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Shocks/struts and mpg

I had new shocks and struts installed a few weeks ago and yesterday I filled the tank ($1.499/gal.! Woot!) and noticed an uptick in mileage. A quick web search indicated that this can be “a thing” but the explanations were all over the map, including “summer gas.” My mpg has improved and I’m happy but what’s your take? Anyone have any ideas? Thanks.

Coincidence with warmer weather, I think.


Agree with @texases coincidental. Shocks and struts don’t affect mpgs.

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Tire pressure a bit higher, due to warmer temps or attention by the mechanic?

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And ‘summer gas’ could also be a factor, it has a bit more (about 2%) energy per gallon.

Was an alignment done? Getting all the wheels pointed straight and true can improve mileage.


Uptick ? What size , small , medium or large ?

The last time I bought gas it was still March, that seems early for “summer gas.” The alignment was checked back in November when I had the tires replaced and deemed okay. Same a month ago when I had them rotated. AFAIK an alignment is required when shock/strut replacement is done so it should be fine now. I’ve kept an eye on pressure and it’s been okay too (average 32 psi cold). Improvement was about 7%, which seems a bit much to be coincidence but maybe not.

7 % is not even worth thinking about. I have 1 vehicle that I expect 32 mpg most of the time . 7 % would make it 34.3 . That can happen with just a minor change in driving patterns just as it can go the other way, down.

Since my mpg and driving patterns have been consistent for months, I’m a bit curious. Lord knows I’m not complaining. You can ignore changes in your car’s behavior if you wish, I choose otherwise.

My family would look at year to year differences more than just seasonal ones. Mileage can vary a little bit depending on the time of year but when it really drops that’s more of a concern.

The Prius in the family goes down to about 45mpg in the cold months and then it’s right back to 50-55mpg if not more the rest of the year. Does this every year for the last 10 years of ownership, give or take a couple mpg.

Did the same shop do the alignment after strut replacement as the earlier alignments?
Not all shops are equally capable and careful. Not all alignment machines are properly calibrated.

That is what I was suggesting with my question.

The shop that sold me my tires concluded that an alignment wasn’t needed. When I went back to have the tires rotated the same shop told me I needed shocks and struts. I went to another shop for a second opinion and had the work done there. It’s possible the first shop missed something and I needed an alignment all along.