The biggest factor in avoiding chafing is your shorts. They are in continual and direct contact with your skin, and if you are going to have problems, that's usually where they start. Assuming you are wearing "real" bike shorts with liner and chamois pad, you should not wear underwear. And if you're not wearing "real" bike shorts, well, that's likely your problem if you are riding any length of time.
Buy the best bike shorts you can afford. The pad will be better, the material will be better and the seams will be sewn (and located) in a way that will minimize friction and rubbing. You'll be able to ride longer and more comfortably. Make sure that your bike shorts fit you properly - extra material means extra moisture and rubbing.
I'm always amazed at some of the big cushy seats you can pick up that supposedly offer a more comfortable ride. They are much wider and much softer, sometimes with gel-filled padding and may well work for some riders. However, what I've found is that it's the narrower, firmer seats that typically work much better.
That may seem completely counterintuitive, but many riders find a wider seat rubs the insides of their thighs and thwarts the natural pedaling motion. More importantly, because moisture and pressure points are the main causes of problems, having a narrower, firmer seat instead of a wide soft mushy one offers a smoother area to support your behind with fewer pressure points and fewer opportunities for friction and rubbing.
If you will be riding for several days in a row, take care of your shorts to avoid problems with irritation. After a ride, get out of your shorts as soon as possible and wash up. This helps get rid of the bacteria that can cause skin irritation, rashes and chafing.
After cleaning your body, next clean your bike shorts too. Use a spot detergent/stain remover like Shout on the chamois and crotch area and a pH-balanced detergent designed specifically for high-tech fabrics, such as Penguin Sport Wash.
Also, using different brands of shorts on consecutive rides varies where seams rub against your body. And the chamois pad will be different from one pair to the next, varying the pressure points where your bottom meets the saddle.
For women, to help prevent chafing and irritation when shaving, use something like Noxzema Bikini Shaver to avoid irritation of this already sensitive area. Be sure to shave in the same direction of the hair growth to avoid razor burn and ingrown hairs.
Next, to reduce moisture -- again a primary irritant when it comes to chafing and discomfort in this area -- take an acidophilus dietary supplement or eat yogurt regularly to help eliminate yeast infections. Tampons will also help reduce moisture if you have had recent sex or are ovulating. After the ride try wearing tennis skirts with the soft undershorts built in so you don't need panties to help give your bottom a break from irritation caused by seams.
Many cyclists have found that creams and lotions can help prevent problems. You may have to experiment to find what works best for you as there are a number of recommended solutions. One possibility is to put a light coat of petroleum jelly and shea butter right on your most delicate parts before riding to help reduce the friction in that area from your shorts or bike seat. Commercial products such as Chamois Butt'r or Brave Soldier have the same effect, as they are both a lotion and lubricant.
After the ride, you might try using a diaper rash ointment with zinc like Desitin to help your skin stay dry and clean and to quickly heal any irritated areas that may be prone to give you more problems.
6. Other Types of Lubricant - Ooh La La!
A reader named Laura related to me that the stuff that may help you in the bedroom may also be useful on the bike. She said that a female cycling consultant from an outdoors co-op said to try using K-Y type jelly to ease problems in this area may be effective, particularly for women.
"After I got over the laughing and then wondering what people would think if they found it in my panier, I gave it a whirl, and it has made all the difference in the world," says Laura. "I don't have to skip days of riding to recover, no infections, I even use it in winter when I'm using the indoor bike trainer."
7. Change Riding Positions
Our last item is a last ditch, desperation manuever. If you're out riding and you feel your backside getting chewed up from your bike seat and/or your shorts, the best thing you can do is to change riding positions.
You can stand up and pedal, or else move yourself either farther back or closer up on your seat. Or you can even shift your weight from one side of the saddle to the other. This is about the only way to ease the discomfort if you're actually in the middle of a ride. Should you find yourself in this predicament, tough it out as a long as you can. Then when you're finished, take advantage of the tips above to make sure it doesn't happen again.