Unusual gravel bikes: Suspension gravel bikes – key information & an overview of 6 models
Timo Dillenberger
· 19.05.2024
When you’re out in the woods on your gravel bike, leaving one mountain biker after another in your wake, it’s not least because you’ve stripped the gravel bike of everything unnecessary for such moderate terrain. It’s a machine designed for riding, where the rider’s arms and legs take on the shock-absorbing work, at least when it comes to rougher bumps. The only other thing that takes care of the rest, if anything, is the chunky tyres.
However, depending on the terrain, the time spent in the saddle or the rider’s comfort requirements, this is not always sufficient. Every now and then, models appear here and there that do, in fact, feature ‘genuine’ suspension elements. These primarily include suspension forks, but also shock absorbers between the fork and frame, as well as elastomer pads integrated into the rear triangle. Strictly speaking, even the seatpost on the Rose Backroad – which is deliberately designed to flex significantly – is a form of suspension, just like the ‘floating’ frame junction on the rear triangle of the carbon version of the Trek Checkpoint.
Suspension gravel bikes: a concept rather than a conversion
Anyone who’d like to add a bit more comfort to their gravel bike will need to be resourceful. It’s not easy to do this as a retrofit. A suspension seatpost would be the simplest solution, provided the original seatpost is round. This modification works particularly well on models with a flat seat tube angle of less than 73.5 degrees, but the extra weight at this centre of gravity is definitely noticeable as a drawback. Fitting a suspension fork, on the other hand, changes the bike’s entire geometry.
A gravel bike with a suspension fork that was tested last year proved to be extremely twitchy and very poorly balanced; the frame had clearly not been designed for that purpose. In addition to increasing tyre clearance, the suspension struts actually raise the front section of the frame. To ensure the bike remains rideable, the geometry must be adapted to accommodate a suspension fork from the outset.
For extra cushioning on the handlebars, there’s, for example, the Kinekt suspension stem, which absorbs moderate impacts but, unfortunately, also dampens abrupt steering inputs and hard accelerations. For a bit more comfort in your hands, Ergon offers gel pads, amongst other things, which, when wrapped under the handlebar tape, help to absorb shocks slightly; budget-conscious riders can simply wrap the tape twice instead of using extra-padded handlebar tape.
Manufacturers such as Giant, Canyon, Trek, Specialised, BMC and YT have redesigned their suspension gravel bikes from the ground up to address this retrofitting issue. The solutions they’ve come up with to enhance comfort range from innovative to ingenious. That said, we’re already familiar with the lockable flat shock absorber between the fork crown and the head tube from the 1990s, when it proved its worth on road racing bikes during races over brutally rough cobbled roads in France. It suits a gravel bike just as well, if not better.
Suspension gravel bikes: Is it all just a compromise?
Suspension is, by its very nature, a compromise. Standard components deliberately designed to be slightly more flexible – such as flexible or split seatposts, extra-thin rear stays or softer handlebar bends – have little negative impact on the bike’s handling, but do help to absorb bumps in the road, albeit only slightly. Giant, Koga and Canyon scored well in our test in this respect. The same applies to frames with good comfort ratings.
If genuine suspension components such as air bellows or coil springs are fitted, this results in greater suspension travel and better absorption of bumps; however, the weight increases, additional components are more prone to failure, and the handling changes. There does not (yet) appear to be a gravel bike with a full-suspension frame. According to Giant, full-suspension bikes are no longer available in the lightweight segment because, across all brands, the moving mechanism did not offer the desired level of reliability.
Are such prominent suspension components necessary on a gravel bike? Yes and no! Depending on the intended use, either comfort or the bike’s dynamic performance takes precedence. You’re unlikely to find suspension forks on the vast majority of models, though most will never see rough terrain anyway. On tours with unpredictable terrain, however, they are a viable option, just as they are on commuter bikes. Discreet ‘add-ons’ like those on the BMC or Cinelli could become more widespread; they neither alter the bike’s sporty silhouette nor do you really notice them when handling the bike. Note: Being jolted about is just as tiring as pedalling.
Innovation Award
In terms of design, the Specialized Diverge STR stands out. The shock absorber beneath the head tube works in the same way as the one mentioned from the 90s. The one acting on the seat post is completely new. The damper is positioned horizontally and is fitted within the top tube. Its head is connected to the extra-long seatpost, which is mounted on a movable bearing near the bottom bracket. The damper can move up to two centimetres in the direction of travel and against it.
The saddle therefore moves downwards and backwards along a circular path, whilst its distance from the pedals remains constant at all times, so you don’t lose any pedalling energy. The idea behind this design is that even when riding over obstacles, they do not suddenly strike the rear wheel from below. After all, both wheels ‘bounce’ horizontally against a bump, kerb or tree root. The bidirectional damping absorbs the impact in both directions. As research currently underway at the German Sport University Cologne shows, this not only delays rider fatigue but also allows obstacles to be negotiated more dynamically.
Information, reviews & tips: Overview – Gravel Special 2024
>> Unusual gravel bikes: With suspension and shock absorbers – an overview of 6 suspension gravel bikes (now open)
Top picks: 6 suspension gravel bikes
BMC Urs LT Two
The Urs is the Swiss adventure bike. It is further divided into the lighter Performance version and the LT version, which is better suited to long-distance riding. Depending on the price range, one to all three components of the brand’s own Micro Travel technology are integrated. At the heart of the system is the elastomer buffer, which sits between the seat stays and the main frame and largely isolates the saddle from vibrations. Between the frame and the fork sits a stiff coil spring with a hydraulic damper and 20 mm of travel, which, together with the slightly springy stem, ensures a comfortable ride.
- Price: 6,499 euros
- Weight: 9.1 kilograms
- Stack/Reach: 1,371
- Drive: SRAM GX Eagle AXS 1x12
- Brakes: SRAM Rival eTap AXS HRD
- Variants: 7 completely different bikes ranging from 3,499 to 10,999 euros, fitted with SRAM Apex AXS components
Trek Checkpoint SL 5
Whilst we criticised the ride comfort of the ALR model in our test, its carbon-framed sister models – rather than the aluminium ones – already feature the relatively new IsoSpeed module in the frame. It works in much the same way as the shock on the Diverge STR: the seat tube is decoupled at the frame junction, so it can flex along its entire length from the bottom bracket to the saddle, whilst a mechanism inside limits this to just a few millimetres. As you sit in a slightly more upright position on the SL and SLR models, the improved saddle comfort is all the more significant here.
- Price: 3,999 euros
- Weight: 9.6 kilograms
- Stack/Reach: 1,455
- Drive: Shimano GRX 810 2x11
- Brakes: Shimano RX400
- Variants: A total of 12 carbon models in 6 sizes, available in up to 5 colours, with Shimano GRX or SRAM AXS, prices: 3,699 to 10,499 euros (with power metre)
YT Scepter Core 4
This exotic model among exotics clearly has mountain bike DNA. The STR reach value is derived more from the top tube than from the short MTB stem. The Rudy Ultimate suspension fork is the same as the one on the Giant below, except that it’s set at a steeper angle of 69 degrees, which is intended to provide greater stability on rough terrain. Its 40 mm of travel feels very vertical as a result; the air springs should be set a little softer here. The rear triangle of the carbon frame is designed for lateral stiffness with slight vertical flex. The extended wheel guard is more of a design feature than a mudguard.
- Price: 3,999 euros
- Weight: N/A
- Stack/Reach: 1.475
- Drive: SRAM Force XPLR eTap 1x12
- Brakes: SRAM Force eTAP AXS
- Variants: 2 models with SRAM Force or Rival groupsets, each available in one colour and 5 sizes.
Specialized Diverge STR Expert
Specialized calls the combination of the shock in the top tube and the suspension system – which allows the stem to slide 20 mm along the steerer tube – ‘Future-Shock 2.0’. Videos show that the components do not jam against each other and compress smoothly. If not required, the shock can be locked out completely – the same applies to the rear shock. ‘Absorbing the rider’s movements rather than the frame’ is the design philosophy behind this system, which naturally comes at a price. A highly ergonomic handlebar, optional 26-inch tyres or the storage compartment in the down tube make up for this.
- Price: 7,000 euros
- Weight: 9.86
- Stack/Reach: 1,548
- Drive: SRAM GX Eagle AXS 1x12
- Brakes: SRAM Rival eTAP AXS
- Variants: 4 configurations in 2 colours and 6 sizes, with Shimano GRX or SRAM eTap components, priced from 5,500 to 14,000 euros.
Cinelli Nemo Gravel
Cinelli’s steel frames are manufactured in Italy from high-quality, triple-butted Columbus tubes and are true works of craftsmanship. Very specialised chainstays and – according to the manufacturer – the stiffest fork blades allow for tyres up to 47 mm wide. The offset of the rear stays and top tube is also designed to provide a little extra comfort at the rear. The geometry is geared towards long-distance riding; whilst the frame isn’t extremely short, the spec sheet indicates that the riding position is fairly upright. The shock absorber beneath the head tube, with 20 mm of travel, is designed more for adventurous trails than hard downhills.
- Price: 5,200 euros
- Weight: N/A
- Stack/Reach: 1,519
- Drive: Shimano GRX 820 2x12
- Brakes: Shimano GRX RX-820
- Variants: 6 sizes from 48 to 61 cm, 69 colours, SRAM Rival, Shimano GRX, Campa Ekar or as a frameset, prices from 5,100 to 5,700 euros
Giant Revolt X Advanced Pro
The brand-new Revolt with suspension fork looks very similar to its sister model in our test. The standard, comfortable D-Fuse rear end – with its thin, more flexible struts – is complemented here by the comfort provided by the 40 mm travel of the RockShox Rudy Ultimate fork. It isn’t the same frame as the Revolt; despite the long fork legs, the STR value indicates a slightly more stretched geometry, so you sit in a more sporty position. Top marks: even in the most affordable version, a suspension seatpost that can be lowered is included as standard.
- Price: 5,999 euros
- Weight: 10.2 kg
- Stack/Reach: 1.48
- Drive: SRAM GX Eagle 1x12
- Brakes: SRAM Rival eTap
- Variants: 5 models, each available in 5 frame sizes, priced from 2,999 to 7,499 euros, with SRAM Apex or eTap
Suspension gravel bikes in detail
A gravel bike?
The shock absorber fitted to the top tube of the Specialized bike has a total of 30 mm of travel and acts on the inner seat tube. It is mounted just above the bottom bracket and moves lengthways within the outer frame tube. Thanks to the low pivot point, the adjustable shock stiffness and the horizontal alignment, there should be neither bobbing whilst pedalling nor bouncing over bumps.
Reissued?
Ever seen one? Cannondale actually tried fitting a shock between the fork crown and the head tube on road bikes back in the 90s, just like on the Cinelli Nemo. They’re much more likely to catch on with gravel bikes. The hydraulic damper on the specially developed, extra-stiff HiRide Sterra fork compresses by up to 20 mm and is maintenance-free. Any more travel would introduce too much movement into the system.
A break in style?
So far, classic suspension forks with hydraulic or pneumatic dampers have only been seen on three or four models. On the one hand, such ‘obvious aids’ are still frowned upon by cycling enthusiasts; on the other, they require frames with the appropriate geometry and particularly lightweight forks with just 20 to 40 mm of travel, such as the RockShox Rudy Ultimate air fork fitted to the YT Szepter.
Rigid or flexible?
The BMC Urs features one of the lightest suspension systems available. Whilst incorporating elastic materials into the frame is nothing new, completely decoupling the rear triangle and seat tube – and doing so only in those areas – is a new development. The chainstays are not mounted on pivots, but thanks to the elastomer they can flex much more freely than with rigid triangle designs. Guide rods running through the shock prevent lateral misalignment.
Lured out?
On sport bikes, so-called ‘lock-out’ functions make even more sense than on off-road bikes. With a single hand movement, the suspension is locked out to prevent unnecessary bobbing on flat surfaces. On the Specialized Diverge, for example, the hydraulic shock absorber beneath the stem – known as ‘Future Shock 2.0’ – is activated by a slight twist towards the taller stem cap.