“Shorts are the most important item of bike clothing as well as the most misunderstood, especially among non-cyclists. ”
Biking Shorts: 3 Functions
Biking shorts have three primary functions and is an important piece of gear for comfortable riding:
1) Make you more aerodynamic
- Only important in cross-country mountain biking (XC-MTB) and road cycling. Most mountain bikers don’t care about aerodynamics and select shorts based on style and comfort.
- MTB shorts are more comfortable than Roadie shorts and also have pockets.
2) Create a friendly relationship between your butt and seat
- The butt/seat relationship is super important in avoiding saddle sores and skin chafing.
- The sewn-in pad inside the crotch is called a chamois, and adds padding between your butt and the seat or "saddle."
3) To distribute & dissipate pressure
- To distribute and dissipate the pressure, shock, and vibrations transmitted to your MTB seat/"saddle
Notice the tight, more aerodynamic biking shorts that this XC-MTB rider is wearing
Do you wear underwear underneath MTB Shorts?
“Avoid the rookie mistake of wearing underwear beneath cycling shorts. This defeats the idea of special-purpose cycling shorts. Nothing should come between your skin and the chamois, except, perhaps, some lubrication. ”
NO. Both male and female riders should wear their mountain bike shorts DIRECTLY against their skin.
You do NOT wear underwear beneath mountain biking shorts with a built-in chamois pad
The MAIN point of the pad is to provide a contact surface that absorbs moisture and does NOT chafe your skin
Wearing underwear not only defeats the purpose but will lead to:
Chafing: Cotton underwear becomes abrasive once it’s wet.
Seams & Ridges: Underwear, regardless of material, creates seams and ridges which are unconformable and lead to saddle sores.
Seams for cycle and MTB shorts are located away from delicate areas and are flat-stitched to prevent irritation.
Notice the baggier and more stylish MTB shorts in more downhill focused mountain biking (less time sitting on the seat)
If you must wear underwear & mtb shorts
“Do not wear regular undergarments while using cycling shorts, as the seams of the underwear can cause saddle sores.”
If you must wear underwear for some reason, wear underwear that has moisture management characteristics, such as Coolmax.
The pad is designed to absorb perspiration, so if you must wear underwear, you will need to wear an undergarment that absorbs moisture and has the least amount of seams.
Difference between road & mountain bike shorts
Generally, road cycling shorts are tight-fitting spandex with a pad (chamois) built into it.
Designed to be close-fitting and aerodynamic
No pockets - Pockets flap & rattle
Roadies spend considerable time in the saddle compared to mountain bikers. If you plan on mountain bike touring or going on long MTB rides, you might want to consider wearing cycling-shorts as they are designed to be ridden for extended time over many miles.
Ricardo (guide for us) wearing cycling shorts on his road bike
Mountain Bike Shorts
Mountain biking shorts are generally loose or “baggy” that comes with a removable padded liner (chamois). These shorts look like regular shorts and include pockets. Some mountain bikers (MTBers) especially, downhill (DH) MTBers don’t spend much time in the saddle, these shorts are more comfortable when off the bike but don’t have extended pedal comfort.
MTB shorts look like regular athletic gear
Wash chamois after every ride
As the case with regular underwear, it’s important to wash your chamois after every ride.
Microbial infestation happens with next-to-skin clothing, especially athletic underwear. Bacteria thrive in a dark, warm, and moist environment, such as your used chamois.
If you don’t wash after every ride, you will be ripe for infections, UTIs, rashes, and saddle sores.
Wash your padded liner after every ride
Air dry if you want the chamois to last longer
Soiled shorts don’t perform as well as freshly washed ones (because of those dirty microbes)
Jesse is Director of Pedal Chile and lives in Valdivia, Chile. Jesse has a Master of Science in Health & Human Performance and a Bachelor of Science in Kinesiology. Hobbies: MTBing, snowboarding, reading, taster of craft beers, researcher, & user MTB shorts.
More articles from Pedal Chile
Sources for “Do You Wear Underwear With MTB Shorts?”
“Shorts designed for mountain biking have built-in padding, called a chamois, that will increase your comfort and your ability to ride for long periods of time. ”
Bridge, R., Lencicki, J. and Club, S. (2009). Bike touring : the Sierra Club guide to travel on two wheels. San Francisco: Sierra Club Books.
Bury, Keira et al. “Prevalence, Prevention and Treatment of Saddle Sores among Female Competitive Cyclists: A Scoping Review Protocol.” Methods and protocols vol. 3,1 4. 6 Jan. 2020.
Edwardes-Evans, L. (2017). Road cycling manual : the complete step-by-step guide. Sparkford: Haynes Publishing.
Klinge, Sven. (2000). Mountain biking : the fundamentals. Pubblicazione: Frenchs Forest, N.S.W.: New Holland Pub.
Miller, M. and Berry, D. (7AD). Back in the Saddle Again: How to Prevent Cycling Saddle Sores. International Journal of Athletic Therapy and Training, 12(4), pp.19–21.
Marcolin, Giuseppe et al. “Biomechanical Comparison of Shorts With Different Pads: An Insight into the Perineum Protection Issue.” Medicine vol. 94,29 (2015): e1186. doi:10.1097/MD.0000000000001186
Molenberg, P. (2019). LET’S MOUNTAIN BIKE! : the complete guide to mountain biking. S.L.: Gatekeeper Press.
Pavelka, E. (2009). Bicycling magazine’s complete book of road cycling skills : your guide to riding faster, stronger, longerm and safer. Emmaus, Pa: Rodale Press.
Pruitt, A.L. and Matheny, F. (2006). Andy Pruitt’s complete medical guide for cyclists. Boulder, Colo.: Velopress.