How Much Performance Loss From Larger Wheels/Tires?

2018 TRD Off Road Long Bed - I am considering larger tires and a small lift on my 2018 TRD. I plan to do it in steps, starting with a slightly larger tire (265/75 R16) on the factory wheels. The 265/75 has a 31.65 inch diameter compared to the stock 265/70 30.61 inch. I'm considering the 265/75 Copper Discoverer tire which is about the same weight as the stock 265/70 tires. After seeing how the tires work out I may consider a Bilstein 1-2 inch lift front and rear.

Given that the V6 is already struggling with the stock tires regarding performance (acceleration, highway passing, cruising on a grade etc.,) I'm wondering if the lager diameter tire will be noticeably worse. Also wondering if gas mileage will be significantly reduced. I love my TACO but the engine lacks low/midrange torque and is really not suitable for a truck. I recently discovered the engine is actually Atkinson cycle in cruise mode. This explains why it is so reluctant to downshift on the highway, and then suddenly explodes dropping 2-3 gears to accelerate.

I would greatly appreciate anyone's experience on this issue after switching to larger tires.

 

About 50 percent

 

I switched from stock tires to the 265/75 Discoverer AT3 4S and felt a noticeable decrease in performance. I've run them for about 15,000 miles. Objectively, my Fuelly stats went down by an average of 1.5 MPG. Subjectively I notice slower acceleration and decreased braking performance. They're nice tires and I like the look and off-road performance of the bigger tires. But for me it hasn't been worth the sacrifice in performance. I was about to post my AT3 4S in the buy/sell/trade forum. Make me an offer I'm going back to the stock size.

 

The actual weight difference in the tires is where the most effect comes into play. If you can keep tire and wheel weight low enough, the difference will be way less than other tires of the same size.

 

This is true. But most of the time people also go to a more aggressive tread when they increase the tire size. More aggressive almost always mean heavier, even within the same tire size. Toyota must use the Goodyear Kevlar ATs as the stock tire because it's about as light as you can get in an "all terrain" tire.

 

If it’s a concern, just leave it alone.

 

Definitely. I have a 4cyl AT and I kid you not, I got new wheels this morning that are about 3 lbs lighter IIRC. There was a noticeable difference on the butt dyno driving around today

 

This thread should be merged with all the "why is my gas mileage so bad" threads.

 

You can expect 25-30% loss of mpg. You can expect even more sluggish acceleration.
Regearing will help with the acceleration but hurt efficiency even more. When you add more drag (lifting) more unsprung weight (heavier tires) and rolling resistance (wider tires with more aggressive tread) you have to pay for it somehow because... physics. The payment is loss of mpg or efficiency.
Remember everything has to work harder when you add stuff... engine, transmission, cooling system, power steering and pretty much everything else including brake system.

 

See, I knew somebody with real good words would come in here and set us straight.

 

He could tune it as well to help with what you described. The tire size increase is marginal but you will feel it most likely

 

Not sure if serious or not.

 

Not at all

 

Yes he could but he still can't break the laws of physics.
There is a law in Thermodynamics that roughly translates to "nothing is free."
This is both a science rule and a life rule lol.

 

You’re adding unsprung weight with the tires and decreasing aerodynamics with the lift. Acceleration, braking, handling, gas mileage will all take a hit but it’s going to be hard to quantify by how much for your specific application. That said, I’m guessing those qualities aren’t why you bought a Tacoma so...

 

Hey Joe, Welcome to TW! I'd say that your idea of going from a 30" to 31" tire, with slightly aggressive AT tread, and adding a modest 2" lift, is a happy-medium. You'll get the look and clearance gains that you're looking for, while sacrificing the least amount of fuel efficiency. The only way to fix the sluggish engine is to regear

 

Tune definitely wakes up this 3.5L. I get that they alway de tune engines in trucks for longevity but IMO they over did it, not that I had any issues on stock tune with power.

 

That is good. Carry on...

 

Yeah I drive mine slow af so doesn't bother me at all. Im sure a tune makes it nice but I also worry about longevity as most of these tunes haven't been on for 5 years or more

 

FWIW I get the same or better MPGs on 265/70/17 C load KO2s than my buddy with identical truck on stock Firestone SL tires. We are both on stock sport suspension and both MTs.