CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

MPG drop?

prolinews

1/2 ton status
 Premium
Joined
Nov 12, 2013
Posts
313
Reaction score
30
Location
Georgia
I'm currently running 33's with 3.73 gears 15-16 mpg , if I went with 35's and 4.10s would there be a drastic drop in mpg or just 1-2 mpg? This is one of those mods I would like to do but been a little nervous since I drive this all over creation and rack up a lot of highway interstate miles.
 
Goes up about a 100 rpm at 70 mph if I read it right. Not a real drastic difference. Maybe exhaust and a couple other things could keep mpg close.
 
on what powertrain?

You will lose mpg. I'd bet 3-4 from where you are. Your current figures look pretty high.
 
700r4 slightly modified tbi 350. The axles in mine are stock but my buddy has a set of 8 lugs under a clapped out suburban that has 4.10 gears and has military 16.5 wheels and 37's that actually look to be in good shape for cheap. I might just buy it and save it for a later on project. I definitely don't want the 16.5s and 37's but they still have Craigslist value lol
 
With all other things equal in regards to the tire I would suspect it to lose at least some MPG going to a larger size. For example if you went from a 33x12.50 to 35x12.50 of the otherwise exact same tire you are adding weight, rolling resistance, and wind resistance (truck now sits an 1" higher). Regardless of the gears it now takes a little more power to get the truck going and maintain highway speeds.

Now with that said, I don't think it will be major difference again assuming it is an equivalent style tire. If you change the style of the tire it can affect it quite a bit. For example if you go from a 33" all-terrain radial to a 35" bias ply Bogger I would expect a noticeable decrease in MPG, and on the other hand if you go from a 33" Bogger to a 35" AT radial the MPG could get better......but that is a drastic difference in tire styles.

The other big thing to consider when checking MPG's after changing tire and gears is to make sure the speedo and odo are reading correctly.
 

Latest Posts

Top Bottom