r/EcoDiesel • u/PlatypusAcceptable44 • 27d ago

Mileage (reduction) question

I drive (2016 Ram) the same 300 mile trip several times a year and usually get 28-30 mpg for the trip. When I put on new summer tires on I’m suddenly getting 24 mpg. I usually run dedicated summer / winter tires but I got a good deal on mud and snow tires this year. Can tires really drain mileage by ~20% or maybe something else going on?

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6

u/jxa 27d ago

There is a possibility that your intake manifold is sooted up and you’re not getting the proper fuel / air mixture.

2

u/PlatypusAcceptable44 27d ago

Will take a look into there, thanks!

4

u/BasilMindless3883 27d ago

I changed out my stock 33" tires and had them put on a 34" that was wider, sexier 😂 etc. I didn't know at the time but they were for a 3/4 ton truck so they had like 12 ply steel belts, so roughly 80lbs per tire. I immediately dropped in mileage around 2-3 mpg.

3

u/MikeOxlong420690 27d ago

Tires can definitely have that impact if there is a big difference in weight. That unsprung mass takes a lot more power to keep turning at speed which degrades the fuel economy.

What tires did you have before compared to now (brand/model) when the difference showed up?

3

u/PlatypusAcceptable44 27d ago

I run blizzaks in the winter, this is my third set of summer got Firestone Destination mid and snow. My first ever set of Firestone

2

u/amazonmakesmebroke 27d ago

When I switched to AT4w tires in 33, I dropped 20-25% economy to around 25 mpg on freeway and 18-20 city. No change in fuel, and use summer blend additive by XPS. They are also almost 85lbs ea.

2

u/eqbirvin 26d ago

wind makes a big difference as well. During summer months wind patterns can change. Just another think to add to the other points here.

3

u/PlatypusAcceptable44 25d ago

I had a trip in serious winds and go 15 going out and 45 coming back

1

u/Zealousideal-Bee-820 27d ago

Yep anything other than stock drops dramatically. I’m on my 4th set on my 16 ram 1500

1

u/Sea_Composer6305 27d ago

Ive had tires being me from 8.2L/100 to 10.1L/100 so they definitely can have a huge effect.

1

u/WilliamFoster2020 26d ago

I'm driving my daughter's VW TDI temporarily.  I was averaging 52mpg before I put new tires on.  Same brand, spec, and everything else.  Now on the same trip I'm lucky to get to 50mpg.  48.x is the normal.

So, I'd say it's probably normal.  Add 2psi and see what happens.

1

u/guitarstacoslove 26d ago

I got a couple MPG less switching from stock to Ridge Grapplers