Tire Inflation, Really?
 

I thought everyone might find this one amusing.

Working in the Electronics department of a Supercenter I have a lot of excited vacationers come through my department, or more than average comments about the price of gas.

I have recently in the last month or so encouraged my customers to check his or her tire pressure checked. Even so far as to swing by the tire and lube in some instances: thumbup:

I have also encouraged them to check out this wonderful sight. :D So if any of my customers are reading, Thanks for following through, :D I hope the advice you find here works for you.

Back to topic.

One recent customer was really surprised that he or she needed to have the tire pressure checked at least once a month or thousand mile. I had asked when was the last time they had it done. They responded it was done six months ago. (Don't cringe, we all know it happens.) Turned out they had the car serviced a month ago and was wondering if the air pressure could go down that quickly. I know its enough to effect fuel economy. I honestly believe the customer will have the tire pressure checked before he or she leaves for vacation.

My good deed for the month has been done. :D

One thing I wonder about is if the psi reading on your door is totally accurate or if you should fill your tire with more air then that to get better mpg... I like to fill mine 5 psi higher, but sometimes I wonder if 10 could be better or if the wear to the middle and lost traction is worth it.. :confused:

10 (or more) would be better and it is highly unlikely that it would reduce your traction. Read the tire pressure link in my sig. I run most of my tires at the maximum stamped on the tire's sidewall and have better wear, better FE, and better handling as a result; I pay by getting a slight amount of additional road feel.

I go with what is printed on the tire wall.

I needed to pump up my tires before my return trip home, but I didn't have a pressure gauge, unfortunately. I probably lost a good deal of FE over that long distance.

In 2 weeks I'm going out for a road trip to seattle. I'll have 5 people in the car, so you can be sure I'll have the tires inflated up, as they'll be loaded. With 2 people I could get 32-35mpg, so I'm hoping for 29-32mpg with 5 people. I plan to do holycow's injector view, just to see what fuel I'm pumping going up the 2000-3000ft mountain passes. Hopefully I can save alot by knowing.

I bumped mine up to around 40 psi and now the center tread on my tires is visibly worn down more than on the edges.

Ah! Finally a useful data point showing the much-discussed but rarely-observed center wear.

What size are the tires? Tirerack.com says OEM size for 2wd 1994 Geo Tracker is 195/75-15, and 4wd is 205/75-15.

How does it ride and handle at 40psi compared to 25psi?

Prius tires at Toyota's specified pressure.
https://techno-fandom.org/~hobbit/car.../treadwear.jpg

Also, my last set of tires - car says 32psi, sidewall max 44 psi. I ran them at 35 for the lifetime, and they wore down on the edges first, indicating they were UNDERinflated.

Another - Wayne at Cleanmpg has over 100,000 miles on his Accord's original tires. ~60 psi the whole time. I've seen them, and the treadwear is completely even.

p205/75 R15 Goodyear Regatta... I just looked and the center wear is mostly on the back tires. I get a tread gauge and report back later.

What pressure does Toyota recommend for Prius tires? I'd assume a lot, but maybe not. It's a pretty heavy car, IIRC.

finfin's Tracker weighs a measly 2189 pounds, slightly less than your Civic. Also, you probably have different sized (and of course different brand/model) tires. Altogether the results are bound to be different.

I think that in MOST cases, center wear is tough to find, but there are isolated cases where conditions come together just right to cause it. I'd love to know what those conditions are.