Curve GXR Kevin of Steel review: We need to talk about Kevin

The Curve Kevin of Steel is a gravel bike that's here for a good time.

Don’t miss out on the latest CyclingTips updates.

If you’re looking for a bike that you can depend on, you could do a lot worse than Curve. The small Australian brand has evolved over the last decade from a carbon wheel importer to a fully-fledged bike brand with a cult following, most prominently as a standard-bearer for the bikepacking category.

Story Highlights

  • What: Curve’s steel do-anything gravel bike.
  • Key features: Tyre clearance up to 700×45 mm or 650×2.2″, Columbus Zona main triangle, custom chromoly yoke at bottom bracket.
  • Weight: ~10 kg as tested (size large, with pedals and cages); frameset weight from 2.2–2.4 kg; fork weight 535 g (both claimed).
  • Price: Completes from AU$4,499/US$3,477; frameset price AU$1,999/US$1,545.
  • Highs: Super fun, engaging ride (particularly with 650b), attentive design.
  • Lows: Firmer ride quality, tall standover.

When you’re crossing continents or racing ultra-endurance events, you need to be able to have faith in your gear. Investing in a Curve is to believe in the company ethos, and the promise of rigorous quality control from the company founders and sponsored riders (among them ultra-endurance racing legends, Jesse Carlsson, Sarah Hammond and Kristof Allegaert). 

Curve’s diverse line-up of bikes sprawls across the (all-)road, gravel and mountain bike categories, with a preference toward titanium as a frame material. Those framesets tend to blur some lines – drop bar bikes that are effectively rigid mountain bikes, road bikes that have clearance for 35 mm tyres, and mountain bikes that are built for rough-as-guts touring. 

The Melbourne-based brand has just one steel frameset in its current range, whimsically called the Kevin of Steel (also known as GXR). It’s based on the same geometry as the Titanium GXR and sits nicely in this line-up as a bike that can handle a bit of everything, while offering a more accessible entry-point to the Curve brand.

The Kevin of Steel is now in its third generation, first seeing the light of day as the sliding-dropout-equipped Grovel. The third generation was available up to last year in a lovely blue/yellow and khaki/yellow colourway, and is now available as a frameset (AU$1,999) or a complete build featuring SRAM Rival 1x and a 650b Curve Grav Al wheelset (AU$4,499), in either the brownish ‘Hero Green’ or ‘Handsome Blue’, as reviewed here. 

Image: Curve.

Tech talk

The Curve Kevin of Steel is designed to accommodate a broad spectrum of possible riding styles, and like many others in the gravel category, it’s built with scope for two different wheel sizes. Tyre clearance is officially pegged at up to 700 x 45 mm tyres or up to 650b x 2.2”, giving a fair amount of scope for fun on a wide range of terrain. 

The frameset, built to Curve’s design and specifications in a quality Asian factory, features a double-butted Columbus Zona main triangle with 4130 chromoly stays.

They marry to a 4130 chromoly yoke at the bottom bracket that ekes out more tyre clearance while also enhancing stiffness, and a full carbon fork featuring a 1 ⅛” – 1 ½” tapered steerer. Frame weight is claimed to be between 2.2–2.4 kg, with a 535 g fork. This (non-stock) build, with SRAM Force 1x and Curve’s Carbon Dirt Hoop wheelset, came in just below 10 kg. 

This custom yoke allows Curve to increase bottom bracket stiffness, while simultaneously giving a bump in tyre clearance. There’s chainring clearance up to a compact double crankset (50/34T) or a 44T single chainring.

Elsewhere, things are built with an eye on practicality. The frame accepts a round 27.2 mm seatpost, clamped externally. All cabling and hoses are routed externally, other than a brief internal detour through the fork leg on the way to the front brake, with tidy fittings on the underside of the down tube to keep things neat. The Kevin of Steel is mechanical (or wireless) capable; if you want Di2 or EPS, you’ll have to splash out for the GXR Titanium.

Otherwise, there’s a T47 threaded bottom bracket, and the frame is quite generously appointed for carrying stuff, accepting fenders, a rear and/or front rack (with some fettling), and three bottle cages. The fork has mounts for more bottle cages or extra cargo, and is rated up to 3 kg per side. 

The finish of the frame is both understated and classy, with minimal branding and a cleanness to the glossy paint. The hooded rear dropouts are particularly lovely, and the ‘handsome blue’ is, indeed, handsome. 

Special mention also to the head badge, which is an endearing depiction of a Sulphur-crested cockatoo (a type of Australian parrot). This doesn’t just look fantastic; it’s also a perfect visual representation of the cheeky, friendly identity of the Curve brand as a whole.

Lovely.

Geometry

In the Kevin of Steel, Curve is seeking to produce something that appeals to a broad array of customers, rather than a hyper-specific vision of a particular use-case. It’s a bike that needs to handle everything from the commute to cross-continental vision quests.

The bikepacking chops informing Curve are fairly prominent, with all those mounting points plus a generously proportioned front triangle that offers plenty of real estate for frame bags. The top tube is high – almost level –  thanks to a long seat tube, with a standover height on this large size of 838 mm. Of the crop of bikes we tested at the Bright Field Test, that’s (un)comfortably the tallest – a centimetre higher than the Giant TCX Advanced and the Fuji Jari Carbon, two centimetres taller than the Ritchey Outback and seven centimetres taller than the Giant Revolt Advanced. Something to be mindful of in more technical terrain.

There are six frame sizes available, catering well for riders up to either extreme of the sizing spectrum with a fairly linear progression between sizes in frame reach and stack. On the large we tested, there’s a fairly long effective top tube of 575 mm, a 73º seat tube angle (consistent across all sizes), a 72º head tube angle (which gets progressively steeper through the sizing range) and a 432 mm chainstay length. The bottom bracket drop is a road-like 68mm, and the wheelbase is somewhat on the longer side at 1,042 mm (although not as long as the super-stable Ritchey Outback, at 1,069.6 mm in the equivalent size). 

Curve Kevin of Steel geometry.

The review sample that we got our hands on for review was slightly different to the stock build, owing to the fact that it belongs to Curve co-founder Steve Varga. As pictured, it is running a non-standard fork with a flip-chip, a slightly taller axle-to-crown height and a slightly different offset. The build kit, likewise, has some differences to the standard SRAM Rival build. (Note: both the frameset and complete bikes are low in availability at present, so contact Curve for stock).

On returning to Melbourne, I borrowed the bike for a second stint, testing it with the production fork and a 650b wheelset as opposed to the 700c one in Bright. In sum, I feel I was able to get a pretty good insight into the Kevin’s ride characteristics across two forks, four different wheelsets, and three different sets of tyres, on both my local gravel loops and on the fireroads and trails of alpine Victoria. 

Plenty of clearance around these 700×40 mm tyres.
Things are a little tighter with 650b x 2.2″, but there’s room.

The ride

Across the spectrum of the bikes we rode at Bright there are some obvious similarities, but plenty more differences. The Curve and the Ritchey Outback sit at similar price points and share a frame material, but the Kevin’s geometry chart probably has more in common with the Fuji Jari or Giant TCX than the Outback or the Giant Revolt. And then, it has a different personality than all of the aforementioned. 

If I was to boil the Kevin’s ride quality down to one word, it would be ‘solid’. It feels utterly unflappable, with a stomp-and-go stiffness to the bottom bracket that is a good match with the stoutness of the front end. The ride quality isn’t tremendously plush, although it’s noticeably more comfortable on fatter tyres (I tested it up to 27.5” x 2.2”, which was my favourite configuration).

The tall seat tube – which is 580 mm centre-to-top in the large size – means there’s minimal flex possible through seatpost extension, and although the review bike was supplied with an aluminium seatpost, there wasn’t all that much more comfort gained even once I fitted a comfy-riding carbon post. The Kevin is never harsh, per se, but it leans much more that way compared to, say, the smoothness of the Ritchey Outback.  

The riding position – in part due to the slammed and short 70 mm stem fitted – was both lower and shorter than my personal preference, leading to a somewhat cramped feeling. On the stock version, there are short stems throughout the size run – the large, for instance, normally comes with an 80 mm stem – and Curve says the geometry is designed with a shorter stem in mind.

While any buyer would sidestep the cut-steerer issue, it’s still a more compact frame than you’d expect based on the geometry chart – particularly given the short stem – while simultaneously feeling quite tall due to the bottom bracket height and the top tube height.

The experience of riding the Kevin is a rebuttal of the perceptions many people have of steel as a frame material. It’s more responsive, nimble, and playful than it perhaps looks, with a pretty quick trail of 60 mm (650b x 2.2”) or 62 mm (700c x 40 mm) keeping things agile.

The Kevin especially loves being ridden aggressively and out of the saddle, and with a mountain bike tyre you feel capable of just about anything. It’s an efficient climber, a blast to descend on, and hums along nicely on the flat. In short: it’s a hoot.

I liked it slightly less with the 700 x 40 mm wheelsize, which consistently felt a little more nervous and slightly tippier than when I had it set up in ‘party mode’ with 650b wheels. Part of that likely comes down to the way that I was riding it – if you’ve been running a tacky XC MTB tyre and switch to a skinnier gravel tyre, you’re going to feel less inspired to commit to the most aggressive lines.

The handlebar specced on this bike – Curve’s infamous Walmer bar, in its narrowest (!) 46 cm width, with a 29˚ flare to 61 cm at the drops – has a disproportionate impact on rider perception of the Kevin, too. 

There’s a learning curve to the weight distribution, which puts your hands out wider than you’re likely to have ever experienced on a drop bar bike. While that works in tandem with the shorter stem to balance out the reach, it also means that the handling pivots around a different point and contributes to a more top-heavy transition into corners, particularly when riding in the drops. And because it’s got quite a low trail, you’re steering more from the front regardless.

Super flared handlebars are a bit of an acquired taste at the best of times (and as you’ll note from the video above and the rest of the Field Test content, it’s not my personal preference), so I’m perfectly happy to accept that these may be your dream setup – and they undoubtedly offer a stack of extra real estate for bar bags.

The Walmers come specced as standard on the Curve Kevin complete builds, in the 46 cm for up to medium frame sizes, and 50 cm (65 cm at the drops) in large and XL. If you don’t get along with them, they’re at least fairly easy and cheap to swap out to something more conventional. 

Otherwise, the build of this particular bike – featuring SRAM’s reliable, tactile Force 1x groupset, alongside Curve’s carbon fibre Dirt Hoops wheelsets in 650b and 700c – offered trouble-free performance that was a beautiful match to the scrappy, rough-and-tumble energy of the Kevin. The stock build, with Rival 1x and an alloy Curve wheelset, should be a pretty close match to my experiences here.

Note that the stock build doesn’t come with the fork with a flipchip, the Chris King headset or the dynamo front hub.

Summing up

Riding the Kevin of Steel was a fascinating and enjoyable experience. It’s a bike that manages to combine practicality with a sense of play, and it’s a genuinely fun bike to ride. It’s also dramatically different to the other steel gravel bike we tested up in Bright, the Ritchey Outback.

They’re both great – and my stand-outs from the crop I tested – but in entirely different ways. The Kevin’s a party-starter that wants to crank the stereo to 11, and the Ritchey likes watching dappled sunlight on a burbling creek while pondering the enormity of everything.

While the Kevin is a hugely enjoyable bike to ride and look at and just generally be in the company of, it’s worth approaching its purchase with a detailed eye on the geometry to see whether you’ll be comfortable with its height and the reach to the handlebar, which are both leaning toward being outliers for this size range.

And if you like a playful, firmer ride quality and the position will work for you? 

Well, perhaps you’d better get to know Kevin – he’s a heap of fun, and I reckon you’d be mates.

For more details, see curvecycling.com.au

Photo gallery

Editors' Picks