Keep my 04 wheels on 08 Duramax?

[Truck Owner 901]

I'm thinking of trading my 2004 for a 2008 Duramax. I believe the new models have 17 inch wheels. I'd like to keep my older 16 inch wheel (stock) from the 2004 Duramax . I have these thoughts and concerns:

• I just put on new Bridgestone Revo Duelers (best tire around for me!)
• I tow a fifth-wheel trailer and I want to avoid having the truck any taller than it is now.
• Can my speedometer be easily re-calibrated for a non-stock tire size (on the 08)

Another item, I know the bed rails on the new model are about 2.5 inches taller than the 2004. Those of us towing fifthwheel trailers are concerned with the clearance between the FW 'overhang' and the top of the bed. We like to keep at least around 6 inches clearance when the rig is level.

I have heard the stock 08 Duramax uses shims to raise the height of the bed; anyone confirm this? And is it practical to remove the shims to lower the bed to provide more clearance between the truck and FW?

Thanks.

[rmk8]

the wheels on your 04 will stick out past the fenders on a 08
08 has a different back spacing 08 is +25--+30

[jaydawg]

Clerance is minimal if u stick the 16" RIMS ON THE 2008. It is maybe 1/2 inch or less.

[Truck Owner 901]

Thanks for the info people. I was hoping I could just do a wheel swap. I test drove a 2008 and it did indeed have the taller (17 inch) tires. The top of the tailgate sits 2 inches higher than my 2004 Duramax. Might cause a clearance problem with my 2007 fifthwheel.