275 to 285 fuel economy change after speedo correction

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KlausVanWinkle

KlausVanWinkle

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I know this is a well discussed subject. But no one seems to report a fuel economy change after correcting their speedometer for the new tire size.

How much will fuel economy actually change when switching from 275/70-16 AT tires to the 285 equivalents?

I feel like my truck looks lower to the ground than a lot of your trucks. Also the wheel wells make 275 look tiny.

When looking at tires on tirerack.com 285s for 18" wheels weighed 15lbs less than 275 for 16" wheels. I doubt 18" rims weigh that much more. So switching to 18" rims with 285 tires might actually improve gas mileage while allowing for bigger brakes. Has anyone tried this?
 
KlausVanWinkle said:
When looking at tires on tirerack.com 285s for 18" wheels weighed 15lbs less than 275 for 16" wheels. I doubt 18" rims weigh that much more. So switching to 18" rims with 285 tires might actually improve gas mileage while allowing for bigger brakes. Has anyone tried this?
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Which tires are you referring to?
 
Had this same question

Would I get better mileage with a 305/75/16 nitto tg on lx470 wheels, or 275/70/18 BFG on tundra steelies? How bout compared to 275/65/18 BFG on tundra steelies? Considering trading my current tire and wheel combo so I am doing my research ahead of time. Is the loss in mpg most influenced by the height of a tire, width of a tire or weight of wheels/tires?
 
Is the loss in mpg most influenced by the height of a tire, width of a tire or weight of wheels/tires?[/QUOTE]

All of the above.

I lost 1 to 1.5 corrected mpg going from stock to 295 75 16 Nitto Terra Grapplers.
 
it takes more energy to get a tall tire rolling, so youll probably see a drop in the city, but it gives the effect of gearing up, so youll get better on the highway. however, width and tread pattern induced rolling resistance can be a killer, especially with more aggressive patterns. if you can get the wheels lighter, thatll reduce your unsprung mass which helps handling
 
The tundra steelies are heavy. I did a 3K mile road trip with 16" alloys and 295 Nitto TGs and got an average of 16 MPG. Did an 8K mile road trip this summer and struggled to get just under 15 MPG with 18" tundra steelies and 275/65/18 Bridgestone dueller ht's. So in my case, weight trumped size and tread. Load, driving style, road type, were pretty comparable between the two trips. I was a little disappointed by this. The ride was quieter and smoother with the highway tread, but oi should have gotten the alloys...

Typos sent from my HTC EVO using the IH8MUD app...
 
re_guderian said:
The tundra steelies are heavy. I did a 3K mile road trip with 16" alloys and 295 Nitto TGs and got an average of 16 MPG. Did an 8K mile road trip this summer and struggled to get just under 15 MPG with 18" tundra steelies and 275/65/18 Bridgestone dueller ht's. So in my case, weight trumped size and tread. Load, driving style, road type, were pretty comparable between the two trips. I was a little disappointed by this. The ride was quieter and smoother with the highway tread, but oi should have gotten the alloys...

Typos sent from my HTC EVO using the IH8MUD app...
Click to expand...

295's are taller than the 275 18's. Did you take into consideration the added distance that the meter is recording due to the larger overall diameter?
 
LJ_24 said:
****it haha I was hoping that adding 275's on 18 steelies would be better mileage than my current setup
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Put 'em on 18" alloys, and maybe, but don't forget to figure your ROI. If you went from 14 to 15 MPG long term, you'd only be saving $250/year in gas, if you drive 15K miles. What's the going rate on 18" alloys + mount/balance? Bottom line is your likely better of sucking it up with the crappy mileage. I found out the hard way.
 
That makes sense. The height of the tire would require more power because it's like gearing up. The tread pattern, width/contact patch would create more friction/rolling resistance. And I think the increased rotational mass is the real killer. I looked at 285/70/16 BRG ATs compared to my stock 275/70/16 Michellin LTX M/S. It was like a 15lbs difference per tire. From what I've heard you can multiply rotational mass by 4 to figure out the simulated sprung weight gain. That's like adding 240lbs to your truck.
 
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