I'm taking a 330 mile trip tomorrow and have a lot of stuff packed into the trunk and some in the back seat. I've heard you're supposed to inflate your rear tires more to accommodate for the added weight. I was already planning on pumping up my tires to 40 psi from 32 psi, so my question is how much more should I pump them up in the rear? Should I pump them above 40 psi, or would 40 psi all around be enough to take car of that extra weight?
I'd go to the maximum rating, and if it's squirrelly or sketchy, back it off a little. Do you know the normal weight distribution for your car? Tire pressure depends on weight, and the front is probably heavier. According to Edmunds.com the 2009 Corolla is distributed 59% front / 41% rear, and the 2007 is probably similar, so you'll probably be evening it out, or at worst, making the rear a bit heavier.
See also the link in my sig about tire pressure, if you want.
The Max Sidewall PSI is 51 PSI @ 1,356 lbs, however it also says on the sidewall not to inflate beyond 40 PSI, so I'm a little confused as to which it is. I'd like to try 50 PSI soon to see how much better MPG I can get, but not while it's loaded up so heavily.
The weight distribution is 60/40 and the total weight added is just shy of 200 lbs.
Ahh ok yeah it did say to seat beads I just didn't know what that meant hehe.
It's a Yokohama YK520, Discount Tire specific tire that is closely related to one of Yokohama's other tires, not sure which. 225/45/17 as opposed to stock size of 195/65/15, obviously I could do better on stock size but I'm an enthusiastic mountain driver and I like grip.
Could be weight (don't forget about weight of the tire too), aero, differently constructed tires, or any of a million other variables. If your new rims are a larger diameter, then that will affect the way the tire has to deflect; less sidewall means more sharp deflection, so more RR.
It's a good piece of info to add, I think I'll try to add something like that to the post. Thanks.