If you mean the difference between a P265/70R16 31" and a P265/75R16 32" then it is about 3.4% off.

 

I have 31x10.5x15 tires. I assume thats around 5% too?

 

Found another person on another forum who mainly does city, stop and go driving, and he got only like 165 or so miles.

 

No, 31s are a stock size tire, 32s would add to your mileage.

 

My stock on the door panel says my stock are 225/xx/15

 

My $0.02 -

Why if someone asks about suspension or lockers, people on this forum beat the heck out of them demanding a search first, but when someone asks about fuel consumption, I never see that happen? I think people ask, "Why does my mileage seem low" about as often as other common threads.

I would just like to think we don't discriminate.

Search please . This has been covered 1800 times this month.

 

I tend to get around 15-16 city (i'm not the most conservative driver" and aorund 19 highway.

 

My 33x12.5's actually cause a discrepancy of about 18%, and that obviously is reflected in teh calculations I do to figure out my mileage. Also consider stick vs automatic (I don't recall you saying) and surely the city driving, hilly terrain, and a cold engine will impact it. My 3.0 stick with 33x12.5's gets 15mpg, my 3.0 stick w/ stock tires gets 17, and my 3.0 auto with 265/70/15's (or something like that) gets about 15 also. All have stock air filters/ intakes, no real mods yet. Lots of factors to consider....

 

One thing I get tired of is the way some people like to jump on a new guy on here and yell at him to use the search function and they are not even moderators or the local police.
You can do searches but you may not get the answer your looking for so some people post the question again in another way hoping to get an answer or some help with there specific problem. That's when the problems arise and someone feels they just have to jump in here and tell them off anyway.
Don't get me wrong here, I'm not jumping you and you are right about what you stated above but in all fairness this guy may not have found the answer he was seeking or he's hoping for more info from anyone who can help him out.From the looks of all the post on here he is not the only one .
If people don't like the question then they can always just ignore that person rather than playing internet cop or they can choose to help him out anyway just as many have done here. Mike

 

I just did a check on my Auterra OBD using the fuel economy function to see what mileage looked like for city vs highway driving on a vehicle I am sure is in good condition and the results surprised me a bit. I used both instantaneous and trip functions (ie realtime vs avg mpg) so I could see the effects of both.

Highway was no surprise, I was getting between 20-22 MPG cruising at about 65-70 mph (downhill it goes to like 40+ mpg and uphill at speed is usually about 10-14 mpg both will depend heavily on the % grade of the hill).

The city mileage is the surprising part. When you accelerate at about 60-70% throttle your mileage goes to about 2-4 mpg and when you sit at a stoplight idling your average fuel economy drops by about one tenth of a point per second when slowing from highway speed(obviously the average can't ever reach zero, but if you idle long enough it can get close). I waited 3-4 minutes for one light and my average fuel economy went from 19 mpg down to 10 mpg (again it will depend on the % of stoplight driving vs % highway driving as to how fast it drops).

 

The way i always tested mpg is to fill it up but not just until it stops, fill up the whole filler pipe too, this way you know 100% that the first time and the second time you fill it up that the tank is to the same level of fullness? lol of course write down the odo reading on first and last and subtract, blah blah blah.

 

I'm new to my 4Runner, but got comparable numbers going from Tuscaloosa to Savannah. 23.3 MPG with 90 minutes stuck in construction-related traffic, and the AC running half the time. This is on a stock truck that's basically just been serviced according to the recommendations, usually at the dealership.

I think the key is driving style -- I'm used to my VW Jetta diesel, so I tend to shift before 3,000 RPM, and on the highway I was willing to be the slow guy and set the cruise control between 65 and 67 mph. It's easier than I thought -- I can't keep my Jetta below 80 (with 41 MPG at 80 MPH, who cares about gas price?) but it's not a big deal for me on the Toyota.

Go figure.

 

Overfilling the gas tank is a major no, no on today's cars.

 

Good report! I do find some of your observations a little strange but that's not unusual with todays engines. When the Gov. insisted on all these cars and trucks have so much pollution control gadgets on them it really dropped the gas mileage for most vehicles and now they want us to use less gas,Lol.....Go figure!!, Mike

 

Jamie, "Overfilling the gas tank is a major no, no on today's cars"


Why?

 

The main reason is because it begins to interfere with the vapor venting mechanisms on the gas tank. The problem with filling it all the way up to the filler neck is that you will flood the charcoal canister with gas and repeatedly doing this will supersaturate it to the point where it can't release all the gas contained and bingo, CEL, time to replace the canister.

 

Thanks for the heads up on the over fill. I have been filling mine like that for about the past three years, Hope I haven't damaged anything. Guess time will tell. Mike

 

If your VSV has not gone bad the truck will usually recover since more than likely only a little gas got in there but it is one of those things that only time will tell. Just stop doing it and the truck will hopefully be fine.

 

oops- my 4runner - 9 years of doing this
Aunts LX470 - 2 years
Uncles sequoia - 5 years

 

If you ask "can you overfill the tank?", the answer is "yes, of course".
If you ask "can you always do it and not hurt anything?", the answer is "only time will tell".