ian515

I have had my truck about a year now, and there have been some accessories added since then. Topper (flush with the cab) yakima rack and cargo basket, and most recently leveling kit and mickey thompson atz (305/60/18) and new rims of course.

I expect to get less mileage than average, but I went from 15/19 to 9mpg about 2 months after I got the tires. I am getting a shudder between 55 and 60mph which seems to be common for a lot of people. I did have a part replaced 7 months back, and its name escapes me, but it was not warming the air and causing condensation in the turbos, which led to surging and a limp mode. When that was a problem, I lost mileage as well.

I wanted to eliminate the accessories first and wanted to get opinions of other people with leveling kits and bigger, more aggressive tires. What are you typically losing mileage wise? I am bringing it in the shop, but I know they will try and blame the tires first, I just want to have my facts in order before I get there!

thanks in advance.
cheers

TJPlatinumEB

When did you get the tires? Has the speedometer been calibrated to adjust for the tires? If it hasn't, then your mileage calculations will be off.

Add that to the fact that you raised the front end of the truck up plus added the tires plus the winter blend of gas and it could result in 3-4mpg loss over an otherwise stock truck during the summer months. But again that is assuming the computer knows you have the larger tires.

ian515

thanks for the response. Not sure if the shop calibrated, but hand calculations were pretty close to the computer. So I assumed it was good. I expected a loss of about 3, but I was getting 9/10 on the HIGHWAY. should have specified that. so thats a huge loss.

Wanted33

Seems the only variable here is the level, along with the wheels and tires. I'm thinking that's your culprit for the mpg's, and the shudder.

ian515

the tires are definitely not the culprit on the shudder, since it only happens when its under power, if I am coasting at 55/60 its smooth. I was thinking something is off in the transmission. I just find it hard to believe that tires would account for a loss of almost 10mpg.

Bosro

If you are thinking a tire shop recalibrated for increased tire size I would bet not...
Correct me if I'm wrong but your miles driven will be off too....
The truck computer still thinks its spinning stock tires,bigger tires putting on more miles than computer is showing.

TJPlatinumEB

Take your truck out and take a Garmin or app on your phone that will check your speed. I think you will find out pretty quick that your MPH, miles drive, etc is off and therefore your mileage calculations are off too.

tyees2002

iTrader: (1)

What he said. Your hand calcs are no good if you are still using the truck for how many miles u've travelled.

ian515

interesting. I will do that tonight. thanks!

ruff rider

As far as mileage goes. I have put on 275/65/20 tires on my truck. Stock tires were 275/55/20 and when I travel 100 miles on the truck odometer I am actually traveling 111 miles off of my Garmin. 60mph is really 63.4mph now.