The Rise Of Full Suspension
It’s the age-old question; “Should I get a hardtail or a dually?”
Having worked in many bike shops over the years, this is without doubt one of the most common questions I’ve heard from mountain bikers who are in the market for a new XC bike. And it’s likely a question that you’ve also asked yourself at one point or another.
Ever since full suspension bikes first hit the mass market over two decades ago, they’ve been steadily increasing in popularity. While first appearing as a fringe product, these days they far outweigh their front-suspended counterparts on the trail. It’s been a long road though, as early full suspension bikes were, in all honesty, pretty crap. Terrible reliability, poor pedal efficiency and excess weight were enough to put people off the concept for life. But unlike Donald Trump’s haircut, a lot has changed since the early 90’s.
Modern full suspension bikes are fast, smooth, and efficient. They’re also highly adjustable, while the use of clever dampers and electronic trickery has significantly lifted the performance bar. Most riders are aware that suspension on a mountain bike is a good thing, and as the weight has come down and reliability has improved, many of those traditional barriers to owning a full suspension bike have largely been removed.
Of course much of the commercial success of full suspension bikes can be attributed to success on the racetrack. Because when it comes down to it, there is no better proving ground than the highest levels of competition. And with riders such as Julien Absalon, Catherine Pendrel and Jaroslav Kulhavy notching up World Cup and World Championship victories aboard fully suspended race rigs, the proof is well and truly in the pudding. Or dirt as it were.
But as lightweight and efficient as full suspension bikes have become in recent years, you wouldn’t exactly need a detective to work out that hardtails are still a common sight on the start line of a World Cup race. Sure, most teams will turn up to each round with both a hardtail and a full suspension option for their racers to choose depending on the terrain. But for the large part, most of the Elite field are still sticking to rigid frames.
So if full suspension is so good, then why do these racers still consider hardtails as a viable option?
The Weight Debate
Weight – that’s why.
Well, there are a few more reasons than that, but weight is a huge factor. And especially when the UCI doesn’t impose a legal minimum weight limit on mountain bikes like they do for road bikes.
While high-tech carbon fibre and advanced construction techniques are constantly reducing the amount of bike you have to lug around on the climbs, a full suspension bike is always going to be heavier than a hardtail. And that’s a fact that no one can get away from. Typically a rear shock weighs 220 grams on it’s own. Factor in pivot hardware, cartridge bearings and some kind of suspension linkage, and you can easily add 800-1000 grams over a hardtail.
A prime example would be Scott’s flyweight Scale 900 hardtail frame, which weighs just 946 grams. Compare that to the Spark 900 (the full suspension equivalent to the Scale) that comes in at a claimed 1850 grams. That’s a difference just shy of a kilo, or roughly 10% of the total bike weight.
Whether you race or not, most mountain bikers will understand how significant it is adding 10% to the weight of your bike. And given that most World Cup XC racers resort to using weight-saving tricks like foam grips and Titanium bolts to shave every gram possible off their race rigs, you can understand why the decision to ride a hardtail or a full suspension bike is one that isn’t taken lightly (pun intended!).
The Contemporary Hardtail
But it isn’t just weight why some of the world’s fastest riders still opt for hardtails.
Anyone who’s spent time on a modern hardtail will understand the handling advantages, as there’s a certain ‘directness’ that comes from having a rigid back end that no dual suspension bike can ever replicate. Shorter chainstays aid in steering around tight switchback corners, and with the rear wheel sitting in a fixed position behind the bottom bracket, a hardtail offers unrivalled feedback to the riders contact points.
This has only been improved by newly established standards such as press-fit bottom brackets, tapered head tubes, and direct mount front derailleurs, which offer frame designers greater flexibility to utilise oversized downtubes and massive chainstay profiles. Thru-axles also improve the front and rear wheels ability to track in a straight line, giving the pilot laser-like accuracy when picking a line on the trail.
Progressive geometry numbers are only enhancing the handling abilities of the modern race hardtail, and that’s particularly the case with 29ers. In fact, I’d go so far to say that we’re witnessing a revolution amongst the XC crowd, which has traditionally been dominated by 560mm wide flat bars and 72-degree head angles.
For the 2016 model year though, we’re seeing more manufacturers moving away from this old-school mentality. Instead, inspiration is being drawn from longer travel trail bikes, with hardtails shifting towards longer top tube lengths, slacker head tube angles, lower bottom brackets and shorter chainstay lengths. Cockpits are evolving too, with bars getting wider and stems getting shorter to mate with these new frames. And so compared to their twitchy ancestors, this new breed of race hardtails are delivering more control and confidence on increasingly difficult World Cup XC race courses.
Big Wheel Efficiency
Of course the 29” wheel has played a massive role in the resurgence of the race hardtail. Before the big wheelers arrived, lightweight 26” full suspension race bikes looked set to take over as the primary choice for the World Cup athlete. Thanks to the added stability and momentum-carrying abilities that 29ers brought to the table however, racers were suddenly presented with a valid option that would still allow them to enjoy the lightweight and snappy handling qualities of a hardtail, while getting more comfort, more traction, and more control. In some respects, the 29” hardtail offered a neat middle ground between a 26” hardtail and a 26” full suspension bike. As such, the vast majority of both the male and female elite fields have moved to the big wheels for their race rigs, allowing them to stick with the lighter hardtail option for more of the time.
But frame weight and handling advantages aside, the last – and arguably most important – reason why the hardtail is still alive and kicking on the World Cup race circuit, is pedal efficiency.
Racing is a numbers game, and the primary number that team coaches are interested in is their athlete’s power-to-weight ratio. The lighter the bike and the more power the rider can dish out, the faster they can therefore travel. And so with no pivots or rear shock to absorb any pedalling forces, a hardtail presents the most economical method for delivering Wattage from the pedals into the rear tyre.
The big variable there is of course terrain and the riding surface. Power delivery is useless if the rear wheel spends most of its time bouncing around in the air, so a hardtail isn’t always going to be the most effective tool for propelling the rider forward on overly rough race courses. But for those lung-busting climbs and long flat stretches, most of the pros will tell you that nothing beats the unrivalled efficiency of a hardtail.
But What About Compliance?
Although hardtails will always be lighter than their fully suspended counterparts, there is still one area that they will never win, and that’s comfort. Typically a rider has to concede a compromise in comfort when choosing a hardtail for its lighter weight and pedalling efficiency. And you can’t have it all.
That hasn’t stopped bike manufacturers from addressing this compromise by engineering specific solutions to deliver more compliance to their hardtails. Because if they can provide more comfort for the rider, then that rider can remain in the seated pedalling position for longer. That means they can put more power through the pedals, while experiencing less fatigue as the clock ticks on. After all, it’s no good having the lightest bike on the course if it beats you up every time you hit a rock or a tree root.
Over the years, many different methods have been employed to varying levels of success and failure. In recent months however, there have been several new flagship race bikes that have hit the World Cup circuit, all of which offer a new take on the hardtail’s ability to offer rider comfort. Here we take a look at 3 of the most exciting examples that are keeping the hardtail (or is it soft-tail?) dream alive.
Back in April of this year, Swiss company BMC unveiled the brand new Teamelite, which they’re calling “the world’s most technically advanced hardtail”. Except it isn’t really a hardtail.
Having been in the lineup for a good few years now, the Teamelite has been the weapon of choice for the likes of Julian Absalon, who has piloted this high-tech carbon race hardtail to many a victory all around the world. The 2016 Teamelite represents a radical departure from the existing model however, with a design that harks back to those glorious days of the soft-tail.
Employing a design called MTT (Micro Travel Technology), BMC’s engineers sought to increase the amount of compliance of the Teamelite hardtail frame by placing a small elastomer between the seat tube and the top of the seatstays. The concept was cooked up by BMC’s Impec lab, who worked with the World Cup XC team to prototype and test various solutions out on the race course. Their sponsored riders had asked if the existing hardtail could be built with more comfort to stave off fatigue. The end result was the MTT system that delivers 15mm of compliance. Note that BMC don’t refer to this movement as ‘travel’, which firmly keeps the Teamelite in the hardtail category.
The differences between the 2016 Teamelite and those early soft-tail designs are many. Instead of spindly tubes of aluminium or steel, the Teamelite features a carefully engineered carbon layup that concentrates maximum stiffness around the bottom bracket area for superb power delivery. Combined with that enormous downtube that forms the Teamelites spine, the frame has been designed to maintain the crisp handling and responsive acceleration of the outgoing model, but with more comfort.
The elastomer may seem like a lowbrow solution, but its simplicity is its real beauty. It’s much lighter than a rear shock, and there’s next to no moving parts to maintain. Hidden inside the black elastomer, you’ll find two hard-anodized studs that extend from the seatstays and pass through a pair of DU bushings, much like you would find on each end of a rear shock. These struts help to guide the seat stays through the 15mm of movement, while maintaining necessary lateral rigidity so that the frame doesn’t end up squirming under power.
Aside from the added comfort, the MTT design also offers more traction than a rigid hardtail. Although it’s only 15mm, the compliance through the seat stays allows the rear tyre to dig into the terrain just that a little more, with less of a tendency to bounce off from trail impacts. This characteristic can also be fine tined. The rider can choose from 3 different durometers for the elastomer (soft, medium or firm) depending on their weight or ride preference.
The MTT design does add a little weight to the frame, but with layup improvements elsewhere, the new frame stays about the same as the previous model, with BMC claiming a Medium sized Teamelite tips the scales at 1080 grams.
Not long after the Teamelite had been unveiled, it was already being proven on the racecourse, with Julien Absalon notching up a historic 30th World Cup victory aboard the new Teamelite in Albstadt, Germany. Absalon spoke of the new frame as being significantly more comfortable than his previous race hardtail. This allows him to choose the lighter Teamelite over his heavier Fourstroke full suspension bike more of the time.
Focus Raven Max
First seen during the Nove Mesto round of the World Cup, the Raven Max was spotted in the race pits with some suspicious chequered tape wrapped around various parts of its frame, including the seat tube junction. In much the same way that car manufacturers use patterned tape to conceal the shape of new prototype vehicles, Focus weren’t quite ready to show off the final details of their new flagship XC race hardtail.
When the wraps were pulled off the new bike a few weeks later, it turned out that there was no funky linkage or elastomer damper as some people had speculated. Instead, it was revealed that Focus’ engineers had conducted a serious rework of the tubing architecture. In a method somewhat reminiscent of GT’s Triple Triangle, the new Raven Max sends the seat stays past the seat tube, where they transition smoothly into the top tube. Unlike the Triple Triangle design however, the seat stays bypass the seat tube completely.
In speaking with Focus’ engineers, it was revealed that early design iterations had considered a soft-tail design, but those plans were ditched in favour of simplicity and lighter weight. Instead, the engineers employed a specific carbon layup and clever tube shaping to allow the seat post to rock back and fourth, reducing the amount of feedback being transmitted up from the rear wheel.
Utilising the magic of carbon fibre to deliver comfort is nothing new. Many other companies employ super-thin seat stay tubes to encourage flex and vibration dissipation on their high-end carbon road bikes and race hardtails. You’ll also find many frames that see the seat stays worked into shapely S-bend tubes that help add some spring to the back end of the bike. The difference between these designs and the Raven Max however, is that Focus have aimed to deliver the compliance through the seat tube, and not so much through the seat stays.
If you look closely at the seat tube of the frame, you’ll notice that this round tube morphs into a thin oval shape towards the bottom bracket shell, which encourages the entire seat tube to flex like a leaf spring. Further helping to isolate trail buzz from the riders perch, Focus have developed a new seatpost called the CPX Plus. The seatpost features a cut-out just underneath the saddle rail clamp, adding some vertical ‘give’ between the saddle and the frame.
Combined with the new seat tube junction, the new Raven Max is considerably more comfortable to ride compared to the outgoing model. It’s also a lot lighter, shaving over 30% of the weight over the current Raven Max, with a claimed weight of just 885 grams. That makes it the lightest of the bunch in this article, but then again it is also the simplest.
I had the pleasure of test riding a Raven Max during its release in North America, and I can attest to the buzz-erasing compliance that Focus have been able to build into the new frame. It’s still a responsive race hardtail, but it has a far greater ability at muting the high-frequency trail buzz that you’d normally experience when scrubbing along at race pace. I was also impressed with the new geometry numbers that Focus elected for the Raven Max, with a longer front centre offering more stability, and a shorter rear centre assisting with carving tight corners. Focus have built each frame size around a 90mm stem and 720mm wide handlebars, which work beautifully to balance the Raven Max’s steering dynamic. It’s handling is quick, but not so snappy to have you on edge during descents. As such, it’s a fantastic example of the capability and comfort of the modern 29er race hardtail.
The most recent addition to the latest crop of soft-tails is the brand new Procaliber from Trek. Spied on the race circuit for a number of months prior to the bikes release date, the new Procaliber has emerged with a very clever trick up its sleeve.
Most Trek enthusiasts had already guessed that the time was right for Trek to implement their patented IsoSpeed technology for the mountain bike world, given that its arguably the most useful application. IsoSpeed originally debuted on the Domane endurance road bike, where it won media accolades for its bump-soothing ride qualities. More recently the technology was applied to the Boone cyclocross race bike, so it was only a matter of time before Trek would employ IsoSpeed for its flagship XC race weapon.
IsoSpeed works differently to the BMC and Focus. There is one pivot, but no shock. Instead, the pivot forms the only connection between the top tube and the seat tube, essentially decoupling the seat post from the rest of the frame. The concept is closer in purpose to the Focus, as the pivot allows the seat post to flex back and fourth. Like the Focus, the Procaliber frame features a shapely seat tube that flattens out towards the bottom bracket shell to provide more flex throughout the entire length of the tube. The result is 11mm of compliance at the saddle, though heavier riders may experience a little more. Again, this movement is not regarded as suspension travel, which is how the design differs from the BMC Teamelite. Instead, Trek have kept the back end of the Procaliber rigid to maintain power delivery and lateral rigidity.
IsoSpeed isn’t the only unique feature of the new Procaliber, as it’s also the first race hardtail to feature Boost hub spacing front and rear. This sees a 148mm wide hub used out back, and a 110mm wide hub up front. The wider hubs allow for greater chassis rigidity, but they also widen the spoke bracing angle, making for stiffer and more responsive wheels. Because of the offset drivetrain that comes with the Boost design (the chainring is pushed out 3mm from the frame), Trek has been able to shorten the chainstays on the Procaliber to just 435mm. As with Trek’s other 29ers, the Procaliber receives the 51mm G2 fork offset to speed up the steering and reduce ‘wheel flop’ on the climbs. Combined with the Boost hubs and short chainstays, this should add up to a very quick and direct handling race bike, which is exactly why would you choose a hardtail over a full suspension equivalent.
Going back to the IsoSpeed design, Trek claim that the new Procaliber offers 70% more compliance than competing hardtails, though I’m guessing that doesn’t include the new BMC. Interestingly though, Trek have conceded that the outgoing Superfly SL frame is already regarded as one of the most compliant 29er hardtails on the market, and so the Procaliber only gets you 30% more compliance over the Superfly SL. The Procaliber is also 100 grams heavier at a claimed weight of 1012 grams for the frame. That said, Dan McConnell and Bec Henderson have already given the tick of approval to the new Procaliber, citing the added comfort as being well worth the extra grams.
More Soft-Trails To Come?
Given the recent releases from BMC, Focus and Trek, I’d bet my XTR rear derailleur that other companies will be bringing out their own take on the modern soft-tail design in the coming year. While they’re not necessarily suited for every course, the advantages of racing a hardtail over a full suspension bike are clear. And if companies can offer more comfort and compliance from those lightweight hardtails, then that age-old question of “hardtail or dually?” should get a little easier to answer.