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Have Questions or concerns about your order? Call Us now at (833) 910 3416!
Have Questions or concerns about your order? Call Us now at (833) 910 3416!
Where the spring sits on the axle sets your ride height and decides which trailer type each setup fits. Read the drawing, pick the configuration, then shop the matching parts.
Same leaf spring design. Only the mount position changes, and that one change sets your whole ride height.
Gives more ground clearance. Ideal for highway trailers and standard loads, and it is the default on most North American trailers.
Lowers ride height for flatbeds, car haulers, and low-profile loads where a lower deck is needed.
NOTE Want the full breakdown? Read our complete overslung vs. underslung blog guide.
Seven specs, side by side. The marked column is the stronger pick for that line.
| Spec | Overslung | Underslung |
|---|---|---|
| Spring position | Above the axle | Below the axle |
| Deck height | Higher | Lower (typically 3–5") |
| Ground clearance | Better▸ PREFERRED | Reduced |
| Drive-on loading | Steeper ramp | Gentler ramp▸ PREFERRED |
| Best terrain | Rough / mixed roads▸ PREFERRED | Paved / maintained |
| Tall-load stability | Good | Better, lower CG▸ PREFERRED |
| Most common on | Cargo, boat, utility, livestock | Car haulers, flatbeds, lowboys |
How each one clamps to the axle, what it is good at, and where it falls short.
The spring bolts on top of the axle on a welded spring seat, and the U-bolts wrap under the axle to clamp the pack down. The frame rides above the spring, so the deck sits higher.
The spring sits under the axle and effectively hangs from it, with the U-bolts wrapping over the top of the axle to carry the load. The frame drops with the spring, so the deck sits 3 to 5 inches lower.
Same axle, same spring. The U-bolt orientation flips the spring above or below the tube, and that sets the deck height.
The spring bolts on top of the axle and the frame rides above it, so the deck sits higher. Nothing hangs below the axle.
The axle rides on top of the spring, so the frame and deck drop lower. The spring becomes the lowest point, the tradeoff for a lower deck.
Match the configuration to your trailer type. The colored edge tells you which mount to order.
Taller clearance handles road debris, with no need for ultra-low loading.
Low deck is critical for driving vehicles on without a steep ramp angle.
Extra clearance keeps the frame above the waterline during launch and retrieval.
Heavy machinery and skid steers need the lowest possible deck for safe loading.
Higher stance gives better road clearance, the standard for most livestock haulers.
Maximum load-height compliance requires the lowest possible trailer deck.
Switching setups takes more than springs. Here is what changes, and what to confirm before you buy.
You can convert between setups, but you will need more than new springs. Plan on replacing U-bolt kits, hanger kits, shackles, and possibly equalizer brackets on tandem axles. The axle beam itself does not change.
When converting, measure your current eye-to-eye spring length carefully. A 3-inch axle tube adds roughly 3 inches of height in overslung and subtracts about 3 inches in underslung, which means your hanger spacing may need adjustment.
☎ Call (936) 289-3191 before you order. We confirm hanger spacing and U-bolt length for your axle tube size.
Jump to the most popular load ratings, or open the full range.
The ones our experts field most often about spring position.
Yes, but it requires replacing the U-bolts, spring hangers, and possibly the shackles. The axle itself does not change. It is a common upgrade on car haulers. We recommend consulting our support team before ordering.
Spring position alone does not change rated load capacity. That is determined by the leaf spring's rating, for example 3,500 lb per axle. However, underslung springs may see slightly different stress distribution under heavy loads.
You will need your axle capacity rating, the distance between spring hangers (eye-to-eye length), and the number of leaves. Common sizes are 25-inch and 29-inch. Check your trailer's VIN plate, or contact us with your trailer make, model, and year.
In most cases, yes. The spring itself is symmetrical. What changes is the U-bolt orientation and hanger configuration.
They can accumulate more road grime and moisture since they hang lower. Periodic inspection and greasing of the shackle bolts is especially important for underslung setups.
Our full selection of trailer leaf springs covers both overslung and underslung setups, in all major sizes and load ratings, with next-day shipping.
