Specialized Men’s RBX bib shorts review

Specialized’s RBX bib shorts are designed for comfort and utilise the brand’s Body Geometry philosophy found on many of its other products.

In testing, I didn’t find the chamois pad particularly comfortable on both short and long distances, among other shortfalls.

For those reasons, I don't rate the RBX shorts among the best bib shorts, and I wouldn't be able to recommend them as they are.

Specialized Men’s RBX bib shorts construction

The RBX bib shorts combine a predominantly polyester upper with nylon and elastane for the shorts.

Specialized says the shorts are designed with a ‘Slim Fit’ so they “feel like a second skin” when in the riding position.

Specialized specs its Body Geometry Contour chamois, which uses single-density foam and is claimed to minimise pressure on nerves and soft tissue.

The Body Geometry concept is also found in Specialized’s saddles, gloves, shoes and corresponding footbeds, where the brand optimises comfort in these contact points through scientific research and rigorous testing.

The brand doesn’t specify a suggested distance or time rating for the chamois.

The white bib straps feature small perforations to wick away sweat and there are micro-dot silicone grippers at the hem.

The shorts carry a UPF 50 rating to protect your skin and, as well as two reflective Specialized logos, there’s a reflective band at the back of each leg to ensure you're seen in low-light conditions.

Specialized offers the shorts in five sizes – from S up to XXL. Black is the only colour available.

Specialized Men’s RBX bib shorts performance

The Men’s RBX bib shorts have been tested over a mixture of short and long rides, on both road and gravel.

I found the fit of my size-medium bib shorts rather odd – tight around the pad, but more forgiving at the legs and even looser at the straps. As a result, I’d recommend trying them on for fit before buying, if you can.

The pad packs in plenty of tech on paper, but I didn’t find it particularly comfortable on rides of any distance. While it's reasonably thick, its distribution and positioning wasn’t optimal for my body shape.

I’d have preferred the pad to extend further at the rear and for it to be a little wider to offer more coverage.

I was constantly aware I was wearing the shorts and felt a disconnect between the pad, skin and saddle.

I put this down to the slippery shorts fabric, and the fact the left seam on the inside of the upper thigh is positioned very close to the pad. As a result, I could feel it dig in when out of the saddle, which caused some discomfort.

Of course, it’s worth recognising that fit is subjective and others might find them more comfortable than I did.

On the plus side, the pad didn’t degrade over the test period, nor did any of its properties change after multiple washes.

The bib shorts were tested on four different saddles – a Forza Stratos, a Fabric Scoop, a Bjorn Setka and a Specialized Power Pro Elaston.

I found the material of the shorts to be slippery across the top of my Fabric Scoop saddle during gravel riding – an issue I also experienced with the Van Rysel Road Cycling Bib Shorts Racer 2.

I also struggled to find a comfortable position on the Specialized saddle, despite it being my preferred perch for long-distance riding.

My most comfortable ride with the shorts was when using the Bjorn Setka, a 3D-printed lightweight saddle that is significantly firmer than the other saddles I tested them with.

The narrower profile of the saddle seemed to better suit the distribution of the padding.

I found the straps to be fairly comfortable – they didn’t dig into my shoulders and they were reasonably well ventilated.

The leg grippers also performed without fuss, although I was disappointed to see the elasticity of the hem start to loosen at the end of the test period.

I found the shorts to be fairly well ventilated, keeping me cool in temperatures up to 23°C.

Specialized Men’s RBX bib shorts bottom line

Although the Specialized Men’s RBX bib shorts are well priced for the technology they incorporate, I didn’t find them particularly comfortable on rides of any length.

The pad didn’t feel optimally distributed and it’s unfortunate the left seam on the inside of the upper thigh is positioned so closely to the pad – I felt it dig in when out of the saddle.

If your rides are under three hours, I’d point to the Sportful Neo bib shorts as an alternative at £15 more expensive. If you’re seeking comfort over longer distances, I’d recommend stepping up to the £100 price bracket because you get what you pay for.