TowingMath

Trailer Axle Weight Chart

Common axle capacities, roughly what a bare axle weighs, and how to work out which one is under your trailer.

Capacity (GAWR)SpindleBolt pattern Bare axle weightBrakesTypical use
2,000 lb 1-3/8" x 1-1/16" 5 on 4.5" 85 - 110 lb usually none Light utility, small boat trailers
3,500 lb 1-3/8" x 1-1/16" 5 on 4.5" 130 - 165 lb electric or none The most common trailer axle. Single-axle utility, small campers
5,200 lb 1-3/4" x 1-1/4" 6 on 5.5" 165 - 200 lb electric Tandem utility, mid-size travel trailers
6,000 lb 1-3/4" x 1-1/4" 6 on 5.5" 175 - 215 lb electric Larger travel trailers, car haulers
7,000 lb 2-1/4" x 1-3/4" 8 on 6.5" 215 - 260 lb electric Heavy equipment, large travel trailers, toy haulers
8,000 lb 2-1/4" x 2" 8 on 6.5" 250 - 300 lb electric or hydraulic Heavy equipment and commercial trailers
10,000 lb 2-3/8" x 2" 8 on 6.5" 300 - 370 lb hydraulic or air Commercial and heavy equipment

Bare axle weights are ranges because actual weight varies with hub face width, spring seat placement, brake type and manufacturer. Spindle sizes and bolt patterns are the most common pairings, not the only ones. For an exact figure, use your axle manufacturer's documentation.

Verify before you tow. These figures are a planning aid, not professional or engineering advice. Your real limits are the ones printed on your vehicle's door-jamb placard, your trailer's VIN plate, and your owner's manual - and those override anything calculated here. When numbers are close, weigh the rig and go with the more conservative answer.

How to identify your axle

Work through these in order, and stop as soon as you get a definite answer.

  1. Look for the capacity tag. Most axles carry a sticker or stamping on the tube or a spring seat. If it is readable, you are done.
  2. Check the trailer's VIN plate. Usually on the front left of the frame near the coupler. It lists GVWR and the GAWR for each axle. This is the figure that governs legally, and it overrides anything you infer from the hardware.
  3. Count the wheel lugs. Five lugs generally means 3,500 lb or below, six lugs points at 5,200 to 6,000 lb, eight lugs at 7,000 lb and up.
  4. Measure the spindle. Requires pulling a hub, but it is definitive when the tags are gone. Cross-reference against the table above.

The lowest-rated component wins. Axles, tires, wheels, springs and hubs each carry their own rating, and your real capacity is the smallest of them. Tires are the most common weak link because they get replaced over a trailer's life, often with whatever was in stock. Check the load rating on the sidewall against the axle rating - the axle weight calculator compares both for you.

Working out load per axle

Tongue weight is carried by the tow vehicle, so it never sits on the trailer's axles. Subtract it first, then divide: 

Weight on axles = Loaded trailer weight - Tongue weight
Load per axle   = Weight on axles / Number of axles

Example, 7,000 lb tandem with 910 lb tongue:
  (7,000 - 910) / 2 = 3,045 lb per axle

An even split is an estimate. Tandem axles rarely carry identical loads in practice, so leave margin, and weigh the trailer if the calculated figure lands close to GAWR.

Common questions

How much does a trailer axle weigh?

A bare trailer axle typically runs from around 85 lb for a 2,000 lb capacity axle to roughly 300 lb for an 8,000 lb axle. A 3,500 lb axle, by far the most common size, is usually in the 130 to 165 lb range.

Those figures are for the axle assembly itself. Wheels, tires, brakes, drums and springs add substantially more - often another 60 to 100 lb per wheel position once tires are mounted.

How do I identify what axle I have?

Start with the capacity tag or stamping on the axle tube, usually near the centre or on one of the spring seats. If it is legible, that is your answer.

If it is not, three physical clues narrow it down quickly: the wheel bolt pattern (5-lug is typically 3,500 lb or under, 6-lug points to 5,200-6,000 lb, 8-lug to 7,000 lb and up), the spindle diameter, and the tube diameter. Cross-reference all three rather than trusting any one, and confirm with the trailer's VIN plate.

Can I tell axle capacity from the tube size?

It is a useful indicator but not proof. Tube diameter generally rises with capacity, and round versus square tube differs between builders, so the same tube can appear under different ratings.

The capacity that actually governs is the GAWR on the trailer's VIN plate. Guessing high from a tube measurement is exactly the wrong direction to be wrong in.

Do axle ratings include the wheels and tires?

No, and this catches people out. GAWR is defined federally as the capacity of the axle system "as measured at the tire-ground interfaces", but the tires you actually fitted have their own separate load rating.

If your tires are rated lower than the axle, the tires are your real limit. A 7,000 lb axle on tires rated 2,800 lb each is a 5,600 lb axle in practice.

Related tools

Sources