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Prologo Dimension AGX 143 T4.0



A decent spec for the money, backed up by excellent comfort and shape to create the ideal saddle for all kinds of riding
Supportive padding for road and off-road riding
Subtle shell flex aids comfort
Very neatly finished underside
248g Recommends

This product has been selected to feature in recommends. That means it's not just scored well, but we think it stands out as special. Go to recommends

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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The Prologo Dimension AGX 143 T4.0 saddle is designed to work across a range of terrains – and I found that it did so very well indeed. This is one impressively comfortable saddle, the shape works, the padding is effective and it doesn't cost the earth, which is a winning combination as far as I'm concerned.

Our best road bike saddles buyer's guide rounds up our favourite road saddles, while our sister site lists its top mountain and gravel bike saddles. 

AGX stands for 'adventure, gravel and cyclocross', so first up I bolted the Prologo to the Fairlight Secan gravel bike I'm reviewing and headed straight out onto the trails. The Dimension felt as if I'd been using it for years – like a saddle that had bedded in and compressed to my shape over time. That's how good the comfort was.

2023 Prologo Dimension AGX 143 T4.0 - nose.jpg

I'm not a big fan of a lot of padding, especially if it's overly soft and squidgy. While some think more padding equals greater comfort, I just find it causes numbness and/or hot spots as a ride progresses. So, I was glad to find that while Prologo has added a touch more padding thickness than you'd find on the road version of the Dimension, of which I've ridden loads, it still maintains a firmness that while supportive, doesn't dull any of the feedback coming to you from the frame and your rear tyre.

2023 Prologo Dimension AGX 143 T4.0 - rear.jpg

The AGX has a curved upper, which is a shape I like. The slightly curved rear section gives you something to push against when you're climbing, and thanks to its 'shorty' design and the fact that the nose drops ever so slightly, there is nothing to apply pressure to your vulnerable bits when you're hunkered down in the drops.

2023 Prologo Dimension AGX 143 T4.0 - underside.jpg

A large central cut-out also helps blood flow.

2023 Prologo Dimension AGX 143 T4.0 - from rear.jpg

During the review period I also did a few gravel rides over three-and-a-half hours long – and I found that the padding didn't compress over time and the Prologo felt just as comfortable at the end of the ride as it did for the first hour. There is some subtle flex in the shell that helps reduce some of the small bumps too, although it's not enough to feel too flexible when you're pedalling hard in the saddle.

2023 Prologo Dimension AGX 143 T4.0 - top.jpg

If you aren't a gravel rider but want a comfortable saddle for the road with a bit of extra padding, then the AGX is definitely worth a look.

The Dimension AGX features a carbon fibre shell underneath the foam padding and a microfibre upper. The T.4.0 model's rails are made of 7mm diameter chromoly steel. This makes the T4.0 the heaviest saddle in a three-saddle range; a Tirox rail option comes in about 45g lighter, with the carbon-railed Nack model around 60g lighter.

2023 Prologo Dimension AGX 143 T4.0 - underside nose.jpg

The overall finish is to a high quality, with the durable upper tucked under the padding before it is mounted on to the shell, which gives a clean edge all the way around. On some saddles the upper is glued or stapled to the underside of the shell, which can look a bit rough and ready.

2023 Prologo Dimension AGX 143 T4.0 - underside rear.jpg

This T4.0 model weighs 248g and is 143mm wide and 245mm long.


Fizik's gravel-specific shorty saddle is the Terra Argo, which like the Prologo saddle, is available in various builds at difference prices.

The full carbon X1 model that we reviewed costs £179.99, but Jamie rated it highly for its shape, comfort and its overall build quality. The entry level X5 model, which has a similar tech spec to the Prologo, is £99.99 although I'd say the Prologo has the win when it comes to aesthetics.

The Prime Primavera Shorty carbon saddle impressed me very much, and until the AGX came along it was the one that was fitted to my gravel bike. It has an RRP of £119.99 but is currently just £94.99 online and for that you are getting a full carbon construction and a weight of 175g.

The Prime Doyenne road version comes in at just £59.99. It has titanium rails, Tom rated it very highly and it looks like it has slightly thicker padding than most road saddles have.


The shape, padding thickness and the quality of the Prologo Dimension AGX just works from all directions from me. It's comfortable, well made and comes in at a decent price overall.


A decent spec for the money, backed up by excellent comfort and shape to create the ideal saddle for all kinds of riding test report

Make and model: Prologo Dimension AGX 143 T4.0

Size tested: 245 x 143mm

Tell us what the product is for and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

Prologo says: "Connecting with nature, challenging oneself and living the moment, this today more than ever is the spirit of the gravel. As an official technical partner of white streets, an iconic and unique race in its kind that combines different landscapes inside, we wanted to create the most versatile line of saddles ever, ready to accompany you and support you in any condition and environment.

So she was born AGX, acronym of Adventure – Gravel – Cyclocross who looks to the outdoor world but also perfect for those looking for a comfortable saddle from every point of view."

The AGX's shape and padding works very well for gravel riding, but it'll find plenty of use on the road bike too.

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

Size: 245 x 143mm

Rail: T4.0 Steel 7mm

Cover: Microfibre

Padding: Light Foam

Rate the product for quality of construction:
Rate the product for performance:
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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

Good firm padding that is well suited to gravel or general off-road riding.

Tell us what you particularly liked about the product

Very comfortable shape and padding.

Tell us what you particularly disliked about the product


How does the price compare to that of similar products in the market, including ones recently tested on

It's pretty much the same money as the similarly specced Fizik mentioned in the review, although the Prime models offer very good value for money.

Did you enjoy using the product? Yes

Would you consider buying the product? Yes

Would you recommend the product to a friend? Yes

Use this box to explain your overall score

There are no weak areas anywhere on this saddle. About the only downside is that some other brands will offer higher-spec models for not much more money. But I reckon the AGX has the ideal density for gravel riding while its shape allows you to get the power down.

Overall rating: 9/10

About the tester

Age: 44  Height: 180cm  Weight: 76kg

I usually ride: This month's test bike  My best bike is: B'Twin Ultra CF draped in the latest bling test components

I've been riding for: Over 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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