More Tires

What follows is my response to a post by Dr. Wrench about tire pressure. I wanted to repost it here not because I think I know it all, but because it is very important and to the best of my knowledge accurate. Also, second only to your brakes your tires are the most important thing on your bike for your safety. This is only slightly edited because I’m too lazy to do it all again. So if it seems I’m talking to a third party it is because I was responding to a response in the good Dr’s. post. To understand this it might be worth your time to read the Dr’s. post if you haven’t done so already. With that out of the way…

fasthair said…

I'll add my two cents here. As mentioned weight is also a factor. If you are going to be riding two up with lots of stuff (face it if your riding two up number two SHOULD be a female and they always have to bring lots of stuff) Then max out the pressure. If you read your owners manual (yah I know who does that?) it will even state this.

And Mr. Baron with all due respect you got the logic wrong. As you might know I work on Mercedes-Benz for a living. During service of these fine high performance machines I always check and set tire pressures. Each model has different settings. How do I remember all of these settings? I don't, I look in the gas door. Guess what? I quote, "for driving 100+ mph + 4PSI, for warm tires add + 4PSI."

Here is why your logic is wrong. The extra pressure actually helps the tire hold it's shape and NOT expand as much as if it had lower pressure. Just as someone else said, lower tire pressure will also affect the contact patch of the tire, i.e. the shape. Now before you say "but drag slicks only have about 5 to 6PSI" remember this, these tires are designed (Edit: and sometimes don’t last even the quarter mile because of this) to run at these pressures. Plus have you seen how that tire looks at speed? The back side (in direction of travel) is almost flat against the wheel and it has grown several inches in size. This is all the effect of low tire pressures. There is also this. Lower pressures cause higher tire temperatures too. Why? Friction. This is why properly inflated tires give you better gas mileage, less friction. Less friction equals less heat. A under inflated tire will actually fail sooner (Edit: because of heat… Ford Explore anyone?) then an over inflated tire because of high heat. Which all add up to longer tire life. So in the end, for high speed riding, max it out.

So after saying all of this can you guess where I run my tires? Yup, maxed out, 45 rear 42 front. For all of the reasons above but also because the bike does handle better and it does promote longer tire life.

Last thing for you others who don't check your tires. For the love of God please do so! Not only will it be safer for you but you will save money!

Of course your comments are always welcome.

fasthair