19.1 after 500 miles. 40/60 city highway. I'm happy. Was expecting the worst.
GX550 Real World MPG
- Thread starter supersix
- Start date
1000 miles, 14.4 mpg total average. 60/40 city vs. Highway
My theory still stands that the people posting the best mileage have the Premium (+) model on stock 20's, but it's due to a false speedometer reading and not because the GX is living up to it's mileage claims.
The stock tire sizes are as follows.
Premium 20" - 265/55/20 - 31.5"
Luxury 22" - 265/50/22 - 32.4"
OT 18" - 265/70/18 - 32.6"
The diameter of the Premium 20" is 3.4% (~1") smaller than the OT tire and approximately has 22 more tire revolutions per mile (per tirecalculator.com)
if we assume that all GX speedo's are calibrated the same, the Premium wheel is giving a higher speed and mileage reading than it has actually gone. The negative is that you have a mpg higher than what you really have and worse, your odometer is adding miles quicker than it should.
Thoughts? Is that tire size delta enough to make a difference?
The stock tire sizes are as follows.
Premium 20" - 265/55/20 - 31.5"
Luxury 22" - 265/50/22 - 32.4"
OT 18" - 265/70/18 - 32.6"
The diameter of the Premium 20" is 3.4% (~1") smaller than the OT tire and approximately has 22 more tire revolutions per mile (per tirecalculator.com)
if we assume that all GX speedo's are calibrated the same, the Premium wheel is giving a higher speed and mileage reading than it has actually gone. The negative is that you have a mpg higher than what you really have and worse, your odometer is adding miles quicker than it should.
Thoughts? Is that tire size delta enough to make a difference?
16.9 - 17.3 All city stop/go traffic. One interstate drive that saw 17.3 - 17.4. One doesn't buy a GX 550 for high average mileage. This is a great vehicle - cruise control sucks, hvac sucks as it is way to complicated to use I think. Mine will never see a dirt trail and will be left as I bought it most likely except removed the roof rack due to too much air noise, now much quieter above 45 or so.
There is
Definitely some truth to that logic. Additionally, the weight of the wheel tire combo seems to make a difference. I just replaced my stock OT Toyo tires on the stock rims and I'm seeing some mileage impact as well. The stock tires are 32.6 inches tall, my new 275/70/18 tires are 33.2 inches tall, but the weight also went from 43lbs per tire stock, to 50lbs per tire new. I can't feel any performance difference and the new tires, Firestone Destination XTs, ride very smooth. However, my MPGs seems to have dropped from about 17.5 on average over 14k miles, to 15.4 on my first tank with the new treads. Based on the aforementioned logic, it's actually slightly better than that because I went slightly further than the odometer reads, but it does still seem to be affecting it some. I would expect that the Premium and Luxury tire and rim combos are lighter and may improve mileage due to reduced rotational mass and overall weight.
On my next trip, I'll fill-up before I leave, turn on my phone's GPS app and at the first fill-up, tally my GPS mileage, Odo mileage, Odo mpg and calculate mpg based on gallons added. I'm hoping measured is reasonably close to calculated.
I have 10k miles on my Premium+ since November. Up until about a month ago I was getting reliably 19/20 mpg, even got 21 mpg on a road trip. About a month ago I took off the 20" wheels and Geolander tiers and put on Overtrail 18"s and Wildpeak A/T4w's in 265/70/18 and I'm getting 18 mpg now, 19 if I'm lucky.
Perhaps this is obvious but it varies a lot by driving style, the roads/trips driven, how you learn and choose to use the GX's dual clutch(?)/paddles and various sport / sport + / normal modes, and don't forget how "average" is calculated. If you have one trip that was just really bad mileage, while you learn the truck, etc., it's going to throw off the result from a "median." I've seen trips above 20 MPG.
Your speedo's going to be off by about 3%, while not huge, it's going to impact MPG. I wonder how much the OT wheels weigh vs Premium+ wheels, my gut is saying the OT wheels + the AT/4W's are going to be heavier than the Premium+ setup.
Premium 20" setup is about 72 lbs if I recall correctly.
I know my speed is going to be faster than reported but I didn't think about the mileage before you mentioned it. Maybe no hit on MPG then. I wonder if Lexus will ever allow the speedometer to be recalibrated.
500 miles in, mostly city and a little highway, not driving it like I stole it, and only getting 13.5 mpg with 93 octane fuel.
that's my assumption
Posting another update after adding 35" Toyo's...13.3 MPG and dropping. Definitely heading toward an average in the 12's.
What is your range now? Mine went from 299 to 275 after changing to 285/75R17.
GX550 Forum Photos
GX550 Forum Photos
