Prologo Dimension R2 Nack saddle review: the featherweight, short-nosed perch that reveals a universe of riding possibilities

The R2 Nack sits at the head of Prologo’s popular Dimension product line, a range of versatile, broad, short-nosed performance saddles that, whatever your gender, cater for pretty much every competitive cycling discipline.

Need a saddle for MTB? That would be the Dimension NDR. Gravel or Cross? The Dimension AGX. Something a bit wider? The Dimension Space. A saddle specifically for women? The Dimension EVA. For triathlons? Try the Dimension Tri. A premium perch at a more accessible price? Save up for a Dimension 143. A featherweight for fast riding? Enter the R2 Nack.

It's a big range, especially considering that I’ve missed the countless special editions and that many of the above saddles have counterparts that feature eye-catching zones of nano-structured 3D polymer padding. That’s CPC – Connected Power Control – in Prologo speak.

All of these saddles share a similar, but not identical, broad V-shaped outline that places them in direct competition with other short-nosed seats, such as variants of the Specialized Power, Selle Italia Novus and Fizik Argo, which are among the best saddles. If you’re looking for a more T-shaped short-nosed saddle, Prologo’s solution includes its Scratch and Nago lines.

Construction

For a flagship product, the Prologo Dimension R2 Nack looks suitably understated, if anything, perhaps a little too conservative. Other saddles in the Dimension line are embellished with loud graphics, splashed with colour or feature 3D-printed zones. There’s none of that here, just small, subtle logos on the nose, the stern and the right wing.

Its overall shape stays true to the aforementioned ‘V’, a product of its short nose and broad wings. Width is 143mm, which is wide but not ridiculously so, and the total length is 245mm, so it easily complies with the UCI’s 240mm minimum length rule. The nose is quite chunky at 40mm in width; at least a couple of millimetres wider than the entry-level Dimension 143 model.

The very end of the nose has a slight dip to it, but from here back to the midsection the Dimension R2’s profile is flatter than Florida. From the midsection, just forward of the wing tips, to the very rear of the saddle, there’s a consistently shallow 9° rise. All in all, the profile is pretty flat, with no curves or waves.

I measured the pressure relief channel to be 20mm at its widest point, which is half the width of the cutouts on some saddles I’ve reviewed recently. If it’s up to the job and you don’t like that ‘toilet seat’ look, this could be the saddle for you.

If you’re wondering about the relevance of the Nack suffix, it refers to the 7mm x 9.3mm oval rails, which are made from ‘Nano Carbon Fibre’, Prologo’s proprietary blend of carbon fibre, Kevlar and aluminium filaments. Prologo says Nack is extremely resilient, easily up to the rough and tumble of mountain biking and gravel.

The chassis, which catches the light with a subtle sheen, is made from injected Long Fibre Carbon, a material that’s stronger, stiffer and more resistant to impact than components made from short fibres.

In keeping with many other Prologo saddles, the padding and cover don’t enclose the entire saddle top, only the flanks, leaving the chassis exposed along the centre line. This makes perfect sense – there seems to be little point in padding and wrapping areas that never make contact with the rider.

To save weight, Prologo has developed an EVA padding that it says boasts the same comfort levels as the rest of the range, despite being 20% thinner. Certainly, it is very svelte, with the total thickness, including the cover, down to just a couple of millimetres at the saddle edge.

The cover is faux leather microfibre, which is exceedingly smooth to the touch. To help reduce the glide, Prologo has applied faint, narrow ‘Slide Control’ grip lines, which wave their way across the left wing and right nose area.

The carbon fibre construction and innovative use of padding have reduced the weight of the Dimension R2 to a claimed 135g (139g measured), which is ridiculously light. Apparently, that’s about the same weight as half a baguette but infinitely more comfortable and considerably more robust.

The ride

What sets the R2 apart from the other saddles in Prologo’s Dimension range is its impressively low weight and flat, comparatively wide nose. It’s so light it almost levitates.

These characteristics scream high performance. The weight reduction provides a small but obvious benefit, while the level chunky nose enables riders to tuck into an aero stance with both comfort and control.

However, Prologo doesn’t consider the R2 to be exclusively for tarmac, saying it’s a ‘multi-disciplinary saddle perfect for road and XC/Marathon use’.

Having spun some long miles with the R2 on a variety of bikes and surfaces, riding an assortment of tyre widths and pressures, I think that’s a fair assessment. It’s ideal for anything that calls for lightweight performance, whether that be on road, off-road or, of course, gravel.

Now, I’m a big fan of short-nosed saddles, probably because I’m fairly tall with long legs (84cm saddle to BB), so, by default, my saddle-bar drop is quite pronounced – the equivalent of a mildly slammed stem. A short-nosed saddle with a relief channel, such as the R2, enables me to rotate my pelvis without causing discomfort to the soft tissues of the perineal area. However, I readily accept that they’re not for everyone.

Saddles of this type don’t allow for much fore-aft movement, much to the frustration of riders who enjoy the freedom of fine-tuning their riding positions for ascents and descents. Additionally, riders who like to ‘steer through the hips’ can feel more secure using the grip and leverage a longer-nosed saddle provides.

In my experience, the R2’s flat, broad nose not only makes forward rotation more comfortable, but it also reintroduces some of that security. The potential downside, which I didn’t experience but others may, is the increased risk of chafing, exacerbated by the R2’s already wide V shape.

Which conveniently brings me on to the topic of comfort. Prologo only makes this saddle in a 143mm width, which it claims is a good generic compromise that will fit most people. If you need to go wider, consider the broader, but heavier, Dimension Space.

For me, the relatively narrow pressure relief channel worked its magic. I didn’t notice it providing any distinct advantage or disadvantage over the much wider channels found on saddles such as the Vento Argo from Fizik, except that it prevents as much soggy road muck from soaking your chamois. In theory, having a smaller cutout should enable the chassis to remain stiffer for better power transfer, while, in the real world, the stiffness/compliance dichotomy depends on myriad factors. Regardless, the R2’s long fibre carbon shell is noticeably stiff.

The slim-looking EVA padding was a pre-ride concern that made me wonder whether Prologo was foolishly sacrificing comfort in order to boast headline-grabbing weight-saving stats. However, there’s a good amount of depth over the sit-bone area - perhaps 8mm - and, despite being quite firm, the padding does exhibit a fair bit of cushion. Sensibly, Prologo has only reduced the padding where it’s not needed, so rides of up to four hours on this stiff saddle never felt unduly harsh, even towards the finish.

The primary advantage of the Nack rails is their contribution to saving weight, which they achieve admirably. Carbon fibre rails are also said to be stiffer, yet absorb more road vibration, qualities that are difficult to quantify. Much depends on where your saddle is clamped on the rails, and whether it is truly possible to perceive such minor suspension benefits over components that have a more significant influence, such as your tyre and pressure choices.

Value and conclusions

It’s no surprise that the Prologo Dimension R2 Nack saddle ticks so many boxes. After all, that’s the raison d'être of the Dimension line - it’s Prologo’s most versatile saddle range. The R2 is light, slight, comfortable and well up for keeping your posterior happy whatever your chosen discipline. Provided, of course, you get along with short-nosed saddles.

However, its hallmark feature – its impressive ability to defy gravity – must be weighed against its hefty price. At £209/$249, it is more than twice the price of the entry-level steel-railed Dimension 143, yet the weight saving is only 84g. To be fair, the R2 probably benefits from better quality padding, and its carbon rails and chassis may provide a better ride feel. Only you can decide whether these benefits add £100/$100 of value.

The R2 fares better when compared to outside competition. Fizik’s full carbon Vento Argo 00 shares a similar spec to the R2 and matches it gramme for gramme, but it is considerably more expensive at £269.99/$299.99. Specialized’s S-Works Power, which boasts a carbon shell and rails, costs £240/$324 and weighs 25g heavier than the R2.

However, these saddles from Fizik and Specialized are both available in a variety of widths, whereas unless you have generic-sized sit bones you may come unstuck with the R2. The alternative, the 153mm Dimension Space, weighs a substantial 100g more.

Specs

• Weight: 135g claimed, 139g measured
• Size: 245x143mm
• Rails: Nack (Nano Carbon Fiber) composed of carbon fiber, Kevlar and aluminium filaments
• Chassis: Long Fiber Carbon