Buyer's guide to mountain bike waterproof shorts - how to buy the best ones

A good pair of mountain bike waterproof shorts are essential to winter riding, they help keep you dry, warm and crucially more comfortable. They can be a pricey bit of kit though, so to aid you in your search for the perfect pair we’ve created this buyer’s guide, giving you the low down on what’s hot and what’s not where waterproof shorts are concerned.

[Updated 26th October 2020]

What are waterproof shorts?

Most brands have a waterproof short in their mountain bike clothing range these days and they usually extend to feature men’s and women’s versions too which is all great stuff. There can, however, be a large amount of variation between those shorts and the technical features they offer. Do you know your waterproof from you water resistant, what exactly is DWR? Read on to find out…

A waterproof short, in brief, is a pair of shorts that are made of the same sort of material as the raincoat you wear and they replace the pair of baggy short you would wear when riding normally. They are designed to stop water getting in and making your lycra soggy where it will chafe and make you cold pretty quickly. They are usually designed with similar waterproof and breathability ratings as a jacket too, the higher the rating the more waterproof and more breathable, keeping you drier and more comfortable, regulating your temperature.

The choice of waterproof shorts is widening and with that, the shorts on offer are getting more stylish, more comfortable and crucially better performing.

Why do I need them?

A waterproof short is a rider essential for pretty much any winter season all over the globe but especially here in the UK. They will protect you from the elements including rain and snow and they will also keep the wind off you, keeping you warm from the extra chill factor the wind causes. Anything that makes the riding experience a bit more enjoyable, and therefore extendable, is good in our books, protected from the elements you’ll be able to stay out for longer and ride more – result! Handily, they can also save your washing machine from a fair amount of muck and grime, waterproof shorts can we worn, hosed down and left to dry, saving the machine from all that dirt. They will only generally need to be reproofed when the water stops beading, you feel water ingress or if you wash them with a normal detergent.

Waterproof shorts aren’t just for the rain either, if the ground is wet (likely for most of the year!) then they will stop you getting wet from the ground up too, warding off trail splashes and keeping mud an grit from penetrating your under layers. In our opinion, a waterproof short doesn’t look out of place on any bike from a mountain bike to a gravel bike, if it’s raining cats and dogs then it’s the only sensible thing to wear whilst you get your bike fix.

Waterproof, water resistant and DWR explained

Most waterproof shorts will be fully waterproof or they might have a waterproof rear panel with water-resistant front panels. For the former the short will be made completely of the same material and brands will usually promote that they are constructed of 2 or more layers. In a typical 3 layer short the outer layer or face of the fabric give the short their colour and act as a fully sealed layer is the first line of defence against the rain. The middle layer is usually a membrane stuck between the backer or inside of the short and the outer layer. This membrane will be a highly sophisticated material that has many holes across the surface, these holes will be too small to let water in but will allow vapour to be released, the quality of this layer contributes to both the waterproofness and the breathability rating of the shorts. The inner layer protects the membrane from damage.

As for the latter, some shorts are designed with a fully waterproof rear panel and a water resistant front panel. Water-resistant fabrics will have a waterproofing repellent coating applied to the outer fabric to prevent absorption of water letting it just run off. These shorts will keep you protected from trail spray and light rain but you are likely to still get soaked should the heavens open. On the flip side though they will be more breathable so good in warmer or changeable weather, an example of this type of shorts are the Alpinestars Outrider shorts, click here for the review or here for the similar Endura MT50 Spray Short II, pictured below.

In a nutshell, a waterproof material will be fully waterproof and will have a hydrostatic rating letting you know the weather conditions the garment is good for 1500 (light rain) up to 20000 (heavy rain). Hydrostatic ratings are measured by manufacturers by placing a column filled with water over the taut fabric and measuring how many millimetres of water the fabric can withstand in that column before it leaks through.

What is DWR?

DWR stands for durable water repellent, it’s a chemical applied to the outer layer of a fabric so that water beads and rolls off, preventing the fabric from becoming saturated with water. It usually needs to be reapplied to the garment to maintain the performance of the kit, especially if you machine wash kit with a detergent or if it is exposed to lots of dirt and sweat – both imminently likely we reckon!

What about the seams?

A good pair of waterproof shorts will have fully taped and sealed seams, just like any good jacket. Seams should be taped, usually with a strong nylon cloth with a rubber backing, to prevent water ingress where the stitching needle has left a hole. Dealing with the seams in this way ensures water does not get through to the wearer and also increased the durability of the kit.

Breathability

Although there are big old air gaps in the bottom of waterproof shorts allowing air circulation, it’s a good idea to buy shorts with a high a breathability rating as you can afford or find to make sure that any sweat can escape at a good rate, in turn keeping you more comfortable. It is a fine line though as a layer or warm air can equate to warmth as long as your under layers don’t get saturated. If you are riding in particularly cold temperatures and the warm, moist air from your body escapes too quickly then it could leave you cold. A breathability rating in the region of 10,000 to 15,000g will be good for riders that often break into a sweat riding and are going harder for longer. Some shorts have extra zips that can be left open to aid air circulation too, leaving it up to you to balance the rain/warmth situation.

Cut and fit

Waterproof shorts, just like regular shorts come in all different shapes and sizes, from the shorter types for quick cross-country rides to longer varieties which are comfortable cover knee pads. The choice is up to you but in our experience, we’ve found we prefer a longer short, the added length covering the knee stops water getting onto kneepads and therefore seeping up the leg and making lycra shorts damp in the process too.

We took a look at Madison’s Zenith waterproof shorts earlier this month and found the length of these shorts to be ideal, there is a huge amount of coverage for long days in the saddle in the pouring rain. In contrast we have also reviewed the Scott MTN DRYO 50 women’s waterproof shorts which fall to just above the knees. When pedalling this short moves further up the leg, exposing the knee and leading to wet knee pads and lycra as you ride.

We recommend you look for a garment that has articulated knees so the shorts don’t move when you pedal and also one that offers good freedom of movement via well located and cut panels, its worth bearing in mind that waterproof fabrics won’t stretch as much as regular shorts so a good fit is a must have.

Fixtures and fastenings

Some waterproof shorts, like the Madison Zeniths or the Scott MTN DRYO’s, have a simple and lightweight style with an elastic waist and no pockets at all. Although this doesn’t leave you any storage options, the elastic waist with drawstrings will fit most riders and the lack of other fastenings means there is nothing to break or go wrong when encrusted by mud.

Madison, actually also have a pair of shorts at the other end of the scale, the DTE waterproof shorts, these are all singing, all dancing, pocketed shorts with a popper waistband, zip fly and waist tabs, providing a fine-tuned fit. Brands using chunky easy to use fastenings like this are better here, they are easy to grab when covered in mud and will withstand some hard use!

If you know you are going to treat you waterproof shorts to a hard life then it might be best to look for something that has a reinforced rear panel to help give it a longer life against the continuous rubbing of grit between the saddle and the short.

A note on pockets

If there are zips on the short, for example at the pockets then is pays for these to be fully waterproof zips too, especially if you are planning to put something valuable in there such as a phone. Some waterproof shorts have mesh backed pocket, which if positioned lower on the leg, will leave them vulnerable to splashes – best to check first.

Anything else to know?

Well yes, just one more thing. You can also get a couple of other different types of waterproof garments for the lower half which we think are pretty good too. Some shorts as well as being waterproof are also lined with a softshell or fleece like material, like these DTE softshell shorts from Madison.

Not only will these keep you dry but they’ll also keep you much warmer than the thin material of a regular waterproof short. We’ve also been pretty keen on waterproof trousers too lately, there is something supremely satisfying about enduring super muddy riding knowing that your legs and knee pads are clean and dry underneath. Trousers also stop water from getting down the top of waterproof socks meaning dry feet all day too – winner winner!