Changed tires and gas mileage is down

[cb5300]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by diandtom:
My wife's car a 04 Buick Rendezvous with 45,000 miles is getting 3-4 mpg after changing tires. I got the same size as what came on the car. I did change brands. we were getting 24- 25 everyday driving and now it is 23-23. On a trip it would do 28 mpg and now 25 mpg. The car seems to be running perfect, just the mileage is down. Yesterday on a trip to Myrtle back and back it did 23.5 mpg. I know this is not a rv question but wondering if anybody had this problem ?
Tom </div></BLOCKQUOTE>

Tom, I replaced the tires on my Expedition with Michelins and I lost about 2 miles to the gallon. It seems that the Michelins have more rolling resistances then the tires that were oem. The more resistance the less mileage you will get.

[diandtom]

Charles, You are probably right about the rolling resistance. I am going to take it in and have it checked after we get back. This car is going to be mine when Dianne gets a new one, so I am going to keep it awhile.
Tom

[Johnny]

Stupid question, but: especially if they don't call for the "standard" 30-35psi, are they inflated properly? Running 32psi instead of, say, 40 could easily drop mileage 5-10%.

I had 2 front tires put on my old J-20 pickup, and noticed it was handling (term used loosely when referring to an old Jeep pickup, but anyway...) kind of mushy. I knew the tires were good (the venerable BFG All-Terrain), so I stuck a gauge on the valves. Instead of the correct 50psi, the tire shop had only put about 32psi in them! When I returned to the shop, they saw nothing wrong with this & refused to inflate them properly. They also charged me $5 for new valve stems, despite my J-20 having metal screw-in stems that do not need to be replaced.

I no longer buy tires (or anything else) from these yahoos, needless to say.

[diandtom]

I went from 32 psi to 35 psi as soon as I saw the mileage drop. I am wondering if it could be something like the oxygen sensor. It would run ok but the gas mileage would be off. just a guess.
Tom