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The aluminium Allez has been been a stalwart of Specialized’s road collection for several years, remaining relatively unchanged from its original incarnation as an entry-level, endurance-orientated frame. However, possessing the resources to continue in the research and development of aluminium alongside carbon fibre, Specialized has been able to radically change the way it’s Allez frame is produced.
The Specialized Allez DSW SL Sprint Expert uses SwartWeld technology – developed by Specialized’s creative specialist Chris d’Alusio – whereby instead of using mitred tubes that are TIG-welded together, the frame is constructed in hydroformed sections.
Case in point is the bottom bracket shell – two huge hydroformed clamshell pieces are brazed together, to which the down tube, seat tube, and chainstays are welded, creating a BB shell more reminiscent of carbon fibre tube-and-lug construction than aluminium.
This moves the tube welds away from the points of stress, which Specialized claims increases stiffness, and as the tube walls can then be made thinner around the joints, it makes for a lighter frame too.
Along with appropriate tweaks to the geometry and Specialized’s top-tier FACT carbon fork, this new manufacturing method has changed the Allez into an aggressive, race-orientated bike that is now less packhorse, more thoroughbred.
Regardless of performance, the SmartWeld technology certainly creates a striking looking machine.
Weld neatness is usually classed as a prized attribute on aluminium frames yet the Specialized Allez DSW SL Sprint Expert’s joints are obvious and large.
However, rather than point towards manufacturing inadequacy the distinct welds seem an appropriate residual tribute to the radicality of SmartWeld – visible evidence warning the rider to expect something different to other aluminium frames.
Primarily this manifests in lateral stiffness. Specialized claims this frame is equal to the Tarmac SL4 in this area, and this race-machine rigidity is evident under hard accelerations – the Sprint moves forward with an urgency I’ve not encountered from any other aluminium frame.
The efficiency in acceleration tempts you to ride aggressively so Specialized have modified the the Sprint’s geometry compared to a regular Allez to account for this.
Stack is 20mm shorter, reach 3mm longer and wheelbase is 6mm shorter, while it’s headtube angle is 73.5°.
It makes the Sprint’s handling a lot more reactive and creates a riding position better suited to crit-racing than sportive riding, sharing far more similarities with the Specialized Tarmac and Venge designs.
The common ground extends to sharing a fork with the S-Works Tarmac and a seatpost with the S-Works Venge – indeed, the entire seat tube closely replicates the Venge’s aerodynamic design.
This is no mean feat in aluminium but Specialized had solid rationale behind the complex addition.
‘We’ve found that the seat post and upper seat tube shape (including the seat stay junction) are very critical areas for aero performance since airflow is typically accelerated between the legs of a rider,’ says Chris Yu, Specialized’s head of applied technologies.
‘As a result, the drag contribution of this area is actually magnified rather than diminished by the presence of a rider.’
The design’s effects on drag are impossible for me to quantify but anecdotally it wasn’t particularly noticeable when I would normally expect to feel the advantage of a feature claiming to reduce drag – for example, maintaining speed above 40kmh didn’t feel any easier than normal.
Adopting some of the Venge’s other features as well, like its narrow head tube for example (to minimise frontal aera), would make the benefit more noticeable but I understand the limitations of aluminium might restrict aerodynamic styling to just the seat tube for the time being.
In any case it is a huge step in the right direction to make aluminium bikes more aerodynamically efficient.
The shaped seat tube adds some weight though, so along with the mongrel groupset, basic finishing kit and set of workmanlike Axis Elite wheels (the Sprint’s most obvious cost-cutting inclusion), the bike tips the scales at 8.32kg.
It’s efficient frame means it doesn’t climb like a rock but a wheel upgrade is almost essential to bring the best out of the bike.
The Specialized Allez DSW SL Sprint Expert’s other adopted feature has more of a tangible effect on performance.
The top-tier FACT 11r carbon fork is very good – stiff enough to match the frame and it enables the bike to track well through corners, an area where the bike could be in danger of being too skittish.
Again, this makes the Sprint ideal for technical criteriums, yet beyond a racing application its case becomes slightly less compelling.
Most riders rarely buy a bike for only one type of riding and the trade off for stiffness and low cost is a singularity of purpose – the Sprint cannot combine this efficiency with comfort.
That would allow it to cope with a range of riding environments but the large tube diameters, aero seat post and stiff front end transmit a lot of road buzz which is noticeably fatiguing on longer rides.
This harshness could be mitigated to some extent by using larger volume tyres (going tubeless would help even more, but the Sprint’s stock wheels are not tubeless-ready) run at a lower pressure, but this would sap speed from the bike and seems counter-intuitive – why make the Sprint a jack of all trades when it is a master of one?
It is bold of Specialized to make a bike so specific in its ideal application, yet it is a move to be admired and proves aluminium has potential way beyond its current entry-level stereotype.
specialized.com
