Are the new and updated Prologo AGX saddles the new benchmark perches for gravel and adventure riding?

The top down view of the new Prologo Dimension AGX and Scratch M5 AGX saddles
(Image credit: Prologo)

Fresh from the recent launch of the Prologo Scratch NDR saddle which the renowned Italian saddle manufacturer claimed was one of the best mountain bike saddles on the market. Prologo has expanded its gravel, adventure and cyclocross saddle range, with new and updated saddles in the Prologo AGX range which the brand says are now the benchmark for performance and comfort, dedicated to gravel bike racing, the best gravel bike adventures, and all types off-road terrain.

Prologo introduces four new versions of the Scratch M5 AGX and Dimension AGX models, two saddles equipped with carbon Nack rails, making them lighter and more performance-oriented, and two new Space versions, which are more padded and wider with an emphasis on comfort.

Having tested some of the Prologo mountain bike-specific saddles in the past, they have always come out highly rated, and archived Bike Perfect reviews also include the previous incarnation of the Scratch M5 AGX which is rated as one of the best gravel saddles, ridden by mega endurance athlete, Lachlan Morton. We had a delve into some of the details and differences between the new AGX saddles.

Prologo Dimension AGX saddle

Prologo has designed these saddles to cover all riding choices from performance to comfort (Image credit: Prologo)

Scratch M5 and Dimension AGX

The Scratch M5 AGX and Dimension AGX come with Nack rails which is the innovative Carbon Fiber system developed by Prologo with rails composed of carbon fiber, Kevlar and aluminum filaments. The Nack rail system is already widely adopted by Prologo for its other top-of-the-line saddles successfully used by professional riders in MTB World Cup wins and Grand Tours.

Along with the Nack rails, these versions of the Scratch M5 AGX and Dimension AGX come with a new base made of Carbon Long Fiber (long fiber carbon injected Nylon), which provides further weight reduction and increased stiffness which is aimed to further increase power transfer during pedaling. 

View of the differences between the Scratch and Dimension AGX

The main difference between the Scratch and Dimension AGX is the cut away section on the Dimension (Image credit: Prologo)

Both these saddles are almost identical in appearance and specification though the Dimension AGX difference is the central V-shape cutaway that allows a more advanced position in the saddle, and is also designed to eliminate the pressure in the front perineal area. The measurements are very similar with the Scratch M5 AGX measuring 250x140mm and the Dimension AGX 245x143mm.

They are also a claimed feathery 172g for the Scratch M5 AGX and 169g for the Dimension AGX, and are specifically aimed at professional gravel racers, with the likes of Nicolas Roche, Alex Howes, and Emily Joy Newsom riding them in their race seasons. Prologo adds they are also ideal for riders seeking lightweight components, without sacrificing strength and durability.

Top down view of the Prologo Scratch M5 AGX saddle

The AGX saddles will be raced by Nicolas Roche, Alex Howes, and Emily Joy Newsom (Image credit: Prologo)

Scratch M5 AGX Space and Dimension AGX Space

Graphic showing the differences between the Scratch M5 AGX Space and Dimension AGX Space saddles

The Space versions are all about comfort with extra padding and width (Image credit: Prologo)

Measurement of ischial bone distance (sit bones) and body mass index, are just some of the key parameters used in the Prologo MyOwn system, Prologo's bio-mechanical system that allows riders to find the most suitable saddle and is done free of charge at selected Prologo retailers, or if buying online you can easily measure your sit bones at home with our linked guide.

Compared with racier AGX models, the two Space versions feature a wider width of 7mm for the Scratch M5 AGX Space and 10mm for the Dimension AGX Space. Also added to maximize comfort, the new Scratch M5 AGX Space adopts the TiroX rail, and weighs 201g, made of light-alloy steel, a material that has a claimed excellent balance between weight and strength. The Dimension AGX, on the other hand, is available in two versions, with TiroX rail and T4.0, a chromoly rail specifically for the Dimension line, made through an advanced process that ensures greater lightness and technical strength, and weigh in at 219g and 228g.

So what's your saddle of choice? It's an interesting debate, race performance over extra comfort or a full saddle over the pressure relieving cut away. Prologo certainly appears to tick all the boxes with choice and build and therefore should have you covered for any option you prefer.

Gravel rider on the new Prologo saddle

Prologo say their MyOwn system allows riders to find the most suitable saddle (Image credit: Prologo)

Pricing and availability 

Prologo AGX saddles with Nack rail and the new Space versions, are already available online at and at top Prologo dealers at the following prices, Scratch M5 AGX with Nack rail is priced at £191 / €219 and the Dimension AGX with Nack rail at £191 / €219. The Space versions are priced at Scratch M5 AGX Space with Tirox rail at £122 / €139, the Dimension AGX Space with Tirox rail at £122 / €139 and Dimension AGX Space with T4.0 rail at £101 / €115.

Paul Brett
Staff writer

Paul Brett is a staff writer for He has been an avid cyclist for as long as he can remember, initially catching the mountain biking bug in the 1990s, and raced mountain bikes for over a decade before injury cut short a glittering career. He’s since developed an obsession for gravel riding and recently has dabbled in the dark art of cyclocross. A fan of the idea of bikepacking he has occasionally got involved and has ridden routes like the North Coast 500, Scotland and the Via Francigena (Pilgrim Route), Italy.

Current rides: Marin Alpine Trail 2, Ribble 725, Cube Stereo 160

Height: 175cm