ericantonio

I seem to recall I was getting the standard 12MPG for a while when I got this old '95.
I was able to fix a lot of problems (bucking, stalling uphills..almost stalling, idling, etc, etc). Then I started getting 10MPG and sometimes less. I do a lot of stop and go and go and stopping here in the 'burbs.

I had this idea of "crap, gas prices are getting better, and this is just my "fun truck" to learn how to wrench and take it to my bicycling events.

So getting inspired for a while to put those nice 4" RC lift and 32" tires and thinking "wow, 32" - 33 tires probably will suck even more in mileage"

Well.....I DID get a set of 265's when my 235's wore out just over a year ago ( yeah they actually fit in my 15x7 stock steel wheels!!). And it hit me just now that 'THAT'S WHY I'M GETTING CRAPPY MILEAGE'. Not the engine, but my gosh darn 3.02 Axle with 265's (or 30" tires!)!!!

Well, regearing, looking at prices is OUT OF THE QUESTION. Wow! $500 for gears plus labor to install those. Dang!!!!

Looking at this chart http://www.offroaders.com/tech/gear-ratio-chart.htm and ideally I should be running at least a 3.55 and prefereably a 3.73 with these tires.

BLDTruth

You also went from a roughly 29" tire to a roughly 31" tire, so your speedometer will be registering lower than you are actually going, which means you will think you are going less total miles per tank than you actually are, which will lower your calculated mpg.

ericantonio

Damn science!!! I knew I should've paid attention in that class. Darn Brooklyn education!

Chris_1

iTrader: (1)

Your odometer is adjustable. PSOM stands for PROGRAMMABLE Speedometer Odometer Module. Look up how to do it (google, youtube etc).
They used the same speedo for 150's and 450's so it's designed to be changed for different tire sizes.

95SWB

Width of your tire doesn't affect gearing, it's the overall height of tire. I run 275/45/20 with a 3.08 and get 20cty30hwy

BLDTruth

20 city, 30 highway on one of THESE trucks?

With all due respect, I call BS. 275/45/20 is basically a 30" tire. 20 on the highway MAYBE but I am still doubtful.

Chris_1

iTrader: (1)

^^^^^ What he said. No way anybody's getting 20/30 in an F150. Unless you got that flux capacitor working finally.

ericantonio

Best I got with 235's was about 15 HWY. That was before my "tuneup". 275's that's like 32" tire?

I should start looking at a used 3.55 or 3.73 axle. I saw a decent 1996 online at the closest pick/pull place for a front bumper. I'll start looking at the door codes to see what axles these things at the pick/pull has. Maybe it's way more cheaper to swap it than spend $1,000 for regear and truck is nowhere near worth it.

BLDTruth

Alright a real quick tire lesson:

265/75R15

The 265 is the width, in mm.

The 75 is the percentage of the width and detemines the sidewall height (from edge of rim to edge of tire)

The 15 is the size of the rim in inches, obviously.

So a 265/75R15 will be 265mm wide (~10.5")
It will be (0.75 x 265mm x 2) + 15" = ~30.5" tall

A 235/75R15 will be (0.75 x 235mm x 2) + 15" = ~29" tall.

A 275/45R20 will be (0.45 x 275mm x2) + 20" = ~30" tall

As far as axles go, They sell used 3:55 rear ends for ~$250 at my local yards, so definitely check them out.

ericantonio

Damn, you lucky. SoCal like everything else is expensive. We are still paying $2.50 for gas!