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Avanti has taken the aero design of its Corsa DR and refined it, reportedly with a fresh emphasis on weight and stiffness. The new bike is called the Corsa SL and while its marketing may appeal to climbers, the bike’s strengths lie elsewhere. CTech editor Matt Wikstrom put the Corsa SL through its paces and wrote this review.
Avanti was founded in New Zealand in 1985 and the company has grown steadily ever since. The company’s current catalogue comprises over 100 bikes spanning all categories, including kids’ bikes and BMX. The company now has offices in both Melbourne and Auckland and is proud of its Australasian heritage.
Avanti started using carbon fibre for its frames in 1999, though it did not offer a full carbon road frame until 2005. In that time, the brand has worked closely with many elite athletes, such as champion New Zealand track rider Sarah Ulmer, to refine its designs.
For 2014, Avanti has taken over headline sponsorship of the Continental team run by Andrew Christie-Johnson with the Avanti Racing Team contesting the Oceania Tour and Australian National Road Series events on Corsa DR and SL road bikes.
Avanti introduced the Corsa DR last year when it reportedly applied the lessons learned from refining its TT/triathlon Chrono platform. The Corsa SL is the next iteration in the company’s thinking, where the focus has shifted from aerodynamics to weight and stiffness.
Before the ride
Avanti utilised Finite Element Analysis (FEA) to refine the carbon layup for the Corsa SL frameset to ensure that the final product was as light as possible without compromising stiffness. The key to the success of FEA is that algorithms are used to break up a large complex structure (like a frame) into smaller components to analyse them individually before recombining them.
As a result, Avanti’s engineers were able to experiment with a multitude of virtual prototypes. The company is proud of the final result, claiming that the Corsa SL has the best stiffness to weight ratio of all its products.
The Corsa SL frameset is built with Avanti’s highest-level (level 6) carbon fibre with a unidirectional finish. The headtube utilises an oversized 1.5-inch lower bearing mated to a tapered fork steerer to improve stiffness and steering precision. Similarly, a BB86 bottom bracket was chosen because its extra width better resists torsion and provides a larger contact area for the downtube compared to a standard bottom bracket design.
Two strategies are employed to contend with the unwanted effects of a stiff frame design: first, slender chainstays are used to introduce some compliance and second, an “undersized” 27.2mm carbon seatpost is used to further dampen road shock.
The post itself employs a two-bolt cradle design, where the front bolt has a wheel to provide for some tool-free adjustment. In practice though, this wheel is too hard to turn by hand until the rear bolt is backed off completely, making fine adjustment tedious.
The gear and rear brake cables are internally routed through the Corsa SL frame. Entry and exit ports are designed to suit both mechanical and electronic groupsets.
In another concession to aerodynamics, the Corsa SL frameset relocates the rear brake caliper to the underside of the bottom bracket. Here, a dual pivot direct mount caliper is used, coupled with an inline quick release and adjuster. The latter is a welcome addition because the caliper does not have a built in quick release for wheel removal.
The geometry tends to favour an aggressive racing position but racers looking for a very low front-end may find the stack of the Corsa SL too high. Note that the Corsa SL Team bike is not offered in sizes 52 or 59.5, but prospective buyers can get these sizes by buying the frameset or other models in the Corsa SL range. You can view a detailed geometry chart for the Corsa SL here. And to learn more about how a bike’s geometry affects its handling, click here.
The Corsa SL Team enlists Shimano’s mechanical 11-speed Dura Ace groupset (53/39 crankset, 11-25 cassette) for the build and mates it with Zipp’s Firecrest 202 carbon clincher wheelset shod with 23mm Kenda Kountach tyres. The remainder of the build is supplied from Avanti’s Zero parts line: Attack Team carbon bars, Attack Team stem, and Zenith Team SL saddle. The size 56.5 provided for review weighed 6.48kg (sans pedals and bottle cages) and retails for $9,180.
The Corsa SL Team is a fine looking bike finished in matte grey with white highlights and logos. The lines of the frameset are clean and pleasing, drawing the eye in easily from any direction. The seat stays in particular intersect with the seat tube perfectly without the clutter of the rear caliper to distract. Owners can expect to spend time keeping the frame clean as smudges and smears show up quickly on the white highlights and are difficult to remove without degreaser.
It is worth noting that there is a second build option for Corsa SL Team at the same price — Team Huon-Genesys may have morphed into the Avanti Racing Team but the team bike lives on. SRAM 22 replaces the Dura Ace groupset for the Genesys Team Edition build, which should reduce the weight of the bike by at least 100g, while the frame receives some orange and blue highlights along with a few sponsor badges. The rest of the bike remains unchanged. See the full specifications here.
For more information on the Corsa SL and the rest the catalogue, visit the Avanti bikes website.
After the ride
The Corsa SL is a light bike, the kind of weight that easily impresses most people when they pick it up. At 6.48kg for size 56.5 without pedals or cages, it won’t impress weight-weenies, but for everybody else this weight promises a bike that is easy to ride up hills.
Indeed, the Corsa SL is an easy bike to ride uphill. It’s hard to reconcile how a difference of just 1kg can improve one’s climbing ability, but this bike was perceptibly lighter on ascents compared to my regular ride.
Part of that sense can be attributed to the Corsa SL’s agility. The bike has quick steering, so it changes direction quickly and easily. The combination of low weight and quick handling makes for a bike that is nice and nimble, perfect if you’re someone who has the ability to ride uphill fast.
As promised by Avanti’s engineers, the Corsa SL is exceptionally stiff. The front end, bottom bracket and stays always felt rigid, but they were unrelenting too, which undermined the quality of the ride and the stability of the bike.
It was difficult to ride the Corsa SL on rough roads. Every hit was felt, front and rear, despite the 27.2mm seatpost and slender seat stays. Long stretches of chipseal roads were tiresome; swapping to wider tyres (25mm) smoothed out the ride a little, but there was little relief from road chatter.
The rigid frame also combined poorly with the bike’s quick handling to make it unstable during descents. Riding in the drops steadied the bike somewhat, but never to the point where I could divert my attention. The Corsa SL’s cornering ability was generally good — thanks to the quick steering — however the stiff rear end had a tendency to come unstuck on tight bends. Everyone has different descending styles and abilities, but personally I didn’t find that this was a bike that encouraged aggressive descending.
Off the descent and on smooth roads, the rigid frame was a delight, highly responsive and exciting to ride. The Corsa SL rolled efficiently over undulating terrain and perhaps the combination of internal cables, the chainstay positioning of the rear caliper, and Zipp’s Firecrest 202 profile reduced the bike’s aerodynamic drag. Whatever the explanation, the Corsa SL was an easy bike to ride fast on smooth roads — a perfect circuit racer.
I have reviewed Zipp’s 202 Firecrest wheelset previously and it is a fine wheelset that adds considerably to the value of the Corsa SL Team. Shimano’s cork brake pads were supplied with the bike and they were effective, although they did not offer the same grip as Zipp’s Tangente pads or Swissstop’s Black Prince pads. They were also quick to wear.
As for the rest of the build, the 11-speed Dura Ace groupset was perfect. The dual-pivot rear brake offers great modulation, though some riders may miss the immediacy of braking that defines Shimano’s conventional calliper design.
The handlebars have a deep anatomical bend combined with semi-aero (flattened) tops that were pleasing to grip. The saddle is flat and narrow — a common choice in today’s market — and can be personalised as required. Finally, the Kenda Kountach tyres provided plenty of grip and rolled nicely; there’s no need to swap them until they’ve worn out.
Final thoughts and summary
To date, the Corsa SL is the stiffest-feeling carbon bike I’ve ridden. The bike is impressive for this as well as its low weight, and the two traits combine to make for a good race bike. However, I found the stiffness undermined the bike on rough roads and during descents, affecting both its overall performance and appeal.
Light bikes are easier to ride up hills than heavier bikes, but are there any other attributes that make for a great climbing machine? The Corsa SL is certainly stiff enough to ensure its responsiveness, in or out of the saddle, but as noted above, it is in excess.
Indeed, it’s hard to see a climber (who normally weighs less than 65kg) hoping for as much stiffness as this bike offers. I also expect climbers would appreciate more stability on descents than the Corsa SL has to offer.
The Corsa SL is better suited to midweight racers looking for a versatile bike, provided they prize stiffness above all. The bike is light, agile, and responsive, perfect for criteriums and undulating road circuits. In this regard, Zipp’s 202 wheelset is a versatile performer, though some may prefer a deeper set of wheels.