Basso Diamante SV Team Issue

The SV is Italian brand Basso's super-duper, high speed version of its well respected Diamante pro-level race bike, with more focus directed towards aerodynamics. If you're after a fast, lightweight, handmade carbon race machine with a bit of exclusivity, then it needs to be on your list.

Cheaper builds are available, from £4,495 for the Shimano Ultegra-equipped model.

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Ride

Like a lot of bikes of this style, the Basso needs to be ridden hard and fast, this is when it comes alive. You can cruise along on it yeah, but you won't be unleashing the magic that's stored inside that frame.

The aerodynamic tweaks to this frame aren't as extreme as those we've seen on others in the marketplace, and I doubt they make much difference in the real world compared to the standard Diamante, but that doesn't stop the SV being quick, very quick, with that thrill of travelling so fast on a bike that weighs virtually nothing gives you the feeling of floating. You can cover a lot of ground very quickly and it's a relief to get plenty of use out of that 53-tooth chainring and the smaller end of the cassette.

Even with the 20mm integrated frame spacer in place and another 15mm on top of that, the Basso is still very long and low, which gets you in the mood for concentrating on your position, keeping things tucked, whether you are on the hoods or down in the drops.

The handling is lively and quick, like you'd expect from a bike of this style, but never overly twitchy, and it's pretty easy to settle things down a bit if you do go outside of your comfort zone, as long as you aren't too heavy handed. The smoother you are, the smoother the bike will respond to your touch.

This shows up when descending, if you choose the perfect line through a twisty couple of bends, as the SV will just swoop round thanks to a very tight front end and the short wheelbase. No fuss, no bother.

If you've got to adjust things for some gravel or a pothole or something, then little tweaks, a dab of the front brake or a shift of your body weight, is all it takes; they need to be tiny changes. If you panic or tense up a bit, the Basso will take a little tussle to keep things on track. You soon learn, though, and as your confidence grows, the more and more you get back from the SV.

At 6.65kg the Diamante SV is fun when ascending too, not only because of the stiff and lightweight frameset, but because of the Microtech M138 carbon fibre tubular wheels. A claimed weight of "1,175g (+/-5%)" means they don't take much effort to get spinning, and they laugh in the face of gravity.

Braking is very good on them as well, at least in the dry, so descending isn't the white knuckle ride it often is with carbon rims.

Gear-wise our test model comes with a 53/39 chainset up front and I'm guessing an 11-29 cassette. I say guessing because it looks as though the 29-tooth sprocket has been swapped out for a non-Campag 30 tooth. It's a good spread of gears for this style of bike, where speed is the main goal.

If you're going to be spending a few hours riding the Basso you'll find that the comfort is pretty good. It's a stiff beast but that doesn't necessarily mean it's harsh. It does suffer with resonation a bit from rough road vibration, in the same way a lot of lightweight carbon fibre frames do. It's there in the background so not really a major issue when it comes to longterm comfort on a ride.

I covered a few three hour rides on the Basso and I found it a very pleasant bike to be on, and you can cover a lot of ground without really noticing it.

Frame and fork

If you're trying to get your aluminium consumption under control then you'll like the Diamante SV, as Basso describes it as 'alloy free'. It's a full-carbon fibre construction using a mixture of Torayca High Modulus in grades T1000 and T800, with no alloy reinforcing parts anywhere, dropouts or bearing seats for instance. Obviously there is a bit of metal in the mix for bottle cage bolts, plus there is a replaceable gear hanger too should you drop the bike on its rear mech.

T1000 and T800 are both Intermediate Modulus carbon fibres with the highest tensile strength (stiffness) from Toray's range. Originally designed for aerospace applications, its properties make it pretty useful for bike frames. With such high levels of tensile strength you can make a frame very stiff without using much material, so it's lighter than one that uses a lower grade of carbon fibre.

We talk about carbon fibre layup a lot here on road.cc, purely because the direction you lay the fibres as well as what grade you use pretty much dictates the ride comfort, stiffness and feedback from the frame. One thing I've never seen mentioned by a manufacturer before is the specific layup for each of the tubes on its frame, but that's what Basso has done on its website, here.

Going by the performance of the handbuilt frame and fork, the Basso builders certainly seem to know what they're doing.

The head tube is an interesting piece of design, allowing for a 20mm headset spacer to be integrated into the frame. It's not a new thing, we've seen similar on Cipollini's NK1K, but Basso's solution does look exceptionally good. If you've got the back for it you can remove the spacer and run the stem flush with the top of the head tube (like you can see here) for an extreme pro position. It's a neat solution.

As you'd expect, Basso has gone down the tapered route for the head tube/fork steerer relationship. The lower part of the headset has a 1 1/2in diameter with the upper 1 1/8in. Most manufacturers are doing this now, especially on performance bikes as it brings a bit of extra stiffness to the front end under hard braking and cornering.

The down tube is an upside down triangle where it sits behind the front wheel, with aerodynamics being the main concern here. This shape also gives a flat top section wide enough to swallow the two internal cable guides, which looks neat. The SV is designed to work with both electronic and mechanical groupsets.

As the down tube gets towards the bottom bracket area it flares out to create a large junction where the seat tube and chainstays join the mix. The Press Fit bottom bracket area is a massive 86mm wide, which allows a large cross section for bonding to the other tubes, so they can all be oversized for maximum stiffness and, therefore, power transfer.

Access to the cable or wires for the gearing is under a cover on the bottom of the bottom bracket shell, which keeps them out of the elements.

There is more aero thinking when it comes to the seat tube, with the profile mimicking that of the rear wheel, although the two would need to be much closer together for it to make a huge difference.

Basso's seatclamp solution is a nifty one though. The own brand seatpost has a U-shaped profile as it slides down into the frame and this allows the clamping system, an expanding wedge mimicking the U-shape, to be pushed against the seatpost via the rear bolts to keep things tight. It works well as there is no slippage whatsoever. The post is also surrounded by an elastomer to provide a bit of vibration damping between the frame and seatpost, though if it does it's negligible.

The fork has been designed to match the profile of the down tube to carry on the aero theme plus it also allows for a massive crown section, giving more stiffness under braking. Basso has decided to go with direct mount brakes here, as it has on the rear of the frame, where the brake callipers are screwed directly into the frame and fork, one on each side.

Being attached directly to the frame removes any movement from a more traditional bolt-through design, like most dual pivots, so in theory you should get more stiffness and better braking. The Record Skeleton callipers are excellent in a dual-pivot design so it's no surprise they work unbelievably well in this direct-mount guise, although how much better is difficult to gauge.

Finishing kit

This model is the SV in its Sunday best, so it's not surprising to see such a high price. The full (apart from the brakes) Super Record EPS is a lovely looking piece of kit and certainly suits the style of the Basso, but I wasn't overly enamoured with the feel of the shifting and would actually take the mechanical version every time, saving a good chunk of cash at the same time.

I didn't like the feel of the gear change at the lever, the way it clicked, much preferring the softer button touch of Shimano's Di2.

That aside, the shape of the Ergopower levers is spot on, and the hoods are very comfortable to use for hours on end. The speed of each gear change is very fast and precise, too, both front and rear.

There is also a Chorus version, but if you don't fancy Campagnolo you can always kit out the Basso with Shimano Dura-Ace, Ultegra Di2 or Ultegra mechanical. The latter spec comes with alloy Microtech MCT-38 wheels and a price tag of 'just' £4,495.

The M138 wheels fitted here, as I've mentioned, are very light and very stiff, and being just 38mm deep don't suffer from crosswinds at all.

The front wheel has 18 spokes, with the rear getting 24, which seems a sensible build as they feel strong in use, especially when you inevitably hit that pothole. They remained true and the hubs very smooth throughout testing.

The rims aren't massively wide, unlike a lot of newer wheels, so anything bigger than the 25mm Michelin Pro 4 tubulars fitted will be wider than the wheels themselves, which isn't ideal for aerodynamics – remembering this is supposed to be an aero bike.

The alloy stem is Basso's own and it works perfectly with the frame in terms of aesthetics. It's a sizeable unit too, which brings a lot of stiffness to the front end. Offsetting any harshness is the carbon fibre handlebar, which has just a little bit of up and down flex at its extremities. It's minimal, so you don't feel like you're bending the bar or anything, it's just enough to offset any road vibration before it gets to your wrists.

The Selle San Marco Mantra saddle took a little while to become friends, as it's a pretty rigid seat straight out of the box, but after a few rides I started to get on with it. It's got a bit of flex in both the hull and the carbon fibre rails, which all helps out.

Value

I can hear breath being sucked in through a few teeth here.

The Diamante SV is a handbuilt, Italian superbike and thanks to the levels of craftsmanship and timescale in its construction, the price is always going to be on the steep side. But when you get aboard you realise you are riding something near the pinnacle of what is achievable when creating a road bike. It's not perfect, but it ain't far off.

> road.cc Superbike of the Year 2016-17 

Comparing it to the competition we've recently tested shows that it isn't actually that expensive: Bianchi's Oltre XR4 with the same groupset comes in at £9,500, and the Cipollini NK1K I mentioned earlier is £4,200 just for the frameset. When you consider that you can get the entry-level SV for just a few hundred quid more than that, it helps put things into perspective.

Verdict

A beautiful looking machine backed up by top-end performance and handling