H07

Iupgraded from 265/75-17 to 305/50-20 ....do I need to take it to the Dealer for a recalibration?

From what I can tell the diameter didn't change that much if any,would this throw off shift points or cause drivability issues?

H07

Anyone? I'm sure someone has upgraded from 17's to 20's and either had the Dealer recalibrate or left it alone and not had any problems.

ZX1100F1

You should get a new VCI code that recalibrates the BCM for the 20" wheel/tire combo.
Not only will this correct the Speedo (even though it should read good now as the diameter is close) it will also provide the necessary new tire size including width to the ABS and Stabilitrak system so they use the proper algorithm when active.

I can provide you with the VCI code for 20” tires if you give me your VIN but you would still need to have the code installed by the dealer.

GM does not charge dealers for these VCI codes so don;t let them tell you otherwise although expect to pay the dealer for the service 1/2 to 1 hour labor is standard.

H07

Awesome....appreciate the help, I will PM you the VIN later this evening when I get home.

H07

ZX, sent you a PM [sm=smiley20.gif]

romis

I went from 17's to 20's months ago. Is updating the VCI code critical or can it wait until the truck goes in for regular service?

Is this something that a programmer can do? I notice that superchips says that it can program for different rim/tire sizes.

ZX1100F1

The programmer cannot change settings for the Stabilitrak system it only corrects the speedo.

It not critical but it is recommended, just don't forget to have it done.

ZX1100F1

H07,
Your VCI code for the 20" ties is 1049264
And to go back to stock is 109260

Just have the dealer reflash the ECM, I already have pre-loaded the 20" VCI to your VIN.

H07

This site isawesome especially to have an in house GM guy like ZX....Thank you very much for the help !!!!![sm=groupwave.gif]