MPG with slightly larger ATs and tonnaeu cover?

Hey all, recently purchased a 2017 DCLB TRD Sport. When I drove it off thr lot with 2km, I was getting about 20mpg average. Now, after putting on slightly larger (0.5") All Terrains (General Grabber AT2 265/70/17), and installing a Bakflip G2 tonnaeu cover, my mileage is down to about 16.5mpg.

I was expecting a drop in mpg, but not as much as I'm seeing. It also seems to be quite worse with the tonnaeu cover. Is this roughly what I should be expecting, or is it lower?

Thanks!

 

that's a bigger drop than expected. tonneau should be worse in city, better highway - but only marginally. tires should be the same.

I went from 18.4 to 18.3 mixed by switching to heavier tires in a slightly larger size. falken wildpeaks 265/75/16, and I have a tonneau.

 

Heavier tires will cause the most dramatic change, especially with stop-and-go driving. The added weight of the tonneau cover is negligible

 

Do you have any idea what could be causing the large decrease? I only have about 300 miles on the odometer. Could it be that its just not broken in yet?

 

As it breaks in things will improve. Also try keeping it at 2 grand or less at all times.

I'm at 80 lbs per corner with my 265/70r17s mounted on SCS Ray 10s, and a BAK Revolver X2.

Here's proof that even with larger, heavier tires, and added weight you should be able to do better:



This is after filling up and getting on the road with the bed full (under the cover) on a trip from our house up in farm country down to the beach 276 miles in under 3.5 hours.

My daily commute is 88 miles round trip. It's about even 3 ways, splitting it between country, highway and into the city, then back home in reverse order. I can't avoid the stop and go traffic in the city, and on the highway I average 70 at 2 grand or less, and then the hills as I get closer to home always cause it to tach up some. I do drive spirited when I have to and my ego does get the best of me sometimes. Especially when I feel threatened. Meaning I ain't letting a prius push me around. I can make that commute, one way in an hour as long as there aren't any accidents or bad weather.

My commuting average is around 17ish



But if I take it easy I can pull 18 - 19 mpg.

In the beginning I was upset how inadequate the tranny was at stretching into 5th and 6th. I drove the hell outta it too in the beginning. I wanted to break it in and I was taught a long time ago, you do that by driving them like you stole them.

I have over 6k miles now and it shifts much better into 5th and 6th now than it used to for sure. I hear with age that just gets better.

In the beginning I was in the same boat as you. Now things have improved. Knowing I can get over 20 mpg's with a fully loaded bed gives me the peace of mind when I spend a couple days driving it Baja style and I see 15 or 16 mpg on the dash.

Oh check your air pressure in your tires too. Mine are E range Nitto Ridge Grapplers and I run the fronts at 36 psi and the rears at 37 psi, not the 32 like it says on the door jamb sticker.



Hope this all helps.
Rob

 

17ish with my pro. 265/70/17 grapplers. sr8's...... ive seen 20 mpg once. long down hill road.

 

I had a sharpe mpg drop from 200-500 miles.

caused by adding a lead foot to my driving attire once I got used to it.

 

I was getting 20.5 stock tank average on the liar screen, 19.1 to 19.5 now, but I didn't correct my speedo going to 265/70-17 Wildpeaks, so it's a shade better than that.

 

Snugtop Rebel and F5's with 265/75-16 Duratracs my mileage dropped from ~20.5 to 19 MPG...even worse when there's traffic in Seattle.

 

Was your initial mileage done with summer gas or winter? That'll make a difference.

SB

 

Make sure you are accounting for the larger circumference tires and correcting the odometer discrepancy when calculating mpg. It won’t be much different, but you might be getting 0.5 mpg more than your current calculations.

 

Winter. I bought it a week ago.

I just don't know why I'm seeing a drop of 4mpg, it seems much higher than what everyone else experienced. I'm heading to the US today to do some shopping, so I'll gas up once I cross the line and I'll see what kind of mileage I get driving around the city.

Also, is the mileage display on your cluster correct?

 

By the way, my speedo is dead nuts now with the +1 tires.

 

Did you get the normal light weight version or the E rated version? The light weights are 42lbs the E's are 53lbs. I suspect you went with E's which is what has caused the drop.

 

That I will have to check. I didn't order the tires myself, I traded the stock All Seasons for them in exchange for some website work. They are brand new but I didn't check the specs.

 

My tires weigh 55 lbs and my wheels without lugs are 24 lbs.

Just sayin. My money's on lead foot syndrome.

 

Weird I have the same setup but have bfg ko2s C rated and I only lost 1mph over stock went from about 21mpg to 20mpg. Are the general grabbers 10ply or E rated from what I understand? If so they are heavier tires and might have hit your mpg?


Just my two cents

 

I do not drive this truck with a lead foot. I have been careful to break it in gently.

 

Ok. All it takes though is a difference of 2k or less or 3k or more on the tach. I even tried manually shifting for a while but the damn computer doesn't care. There's a mod called the Shift Sense Pro on here if you wanted to make things better if after a while you're still not pulling higher numbers.

Oh, and I forgot about this one. There's a lot of talk on the forum in certain threads about the tranny coming with a lower amount of fluid than the spec calls for. Some guys report better characteristics overall when that is corrected. Although in reading most of those posts it's almost always nearly impossible to get the dealer to own up to it and correct it. Most guys do it themselves and there is a proper procedure explained in those threads.

I'm not even close to being considered an expert but I've read on here that as little as a half quart low can make a huge huge difference.

 

I was considering ordering the ShiftSense Pro as it seems to fix some of the issues with the tranny that leave me dumbfounded. Hopefully that resolves some of the issues.

I'm going to continue driving and see if the mpg gets better over time. I totally understand the mileage isn't going to be amazing on a truck but it's much worse than I expected, and what I was getting before.

Thanks for your input!