Kevin,
Without riding with you, none of us can help much with your riding position and bike fit, but my first recommendation would be to
start by making sure your bike is sized to you and it fits you properly for the kind of riding you are now doing. This is sometimes very complex and
your “ideal” position will change over time and as your riding style changes.
Are your hips only rocking a tiny bit side-to-side or are you sliding from side to side because your saddle is too high up or angled too steeply?
(Someone riding directly behind you or standing behind you while you ride a trainer or rollers can check this.)
Are your sit bones (ischial tuberosities) squarely situated in the “sweet spot” of your saddle in your normal riding position? If you seat is
too far back and you are sliding forward onto the nose all of the time, or if you are “on the rivets” all the time because it is too far forward,
your fit bones are not in the ideal position to be both a pivot for your legs and the point at which your weight rests easily.
Get help from a great bike fitter — probably at a local bike shop that specializes in bikes and gear for racing, touring, randonneuring, and
other long-distance riding such as AIDS/Lifecycle rides (SF-LA in a week) — or from local rando riders you can ride/train with.
If your bike does not fit you well at all, it may sometimes be impossible to place your saddle in the “right” place relative to your
knees, bottom bracket, pedals, and your hands-arms-shoulders’ position. (No one can diagnose these things remotely, of course: I am
trying to cover every possibility so you can check things out: it is unlikely that you could easily complete a 200K ride on a bike that was
really far off in its overall fit…)
I want to second what has been said here, particularly what Wade Baker said about finding high-quality cycling shorts
that fit you well in the riding position. Don’t skimp on quality or price. Ditto for using chamois cream.
Other Possibilities
It is crucial, especially for some of us, to maintain almost-fanatical personal hygiene habits (such as showering ASAP after
every ride and making sure one’s crotch area stays well-vented as much as possible when off the bike), and using a
copacetic chamois cream or lube. Pubic hair can be quite problematic if one shaves it or if there is too much in
the “wrong” places (for cycling, that is). Staying in your sweaty, damp cycling shorts too long after a ride is asking for
trouble: change out of them into something else as soon as you can. (A kilt or wrap makes doing so relatively
discreet and legal almost anywhere.)
Decades ago, when using a single pair of wool chamois shorts with a leather chamois on a multi-day bike tour,
I ended up with a nasty, ride-ending boil that required medical intervention. That was an extreme case that I
never want to experience again so I have learned to prevent saddle sores, rashes, or anything like that.
I hope you find the solution(s) to your saddle sores/chafing issues soon.
Jon Spangler
Alameda, CA USA