Pirelli Scorpion Enduro S 2.4x29in Hardwall Smartgip Compound review

Pirelli’s latest range of Scorpion Enduro mountain bike tyres looks to cater for enduro riders with three distinct tread patterns designed for soft and mixed trail conditions, and a rear-specific tyre.

Pirelli first unveiled its Scorpion MTB tyre back in 2019, launched initially with trail-focused riding in mind. Since then, three new variants have emerged: XC-specific, Enduro and e-MTB. Each has its own casing types, tread patterns, and sidewall thicknesses but all share Pirelli’s Smartgrip Compound and the same conditions-specific naming designations.

This review focuses on the newly launched Scorpion Enduro S tyre, but I have previously reviewed the original Scorpion S that has now been superseded by the new range of discipline-focussed tyres.

The new Scorpion Enduro S tyre has great all-round predictable grip best suited to drier conditions rather than wet slop, but doesn’t quite have the carcass strength for harder or heavier riders to warrant its enduro name.

Pirelli Scorpion Enduro S 29x2.4in Hardwall Smartgrip Compound details and specifications

The Enduro range of Pirelli’s Scorpion tyres has been designed to “withstand the rigours of modern riding”, specifically able to cope with the trend for harder and faster rides and stronger bikes.

The Enduro S tyre’s tread pattern and knob shape have been developed using experience and technology from the Italian brand’s motocross range, like the rest of its range of MTB tyres.

The Enduro range uses Pirelli’s Hardwall 60 TPI (threads per inch where the lower the number the thicker the material) carcass.

This technology uses a bead-to-bead nylon layer built into the casing protection with a rubber insert that runs along the tyre’s bead.

Multiple layers of reinforcement mean Pirelli hopes it can handle high loads and low pressures while providing excellent carcass stability.

How does Pirelli’s Smartgrip Compound work?

Like the rest of Pirelli’s Scorpion tyres, the Enduro versions use its Smartgrip Compound, which Pirelli claims has exceptional tear resistance, where the tyre’s knobs are less prone to flexing, snapping or getting ripped from the carcass.

This should offer the most amount of mechanical grip – described as bite in colloquial terms – in the dry with good puncture protection, requiring more force to puncture the tyre, and a longer lifespan.

The compound has chemical grip too, where the rubber is able to cling onto a wet, greasy or slippery surface.

The tyres also use a single compound where the rubber used in the centre of the knob’s blocks is the same as the outer surface. This is unlike Maxxis’ 3C compound, for example, which typically uses a harder internal compound to give the knobs their strength.

Pirelli claims having these features means the tyre has a longer usable lifespan with even levels of grip for the duration of its use. It should also mean the tyre should grip in both wet and dry conditions.

On paper, the Smartgrip Compound sounds like a winning formula.

What conditions are the Pirelli Scorpion Enduro S tyre designed for?

Crucially, Pirelli states the Enduro S tyre is designed specifically for loose and soft terrain with a focus on aggressive riding, cornering speed and demanding terrain thanks to its widely spaced tread. The Smartgrip Compound means it should grip in wet or dry conditions.

The Scorpion Enduro S tyre's intended use is clearly defined by Pirelli. In dry conditions, it's recommended for use is in either loamy, sandy or loose terrain but can be used on mixed terrain too.

In the wet, it’s intended to be used on mud, wet/loose terrain and possibly on mixed wet roots.

Pirelli clearly says the Enduro S is not intended to be used on rocky or hardpack terrain in the dry or on wet rocks or slimy hardpack.

Pirelli Scorpion Enduro S 29x2.4in Hardwall Smartgrip Compound tyre inflation, width and weight

My test sample was easy and quick to seat on my DT Swiss EX 1700 Spline wheelset, inflating with just a standard track pump. The tyres fully sealed once they were inflated to 23psi and didn’t leak any air.

On the 30mm internal width rims at 24psi the 2.4in wide tyres measured 60mm wide, less than a single millimetre narrower than claimed.

On our scales, the Pirelli Scorpion Enduro S 29x2.4in Hardwall Smartgrip Compound tyre weighed 1,065g – 44g heavier than Pirelli’s claims.

Pirelli Scorpion Enduro S 2.4x29in Hardwall Smartgrip Compound tyre performance

I fitted the Enduro S tyres to both the front and rear wheels of my Marin Alpline Trail XR test bike for the best grip possible an Enduro R tyre is available for the rear.

I tested the tyres in Scotland’s Tweed Valley on my home trails, with weather conditions ranging from very wet to dry summer-like heat.

The test tracks took in a range of trail types from soft loamy hero dirt to hard-pack baked-on dirt and trail centre man-made surfaces. Muddy, boggy and greasy rocky conditions also featured.

Because the trails I tested the tyres on are used on the UK’s round of the Enduro World Series, they were representative of the exact conditions and trail types the Scorpion Enduro S tyres are designed for.

Cornering confidence and predictable grip

Thanks to their fairly rounded profile with angled-out side knobs, the Scorpion Enduro S’s cornering grip was impressive. It was possible to confidently reach high lean angles and push the tyre into the ground without fear of them washing out or understeering.

The confidence they generated was helped by the sturdy nature of the knobs that refused to fold when pushed and there was virtually no squirming even when turning hard on dry hardpack terrain, conditions the tyres aren’t specifically designed for.

At their limits, the point at which they broke traction was easy to predict and control making drifting a fun and exhilarating prospect. This gradual breakaway meant that holding them at the edge of grip wasn’t a roll of the dice and the amount of grip that could be fed through the tyres continued to impress.

Rolling resistance was low for the amount of cornering traction on offer and I found myself entering turns much quicker than I was used to on more traditional enduro-style tyres, such as Schwalbe’s Magic Mary and Big Betty or the Maxxis Minion DHR II.

The central knobs, although quite tall in shape, are fairly closely spaced and because of the tyre’s rounded shape sit proud, meaning the contact patch is fairly small. They also have no cross-tyre siping, helping to further its speed.

However, on the brakes, there wasn’t quite the same amount of bite as a Big Betty or DHR II, thanks to the limited space between the central blocks. Despite there not being a huge amount of instant stopping power when on the brakes, the Scorpion Enduro S tyres had marginally more mechanical grip compared to a Maxxis Minion DHF or Vittoria Mazza.

Wet weather worries

True to Pirelli’s claims, on greasy and damp hardpack terrain the Scorpion S didn’t offer a huge amount of grip. Although the traction limit was easy to find and hold, the point at which they broke into a drift was much sooner than I was expecting, and they had less bite than the Magic Mary or Minion DHF in similar conditions.

They felt like they were skirting over the top of the terrain rather than chewing or clinging onto it. The same could be said for greasy and wet rocks and roots – the tyres were unable to provide predictable traction. However, it’s worth remembering that Pirelli doesn’t claim the tyres work in these conditions.

Their soft dirt traction, unsurprisingly, was impressive. They performed best in damp to dry conditions – frequently known as hero dirt – where the knobs were able to penetrate into the dirt to provide grip.

In these conditions, rocks and roots weren’t any trouble and didn’t cause the tyres to slip. I found once conditions had dried further and the ground became loose, they also gripped well.

In soft wet ground, traction was good as long as the runs weren’t peppered with greasy, harder dirt or rocks or roots, where they’d slip more easily than a Magic Mary, for example.

However, in gloopier boggier mud, the tyre’s limits were easy to find. Compared to a set of Maxxis Shorty cut spike tyres or Schwalbe Dirty Dans, the closely packed and relatively short blocks were unable to penetrate or bite into boggier mud. This was disappointing given Pirelli claims they’re designed for wet, muddy conditions.

Sidewall strength and carcass stability

At 1,065g a tyre, the Pirelli Scorpion Enduro S is marginally lighter than Specilaized’s Burcher GRID Trail T9 29x2.3in and slightly heavier than a Maxxis Minion DHF 3C MaxxTerra EXO+ TR WT 29x2.5in.

They’re significantly lighter than Schwalbe’s Magic Mary Super Trail casing 29x2.4in wide tyre that weighs 1,244g and a full 331g lighter than their Super Gravity casing Big Betty EVO 29x2.4in tyre.

This positions Pirelli’s enduro offering in a middle ground that’s undeniably more robust than a Maxxis EXO or equivalent casing tyre, yet not as sturdy as other brands' enduro-style casing, such as Schwalbe’s Super Gravity or Maxxis’ Double Down (a Minion DHR II Double Down casing 29x2.4in tyre weighs 1,239g).

Out on the trail, the enduro tyre’s Hardwall casing wasn’t as strong as I was expecting given its intended use. More often than not, I would get to the bottom of a run and discover sealant had sprayed up the rear tyre’s sidewall or over the rim as it burped under high loads, especially through rough and rocky sections and at high speeds.

The majority of the burping was caused by impacts deforming the sidewall rather than cornering-based folding or rolling of the tyre, although at lower pressures the tyre’s sidewall did flex enough to burp air.

Generally, though, carcass strength in corners was impressive but totally at odds with how much protection there was against impact-based air loss.

To mitigate the burping, I found myself running higher pressures than I would on other enduro casing tyres, with between 29psi to 31psi in the rear depending on conditions. Although increasing pressure did reduce burping, unsurprisingly it also made the tyres feel quite pingy and harsh over chattery terrain and reduced overall grip.

Burping was only an issue with the Scorpion Enduro S set up as a rear tyre, however, and I experienced no air loss at the front of the bike.

I also managed to rip and puncture the carcass of the rear tyre during the test period while riding a red-graded trail centre run.

Although the puncture was repairable trail-side with a tubeless repair plug and the tyre has since held air, I was disappointed the carcass wasn’t strong enough to withstand trail conditions well beneath its enduro remit.

Although the higher tyre pressures required to stop burping could have contributed to how easily the tyre ripped, even at the highest pressure I ran they were still inflated 14psi lower than Pirelli’s 45psi recommended upper limit.

I would expect the carcass to withstand trail centre-style riding regardless of how close the tyre is to its stated maximum inflation figure.

Wear-wise, the side knobs on both the front and rear tyres have remained impressively intact during the test period. The rear’s centre blocks are showing some signs of degradation but there has been no perceivable drop-off in traction.

Wear rate is comparable to Maxxis' 3C compound or Vittoria’s Graphene 2.0 but slower than Schwalbe’s Addix Soft tyres.

Pirelli Scorpion Enduro S 29x2.4in Hardwall Smartgrip Compound tyre limitations

Although Pirelli’s attempt at simplifying the approach to which tyre is most suited to the terrain conditions with its S, M, H and R models is commendable, it’s also fundamentally flawed.

There have only been a handful of times when I’ve ridden on entirely one trail surface type during a ride or even during a single descent. And therein lies a significant problem; trail surfaces change from hard to soft, wet to dry, rocky to rooty and grippy to loose so frequently that by limiting the tyres’ usage to certain terrain types makes choosing which tyre to spec a theoretical conundrum.

In reality, this issue is much less of a problem because the S tyres aren’t uncontrollable to ride in dry, wet or greasy rocky and hardpack conditions but they certainly don’t excel.

Another problem lies with how well they perform in both the wet and dry. While I found general wet grip on softer terrain to be commendable, in muddy conditions they don’t really stand a chance against dedicated mud tyres, despite Pirelli stating they’re indented for use in the mud. I had a similar issue with its trail-focused S tyre.

Finally, carcass strength isn’t as good as it should be for an enduro tyre. Relying on increases in pressure to improve carcass stability and stop burping is a compromised solution that negatively affected performance, feel and grip.

I would argue the Scorpion S Enduro casing tyre is closer to a trail tyre than a gravity performer, and this limits who can ride it and where.

I think the enduro casing is best suited to lighter enduro riders both front and rear, or heavier enduro-style riders on the front only.

If you’ve got your heart set on a Pirelli Scorpion tyre for the rear and ride hard or are a heavier rider, I would seriously recommend considering the e-MTB version of the Scorpion S that uses the brand’s Hyperwall carcass tech.

Pirelli Scorpion Enduro S 29x2.4in Hardwall Smartgrip Compound bottom line

It appears the Scorpion Enduro S is best suited to damp to dry conditions across the majority of trail types and terrain you might encounter on an average ride, including hard pack and rock, despite Pirelli’s claims they’re not intended for those surfaces.

However, ramp up the conditions beyond damp to wet and the tyre’s grip limits become clear pretty quickly, even in mud where its claimed to work well.

Factor in carcass strength limitations and, once again, as soon as the trails become faster, rougher or gnarlier, my experience was that the Scorpion Enduro S couldn’t quite cut it as a fully-fledged enduro-focused tyre.

For lighter riders or less extreme conditions, the Scorpion S’s predictability and general grip was truly commendable and puts up a good fight against the Maxxis Minion DHF, Vittoria Mazza or Specialized’s Butcher. Just don’t expect it to grip as well as a Schwalbe Magic Mary, Maxxis Minion DHR II or Vee Tire Attack HPL when conditions deteriorate.