Fuel Mileage after new wheels/tires

[mickey5978]

I was seeing around 18 mpg on the stock 18 inchers. I bought the 20 inch Procomp 6066 (that are on the toytec tundra from the website) and put on cooper zcon 275/60-20 tires. I am now around 16 mpg. The tires are less than half an inch taller than the stockers and according to GPS, the speedo is right on the money.
Is this normal. Are others experiencing this as well. Is is possible that with the stock rims/tires showed more miles than I was actually going?
Please let me know your thoughts. I have done the math for the slightly larger tires and there is less than a 3% difference in tire diameter and revolutions per mile.
Thanks guys.

[TampaTundra]

That +3% tire diameter could equate to maybe 10%+ percent increase in rotational weight, which would need more power to go the same speed compared to the stock tires. The same goes for the wheels, 2 inches bigger in diameter will add some weight, and if they are any wider than the stock 18"s there is a little more weight.

Rotational weight is the biggest killer for gas mileage.

[2008_CrewMax]

worded perfect ^^

so in response to your question, yes it is normal to see a decrease in mileage

i went from 16-18


to around 12

[Andres]

I really wanted 20's with some nice all terrain tires . But I decided just to upgrade to alloys at the end. The tires I wanted were all like 55 lbs++. Not really looking to lose 2-3 mpg while spending $2k on the new set up (out of my budget).

I have the stock Michelin tires and they weight like 38 lbs each. Call discount tire and find out the weight of yuor tires, that will probably answer yuor question.

If you don't mind about the gas just enjoy the truck and don't think too much about it. I bet those look nice. Get some pics when you have a chance

[08 LIMITED CREWMAX]

I haven't changed to new tires and rims yet, but I'm hoping that a few engine mods will offset the gas mileage loss when I do.

[ontheway]

which kind of engine mods are you thinking. I am changing from my stock 275 55 20 tires to nitto 305 55 20's. I know the mileage will take a hit, but trying to offset as much as possible. I know that if i am concerned about mileage that much i should not have put the tires on, but if i can do both then i will.

[2008_CrewMax]

intake and exhaust usually helps

also when they come out with a programmer .. that will also help

[ontheway]

Do you think the cai is that much better than just getting say a k&n drop in filter? Which brand did you go with?

[08 LIMITED CREWMAX]

I put a K&N cai on it wednesday night. I'm not sure about the mileage increase yet. I've been enjoying the power increase. I'm taking a trip tonight, so I will know tomorrow about the mileage increase. I also want to get exhaust and a chip...eventually. I don't want an exhaust that is too loud. I'm thinking a 60 or 70 series flowmaster.