bigger tires

[CCRanch]

talking to Discount tires about going to 285 tires from stock 245. He said I would have to re-program for the Allison to read the correct speed on the speedometer. Is he correct. Also, what kind of programmer do I need, or is it too much trouble, and can it void my warranty. I have 4000 miles on my 06 2500HD 4x4. I see alot of trucks with the 285-75-R16 tires and wonder if they all re-programmed. Thanks for any info.

[DmaxMaverick]

Most folks just upsize, and live with an inaccurate speedo/odo. The upside is your warranty will last longer (less miles racked up per actual). The downside is, of course, not being accurate, and the problem the dealer might have with it. I have 285's on, and correct the speedo/odo with a Predator programmer. The dealer can't/won't reprogram for larger tires. They can/may reprogram the PCM for ABS function, but that won't correct the speedo/odo. The programmers that will do it are Predator, Hypertech, Superchips, and maybe a couple others that don't come to mind right now.

My dealer doesn't have a problem with the larger tires I have, which is not typical of all dealers. They did ask if I calibrated my speedo/odo, and verified it.

[upsguy]

Would larger tires affect gas mileage. When I had a dodge gasser, I went from 245's to 265's and didn't notice a difference, but from 245's to 285's is a pretty big jump. I was just wondering. I'd like to put some bigger tires on mine too. Those 245's look kinda wimpy.

[FBJR]

Most of the handhelp programmers will let you set the tire size. You can add power or not. It will let the brakes work correct too which many don't think about.

You can also use them to check for codes and such. They go for around $300 and you it forever.

I am using the Diablo which lets you adjust alot and can be upgraded over the internet

FB

[cwood]

I had an 04 LB7 with 285's and didnt reprogram anything had no problems just knew spedo was off. Just bought an 06 LBZ and had the dealer put my 285's on new truck after they switched them they told me that they would void the warranty. they said that 275's and smaller were fine.

[Melvin P. Thorpe]

My tire dealer said that for them to put 285's on my truck I needed to change out the rims to 7" from the stock 6 1/2" rims. They told me they had all kinds of trouble with the larger tires on smaller rims. Just bull or true?