How Is Trailer Weight Capacity Determined and Can It Be Increased By Adding Different Components


I have a 4x6 trailer with 26 eye to eye springs. I carry a 800+ lb atv and it flattens the springs out when the atv is loaded onto the trailer. Are their the same length spring that carry just a bit more weight or do I need a complete new axle, wheels... Thank you.


Expert Reply:

When it comes to any trailer, including your small utility trailer that transports your Kodiak ATV, the trailer's actual weight capacity will be a function of which of its component parts has the lowest weight rating.

A trailer's capacity will be limited to that of the lowest-rated part, either the trailer tongue, the frame, the axle, the suspension, the wheels or the tires. It is the classic "weakest link in the chain" situation. If you were able to know for certain that the weakest link in the chain happened to be the trailer axle, then changing the axle could increase the trailer's weight capacity, but only up to the capacity of the next weakest component. The problem is that knowing this requires some engineering background, which most of us do not have.

It could also be the case that your springs are worn, and that is why they are sagging under load. If you're lucky, this is the case.

In your 26-inch eye-to-eye spring dimension we do have double-eye leaf springs available in several axle weight ratings, from 2000-lbs up to 6000-lbs. I doubt very much that your trailer is rated for anything more than 2000-lbs, if even that. If your trailer leaf springs are rusted at all you may need only new 2K-rated ones # SP-124275. If they are in good shape, but sag under the ATV load, then you could try using higher-rated 4000-lb springs # SP-051275 but the ride quality from the trailer could very well become a bit stiffer and bumpier. With springs of that much higher a rating, you might find something else on the trailer starting to bend!

It appears your wheels/tires are 4-on-4 bolt pattern 8-inchers, such as Kenda 4.80-8 # AM30040. This wheel/tire combination has a load capacity of 745-lbs per wheel/tire, so the two could handle up to 1490-lbs maximum.

I suggest checking the trailer's VIN sticker for either an axle rating or the trailer GVWR and then ensuring you do not exceed either's capacity.

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expert reply by:
Adam R

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