Bicycle saddles can be uncomfortable for even the most petite, lightweight people. That's because riding a bike requires you to balance the majority of your body weight on two tiny "sit bones" for an extended period of time. For overweight people, riding a bike can seem particularly uncomfortable because of the additional weight and pressure that's put on such a small area. However, choosing the right saddle for your body and weight can drastically improve cycling comfort.
For any cyclist, saddle width should be the first consideration when hunting for the right seat. A saddle should be wide enough to accommodate the spacing between your two sit bones. Women's saddles are generally wider than men's to accommodate their wider-spaced sit bones. Heavy riders may need a slightly wider saddle than average-weight cyclists to comfortably support a larger backside. Just make sure your saddle isn't so wide that it causes excessive rubbing or chaffing.
Cushion the Tush
It's tempting to go for the fattest, most-cushioned saddle you can find, but keep in mind that when it comes to cushioning, more isn't always better. Excessive cushioning can actually end up placing unnecessary pressure on sensitive parts. This happens when the foam or gel padding compresses under your sit bones and balloons up in other areas. Go for a saddle that has the least amount of cushioning you're comfortable riding on. Cycling with a harder saddle can take some initial adjustment, but over time, you'll have a happier derriere.
If you purchase a foam saddle, something to keep in mind is breakdown over time. Foam saddles will compress and wear out faster with a heavier cyclist because of the added pressure from additional weight. This doesn't mean you shouldn't purchase a foam saddle, just be aware that you may need to replace it more often than a smaller cyclist would. Leather saddles can be a great option for heavy riders because they are extremely durable and, after the initial break-in period, become molded to a rider's unique anatomy. Be sure the rails of your saddle are a durable metal, such as chromoly or titanium.
Butt pain isn't reserved just for heavy cyclists; most riders experience it from time to time, even when they've purchased the best saddles possible. If you still experience periodic discomfort after you've bought the perfect saddle, you might need to consider adding bike shorts and chamois cream to your regimen, if you haven't already. Padded bike shorts help absorb road vibration and protect against chaffing, and chamois cream lubricates sensitive regions to help prevent saddle sores. You may also need to adjust the tilt or fore/aft position of your seat if you still aren't quite happy with your ride.