On this page you'll find the exact dimensions for the GMC Sierra Extended Cab 2500 & 2500 HD generation 2, made from 1998 to . Below we'll list the dimensions for this pickup from verified sources. First, let's make sure you have the right dimensions in front of you:

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Dimensions in tables

Sierra truck bed dimensions (Extended Cab)

Truck bed dimensions	Fleetside Short Box	Fleetside Long Box
Volume (cu. ft.)	56.9	70.7
Length at floor	78.7	97.6
Inside height	19.5	19.5
Width at wheelhouse	50	50
Maximum width at floor	64.8	64.8

Wheelbase of the Sierra:

Wheelbase	Length (inch)
Fleetside Short Box	143.5
Fleetside Long Box	157.5

Exterior dimensions of the Sierra Extended Cab:

Dimension	4x2	4x4
Overall length - Fleetside Short Box	227.6	227.6
Overall length - Fleetside Long Box	246.7	246.7
Cab length	138.7	138.7
Overall height - Fleetside Short Box	76.2	76.2
Overall height - Fleetside Long Box	76.2	76.2

Exterior width of the Extended Cab:

Exterior width	4x2	4x4
Width (excluding mirrors)	79.7	79.7

Extended Cab miscellaneous dimensions

Miscellaneous dimensions	4x2	4x4
Front overhang - Fleetside Short Box	37	37
Front overhang - Fleetside Long Box	37	37
Rear overhang - Fleetside Short Box	47.2	47.2
Rear overhang - Fleetside Long Box	47.2	47.2
Front ground clearance - Fleetside Short Box	9.1	10.6
Front ground clearance - Fleetside Long Box	9.1	10.6
Rear ground clearance - Fleetside Short Box	12.1	13.6
Rear ground clearance - Fleetside Long Box	12.1	13.6
Cab length	138.7	138.7

Interior dimensions

1st row dimensions	Extended Cab
Head room	41
Shoulder room	65.2
Hip room	61.4
Leg room	41.3
2nd row dimensions	Extended Cab
Head room	38.4
Shoulder room	66.3
Hip room	61.5
Leg room	33.7