Mountain bike shorts for XC and trail riding
If you're riding single-track, cross-country, or any type of recreational mountain biking, regular cycling shorts may be all you need. These are typically made out of very lightweight, stretchable and breathable fabric that wicks moisture away from your skin and have the chamois liner to keep you comfortable. You can wear them on their own or, if you aren't a fan of the Spandex look, under a pair of baggy shorts to keep you comfortable. Cycling shorts are meant to be snug, so they can also do a bit toward protecting your legs from stray branches on the trail.
Protective mountain bike shorts for downhill and dirt jumping
If you're riding/racing downhill or dirt jumping, the level of protection you need goes way up. If you fall or crash, regular cycling shorts will not offer any protection to your hips, thighs, or tailbone. Protective mountain bike padded shorts are made with lightweight, breathable fabric and incorporate padding for your hips, thighs, and/or tailbones. Most downhill racers/riders spend most of their time out of the saddle, so a seamless chamois liner is less important than the padding.
Things to consider when choosing mountain bike padded shorts
- Pad thickness can range from a quarter to half an inch. While thicker pads are going to provide more cushioning, they can also be a little bit bulkier. Let the crash potential of your riding (trails vs. downhill) guide the pad thickness
- Look for padding in the hip, quad, and tailbone areas, which are the areas you're most likely to hit in a crash
- If there's a mirror handy, make sure to look at the pad coverage as it will be on the bike (i.e., seated) as opposed to standing
- Find a pair with a snug fit--padded shorts that slide around will chafe against your skin
- Some riders don't like the tight-fitting Spandex look; a lightweight pair of padded MTB shorts work well under a pair of light soccer or cargo shorts to keep you protected while you ride but still keeping a look you like
- Remember that cycling shorts are designed be worn without underwear. The chamois liner does not have a seam on the crotch; underwear generally does. No seam=no pressure.
Mountain bike padded shorts: Lets talk about pads
Types of padding in mountain bike shorts
Most protective clothing for mountain biking features padding made from EVA foam. However, some manufacturers use other advanced protective technologies to provide flexible impact absorption. For example, POC has developed a visco-elastic polymer dough (called VPD) that is soft and comfortable but stiffens upon impact to absorb an extreme amount of energy. Each type of padding is designed to dissipate the force of a hard impact. The type of padding you choose is probably less important than the placement of the pads.
Pad placement in mountain bike shorts
A study in the British Medical Bulletin notes that 60-70% of all mountain bike injuries are soft tissue abrasions, lacerations, and contusions. Downhill riders are far more likely to be injured than cross-country riders (injury rate of 0.37 riders per 100 cross country vs. 4.34 riders per 100 downhill racing). You're most likely to go over the handlebars in a fall, so you'll want to find padded mountain bike shorts with thigh and hip coverage. While tailbone padding might sound uncomfortable for bike shorts, if you're spending most or all of a downhill race out of the saddle, then tailbone protection makes a lot of sense.
Considerations for female downhill riders/racers
Most mountain bike shorts - protective or otherwise - are designed to fit men: slim in the hips and thighs and possibly hitting higher on the waist than you prefer. Some manufacturers, like Vigilante, and Crash Pads make padded shorts with a female-specific design. The level of protection and the quality of the material is typically the same, but the shorts are cut differently. Generally the waistband will be a bit lower than on a men's cut and there will be a bit more room for hips and thighs. Check to see if the brand you like comes in a female-specific design. If you're riding / racing downhill, you're probably spending most of your time on the bike out of the saddle. In that case, it might be worth checking out roller derby padded shorts as well. While they may not cover as much of your thigh as mountain bike shorts, they'll offer advanced protection with a proper fit.
Do I Need a Chamois Liner?
The chamois liner in cycling shorts reduces pressure on your rear/crotch area by removing the sewn seam you'd normally find holding the shorts together. In addition, the wicking material in the chamois keeps moisture away from your body, which helps to reduce bacteria that could cause infection and helps prevent chafing. Cycling shorts frequently come with a bit of padding under the chamois liner to offer a bit of comfort during long hours in the saddle. If you're riding single track, fire roads, you'll be more comfortable in mountain bike shorts with a chamois liner, but you probably won't need any protective padding. If you're riding downhill, you probably spend more time standing up on the pedals than seated. In this instance, whether or not the mountain bike shorts have a chamois liner is far less important whether the shorts have protective padding on the hips, thighs, or tailbone.