Does 1" require reprogramming?

[Motovita]

I'd like to change the tires on my badlands to 285/75R17 which is about a 1" increase in diameter. I'm thinking that will be close enough to not require reprogramming as long as I don't mind a minor discrepancy in speedo readout. Can I get any agreement with, or an argument against, with my thinking?

Sponsored

 

[Techun]

Depends if you care or not...

It will be a few off. Some cars are a few off from the factory so...

 

[Motovita]

Depends if you care or not...

It will be a few off. Some cars are a few off from the factory so...

If that is the only issue I'm unlikely to care. I'm just concerned that there could be some unforseen effect on one of the many electronic systems on the Bronco.

 

[Tonka Bronka]

If that is the only issue I'm unlikely to care. I'm just concerned that there could be some unforseen effect on one of the many electronic systems on the Bronco.

I installed 285/75's mid summer. Speedo is one mile off according to my navigation app. I did not reprogram anything and have had no issues, keeping in mind that my Badlands is manual transmission. Perfect size on stock wheels IMHO.

 

[Ducati1098]

If that is the only issue I'm unlikely to care. I'm just concerned that there could be some unforseen effect on one of the many electronic systems on the Bronco.

The only thing it'll affect is the speedometer and odometer

 

[Fastmc25]

Same here. 1 mph difference.

i didn’t bother with reprogramming tire diameter.

so 70 mph on speedo is 71 actual mph.

Only difference on mine is i lost approximately 2 mpg

still love the change

 

[Techun]

Same here. 1 mph difference.

i didn’t bother with reprogramming tire diameter.

so 70 mph on speedo is 71 actual mph.

Only difference on mine is i lost approximately 2 mpg

still love the change

If your car doesn't know speed or miles driven, it definitely can't tell you mpg

 

[userdude]

I went from a 34.4" (GY MT) to a 34.8" (Maxxis Razr M/T). My speedometer with the former was consistently two miles under what the police speed signs said (e.g. it'd say 55 but my speedo said 53). With the Razrs, it is now the same, 55 is 55 on both. If that's accurate, a 1" tire will show you going under the speed you actually are. Note that I thought it'd be the other way around, but it's been pretty consistent for me at least.

 

[Fastmc25]

If your car doesn't know speed or miles driven, it definitely can't tell you mpg

You are correct Obiwan

it’s not exact.
Reprogramming will still reveal you lost 1.5-2mpg with the larger diameter tire and a larger contact patch of tread on the road if you’re coming from 255/75-17 pizza cutters

 

[Motovita]

Same here. 1 mph difference.

i didn’t bother with reprogramming tire diameter.

so 70 mph on speedo is 71 actual mph.

Only difference on mine is i lost approximately 2 mpg

still love the change

Is that actual MPG, or calculated MPG?

 

[Fastmc25]

C

Is that actual MPG, or calculated MPG?

Calculated

I zeroed everything out on a recent 900 mile trip. My average was 19.5 at 70 mile an hour.

The same trip was done three months earlier before the tire swap I got 21.5 mpg

I know it’s not precise

I really am not worried about my mph difference. was just relaying that there will be a difference.

 

[JL8jeff]

C


Calculated

I zeroed everything out on a recent 900 mile trip. My average was 19.5 at 70 mile an hour.

The same trip was done three months earlier before the tire swap I got 21.5 mpg

I know it’s not precise

I really am not worried about my mph difference. was just relaying that there will be a difference.

Colder air and winter gas knocks down your mpg 1-2 mpg so you're probably getting almost the same mpg as the old tires.

 

[Fastmc25]

Colder air and winter gas knocks down your mpg 1-2 mpg so you're probably getting almost the same mpg as the old tires.

Yep. It can

i was in Houston Texas with 85-90 each day. It was warm the whole trip. They generally don’t use the “Winter blends” down there unlike northern states.

I’m honestly not worried about why or any mpg loss. Just letting th OP know he will see a mpg difference with larger tires.

 

[half-fast]

I'd like to change the tires on my badlands to 285/75R17 which is about a 1" increase in diameter. I'm thinking that will be close enough to not require reprogramming as long as I don't mind a minor discrepancy in speedo readout. Can I get any agreement with, or an argument against, with my thinking?

https://tiresize.com/comparison/

 

[Motovita]

https://tiresize.com/comparison/

Thanks, that's a better calculator than the one i was using. I'm not concerned with the slight speedo/odo error, I just worry about upsetting some of the electronic Voodoo on the Bronco

Sponsored