Chimera Frameworks Zenith RD bike review: Aussie brazed steel

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Made in the Hunter Valley, a key wine region a couple hours north of Sydney, Chimera Frameworks is a new name to the handmade bike scene. It’s a brand that specialises in Australian-made, high-end, semi-custom steel frames with stock geometry.

Chimera’s frame builder, Rob Benson, is a lifelong bike nut, collector (he owns over 100 bikes) and mechanic who learned the craft of frame building from legendary builder Paul Brodie. I first met Benson back in 2015 at the Fyxo Melburn Custom Bicycle show. Then, he was a fresh import to the shores of Australia, and had just started making frames under the name of Tempest Bicycles.

Tempest is still going and remains Benson’s full custom label, but Chimera is his latest passion project. It’s a brand that aims to make premium Australian-made steel frames at a more attainable price, free of decision complications and with greatly reduced waiting periods.

And for that, Benson built me a bike to test, the Zenith RD (Road Disc). It’s a modern-retro racer that offers a nod to frames of yesteryear, while offering all the latest flushings. And in the case of the bike tested, it was built as a showpiece for the Handmade Bicycle Show Australia earlier this year, and features an artistic impression of Alexander Calder’s work, done in CyclingTips VeloClub livery.

Custom comes at a cost

Story Highlights

  • What: An Australian-made modern-retro steel road racer.
  • Construction: Fillet-brazed Columbus tubes, Paragon Machine Works, and Bear Frame Supplies pieces.
  • Price: AU$3,400 (frameset)
  • Highs: Balanced and smooth ride quality, classic style, build quality, fair price, can take a knock.
  • Lows: Weight (but hey, it’s a steel frame…), may be too quick for some, potential stiffness issues in largest sizes.

Even the most experienced and talented of builders will tell you that making custom bikes involves a great deal of time going back and forth with the customer on the design, the geometry, the desired ride and the paint. Then the builder will likely order a specific tubeset and frame pieces for the bike. And finally, they’ll dial in the jigs and tooling to turn those pieces into a one-off rideable piece of art. Simply, the process of creating a one-off product comes with a significant time cost.

While not alone, and certainly not the first in this endeavour, Chimera aims to greatly streamline the process. When buying a Chimera, the bike style, tube selection and geometry (with just five frame sizes on offer) are all pre-configured. Your choices are related to the type of drivetrain you want the bike set up for (mechanical, Di2 or wireless shifting), and then which of the five colour options you want it to be painted in.

Fancy something totally unique that’s closer to what’s reviewed here? Full custom paint is available at an additional charge (at the painter’s cost), and design work by Adam Leddin (best known for his website, Cycle EXIF) is available, too.

Benson achieves further efficiencies through purchasing his tubes in bulk, or in the case of the Zenith RD and RR (Road Rim), reaching the purchase quantities to have specific steel tubes drawn (more on that in a moment).

No expense spared — Chimera frames are provided with a Chris King headset.

Those efficiencies result in an AU$3,399 pricetag, including a stock-black Columbus Futura Disc Fork (440g) and premium Chris King Inset 7 headset. That price is in the starting range of other custom options, but certainly isn’t expensive, either. It’s also approximately AU$2,000 less than what a full custom frame carrying the Tempest name will cost you, and turnaround is just 12 weeks from order.

Classic tubes and modern touches

Like so many steel race bikes, the Zenith RD spits in the face of what many modern race bikes have become. It’s as aero as a beer can, and as light as a wine bottle. Rather, it achieves a refined ride that purveyors of steel swear by, all in a build that can take a hit (or a crit pile-up) and that carries a timeless style.

Barely wider than the tyre, the Minimax tubes are wonderfully minimal by today’s larger-is-better standards.

Central to that classic style is Benson’s use of Columbus Minimax tubes at the top and downtubes. The Minimax is a slim, relatively thick-walled (by today’s standards), butted and slightly ovalised tube that was initially designed by Merckx. Benson himself is a huge fan of the classic tubeset, and it’s no coincidence his firstborn is named Max.

“I remember working at a bike shop in the 90s and rode a Minimax bike, and I just fell in love with it,” Benson says of where it all started. “That tubing stuck with me.

“Hamsten Cycles was probably the last bike I remember seeing with the tubes. I too use the Hamsten arrangement, where the toptube is flipped 90-degrees, with the ovalisation sitting vertically to the seat tube. It makes it a little stiffer at the head tube, and it just looks right.”

Such a classical tube set isn’t so easy to come by these days, and Benson suggests his stock comes from a special production, as arranged by Australia’s importer Paul Hillbrick.

The Wishbone seatstay is a (non-exclusive) signature of Chimera frames.

Another classic – and somewhat signature – element of the Chimera Zenith is the wishbone seatstay. It hugs the rear tyre in an aesthetically pleasing way, and the way it connects to the seat tube is gorgeously smooth. Achieving such symmetry is surely no easy feat. Those seatstays are subtly bent for a little added give from the tubes, too.

The wishbone design arguably impacts on tyre clearance, as does Benson’s reluctance to dimple the chainstays to cheat clearance – something he believes weakens the frame. The Zenith RD is rated to fit a 28c tyre, but in reality, anything up to an actual 30mm should work (my measured 28.8mm setup had almost 5mm of clearance on either side of it).

The Minimax tubing and wishbone are a staple of the Zenith frames, but Benson has been tweaking other elements since my first batch sample. The frames are now fillet-brazed with (more expensive) silver, rather than bronze, in effort to keep the brazing heat lower. The 44mm headtubes are now sourced from Bear Frame Supplies, halving the weight of the Paragon headtube used in my sample. And the Columbus Zona tubes used for the chain and seatstays will be swapped for lighter and marginally stiffer Life tubes.

The classic elements are mixed with modern features such as the large 44mm head tube (which allows the use of a tapered fork), threaded T47 bottom bracket, flat-mount brake mounts, and 12mm thru-axle dropouts. Those Bear Frame Supplies dropouts also feature a replaceable stainless steel thru-axle insert and derailleur hanger – a nice touch.

Regardless of your gearing choice, the brake line is always run internally through the downtube. The guides used offer grip on the hose and I experienced no rattling issues from the hose.

As mentioned, cable routing is the customer’s choice. My sample was always intended for SRAM eTap, and so offers a completely clean approach. Di2 setup would be given small entry and exit points, while mechanical drivetrain orders will feature external cable routing. Love it or hate it, there is no front derailleur braze-on clamp, rather an adapter band is required. Personally I love the decision and it affords endless front derailleur adjustment and the option for a clean 1x gearing setup if you acquire an allergy to front shifting.

Overall, the build quality is hard to fault. Benson’s brazing is ground back to smooth for flowing lines, the frame pieces used are all top-notch, and the paint (done by Sydney’s Star Enamel) is a fine match.

The stainless steel thread insert offers a generous amount of thread-depth for the thru-axle, but it could be done just a little neater.

My only critiques are minimal, but on a bike so elegant, it’s the smallest things that stick out. In this case, the thru-axle protrudes the stainless thread insert by a couple of millimetres and the flat-mount brake mounts weren’t faced. I’ll forgive both of those given the bike was built in a panic for the show’s deadline, but fixing them would bring the finished product up another notch – something I hope Benson considers for future builds.

Additionally, there’s the question over product testing that’s rarely spoken of in the custom world. Some builders do strength and fatigue testing on their frames, while others simply rely on experience. Arguably Benson falls into the latter camp, and given his choice of traditional construction, quality components and building experience, I had no hesitation in giving the bike a thrashing. Benson certainly strikes me as a builder who likes to build bikes that stand the test of time.

A medium (54cm) unpainted frame weighs a so-so 1,770g, and Benson suggests the future move to Life stays should lower the figure. The included Columbus Futura Disc Carbon fork adds approximately 440g. As with most steel bikes, it’s not the best pick for the weight-obsessed.

A modern-retro racer

Those small-diameter tubes are not the only traditional element to the Zenith road bikes — the square geometry is another throwback. For this, the bike sticks with classic racing angles, and my 54cm sample offers 73-degree seat and head tube angles, with larger sizes getting steeper head angles again.

The Zenith is available in five common sizes, with well-proven angles.

Those angles, along with a 45mm-rake fork produce a pretty common 58mm trail figure, but to my surprise, the bike feels more nimble than the numbers suggest. It’s certainly a bike that rewards more confident riders — it’s eager to tip into corners with minimal effort and spring back out of them. Nailing the apex or using the full width of the road with pinpoint accuracy is no trouble, but on the flipside, it’s not the type of bike that likes to meander about.

And while this may read as ridiculous, the handling is made faster and more sensitive through a complete lack of cable resistance (eTap wireless and hydraulic discs) and what’s easily the smoothest-turning headset in the business. It’s enough to make a difference at low speeds, where the bars feel eager to turn on you. As a result, it’s one of the harder bikes to ride no-handed that I’ve ridden in recent memory.

How it tips as opposed to leans into corners is something to note, and the bike’s somewhat-tall 70mm bottom bracket drop is the result of Benson wanting the Zenith to be good for crit racing. As a result, it’s a bike that can take stupidly tight lines with a confident hand, and can be pedalled straight out of them without fear of sparking the cranks, too.

Bent for clearance, the chainstays flow onto the cut-plate-like dropouts.

The rear end sits at 415mm long and the chainstays are subtly bent for increased heel clearance. Add in the slim, minimalist dropouts and my heels passed the 142mm rear axle without a whisper.

Despite the angles that scream race bike, the stack and reach figures are kept reasonable and comfortable. Those seeking an extremely low race position may need a -17-degree stem, but most should find joy in the fit with minimal headset spacers required.

While it may have been designed as a racer, the stack and reach figures make the bike well suited to all-day endeavours, as does the narrow steel tube construction. The Zenith offers a wonderfully composed and planted road feel, where significant imperfections in the road are soothed away – leaving a healthy dose of feedback from the wheels without a fluttery feeling.

Most of my local Sydney roads offer sections that were clearly paved on a Friday afternoon. The Chimera laps them up with poise.

Most remarkable is how well-balanced the ride quality is front to rear — where so many bikes feel stiffer at the bars than they do at the saddle, the Zenith doesn’t give such a sensation. And this feeling certainly defies that large tapered fork on the front. Better yet, with a standard 27.2mm seatpost, there are options to get even more seated comfort from this ride.

In part, that smooth ride can certainly be credited to the Minimax tubing used in the front end. It’s a tube with a reassuring ting when you tap it, and it’s not a bike I’d fear dropping or putting into a travel case. However, that tubing is pretty narrow in diameter by today’s standards, and comparing it to the latest race bikes does reveal a hint of front-end flex under power. By a hint, I mean I couldn’t care less about it, but it does raise questions over how suitable that tube selection will be in 58 and 60cm sizes and under powerful riders.

Most commonly that Minimax tubing would be used on the toptube, with the larger-diameter Max tube used on the downtube, but Benson uses the slender tube top and bottom. Certainly, Benson is keeping Chimera small and personal, so it can be discussed directly with the maker if it’s of concern.

Bike weight is one of those things that you can feel more than the clock can count. And those skinny steel tubes do lend to a somewhat weighty frame.

Even under heavy sprinting that flex isn’t a bother, but add in a complete bike weight of 9kg and the Zenith lacks a snappy feel. It’s a feeling that I used to love in my bikes for racing crits, but the Zenith can at times feel like it’s missing its first coffee of the day. A lighter build would certainly help, but really, steel may not be the best material choice if you desire the first-pedal-stroke jump that a modern – arguably-delicate – race bike affords.

Heavier isn’t always bad, and I believe the bike’s composure over poor road surfaces is helped by the bike’s weight. Where lighter bikes tend to skip a little, this one seemingly has a handshake deal with gravity. And with disc brakes, the Zenith RD’s emergency parachute is never far away.

A pointless wine analogy

Chimera sits in a unique space. The stock-model-and-geometry approach pits it against many far-lower-cost options out of the far East. Yet, it’s a bike that still retains a custom feel and undeniable style to it, from a small maker whose workshop door is open to any eager customer.

A bike like the Zenith RD, like a quality drop of red, is an acquired taste. It’s a bike that’s bound with personality and rich in historical elements. Heavy in its ways, it’s not designed to find appeal in the mass market, but rather speak to those with a more sophisticated palate that know whether this will suit.

In many ways, Rob Benson’s Chimera Frameworks is like many of the winemakers that are within short riding distance of his workshop. Hunter-based winemakers have a relatively newfound experience, and work in a region without a deep history in production, yet, they still manage to produce a product that deserves attention.

Benson hasn’t earned himself the reputation to charge Penfold Grange prices (or Lakes Folly for the Hunter Valley), but he’s certainly creating a product that tastes just as good, even if the price tag says it shouldn’t.

The build

The bike I rode was built with the help of PSI Cycling (formerly Monza Imports), an Australian distributor of SRAM and Zipp. The build list below is how the bike was supplied. The handlebar, saddle and tyres were changed during testing.

Frame: Chimera Zenith RD (version 1), 54cm
Fork: Columbus Futura Disc Carbon fork, 1.5in tapered
Headset: Chris King Inset 7
Wheelset: Zipp 303 NSW Disc Clincher/Tubeless
Shifters: SRAM Force eTap AXS HRD
Crankset: SRAM Force DUB, 48/35T, 172.5mm
Bottom bracket: C-Bear ceramic, DUB T47
Derailleurs: SRAM Force eTap AXS 12-speed
Cassette: SRAM Force XG-1270, 10–28T
Chain: SRAM Force Flat-Top, 12-speed
Brakes: SRAM Force HRD Flat Mount, 160mm rotors
Tyres: Continental Grand Prix 4000 II, 25c
Tyres: Continental butyl, 60mm valve
Handlebar: Zipp Service Course SL80, 42cm
Stem: Zipp Service Course SL, 100mm
Seatpost: Zipp Service Course SL, straight, 27.2mm
Thru-axles: Aluminium bolt-up
Bar tape: Zipp Service Course
Saddle: Fabric Scoop Race
Weight: 8.81kg (without pedals or cages)


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