Chevrolet Silverado 2500HD
GMT800/900, 2001–10

Factory gearing, tires, angles and brakes for the Silverado 2500HD, and what the usual upgrades do to it. Every number is from the maker's own figures unless the calculators say otherwise. A few figures here are still waiting on a factory document; the calculators mark them.

Use this truck in the calculators

153 in wheelbase · 37 in front · 47.3 in rear overhang

Stock tireLT245/75R1630.5 in tall

Axle ratio3.73–4.1Factory, by trim

Crawl ratio62.6:1Best trim: 2500HD 4x4, 6.0 gas (2001-07 GMT800)

Angles26 · 17 · 25°Approach, breakover, departure

Clearance11 in10 to 11 in by trim

Highway mpg19Estimate, not EPA rated

Tire upgrades, worked out

2500HD 4x4, 6.0 gas (2001-07 GMT800), 3.73s, from LT245/75R16

Tire	Height	Under the diffs	Speedo at 65	RPM at 65	Gears for daily	Open
265/75R16	31.6 in	+0.6 in	63 mph	1,931	Keep 3.73s	Open →
285/75R16	32.8 in	+1.2 in	60 mph	1,862	4.1	Open →
33x10.50R16	33.0 in	+1.3 in	60 mph	1,852	4.1	Open →
255/85R16	33.1 in	+1.3 in	60 mph	1,848	4.1	Open →
315/75R16	34.6 in	+2.1 in	57 mph	1,766	4.56	Open →
35x12.50R16	35.0 in	+2.3 in	57 mph	1,746	4.56	Open →

Stock turns 2,006 rpm at 65 in top gear. Flotation sizes are nominal; most measure a little short mounted.

Trims

3 we have figures for

Trim	Tire	Transmission	Axle	Angles	Clearance	Open
2500HD 4x4, 6.0 gas (2001-07 GMT800)	LT245/75R16	Hydra-matic 4L80-E 4-speed automatic, NV4500 5-speed manual	3.73 / 4.1	26 · 17 · 25	11.0 in	Use →
2500HD 4x4, Duramax (2001-07 GMT800)	LT245/75R16	Allison 1000 5-speed automatic, Allison 1000 6-speed automatic	3.73	26 · 17 · 25	11.0 in	Use →
2500HD 4x4 (2007.5-10 GMT900)	LT245/75R17	Allison 1000 6-speed automatic, Hydra-matic 6L90 6-speed automatic	3.73 / 4.1	26^* · 17^* · 25^*	10.0 in	Use →

* The maker doesn’t publish this figure for that trim, so it shows the closest trim’s (same tire where we have one), or a close relative’s that shares the same body or front end. Hover the star to see which.

Size

Wheelbase: 153 in
Front overhang: 37 in to 39.36 in
Rear overhang: 47.24 in to 47.3 in
Height: 76 in
Body: Pickup
Stock tires: LT245/75R16, LT245/75R17

Transmissions and low range

Hydra-matic 4L80-E 4-speed automatic (HD): 2.482 · 1.482 · 1 · 0.75
Allison 1000 5-speed automatic (2001-05): 3.1 · 1.81 · 1.41 · 1 · 0.71
Allison 1000 6-speed automatic (2006+): 3.1 · 1.81 · 1.41 · 1 · 0.71 · 0.61
NV4500 5-speed manual (GM, 1994+): 5.61 · 3.44 · 1.71 · 1 · 0.73
Hydra-matic 6L90 6-speed automatic (HD): 4.03 · 2.36 · 1.53 · 1.15 · 0.85 · 0.67
Low range, np263: 2.72:1
Low range, np261: 2.72:1

Axles

Front: AAM 9.25 in IFS
Rear: AAM 11.5 in full-float
3.73 ratio: 2500HD 4x4, 6.0 gas (2001-07 GMT800), 2500HD 4x4, Duramax (2001-07 GMT800), 2500HD 4x4 (2007.5-10 GMT900)
4.1 ratio: 2500HD 4x4, 6.0 gas (2001-07 GMT800), 2500HD 4x4 (2007.5-10 GMT900)
Ratios made for it: 4.1 · 4.56 · 4.88

Brakes

Front rotor: 12.78 in, 325 mm
Front caliper piston: 57.0 mm
Rear rotor: 12.99 in, 330 mm
Rear: disc (vented, 330 x 29 mm)

Suspension

Front: double wishbone IFS, torsion bars
Rear: leaf springs, solid axle
Rear layout: Leaf springs

Fuel economy

Highway, not EPA rated: about 19 mpg
Where it comes from: Owner average, mixed driving (2005 Silverado 2500HD 4x4 crew cab Duramax, Allison 5-speed)
Source: forums.edmunds.com

Aftermarket bumpers

15 listed

Makers almost never publish angles, bottom heights or how far a bumper tucks, so these fill in as owners measure them. Measured yours? Add it on the rig page and every owner of this Silverado 2500HD sees how it does on their tires and lift.

Front 8

Affordable Offroad Full Size Chevy Truck Modular Front Bumper (99-07)130 lb · $950 · winch ready
Chassis Unlimited 2003-2007 Chevy Silverado 2500/3500 Octane Front Winch Bumper$2,110 · winch ready
Chassis Unlimited 2007.5-2010 Chevy Silverado 2500/3500 Octane Winch Bumper$1,907 · winch ready
Fab Fours CH05-S1361-1 Black Steel Chevy Silverado 2500/3500 Classic Front Bumper 2003-2007$1,640 · winch ready
Hammerhead 600-56-0113 Chevy Silverado 2500/3500 2003-2006 Front Bumper Winch Ready No Brushguard$2,056 · winch ready
Iron Bull Bumpers 2003-2007 Chevrolet Silverado 2500/3500 Front Bumper$1,700
Iron Bull Bumpers 2007-2010 Chevrolet Silverado 2500/3500 Front Bumper$1,700 · winch ready
Throttle Down Kustoms 2003-2007 Chevrolet Silverado HD PreRunner Bumper$1,775

Rear 7

Every calculator, set up for the Silverado 2500HD

Tire sizeBigger tires: speedo, clearance, angles and brakes.Compare tires RegearHighway RPM on every ratio and mpg.Pick your gears Crawl ratioHow slow it creeps, against other trucks.Work out crawl SpeedometerWhat it really reads on new tires.Fix your speedo LinksAnti-squat and what a lift does to it.Check your links Your rigBuild sheet and measured angles.Start a build sheet LeaderboardsWhere the Silverado 2500HD ranks against every stock truck.See where it ranks

Source: auto-brochures.com. AAM 11.5 uses different carriers for 3.73-and-down vs 4.10-and-up.

Use at your own risk. These calculators are here to help you plan and to inform your decisions, not to sign off on a build. Many numbers are estimates worked out from factory figures, and some factory figures are not yet confirmed. Check every number against your own truck, its manuals and a qualified shop before you buy parts, cut, weld, lift, regear or drive on it. Long Range Desert Tools is not liable for anything you do based on these calculators or their results. The full terms are in our policies.

Chevrolet Silverado 2500HDGMT800/900, 2001–10