How much do larger tires affect MPG

[maverickeric]

My XL is about to arrive and first thing to go are the XL steelies. I'm looking at two aftermarket wheel/tire setups:

245/65/17 BFG AT (45lbs) + 25lb wheels = 70lbs per combo
245/65/17 Nitto Grappler (34lbs) + 21 lb wheels = 55 lbs combo.
Stock 225/65/17 (24lbs?) + 27lb steelies = 51 lb stock setup?

Does anyone have a ballpark idea on how much the two would affect MPG, even compared to stock on an EB AWD? There's no calculator for this - which is understandable considering there's a lot of variables (overall size and where the weight on the combo is). 10 lbs extra weight in the BFG AT TIRE sounds significant though. Only considering the BFG because I could probably get the BFG wheel/tire combo with 13k miles on them for half the price of the light weight setup ($800 vs $1600 respectively).

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[fossil]

Quite a list of variables. You might need to tap into the latest version of AI for an answer.

 

[kpomeraning]

It's not just weight - you're also increasing contact area so by nature you're likely increasing friction. Depending on the formulation of the rubber tire, you could also increase the coefficient of friction (a softer rubber versus a harder rubber) and the joys mu value calculations F/N.

 

[AutobahnSHO]

I think I read somewhere long ago 1 lb of rotational mass is 7lbs of vehicle mass, in terms of power to push it (and wear on brakes)...

 

[801dute]

I put on 235 65 r17 Toyo AT3 and lost about 1-2 mpg depending on driving conditions. Worth it for me for the extra grip in winter and muddy conditions. I do a fair number of long road trips and you never know when that late spring winter storm (or early October winter storm) will hit. Getting about 24 city / 29 highway. I did get 30 highway on one road trip, but it was mostly 55mph zones and not much freeway.

Most importantly, they look cooler

 

[SHiggs0429]

I lost 2 MPG (41 to 39) changing out my tires.

 

[Johnkn]

OP, If you are referencing Nitto Ridge Grapplers, you may want to re-check the weight. RGs are a great tire, however they are typically some of the heaviest by size.

good luck...

 

[Johnkn]

Quite a list of variables. You might need to tap into the latest version of AI for an answer.

Sorry, AI is temporarily on hold.. LOL



.

 

[LeatherPants]

An important consideration is that unless you edit your vehicles computer, the larger distance you travel per tire revolution isn't going to be translated by the stock vehicle computer. Reasonably expect your stock computer to register a lower MPG with bigger tires - they are probably heavier, lifted your truck somewhat, and probably have a greater rolling resistance than the street-friendly stock tires. But if you want to "old skool" figure it out, look at the revolutions per mile of your stock size versus the revs per mile of your bigger tire and apply that percentage to what your stock computer reports. That's your REAL MPG. SPOILER: You'll almost certainly lose some MPG, but it'll be somewhat less than what your computer reports. Weigh and balance, and manage your expectations. If you're a short distance traveler, the "satisfaction" factor is likely worth it. If you pound miles on your truck, it might pop an eyebrow how much your economy truck just got expensive to operate.

 

[Snowbird]

An important consideration is that unless you edit your vehicles computer, the larger distance you travel per tire revolution isn't going to be translated by the stock vehicle computer. Reasonably expect your stock computer to register a lower MPG with bigger tires - they are probably heavier, lifted your truck somewhat, and probably have a greater rolling resistance than the street-friendly stock tires. But if you want to "old skool" figure it out, look at the revolutions per mile of your stock size versus the revs per mile of your bigger tire and apply that percentage to what your stock computer reports. That's your REAL MPG. SPOILER: You'll almost certainly lose some MPG, but it'll be somewhat less than what your computer reports. Weigh and balance, and manage your expectations. If you're a short distance traveler, the "satisfaction" factor is likely worth it. If you pound miles on your truck, it might pop an eyebrow how much your economy truck just got expensive to operate.

One of the best posts I have read, regardless of forum topic!

 

[Steve Urquell]

I went to Nitto 235/65-17 108 load range 34lb tires vs the stock 225 Conti 23lb bicycle tires and lost exactly 1/2mpg. 26.7 to 26.2 mpg.

I had to change due to the Contis having flats all the time due to the bicyle tire construction. It would not tolerate my 1.5 miles of dirt road/3 miles daily.

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