yes, you can have mods and still get 20 mpg - it's all about the tires

[LGraubner]

I have an AT 4WD FJ and after 24,000 miles and running bone stock, I averaged from 18.5 - 20.5 MPG around town. I drive 20 miles each way to work and sit in stop-and-go traffic for 30 minute each way. When I bought my FJ, I had the OEM rock rails and factory luggage rack, but no other options.

I recently did a few mods and saw my mileage drop. The first two tanks post mods were 15.9 and 15.6 mpg, then my next three tanks were 17, 17.7 and 17.6 mpg. Not too bad considering the window sticker claims 17 / 21 mpg, but with premium fuel at almost $4.00 a gallon, I wanted to see if I could get higher mileage again. For purposes of comparison, I have always run premium fuel.

My mods included All Pro front and rear bumpers, tow hitch, Warn M8000 winch, Garvin Adventure rack, OME 885/895 lift, high clearance exhaust pipe and a full set of All Pro skids including new lower control arms. Total weight added to my FJ for these mods was about 350 lbs.

I also added off-road tires and went with a 265/70R17 stock height tire (32") so I could still park in my parking garage at work. The tires I chose were Pro Comp Xtreme Mud Terrains and I mounted them on my stock alloy rims.

After selling an unused power tool on Craigslist, I used the money to buy a set of 5 alloy rims with Bridgestone tires with only 1,200 miles on them for $475, shipped to my door from a fellow forum member in Boston. I just filled up tonight and my mpg was back up to 20.6. I could tell immediately from the gas gauge I was getting much better mileage, but I didn't expect this much of an improvement considering I added 350 lbs.

To track my mileage as accurately as possible, I go to the same gas station, the same pump and always let it fill to the top and shut itself off. I feel reasonably sure I fill up to the same level each time, so my MPG calculations should be fairly consistent. Both sets of tires are also the same size and any incremental difference in height should be insignificant as it registers on my odometer.

The FJ doesn't look as good with stock tires, but I am in my 40's and am past the point where I really care what people think. Using my impact wrench, floor jack and teenage sons, I can easily switch the tires and go hit the trails.

The noise wasn't that much higher with the Pro Comp Xtreme MT's, but the stock tires are definitely quieter and I like that for my daily commute. My new All Pro exhaust is a bit noisier, but not bad.

I certainly didn't buy my FJ with the idea of buying a Prius and I would pay the price for fuel, regardless of how bad my mpg was as this is simply my favorite vehicle I've ever owned. But for anyone who is hesitating about adding mods because you fear really poor mpg, you can have your cake and eat it too. Now if you add an Inchworm gearbox or huge tires, that is probably a different story.

[awilson529]

Nice write up. How did you like the Pro Comps offroad?

[Air2air]

Graubner thank you for a scientific and content-filled post. That is just the kind of thing I think a lot of us would like to see here. I look forward to more from you

[FJCcrawler]

Good info!!! Looking forward to more feedback.

[OregonSpeedFreak]

LGraubner previously said:

I have an AT 4WD FJ and after 24,000 miles and running bone stock, I averaged from 18.5 - 20.5 MPG around town. I drive 20 miles each way to work and sit in stop-and-go traffic for 30 minute each way. When I bought my FJ, I had the OEM rock rails and factory luggage rack, but no other options.

I recently did a few mods and saw my mileage drop. The first two tanks post mods were 15.9 and 15.6 mpg, then my next three tanks were 17, 17.7 and 17.6 mpg. Not too bad considering the window sticker claims 17 / 21 mpg, but with premium fuel at almost $4.00 a gallon, I wanted to see if I could get higher mileage again. For purposes of comparison, I have always run premium fuel.

My mods included All Pro front and rear bumpers, tow hitch, Warn M8000 winch, Garvin Adventure rack, OME 885/895 lift, high clearance exhaust pipe and a full set of All Pro skids including new lower control arms. Total weight added to my FJ for these mods was about 350 lbs.

I also added off-road tires and went with a 265/70R17 stock height tire (32") so I could still park in my parking garage at work. The tires I chose were Pro Comp Xtreme Mud Terrains and I mounted them on my stock alloy rims.

After selling an unused power tool on Craigslist, I used the money to buy a set of 5 alloy rims with Bridgestone tires with only 1,200 miles on them for $475, shipped to my door from a fellow forum member in Boston. I just filled up tonight and my mpg was back up to 20.6. I could tell immediately from the gas gauge I was getting much better mileage, but I didn't expect this much of an improvement considering I added 350 lbs.

To track my mileage as accurately as possible, I go to the same gas station, the same pump and always let it fill to the top and shut itself off. I feel reasonably sure I fill up to the same level each time, so my MPG calculations should be fairly consistent. Both sets of tires are also the same size and any incremental difference in height should be insignificant as it registers on my odometer.

The FJ doesn't look as good with stock tires, but I am in my 40's and am past the point where I really care what people think. Using my impact wrench, floor jack and teenage sons, I can easily switch the tires and go hit the trails.

The noise wasn't that much higher with the Pro Comp Xtreme MT's, but the stock tires are definitely quieter and I like that for my daily commute. My new All Pro exhaust is a bit noisier, but not bad.

I certainly didn't buy my FJ with the idea of buying a Prius and I would pay the price for fuel, regardless of how bad my mpg was as this is simply my favorite vehicle I've ever owned. But for anyone who is hesitating about adding mods because you fear really poor mpg, you can have your cake and eat it too. Now if you add an Inchworm gearbox or huge tires, that is probably a different story.

I'm 43 but still needed 33"s to feel complete... is there something wrong with me. I only get about 15 mpg because i still drive like i did when i was 39.
i enjoyed your article even though it affected my self esteem thanks.paul

[VooDude]

since i don't have enough $$ for new tires, and the ones I want, won't be the best on factory steelies... my plan when the $$ gets here is to run 2 sets. 17" with factory lame tires for the daily driver FJ... and 16" steel with BFG KM2's 33's as the gnarly ones for the weekend warrior!

[CowboyCEO]

I am going to roll on some Pirelli Scorpions as soon as my stock set gets squirly. One of the things I got out of my old Jeep Cheerokee was testing tires. Seven sets in 220,000 miles. The Scorpions were definately the best I have run.
I don't expect it to help much as far as milage goes because Pirellis are best served up with your foot down!!

[CowboyCEO]

Come on! a Prius!! Dude

Take the five G and spend some of it on your FJ then find yourself a sweet enduro motorcycle. You would get better milage than the Prius and have the ability to sling some dirt.

[LGraubner]

I really like the Pro Comp Xtreme MT's. In Tennessee where I live a MT is really the best choice due to the inclement weather. I highly recommend them and they get good reviews on the various web sites.

[Crotalus]

I'm 42, and like you, just don't give a damn what people think. This is great info and will definitely keep it in mind as I make my mods. I was actually considering having two sets of wheels - one set strictly for offroad and one for daily driving anyway. Great write-up!