Bought this 2000 ranger with a bad transmission and it had these wheels and new tires already on it. Got the transmission swapped out and it's running pretty good. I'm just curious how bad these 18 inch wheels are gonna rob my little 4cyl for power and fuel economy. I bought the truck to use as a commuter to work. Soni am looking for mpg. I'll probably go back to the 15's factory. Unless my Mpg doesn't suffer to bad.

 

Good looking Ranger!
Wheels look great, but Acceleration\LowEndTorq will likely suffer compared to 15s.

 

what size tires are on those rims ?

What size tires does the door sticker say belong on the truck ?

 

If they are new tires, than ride it like that till its time for new tires. Than get what ever you want after that.

 

Size of the wheels/rims don't matter(unless they are to small to fit over the brakes, lol), only the diameter and weight of the tires matter
i.e.
18" wheel 225/60r18 = 28.6" diameter
15" wheel 245/70r15 = 28.5" diameter
So same diameter but different wheel sizes

Get the size of the tire from the sidewall and that will get you the diameter of the tire, google it

Look on drivers door back edge and you will see the Build Label, take a picture of it, lots of good info there specific to this one Ranger
It will have stock tire size listed, get the diameter of that size tire
That tire size is what the speedometer/odometer was calibrated for

Having larger or smaller diameter tires changes that calibration
It also changes the virtual rear axle ratio
So if your Ranger came with 26" tires and you now have 28" tires then speedo and odo will be off, they will both be lower than actual
So if you used odometer to calculate MPG then it would be lower that actual MPG

On the Build Label, at the bottom you will see AXLE, under it will be 2 numbers or a letter and number, this tells you what axle and what ratio you have

Decoder here: https://www.therangerstation.com/tec...ag-door-codes/

Higher ratio numbers means quicker acceleration, but lower MPG at highway speeds
Lower ratio numbers means slower acceleration but better MPG at highway speeds

Most popular ratio in Rangers was 3.73


Weight of the tires and wheels
Obviously all vehicles have a power to weight ratio, so given the same horsepower you will have better performance and MPG with a 2,000lbs vehicle than a 3,000lbs vehicle
So any weigh reduction or increase will effect MPG
The more rubber in a tire the heavier it will be, so the wider it is and the larger sidewalls it has will make it heavier

If you look up a brand and size you can often find the weight of that tire
If you pull off one of the wheels(with tire) and weigh it you will then know how much each wheel/rim weighs

 

H

Here is the door tag

 

AXLE code 87 means you have a 7.5" OPEN rear axle with 4.10 ratio

225/70R15 stock tires were 27.4" diameter, they weighed about 27lbs, tire only

Now you need to look up current tire size

 

The tires that is on it are 29.04 diameter.

 

So according to this calculator: https://www.therangerstation.com/how...er_tires.shtml

The larger diameter tires will change rear axle ratio to "feel like" a 3.87, which should be fine for power and MPG both
But speedometer and odometer will both read lower than actual speed or miles travels

Tire diameter has an RPM, rotations per mile, travelled
A 27.5" tire rolls out at 86.4" per rotation which mean it will rotate 761 times in 1 mile

A 29" tire rolls out at 91.1" in one rotation so will rotate 720 times in 1 mile

So thats about a 6% difference, so your odometer is adding a mile each time 761 rotations are seen on the rear axle VSS
But you have already travelled a mile at 720 rotations because the tires are larger

If odometer shows 100 miles travelled then add 6% so 106 miles and divide that by the gallons of gas used to get a true MPG

If speedometer shows 60MPH you are actually travelling at 64MPH, 6% faster

Larger tires are heavier so take a bit more power to get rolling, and once rolling they take a bit more braking to slow down

For best MPG you want a car, lol, Rangers are a brick as far as aerodynamics, but thinner tires and lighter will help MPH but you do lose traction easier with thinner tires, so its a trade off

In 1998-2000 Ranger the GEM module calibrates the speedo/odo, it can be reprogrammed for larger tires, not sure of the procedure for that, you do need Ford software