Larger Tire Question

[AGT]

So got some 275/60/20 A/T to go with the level and I love em but I know that the tire size calculator says when my speedometer says I am going 58 I am really going 60

 

Does this mean I am adding miles slower than I normally would?

 

Also, will this make my MPGs suck?

[z71MudDog]

ya bigger tires reduce your mpg.you're going 58 on the speedo but you're relly going 60 thats two miles or so of mpg

[AGT]

So what is calculated on the AVG might be lower than what I am actually getting?

[z71MudDog]

yup.it all always changes when you add a lift withh big tires its a sacrifice of milage

[AEB]

Example:Stock LT275/70R18 tires had 629 tire revs/mileand a LT325/65R18, has 599 tire revs/mile. .

 

629 minus 599 = 30

 

30 divided by 629 = 4.77 percent.

 

So your speedo, odo, and tripmeter are all slow by 4.77 percent. If you don't want to have the speedo reprogramed , then to compute accurate fuel mileage, you need to add 4.77 percent to the miles indicated by your tripmeter.

 

Example:

 

24.8 gallons of fuel

 

400.7 miles per tripmeter * 0.0477% = 419.8 miles

 

419.8 miles divided by 24.8 gallons = 16.93 MPG

[AGT]

Thank you.

[jdubub]

Just get a tune. It will make MPG, MPH and actual miles accurate for the bigger tires. It will tweek everything else as well for a lil more power.