, with the middle Traction Control mode providing a firm platform for sprinting uphill and speeding along smoother sections of trail. The remote isn’t perfect though, and certain riders will be turned off by having to use it all the time to get the most out of the bike.

However, in a market where race bikes are typically one-dimensional machines, the Spark stands out for its clever versatility. Whether you’re looking at the regular Spark or the Spark RC, you’ve got options for tuning this bike to your needs. Certainly for those who can handle a remote and are after a contemporary race bike that absolutely rips on the descents, the Scott Spark RC is without doubt the most capable XC bike we’ve tested.

Scott Spark RC Custom Build

• Frame | HMF Carbon Fibre, IST FlexPivot Suspension Design, 120mm Travel
• Fork | Fox 34 Step-Cast, Factory Series, 3-Position FIT4 Damper, 44mm Offset, 120mm Travel
• Shock | Fox Nude 5 EVOL, 3-Position DPS Damper, 165x45mm
• Wheels | DT Swiss XRC 1501, Carbon Rims, 30mm Inner Width
• Tyres | Maxxis Rekon Race EXO 2.4in Front & Aspen EXO 2.4in Rear
• Drivetrain | Shimano XT 1×12 w/XT Alloy 32T Crankset & 10-51T Cassette
• Brakes | Shimano XT M8120 4-Piston w/180mm Rotors
• Bar | Syncros Fraser iC SL XC, Carbon, 740mm Width
• Stem | Syncros Fraser iC SL XC, Carbon, 60mm Length
• Seatpost | Fox Transfer, Performance Elite, 31.6mm Diameter, 125mm Travel
• Saddle | Specialized Power Pro Mirror, 143mm Width
• Confirmed Weight | 11.24kg