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Prologo Dimension Nack Saddle



An interestingly shaped saddle that works, especially for those who spend a lot of time in the drops

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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Prologo's new Dimension Nack saddle is shorter than most in its range, being one of the latest 'stubby' saddles we've seen arriving on the market. Whether you're after a reduced nose saddle for performance or comfort, you'll find it here as the Dimension fits both bills. You don't necessarily need to be a racer who spends a lot of time in the drops to receive the full benefits. If you move around a lot, though, it might not be for you.

  • Pros: Comfortable shape, beautifully finished
  • Cons: Oval rails won't work with every seatpost clamp, and it's £200

Short-nosed saddles aren't a new thing. Seats like ISM's Adamo came out years ago with a design aimed at reducing pressure on your vitals while you're riding.

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Time triallists and triathletes have been using them for years too. When you're spending a lot of time in the tri-bars with a flat backed position, the long nose of a standard saddle can be uncomfortable. This leads you to shift around a lot, which isn't ideal from an aerodynamic point of view or pedalling efficiency.

If you're likely to race in a UCI sanctioned event, there is also the 5cm rule to consider: the tip of the saddle has to be 5cm behind a vertical plane taken from the bottom bracket.

The Dimension Nack addresses all of this in one fell swoop.

Prologo 2018 Dimension Nack Saddle - nose.jpg

My own bikes are set up with quite a large drop between saddle and handlebar, and while I don't race I do tend to trash them about with my hands in the drops quite a lot. After years as a time triallist I'm most efficient when I have the saddle pushed quite far forward (time trial bikes tend to have a steeper seat angle than a road bike, putting you in a more aggressive, forward position), so I was looking forward to trying out the Dimension.

It works very well indeed. The short nose does make it feel like you are perching on the front of the saddle, but when really crouched in the drops and hammering along it feels great.

I managed to get the rear of the saddle about an inch further forward than normal without affecting the distance from tip to handlebar. If I was racing a UCI event it would give me some decent benefits.

I wouldn't say I've ever really felt discomfort from riding like this on my normal saddles but it was definitely noticeable that the Prologo has less up front, which gives more freedom of movement.

Not only is the Dimension shorter than the norm (by about 30mm), it is also wider at the rear, 143mm to be precise, compared with a more usual 135mm. It's not a massive amount but it gives you a good sized platform to really push back against and get the power out of your legs into the pedals.

Prologo 2018 Dimension Nack Saddle - detail.jpg

Comfort & support

It's not just performance riding where the Dimension works, though. Sit up a bit and relax and you'll find that the shape of the saddle and the padding offer a decent balance of comfort and support.

The padding is quite firm, and I wouldn't say that the Dimension is the most comfortable saddle I've ever ridden, but it's pretty close.

One thing Prologo has got correct is the density of the foam around the cutout. This is my biggest bugbear when it comes to saddles with holes in them: if the foam's too soft it'll squidge and flatten out into the cutout, causing discomfort; too hard and you end up with pressure points all the way round.

The cutout itself seems to be positioned right, and I prefer saddles like the Dimension that position it inside a central groove that runs the full length of the saddle, again reducing the chance of pressure points.

Lightweight carbon construction

For the amount of padding that the Dimension Nack uses, it is quite a lightweight saddle: 157g (149g claimed) to be precise.

To achieve this, it uses a fair amount of carbon fibre in its construction, like the main body. This is 5mm thick, and unlike a lot of other saddle shells isn't very flexible at all.

The same can be said for the rails; normally you can get a little give here, but not with the Nack.

The rails join together and plug into the nose of the saddle quite far back, so this probably adds to their stiffness, plus they are oval in design, 7mm x 9.3mm, with the wider dimension from top to bottom. This also means not every seatpost clamp will accept them, the awkward design on my Cinelli Neos post for one.

Prologo 2018 Dimension Nack Saddle - underside.jpg

The Dimension also comes in a metal railed version, the Tirox, which has standard 7mm diameter rails. The Dimension Tirox is a little heavier but £80 cheaper at £119.99.

Like most saddles these days, the Dimension uses a microfibre upper which is pretty grippy. I certainly never found myself sliding around, which is a good thing as there is nowhere for you to move to. This highlights another consideration before you rush out and buy the Dimension: if you change position on your current saddle then this probably isn't going to work for you.


At £199.99 the Dimesion Nack is a lot of money for a saddle, but no way is it alone out there in the marketplace. My longterm favourite for all-round riding is the Fizik Aliante 00, which at the time of testing was a cool £279.99, and the Prologo is every bit as good in terms of design, attention to detail and finish.

More recently we've had Fizik's Arione R1 Versus Evo in on test; £210 for a very similar saddle.

On the flip-side though, we've got the likes of Fabric creating excellent saddles such as the Line Titanium for £69.99.

> Buyer's Guide: 10 of the best high performance saddles

I'd say the Prologo Dimension justifies its price: it looks great, feels great and is very well made. Personally, though, I'd probably sacrifice a bit of weight and buy the cheaper Dimension Tirox version instead, with its round rails.

If you have no qualms about paying extra for the bling factor, though, the Dimension Nack is brilliant.


An interestingly shaped saddle that works, especially for those who spend a lot of time in the drops test report

Make and model: Prologo Dimension Nack Saddle

Size tested: 143mm width,

Tell us what the product is for

Prologo says, "The name DIMENSION contains the importance of the project itself: creating an innovative product in terms of design, size, comfort and performance.

Comfort, Performance, Lightness and Prevention of perineal area problems are its strengths.

The saddle has a short nose (3/3,5 cm shorter than a traditional ones) to eliminate any sort of contact and pressure in the front area, especially in the maximum pushing phase (on the drops).

Design and size are completely new and revolutionary (short and wider than a traditional saddle): 245x143mm, only 149gr in Nack version.

DIMENSION, an Ergonomic, Lightweight and Anti-Prostate for high-end customers seeking their best.

The increased 143mm width, helps to distribute the weight of the athletes on a larger surface, ensuring greater comfort for a long time. The wide anatomical channel 'PAS' runs through the saddle along its central axis, reduce the contact and compression of soft tissues and tendons, eliminating numbness and helping to prevent prostate problems."

I'd say the Dimension is probably suited to those riders who spend a lot of times in the drops or don't move around on the saddle much.

Tell us some more about the technical aspects of the product?

From Prologo:

Size (mm): 245 x 143

Weight (gr): 149 g

Rail: 7 x 9,3 mm

Cover: Microfiber

Padding: Light Foam

Rate the product for quality of construction:
Rate the product for performance:
Rate the product for durability:
Rate the product for weight (if applicable)
Rate the product for comfort (if applicable)
Rate the product for value:

Tell us how the product performed overall when used for its designed purpose

I found the Dimension to be comfortable for all types of riding positions, but it works best when you are hammering along in the drops.

Tell us what you particularly liked about the product

The shape.

Tell us what you particularly disliked about the product

Rail dimensions won't work with every seatpost clamp.

Did you enjoy using the product? Yes

Would you consider buying the product? I'd probably go for the cheaper Tirox version.

Would you recommend the product to a friend? Yes

Use this box to explain your overall score

The Dimension Nack is £200 which is a lot of money for a saddle, but if you want a stub-nosed, lightweight race saddle it's hard to fault when it comes to performance and quality.

Overall rating: 8/10

About the tester

Age: 38  Height: 180cm  Weight: 76kg

I usually ride: This month's test bike  My best bike is: Kinesis Aithien

I've been riding for: 10-20 years  I ride: Every day  I would class myself as: Expert

I regularly do the following types of riding: time trialling, commuting, club rides, sportives, fixed/singlespeed

As part of the tech team here at F-At Digital, senior product reviewer Stu spends the majority of his time writing in-depth reviews for, and ebiketips using the knowledge gained from testing over 1,500 pieces of kit (plus 100's of bikes) since starting out as a freelancer back in 2009. After first throwing his leg over a race bike back in 2000, Stu's ridden more than 170,000 miles on road, time-trial, track, and gravel bikes, and while he's put his racing days behind him, he still likes to smash the pedals rather than take things easy. With a background in design and engineering, he has an obsession with how things are developed and manufactured, has a borderline fetish for handbuilt metal frames and finds a rim braked road bike very aesthetically pleasing!

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part_robot | 6 years ago

Just here to say I absolutely love Prologo saddles. Hard to get hold of to try (I tried a bunch in Italy) but really worth it. These new shorter designs look even better than my Zero II which is already absolutely spot on.

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