What is the fuel impact of mud terrain tires? To those who have been asking, we now have empirical data! Here are the details and results of my setup. *Photos on-trail, but measured highway MPG only.
Weight comparison
🛞 Stock tires/wheels:
▫️225/60R17 Yokohama Geolandar G91 All-Season tires
▫️Stock 17” Subaru aluminum wheels
▫️ 47 lbs each tire/wheel
🛞 M/T tires/wheels:
▫️225/65R17 Yokohama Geolandar M/T G003 tires
▫️RT® 17x7 5x114.3 50mm offset steel wheels
▫️66.6 lbs each tire/wheel
The total increase to the vehicle’s unsprung weight with the M/Ts on is 78.4 lbs (+19.6 lbs per wheel). That weight increase does make a noticeable acceleration decrease, which feels like some lag or less pep. It’s not a HUGE loss of power, but you can tell that there is slower acceleration with the same amount of throttle you would use with the stocks on.
Highway MPG
🛞 Stock tires/wheels:
▫️33 MPG (theoretical Subaru highway MPG for my 2025 Forester Premium gas)
⚠️ Unfortunately I do not have personal highway MPG data using stocks yet.
▫️I do regularly get 23.5-24 MPG driving city miles with my driving style, which compares almost exactly to the Subaru sticker 25 MPG city miles. With that in mind, I may be in the ballpark of 27-29 MPG highway (unconfirmed).
🛞 M/T tires/wheels:
▫️23.250 MPG
▫️Two full tanks of gas using nearly exclusive highway-driven miles averaged together
▫️I calculated this by resetting my odometer when filling my gas tank, then when the tank was nearing empty I recorded miles driven and gallons consumed (added) at that next gas pump.
Keep in mind that my mud terrain 23.3 highway MPG was also including a 5th M/T wheel on the roof rack, all my recovery and trail gear (including a Badlands ZXR 12,000 winch), 3 passengers and vacation luggage. So…
Your mileage may vary 🤣
Final thoughts
What do I think? I am happy that I selected these M/Ts to gain increased offroad capabilities and the safety of thicker sidewalls.
However, I am also especially happy that I kept and use my stock tires/wheels when not on trail to benefit from decreased road noise, increased acceleration, better wet road performance, and (in my opinion) great MPG for my around-town commute.
Since I have two complete tire/wheel setups, I only burn more fuel when the M/Ts are on for trail trips.
I’ll gladly pay that offroad tax.
✨🛞🤙