This year has been horrendous for rain and mud in the south. I have been following standard mud race tactics by lowering my tire pressure from my regular 13.5 psi to 10 psi. This doesn’t seem to help at all in getting hooked up. Should I lower my tire pressure to 8 psi?
You have been doing the right thing by lowering your rear tire pressure to 10 psi or less. That is, as you say, “standard mud race tactics;” however, you have to take into account the type of mud on race day. Not all mud is created equal; there is sloppy wet mud; there is oatmeal-style mud that moves under pressure; and there is clingy or tacky mud that packs in around your tires, swingarm and fenders. Each type of mud requires a different “mud race tactic.”
In sloppy wet mud and oatmeal-style mud, it’s best to lower your rear tire’s air pressure since the odds of a pinch flat are greatly reduced and the tire’s squat will put more knobs in direct contact with whatever is available; however, if the mud clings to your rear tire, especially between the rows of knobs, and has a hard base of dirt under the mud that your tire can get down to or is so tacky that you’re fighting to keep the front end down, you should raise the air pressure in your rear tire to a higher 15 to 17 psi. Yes, this does sound like it is the wrong direction to go, but with higher pressure the rear tire will spin more easily and throw off the mud that is clogging the knobs. It will also break through the top layer of mud and get down to the hard base, where the now-clean knobs actually have something to grip.