The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Would gas mileage improve going from 4.56 to 4.10 gears 72 K10 with 35s

Ziegelsteinfaust · 05-23-2020, 06:06 PM

Tires have alot to do with mpg, and probably more then a gear change. Given you have 35's they are likely offeoad vs AT tires.

If you have mudders or some other aggressive tread. Less rpm can actually mean less mpg. Due to more strain on the engine, and more fuel to run the same speed. We're a extra 500 or so rpm the engine puts down more power with less fuel, and can overcome tire resistance easier. Except maybe on your ears.

A friend i had 20 years ago built 283 in a K30 rclb, and compared to his friend with a 396 in a K20. They got the same highway mpg, but once off road his fuel supplies would last twice as long. That is what I was told. He had 5.13's gears with 35's.

Remember its a combo not just a part.

05-23-2020, 06:06 PM	#5
Ziegelsteinfaust Registered User Join Date: Dec 2012 Location: Temple City Posts: 3,562	Re: Would gas mileage improve going from 4.56 to 4.10 gears 72 K10 with 35s Tires have alot to do with mpg, and probably more then a gear change. Given you have 35's they are likely offeoad vs AT tires. If you have mudders or some other aggressive tread. Less rpm can actually mean less mpg. Due to more strain on the engine, and more fuel to run the same speed. We're a extra 500 or so rpm the engine puts down more power with less fuel, and can overcome tire resistance easier. Except maybe on your ears. A friend i had 20 years ago built 283 in a K30 rclb, and compared to his friend with a 396 in a K20. They got the same highway mpg, but once off road his fuel supplies would last twice as long. That is what I was told. He had 5.13's gears with 35's. Remember its a combo not just a part.