With so many advances in bike design it’s easy to forget that geometry remains critical. Yes it has become fairly standardised, but even within a narrow spectrum there is a sea of difference between bikes pitched at either end.
And here, with Basso’s reincarnated Diamante SV, the geometry dial is turned all the way up to racy. But there is a twist.
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Measured approach
Reading out a string of numbers is boring, which is why robots make terrible speeches. But I’m going to do it anyway because numbers are vital clues to the SV’s character. From the geo charts this size 56cm has 587mm stack, 386mm reach, 406mm chainstays and 985mm wheelbase.
In other words, the SV has a short wheelbase and short rear end, two things associated with fast, reactive handling. A typical middle-of-the-road racer would come in with around 995mm wheelbase and 410mm chainstays.
That said, the bike isn’t quite as aggressive as it once was. As Basso’s Joshua Riddle explains, ‘The previous SV was quite extreme in terms of its racing geometry and some riders had trouble getting low enough to negate the need for spacers.’
Hence this time around the bike has an extra 30mm stack height and a 9mm shorter reach. However it hasn’t lost its racy bent despite now offering up a more upright position, and once again it does so in two clever ways.
First, all spacers can be dropped and the stem slammed into a recess in the frame. Second, that stem has a -11° rise where most bikes have -6°. What that means is that where a 110mm stem adds around 25mm to the effective handlebar height (in how it juts up from the fork at an angle), the SV’s stem only adds around 15mm.
The result is that the SV still offers up an aggressive position when I want it, coaxing my back towards flattened when in the drops. And as a result of that the SV is rapid.
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Up down dream
In case you’re wondering, SV is Italian for ‘well fast’. OK, it stands for Super Veloce, but you don’t need a 2:1 in Italian bike design to have surmised that. The frame shape is what we’ve come to expect for aero: truncated tubes, dropped seatstays, large gaps between fork legs and wheel, and hidden cables.
Basso provides no aero data but I’m willing to overlook this based on experience. Even with relatively shallow 35mm DT Swiss wheels the SV zinged along the flats and chopped into headwinds.
Yes, a lot of this free speed is down to my body position, but that position is afforded by the bike, so the SV deserves its speedy moniker.
It does a splendid turn up climbs too. Aside from being notably stiff the bike is aided by a competitive 7.5kg weight. Specifically it does well on greasy climbs, that short rear end putting the back wheel closer under the rider’s weight as the road pitches up, which aids traction.
But like its forebears it also barrels down descents in spectacular fashion, thanks I think to the wheelbase, which is not so short as to be unstable but short enough to make snap changes in direction.
However like many bikes now the SV also owes a lot to its tyres – in this case 28mm Continental GP5000s. The crucial element being the width.
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As per its predecessor, Basso has added its 3B elastomer insert around the seatpost in an effort to dampen road buzz. And I should imagine it does work, but still I think the real comfort–heroes here are the tyres.
The bike came delivered with tyres at 110psi, and out of curiosity I rode it like that. And boy did I wish I hadn’t – it was more jarring than a jam factory. I then dropped pressure down to 55psi front/60psi rear and the difference in feel was astonishing.
The sprint stiffness remained but the ride turned from agricultural outhouse to acceptably comfy chair.
I’ve noticed this with other bikes too, and manufacturers are increasingly returning to super-stiff frames and then speccing wider tyres to claw back some compliance.
It’s obvious but it works, and here it has turned the SV into something quite brilliant, unlocking its stiffness and poise by providing not just comfort but masses of grip too.
Still, I think Basso could go one better and spec the tubeless version of the GP5000s, which the DT Swiss wheels are compatible with, and if I owned this bike I’d make that switch as soon as possible. And for those in the tyre-swap market, it’s worth noting clearances are up to 32mm.
Yet tyre choice aside there is so much to love about the Diamante SV. It is perhaps better behaved than its predecessors – smoother and a touch less aggressive – but this bike still has a true racer’s heart. So yes it is Super Veloce, but it’s also Super Fun.
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Pick of the kit
Sidi Wire 2 shoes, £340, saddleback.co.uk
Sidi is a law unto itself, with nutty designs, jaw-dropping pricetags and more adjustment options than a Savile Row tailor. But when it gets its shoes right they are brilliant, and none more so than the Sidi Wire 2.
Yes, they’re a bit heavy at around 650g a pair. Yes, Sidi’s Techno dials are more finicky than Boa dials. And yes, by the end of the first day you will have lost the little screwdriver to change the tension of the clasp around the achilles. But all is forgiven thanks to the exceptional build and material quality – these shoes are two years old and still look new.
Buy the Sidi Wire 2 shoes from ProBikeKit
Alternatively…
Down but not out
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Rim brakes still exist and the Diamante (£2,700 frameset) makes excellent use, turning to direct-mount callipers for better modulation via increased stiffness. Plus you can build a bike that will hit 6.8kg.
Cut from the same cloth
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With near-identical geometry to its top-tier siblings, the Astra promises fast handling for half the price. The sacrifice is a few extra grams, but for £3,299 you get an Italian-built, Shimano Ultegra Disc bike.
Spec
| Frame | Basso Diamante SV |
| Groupset | Shimano Dura-Ace Di2 Disc |
| Brakes | Shimano Dura-Ace Di2 Disc |
| Chainset | Shimano Dura-Ace Di2 Disc |
| Cassette | Shimano Dura-Ace Di2 Disc |
| Bars | Basso Aero |
| Stem | Basso Low Integrated |
| Seatpost | Basso Diamante SV |
| Saddle | Selle Italia Flite Boost Superflow Carbon |
| Wheels | DT Swiss PRC 1400 Spline DB, Continental GP5000 28mm tyres |
| Weight | 7.48kg (56cm) |
| Contact | bassobikes.com |
All reviews are fully independent and no payments have been made by companies featured in reviews
