OK, I read through the first page plus a few posts of three pages, and hopefully someone said this already.
Look at the sidewall of your tires, they will list a max weight per tire. Pay very close attention to that number. If you are maxing that number out, or going over it, going 60 in a 55 will be worse than going over what the owners manual says should be your maximum weight.
If you are exceeding the weight limits of your tires, you really do need to slow down, and make sure the tires are at maximum inflation listed. This is a much bigger safety issue in my opinion. You have a a very real chance of a blowout.
