Wilier Granturismo SLR Ultegra Di2 review

3D-printed elastomer-infused endurance ride

This competition is now closed

By Warren Rossiter

Published: June 6, 2023 at 12:00 pm

Wilier's long-established Granturismo endurance platform has been revamped with a renewed focus on comfort and aerodynamics.

For comfort, there is a new iteration of the Actiflex system first seen on the Cento10 NDR, while there's some aerodynamic integration ported over from the Filante SLR.

The Granturismo also features a geometry and ride position that, while sporty, isn't overly low and long.

The result is a contender in our 2023 endurance Bike of the Year category that looks as though it belongs in the pro peloton. However, you certainly don't need to be a pro rider to enjoy it.

The Granturismo's frame design sees the seatstays meet the top tube just forward of the seat tube. However, instead of the carbon running through to the joint, it's bisected by a 3D-printed elastomer section that offers 5mm of comfort-improving travel.

It's designed to take the edge off hits and dampen vibrations from rougher road surfaces.

Wilier has still reinforced the stays with a bridge above the rear wheel to maintain torsional stiffness when pedalling. Said bridge is svelte and dedicated for purpose – it's not drilled to take a mudguard.

The new 3D-printed elastomer has a lattice-like construction, which Wilier claims offers a 20g weight saving over the Cento10 NDR's solid elastomers and leads to a claimed frame weight of 1,100g (medium).

The tube shapes are all based around truncated airfoils, much like those seen on the pro-level Filante.

The aero-optimised head tube flows smoothly into a very widely spaced asymmetric fork that not only offers drag reduction by reducing turbulence from the interaction of front wheel and fork leg, but also provides 32mm of tyre clearance.

The head tube accommodates 1 1/4in bearings top and bottom, enabling Wilier to route the brake hoses through the head tube and fully internally to both the front and rear brakes.

The seat tube has a cutaway for the rear wheel and its shape is mimicked by the dedicated Granturismo seatpost.

The post has a clever flippable head, enabling you to run it at either 15mm setback or zero offset – a great touch for getting the optimal fit without having to purchase another post at extra cost.

Wilier uses a small integrated expander wedge to secure the post.

The braze-on mounting for the front derailleur is removable, giving you the option to run the Granturismo in a 1x setup and clean up the bike's lines.

The down tube broadens and flattens at the junction with the generously oversized bottom bracket shell. This houses a press-fit 86.5 model.

The chainstays taper back towards the rear dropout and transition from a deep rectangular cross-section into a square profile.

The layout is said to provide optimum stiffness through the drivetrain, though I did on occasion find the heel of my size EU45 feet clipped the stays with my normal cleat orientation.

The Granturismo stays true to its racing-influenced roots by omitting any mounts for mudguards or fenders (as evidenced by the aforementioned seatstay bridge).

One could argue this feels like a misstep, because the Granturismo is certainly a bike that's suitable for year-round use thanks to its generous tyre clearance.

That said, Wilier positions the Granturismo as a sporty endurance bike, rather than one for steady wet and mucky winter miles.

Wilier has reduced the Granturismo's head angle to add a bit of stability to the steering – here that means a 72.5-degree angle (race bikes usually sit around 73 degrees), while the seat angle is 73 degrees.

Wilier has also heightened the stack and reduced the reach versus a typical race bike, but not so much as to lessen the bike's racy feel significantly.

My size XL (58cm) test bike came with a 604mm stack and 398mm reach. By comparison, a Cannondale's Synapse has a 610mm stack and 393mm reach in the same size.

When you consider Wilier's Filante in the same size has a low-slung 571mm stack, it's easy to see why Wilier considers the Granturismo as the more relaxed of its offerings.

The same goes for the wheelbase. The equivalent Filante is a short 1,002mm, while the Granturismo sees 1,013mm, which puts it firmly in the sporty-but-stable arena of endurance bikes.

The 47mm fork offset, combined with the 72.5-degree head angle and tyres that measure up at 29mm, creates a trail of 59mm.

That's the sort of number I’d expect to see on a fully fledged race bike. For instance, Orbea's Orca has the same trail, and Cannondale's race-proven SuperSix EVO is only a single millimetre shorter.

All of which shows just how close to race-proven geometry the Granturismo SLR really comes.

Of course, Shimano's Ultegra Di2 R8100 groupset provides the drivetrain and brakes. It's BikeRadar's current top pick if you’re after racy performance without the (even more) expensive price tag of Dura-Ace Di2 R9200.

Wilier has opted for a classic endurance 50/34-tooth chainring, paired with an 11-30-tooth cassette.

In today's age of widening capacities, it's more usual for endurance bikes to come with an 11-32t or even an 11-34t cassette – certainly, these would offer even smaller gears for tougher climbs.

On one of the short, sharp climbs of my test loops, where the gradient exceeds 20 per cent, I had to resort to an out-of-the-saddle anaerobic attack rather than a sit-in and spin tactic as I could on the Merida Scultura Endurance (which features a smaller bottom gear).

The Ultegra brakes are matched to IceTech rotors (160mm front and 140mm rear). The ServoWave-enhanced braking gives superb control from either the drops or the hoods.

At the front, Wilier has used its own one-piece Zero carbon bar-stem. This meets the frame using interlocking spacers (the same as on the Filante), delivering a very aero-tidy front end.

The Zero bar on my XL test bike has an effective 110mm stem and 42cm-wide bars – a solid combination for an endurance-oriented bike.

At the back, the dedicated aero carbon post can be offset by 15mm or set to zero. This is topped with a new 3D-printed Fizik Adaptive Argo saddle, with the upper bonded to a carbon base and carbon rails.

Wilier's official specification for the bike states a Prologo Dimension (itself an excellent example of a short saddle design) should be present instead, but saddles are often a matter of personal choice in any case.

Wilier has a long relationship with Italian engineering company Miche – the Granturismo SLR gets a Wilier-badged SLR38KC wheelset.

It has a 38mm-deep, blunt-edged profile and tubeless-ready rims. The internal width is up to 19mm from the predecessor's 17mm. This is a good thing to support wider tyres.

That said, it shapes up the 700 x 30c Vittoria Corsa Control tyres to only 29mm wide, whereas an even broader rim (21mm is fast becoming an established norm) would almost certainly make the most of the nominal width.

I certainly wouldn't opt to fit anything bigger than a 30c tyre on these wheels, because larger volumes will ‘lightbulb’ out from the bead, which can make for somewhat unpredictable handling.

The Miche-made hubs have an enjoyably smooth quality. The freehub features a 12-degree engagement angle, which is broadly quick enough for road duties.

These are built up with 24 stainless steel spokes per wheel. Wilier claims the wheelset has shed more than 100g from the previous version, positing 1,530g for a pair.

However, compared to, for example, the Prime Primavera 44 wheelset found on the Vitus Venon Evo, complete with an internal width of 23mm, the Wilier wheelset looks a little dated.

Your £8,680 gets a solid overall specification, but it's arguably not great value for money (even viewed through the prism of rising bike costs).

In comparison, to name a few, Vitus's Venon with SRAM Force eTap AXS and carbon wheels comes in at around half the price. Cannondale's Synapse Carbon 2 RLE costs £5,800, while Giant's Defy Advanced Pro 1 with carbon wheels and Ultegra Di2 is £3,081 less.

The Granturismo SLR balances comfort and speed in a very road-focused endurance bike package. It's certainly not designed for light gravel riding, for example.

The SLR's biggest plus is the elastomer-fortified frame. The relatively small amount of movement (5mm) doesn't sound like much at all, but it delivers far more than you might expect.

On the road – particularly on chip stone road surfaces and tarmac ravaged by winter's damage – the bike's back end glides over roughness, removing buzz and chatter impressively.

When it's combined with the Fizik Argo Adaptive saddle as supplied, it offers an impressively smooth ride and – importantly – one that's not hindered by any soggy flex or unwanted twisting under load.

Up front, there's something of a contrast: the head tube, fork and Zero carbon bar combine for a notably stiff ride through the front end.

Thanks to being set up tubeless, I was able to drop my normal tyre pressures a little (around 4-5psi) to help compensate. It worked to a degree, but the front end still felt a little buzzy when the road surface was particularly uneven.

The Wilier/Miche wheels are solid performers and a step up from the previous-generation SLR38s, albeit with the limitations I’ve already mentioned.

As it is, the SLR38KC wheelset looks impressive, with a distinctive high-gloss checkerboard-like UD carbon finish.

The Vittoria Corsa Control tyres are excellent, and Wilier should be praised for not skimping here. They feel supple, grippy in all conditions and quick, albeit not quite as rapid or confidence-inspiring in the dry as the standard Corsa or racy Corsa Speeds.

However, the Corsa Control tyres are tougher than both on paper, so a good choice for a bike built for big rides all-year round.

Overall, Wilier has done a great job of retaining the fun factor while dialling down the snappy handling that's part of the brand's racing pedigree, and is often found among its racier machines.

Having said that, the Granturismo SLR never feels ponderous, largely thanks to the stiff front. It's a great bike to descend on with accuracy, proving especially easy to carve through corners.

I enjoyed the stability afforded by the longer wheelbase, while the Vittoria Corsa Control tyres’ high grip levels help you ride with confidence.

In modern bike design, we’re seeing more and more do-anything approaches to endurance road, with radical designs and extra-wide clearances.

On the flip-side, plenty of race-oriented gravel bikes, such as Specialized's Crux, BMC's Kauis, and Factor's Ostro Gravel, are little more than racy road endurance bikes with huge tyre clearances.

However, the Granturismo SLR has stayed pure to the original brief for endurance bikes – to make a fast road bike that's comfortable and fun to ride, no matter how far.

Wilier has for the most part achieved that, especially if you want race-bike like poise, but unfortunately, it comes at a price.

Each of the bikes selected for our Bike of the Year 2023 endurance category was first given a high-tempo two-and-a-half-hour ride to see if any adjustments needed to be made.

The meat of the testing took place over an 82-mile/132km route.

It was then a case of riding the bikes back-to-back and eliminating them one by one until I was left with the best of the bunch.

My decision reflects each bike's balance, how well it handles, how it's equipped and, most importantly, how much fun it is to ride.

For the endurance bike testing alone, I notched up in excess of 1,200 miles/1,931km.

Thanks to our sponsors, Lazer, FACOM tools and Band Of Climbers for their support in making Bike of the Year happen.

Senior technical editor

Warren Rossiter is BikeRadar and Cycling Plus magazine's senior technical editor for road and gravel. Having been testing bikes for more than 20 years, Warren has an encyclopedic knowledge of road cycling and has been the mastermind behind our Road Bike of the Year test for more than a decade. He's also a regular presenter on the BikeRadar Podcast and on BikeRadar's YouTube channel. In his time as a cycling journalist, Warren has written for Mountain Biking UK, What Mountain Bike, Urban Cyclist, Procycling, Cyclingnews, Total Bike, Total Mountain Bike and T3. Over the years, Warren has written about thousands of bikes and tested more than 2,500 – from budget road bikes to five-figure superbikes. He has covered all the major innovations in cycling this century, and reported from launches, trade shows and industry events in Europe, Asia, Australia, North American and Africa. While Warren loves fast road bikes and the latest gravel bikes, he also believes electric bikes are the future of transport. You’ll regularly find him commuting on an ebike and he longs for the day when everyone else follows suit. You will find snaps of Warren's daily rides on the Instagram account of our sister publication, Cycling Plus (@cyclingplus).