I have an '02 Silverado 6L 1500 HD with around 120k. Runs great no problems. Just recently put new tires on, a little taller and a little wider, and I got hosed on my gas milage. lost atleast 2 mpg's if not 4. That alot when i was only at 13 or 14 to begin with. Sooo... Finally the question: I'm considering intake, exhuast, and/or programer. dont know much about any "set-ups". looking for value (not really expensive). want increased mpg's... and some extra hp never hurts. I have no idea where to start and where to stop. if I did exhaust what I should do? which is the best bang for the buck...
Please Help
Much Thanks

 

1st. not all tires are created equal, even if they are the same size!

What works well for a certain need is completely wrong for another. That's what makes things so interesting.

You said that the new tires were a little taller and a little wider.
A little taller means you have changed your effective rear gear ratio, depending on just how much a little taller means 1 inch 2 inches, or is it more than the original tire?

2nd. you said that the tires are a little wider?? Are they a little wider with a street tire tread pattern or with an off road tread pattern.

Next you have rolling resistance, and this is where you fuel mileage really takes a hit.
Bigger, Taller, Wider, Heavier, and tread patter can all work against your fuel mileage.

As you increase the overall size of the tire you are loosing torque which pushes your truck. If you have gone 2 inches or more in size you are going to need to change your gears just to get back to a stock effective gear ratio.

If you have gone with a more aggressive tread pattern, or you may have tires that are quite a bit heavier than the ones you replaced, again changing your rear gears may help by increasing the torque which will help with the rolling resistance of the tread pattern and or the weight.

Again not all tires are equal they may look OK on the specks, size, weight and the tread pattern may not look that aggressive but the way the tire is constructed to perform certain functions may affect its rolling resistance.

OK, so all of this does not help you with your gas bill, yet go through your truck and change all you oils to synthetic, this should be good for a 1/2 mile maybe a mile per gallon improvement, and at 120K on the truck this can't hurt.

Next look at the size difference if you have impacted your effective drive ratio
look at changing your rear gears. This is going to cost a about what you most likely paid for tires.

A formula that will let you determine what your new effective gear ratio is a follows
divide your old tire size by the new tire size and then multiply by your old gear ratio.

This will give you your effective gear ratio due to the change in tire size.

Hoped this helped a little.

jvp

 

Wow. Suddenly these tires don't look nearly as cool. Thank you for all the info. Am I hurting the truck driving it with these off-road tires that 2-3 inches taller? If it's my intention to go back to a similar sized tire after this set is done and I bought a programmer for $300-$400, would I mess things up? Would I gain back a few inexpensive mpg's?

 

Well , I sure the tires do look Cool on your truck.
You asked if they would hurt your truck ourside of the gas? Again that depends on how you drive.
Larger size more weight put more stress on everything, if you keep that in mind,,,
with reservation, I would no.
Outside of the Ouch! at the gas pump watch for unsual front end issues, tire, brake and alignment issues. This does not mean that you can not enjoy your truck, it just means it will cost a little more.
Have fun
jvp