Originally Posted by Maso08Jk
I have a manual as well (only way to go) what it help maintain my MPG with a regear? I'm currently getting 20 MPG would love to keep that. And what if I were to run 4.88 or is that too much?
Possible, but unlikely.
Regearing can help the around-town miles, but running higher RPMs on the highway sort of cancels it out. Folks get varying results, but the general rule is that getting bigger tires reduces mpgs, it's just the way it is. Especially when the tires are heavier (which I bet they are) and your mpgs is exceptionally high (which yours is).
My entire 33" tire/wheel combo (which you can see here
) probably cost about what you spent just for new tires, but is sufficiently lightweight that it was more or less mpg neutral. I was averaging about 18 before, and I'm getting about 18 now.
If you did regear, the right ratio depends a little bit on the RPMs you're comfortable with. For 33s and a pre-2012 manual, 4.88s would be a little high for me. You'd be at nearly 3000 RPMs on the highway at 70 mph in 6th gear. Plenty of power, but poor mpgs and you couldn't get to 80 mph before you started to approach 4k RPMs. I'd be looking to shift into "7th" all the time. So I'd do 4.56s if I were going to regear, but I'm not.
Take a look at this chart: