QuestionWhat is the correct tire pressure for motorcycles. Is it what the M/C manual says or is it what the tire manufacture says? Should the tire pressure be matched front and rear or should the front tire be less air to prevent washout in turns?
AnswerTire pressure is as individual a choice as oil, choice of tire, choice of riding gear, whether or not to wear a helmet, etc.
If you want to set it and forget it, go with what your motorcycle owner's manual says. It's also probably on the bike somewhere. Check and reset the tire pressures (when they're cold) at least once a week.
The manual gives you tire pressure(s) front and rear--sometimes they are different--based on that particular bike and the OEM tire size. The bike manufacturers are the ones who design the bike and select the best tire, they're the best "default" judge of what the pressure should be--it is a combination of best traction and best tire life and best handling.
The pressure values on the tire carcasses themselves are not as valuable, because a particular tire may fit twenty or more different bikes, each with different geometry, weight, engine size/power delivery, etc.
From the manufacturer's pressure recommendation, you can customize your tire pressures to your liking. Lower pressures will put more rubber on the road and warm up faster, but will make the bike harder to steer and turn. Higher pressures will put less rubber on the road, warm up slower, but the bike will turn much more easily.
To experiment with tire pressure (this can take a while, perhaps a day or two), start with the manufacturer's rating. Let's say, for example, it's 36F 36R. Now go out and ride your bike at highway speeds (45-65 mph) for 20 minutes. Park the bike, hop off quickly, and feel the tires with your bare hand.
The tires should feel very warm to the touch. Not so hot that you can't hold your hand on it, but very warm. If they feel really hot, your pressure is too low. Raise it by one PSI and go ride for 20 more minutes. If they feel at all cool or not very warm, lower the pressure by one PSI and go ride for 20 more minutes. Then hop off the bike and feel them again. Keep doing this until the tire temps are exactly where you want them.
Bear in mind that depending on what the tires are doing, you may be adding PSI to one tire while lowering PSI in another tire. Also, keep in mind that when adjusting tire pressures when the tire is hot, you'll need to check the current pressure before adding or lowering one PSI. Tire pressures go up 10-15% when they're warm, so if you started at 36 and rode for 20 minutes, they will probably be between 38 and 40 PSI. You'll need to add or lower the pressure from that pressure, and not from the original 36!
Once you've gotten both your tires to the temperature you want, let the tires cool for several hours and then check the pressure. That pressure will be your cold pressure that you'll check every week and add as necessary. (In hot months, you may need to decrease the pressure.)
But wait you're not done yet...if you don't want to be. Now, ride your bike for awhile, a week or two, and get a feel for how it handles. Do you like the way it handles? Or does it feel too sluggish? Does it feel too twitchy? You can further adjust your pressures based on how you ride and how you want your bike to feel.
If you want your bike to turn/steer a little quicker and put less rubber on the road, raise the PSI in each tire by 1 PSI and ride for a couple more weeks. If you want it to turn/steer a little slower or put more rubber on the road, lower the PSI in each tire by 1 PSI.
You don't necessarily have to lower or raise both tires the same, either. If you like the way it steers and brakes but don't like the way it feels mid-corner and the way it accellerates, adjust the rear pressure only. If you don't like the way it steers and brakes but like the way it feels when accellerating and in mid-corner, adjust the front pressure only.
You could spend a lifetime finding the perfect tire pressure, and it changes from day to day and month to month with the weather. Have fun and enjoy being a motorcycle nerd like me.
Pat
