Drop in MPG's after replacing left rear tire due to blow out!

assuming you bought it used and didn't put 18,000 on in a couple weeks? 18,000 is almost half the treadware, so you probably should get two new tires and keep the old one as a back up. onthe other hand, the rears don't wear that fast and tread depth measurement is more important than mileage. i don't think that would account for a large drop in mpg. if that is your only concern, replace one and see how the mpg's are before replacing the other.

 

If you can only deduce that then you need to use more imagination
Seriously, there are many variables that play a part in your mileage.

- The new tire will offer more rolling resistance until it's been broken in a little.
- Do know if the tire pressures were the same before and after? It's not unusual for a tire dealer to adjust the tires to what they believe to be best--they may have deflated all tires to the Toyota recommended level, which is a little more comfort-related than thrift related.
- I doubt this is the case, but were you driving on wet pavement? More drag from that, to be sure.
- Did you use air conditioning more on one trip than another? Not a big hit, but could add to other factors.
- What speed were you driving on these legs? If the same speed, trip to trip that can still play part in my next question...
- What was the wind speed and direction on these trips? While a 10-15 mph wind might not be noticeable in your daily driving, on a long trip it can cost extra fuel if it's working against you. To my point above, the drag becomes very significant at higher speeds. If you're driving 70 mph into a 15 mph headwind the car's got to work much harder pushing the air around.
- Are your mileage calculations from the on-board display or by calculating from odometer readings and fill-ups? I'd be positively surprised to see 53 mpg if you were driving 65-75 mph--48 mpg would be more likely. It's possible to have your fill-ups vary by how full the tank is filled and in this mileage range a 1/2 gallon more or less makes a big difference in your calculations.

Things to think about...

 

I assume you were driving on I10. As you know, they have all of those wind turbines once you get past Banning. Those wind turbines are there for a reason ... it gets really windy there and gusty. I believe the general direction of the wind is that it is at your back when going east on I10 (but it can swirl, too), so you got better gas milage going to Palm Springs. Plus all of those hills can cause some havoc, no matter which way you are going. And I think American Tire would have lowered your tire pressure on both tires to about 36PSI (which I believe is recommended PSI stated on the door jam) rather than increase it to 38 or higher. I'm not sure you can get any consistent MPG along that freeway near Palm Springs, going in either direction.

Mike

 

The original tire is Low Rolling Resistance. The Touring S probably isn't. At max sidewall I swapped out my OEM tires at 60000 miles. The lower the pressure, the faster the tire wears.

 

I would check your tire pressure on all four tires, before you start replacing them. It may make a different in your overall MPG.