THE NEW SCHWALBE RADIAL CASING
A TRUE, TIRE REVOLUTION
Words by Robert Johnston | DH Photos by Dusten Ryen | Photos Courtesy of Schwalbe
Video by Brian Niles/Treeline Cinematics
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Taking note from the amazing traction and conformity of trials moto tires, mountain bikers are now seeing their first Radial MTB tire. Schwalbe is launching what they consider to be a revolution in tire construction, with their new Radial casing. Targeting improved comfort, traction and safety, Schwalbe is hoping that Radial will transform the aggressive mountain bike tire as we know it. And so far, we cannot disagree.
Schwalbe’s Radial Casing is one of the most exciting tire developments we’ve seen in our time on a mountain bike. Even more importantly, it’s one of the most pronounced improvements we’ve experienced on the trails in recent years. Let’s dive into what Radial is, and how it’s performed in our preliminary testing.
As with all of our Dissected Features, this is not intended to be a long term review or endorsement of a product but is instead a chance for our viewers and readers to get a deep dive look into some of the newest tech and products in the mountain bike space. We thank Schwalbe for the opportunity to create this feature and getting you some valuable beta on these new tires and Radial casing.
WHAT IS RADIAL?
To better understand Radial, it’s worth looking at the current carcass construction standard. Conventional mountain bike tire casings are made with layers of material sitting at a 45-degree angle. This has been the standard for years and has obviously resulted in suitably well performing tires.
Radial looks to optimize the interaction of the tire carcass with the terrain. The threads on this carcass sit at a shallow angle, which is close to radial (running perpendicular to the direction of rotation). Crucially though, the thread angle is not exactly radial, sitting at an obtuse angle that Schwalbe doesn’t want to disclose for obvious reasons.
This avoids the need for a tire belt as found on a car tire, which impedes the flexibility of the tire and adds significant weight. Schwalbe’s Radial casing leads to less overlap between casing threads, and lower tension on these threads.
HOW IS RADIAL BETTER?
The Schwalbe Radial casing is able to deform to the terrain more sensitively and locally, leading to an increased tire contact patch and a more supple tire to conform to the terrain below. Contact patch at the same pressure is claimed to increase by a whopping 30% on a smooth surface at 22psi (1.5 bar). Even more impressive is a claimed increase of 10% contact patch when comparing a Super Gravity tire at 22psi, with a Radial Gravity tire at 29psi (2 bar).
The interaction between the Radial carcass threads also leads to a significantly improved vibration damping effect, with less oscillation of the tire following an impact. This vibration damping is audible as well. All of our test riders noticed a very distinct and quieter “Thud” of the tires over terrain compared to traditional tires.
Combining a tire that’s able to conform with the terrain better with an improved damping effect, there are considerable improvements to traction, safety, and rider comfort. Schwalbe is initially going to apply the Radial casing to their Magic Mary, as well as two new tread patterns developed specifically around the Radial construction.
Of course, there are some small drawbacks to Radial, which Schwalbe are not afraid to admit. The main one being rolling speed. After all, more tire contacting the ground leads to more friction. Arguments could be made that smoothing out terrain could offset rolling resistance as less energy is coming through to the rider.
Furthermore, thanks to the Radial casing’s benefits, tire pressures can be increased to offset this. There’s also potential to use a slightly firmer rubber compound without sacrificing traction. And finally, a whole new tread pattern can be used to harness the characteristics of Radial… enter the new Schwalbe Albert Pro and Shredda Pro.
THE NEW SCHWALBE ALBERT PRO RADIAL
The new Schwalbe Albert Pro tread pattern was developed specifically around the Radial casing technology, aiming to offer the most security when attacking the trail up and down. Taking the shoulder knobs of the new yet already legendary Tacky Chan for excellent lateral support, the central area is packed with tighter spaced knobs to give lots of rubber on the ground and maximize control.
The Albert Pro is designed to work well in all trail conditions, but specifically targets stability and confidence in hardpack. It’s a tire designed for all-round usage – opposed to the race-focused Tacky Chan – on both Mountain Bikes and eMTBs. The Albert Pro is not Front or Rear specific, so should work well on either wheel.
The new Albert Pro Radial is going to be offered in a Trail and Gravity casing option with either Soft or Ultra Soft rubber. There are 2.4” and 2.6” width options to fit both 27.5” and 29” wheels.
THE NEW SCHWALBE SHREDDA PRO
THE MOST AGGRESSIVE EMTB TIRE?
The second new tread pattern Schwalbe is launching alongside their Radial casing revolution is perhaps the most aggressive tire we’ve ever seen in the mountain bike world, the Shredda Pro. Designed to offer uncompromised traction for eMTB, the enduro motocross-inspired Shredda Pro is an absolute monster that we can’t wait to hit the trails with.
With a front and rear-specific design, the Shredda Pro is optimized for technical trails and loose conditions, primarily on eMTB. Working with the Radial casing construction, Shredda Pro is a tire that’s certainly not for the rolling speed-conscious, but for those looking to clean the most slippery and technical uphills and charge on gravity-fed downs.
The Shredda Pro Front tire features insane 10mm long shoulder knobs that overhang wide of the carcass for maximum traction at high lean angles. The center tread is still a gargantuan 8mm long, longer than even the Dirty Dan mud tire but with a wider profile to retain stability.
The Shredda Pro Rear tire is tailored to offer improved power transfer whilst still delivering high levels of bite in soft ground. The tread pattern sits tighter, and while the knobs are less tall than the front tire, there’s still plentiful overhang on the shoulder knobs and enough space to allow the knobs to penetrate soft ground.
The aggressive intentions of the new Schwalbe Shredda Pro Radial tires are highlighted by the limited options they are offered in. The front tire is offered exclusively in 29×2.5” with Ultra Soft rubber and Radial Gravity casing. The rear is offered in both 27.5×2.5” and 29×2.5”, with the same Radial Gravity casing and Ultra Soft rubber. This is not a tire for the faint hearted.
THE WOLF’S FIRST IMPRESSION
EXPERIENCING THE RADIAL CASING SCHWALBE ALBERT PRO
As part of the creation of this Dissected feature, I (Robert) was hosted in Finale Ligure, Italy, by Evolve Bike Shop on behalf of Schwalbe. We were able to get some purposeful trail time to compare the new Schwalbe Albert Radial tires with the Magic Mary Super Gravity head-to-head, and learn more about them from their team. Secondary testing was conducted by the North American team at Whistler Bike Park over 7 days of downhill laps aboard a GT Fury equipped with Albert Pro Radials in Ultra Soft as well.
Robert’s European testing consisted of two shuttle-assisted days on a Pivot Shuttle AM eMTB, which let me quickly get a feel for the new rubber and push it hard to see how it would perform. It’s safe to say that a couple of big days on the bike highlighted the impressive improvement in performance that the new Radial casing provided.
Day one was concentrated around one segment of trail – the final “San Pantaleo” section of the famous Rollercoaster trail. The trail was primarily hardpack, though greasy in a few spots and sketchy loose-over-hard towards the bottom. Some big compressions and potential for ambitious high lines highlighted traction and stability; and a couple of ragged rock gardens made this a perfect section to test durability and get a feeling for the tires.
Testing commenced with a few runs on this trail with Schwalbe’s Magic Mary Super Gravity in the Soft compound and 2.6” width on both ends. This is a familiar tire for us at The Loam Wolf, having spent plentiful time enjoying them on a variety of bikes over the last few years. We even selected them as the control tires for our recent eMTB Shootout, albeit in the 2.4” width. We’ve had little to complain about with these tires to date…though there’s always room for improvement, as we’ll get onto. They are solid all-rounders, though perhaps not our first choice for pushing hard on hardpack.
Worth noting is my recent trend towards slightly higher tire pressures than many might run. I’ve had a few moments this year where a slightly underinflated tire has led to a lack of control when pushing hard, so I’ve decided to go up a few psi on each end and accept the reduction in comfort and ultimate traction that results. For this test and my 100kg (220lbs) kitted mass, I was running 26 PSI (1.8 bar) in the front, and 29 PSI (2.0 bar) in the rear. Certainly, on the firm side for a 2.6” Super Gravity tire.
Once we were familiarized with the trail and had a good feeling for the traction available with the benchmark Magic Marys, our bikes were equipped with the new Schwalbe Albert Pro tires with Radial Gravity casing in the same Soft compound. At this point, we had no idea what was going on inside the tires, so could only speculate on the tread pattern based on what we could see. With these new tires inflated to the same pressures as the Magic Mary Super Gravity, we got on the bike to put them to the test.
Before the descending would commence, there was a short section of mildly technical climb trail to ascend. Instantly there was a feeling of increased comfort, with small roots and rocks on the climb being muted rather than deflecting like the Magic Mary had. Traction was not lacking on either tire on this climb, so I was unable to fully feel the benefits on the way up.
Dropping into the first descent, I was apprehensive that this comfortable feeling would translate to a reduction in support when pushing hard. The trail had countless hard compressions, which would quickly highlight a tire that was too flimsy. Much to my relief, they stood up fairly well. There were still a few instances where I had a slight “twisting” sensation, but overall, I felt more support and stability from the Albert Pro Radial Gravity than on the Magic Mary, whose knobs were folding in the hardpack and rocks from time to time.
As for the comfort on the way down? It was impressive. Really impressive. In the rougher sections of trail, the bike was more stable and planted on its line, and the bike generally felt calmer. This calmness effectively reduced the perception of roughness on the trail, leading me to feel comfortable opening up the brakes and sticking to rowdier lines. Traction also felt to receive a boost on all but the few powdery loose-over-hard sections. These sensations were undoubtedly aided by the hardpack-focused tread pattern, but I’d feel comfortable in saying that the extra contact with the ground produced by the more flexible casing was also helping. In the loose sections, traction was different in feeling, but not necessarily worse than the Magic Mary.
Rolling speed on the hardpack sections felt to take a slight hit, but the flip side was reduced feeling of “hang up” on the rougher sections, especially the square edges. So, on smoother climbs and descents, astute riders man notice reduced rolling speed and have to expend a bit more energy. But the flip side is that the increased compliance could afford improved climbing traction and reduce wasted energy on spin-outs. You would likely maintain speed better on rough sections of descent, too. Schwalbe reckons you can increase tire pressures a few psi and reduce rolling resistance without losing all benefits of the new casing. It’ll be interesting to put this theory to the test.
At the end of the first day, the Soft Compound Albert Radial Gravity tires were replaced by the same tires, but in Ultra Soft Compound on both ends. Since I was on an eBike – but not actually covering much ground in the saddle – I asked for Ultra Soft on both ends to see how ridiculous the traction could get. Much to my surprise, while traction improved a touch in a few select situations, it wasn’t nearly as profound an improvement as the initial switch to the Radial Gravity casing Albert had made.
Day two of testing was a backcountry epic, led by Ride On Noli, who guided me around some of the best trails in the area. With local bike shop owner Matteo “Bubba” Carubba of Hot Bikes leading the charge on his familiar local trails, it would be an excellent test to see how the Albert Radial Gravity Ultra Soft would fare in durability – both in terms of rubber wear and carcass strength. Over the course of eight long and blind descents, it was remarkable how composed the tires made me feel. There were countless sharp rock gardens; hard compressions and last-second hard braking efforts, and the new Schwalbe Albert Pro Radial Gravity tires didn’t skip a beat throughout.
My one criticism of the new Radial casing is the change in its feel over the bed-in period. You can actually hear as the tire casing threads flex and settle when first using the tire. As this continues to happen, the tire increases in suppleness, and by the end of a few hard runs it felt to be a few psi softer. I checked the pressure with a gauge when I first noticed this, and was surprised to find the same reading on the gauge as I had started with. This was felt on both the pair of Albert in Soft and on the pair with the Ultra Soft compound.
By the end of a big day riding, the casing felt to have fully bedded in and settled. On the trail, the reduction in carcass stability was notable, and I felt the need to increase tire pressure by 3 psi on both ends to retain enough support. Crucially though, the Radial Gravity casing continued to keep the rims safe from sharp rock edges, and fended off the abuse themselves.
Moving over to our initial DH test period, Drew and the crew started the week on a pair of Magic Mary Ultra Soft 2.4 tires before swapping to the new Gravity Albert Radial, also in Ultra Soft. Like Rob, we noticed the initial break-in period and quickly adapted. The conditions at Whistler Bike Park were dry, loose and slippery for the most part, which led us to find newer trails or dropping into the Creekside zone to find some better dirt.
No matter where we went however, the benefits were noticeable on just about every type of trail. The one exception was on big jump lines where the softer-feeling carcass did lead to some squirmy takeoffs. Increasing tire pressure for flow trail lovers would resolve much of that issue, but since we favor technical trails, the soft, supple and ground hugging feel was welcome on most laps.
Along with the increase in traction, allowing us to find high lines, change direction over roots and rocks, the reduction in feedback to the rider was also a highlight.
Stay tuned for us to log many more miles to get to the bottom of this bed-in process and see exactly where the new Schwalbe Radial carcass taps out. But for now, it’s safe to say we’re excited to see this technology become more widespread and to reap the rewards of that increased traction and comfort out on the trails. Over the years brands have been using the word “revolutionary” way too much when referencing minor updates to products. It seems that this could finally be a product that does revolutionize modern mountain bike tire construction moving forward, and that is something we should all be excited about.