I am thinking of putting 256 LTX's on my 2006 Chevy. I now have the factory 245's on the truck. My question is did your fuel mileage change when going up in tire size to 265's?

Thanks
Steve

That size change is minimal, didn't notice any difference on mine. (I run 265's winter only)

You're going to get a lot of different responses / opinions - Here's mine FWIW:

For the past 40K I've had 265's (replaced stocker 245's). I lost 1-2 MPG's going to 265's. I also noticed that the truck had less "pep".

It's now time for new tires again and I am trying to decide if I'm going back to 245's. In my case - there was a 2-3 pound weight difference between the 245's and 265's. Not to mention that it does add a slight height increase to the vehicle.

Many factors come into play - no good def. answer.

Good luck!

I noticed my in town mileage did take a hit, however it’s difficult to quantify as I rarely put only in-town mileage on my truck. My best estimation was I lost 1 mpg during low speed in town driving.

On the highway on the other hand, where I have a 100 mile trip to work every day I was unable to calculate any difference between the stockers and 265’s. Seven of the 100 miles I put on every day are below 55 mph where the remaining miles are all above 65 mph. By stating I’m unable to calculate a difference I’m noting the normal fluctuation between fill-ups I have. Generally I’m at 19.5 +/- with my freeway driving

I haven't changed my tires yet, but am planning to go to the 265s. I wonder if part of the fuel mileage difference is due to the 265s having a larger tire diameter and circumference? The truck odometer will read about 3% less miles travelled than with 245 tires over the same distance, indicating about 3% less miles per gallon than with the 245 tires. The engine should turn a few less RPM when travelling with the larger 265s?

To be a little more precise, I am running 265/75/16 Toyo Open Country AT Load range E. If there is a difference it is so minor that I haven't noticed.

I just swapped to a Dunlop 255/85R16 tire. The biggest thing with larger tires is that you are increasing the contact patch, which is good for traction. But you're also increasing friction, which is bad for fuel economy.

It looks like my mileage is slightly higher, but my new tires are 33" in diameter. The 265's are barely 1" larger than stock.

noticible but minor power loss and reduction in MPG. Can't give exact data on MPG becasue winter fuel blend and warm up periods screwing everything up anyway.

I haven't changed my tires yet, but am planning to go to the 265s. I wonder if part of the fuel mileage difference is due to the 265s having a larger tire diameter and circumference? The truck odometer will read about 3% less miles travelled than with 245 tires over the same distance, indicating about 3% less miles per gallon than with the 245 tires. The engine should turn a few less RPM when travelling with the larger 265s?

Good in theory but I have the speedo corrected with my tuner - close to dead on per GPS.

Thanks guys, I thought that would be the answer I would get. This is my first diesel. Every other truck that I put bigger tires on droped the fuel mileage. I did not know how they would effect a diesel.

Steve

a 265 from a 245 is minimal, your not gonna notice a huge difference in much. and what minimal loss you have you'll gain in looks.

i lost nothing with 265s actually i know ppl that have went 285s and lost a mile or 2

Minimal, but mostly from going from the stock street/towing tire, to an agressive a/t. If you want to keep the milage the same, use a set of street type 265's. A/t's might kill 1mpg. Emphasis on might. :)

Minimal, but mostly from going from the stock street/towing tire, to an agressive a/t. If you want to keep the milage the same, use a set of street type 265's. A/t's might kill 1mpg. Emphasis on might. :)

Agreed - that's why I'm leaning towards staying with 265's but getting n all-season highway tire and not the AT's I have now.

Now I'm rethinking my plans. I tow an 8,000 lb camper for several weeks each summer. I was thinking of again using 265 Michelin E XC LT4 for all season use, but in the past I would have liked a bit more winter traction. Maybe I'll try Michelin E LTX A/T 245's? Anyone heard of experiences with those?

Michelin is a great tire but I would go with the 265.

Michelin is a great tire but I would go with the 265.

Why?