When you browse our axle options you’ll often see two numbers like “94″ HF / 80″ SC.” HF stands for hub face – the distance between the mounting faces of the hubs – and SC stands for spring center, the distance between the centerlines of the leaf springs. Under the spring center you may notice “pads loose” or “pads welded,” which can be confusing at first.

Pads Pre‑Welded vs. Pads Loose

• Pre‑welded spring pads are welded at the factory to fit a specific spring‑center width. If your trailer has a common width (for example, 74″ or 80″), pre‑welded pads mean the axle arrives ready to bolt in.

• Loose spring pads are included with the axle but not welded on. This lets you weld them wherever you need them.

Why Choose Loose Pads?

Loose pads are ideal for custom builds or uncommon trailer widths. They provide flexibility to weld the spring pads (also called spring perches or spring seats) exactly where your springs need to sit. If your trailer’s hangers are already welded in place and don’t match standard spring centers, loose pads let you position the axle correctly without forcing you into a standard width. This extra step does require welding, but it’s worth it for a perfect fit.

When Pre‑Welded Pads Make Sense

For trailers with common spring centers, pre‑welded pads save time. You know the axle will fit your frame out of the box and you won’t need to pay for welding. Just make sure the hub face and spring center measurements match your trailer’s dimensions before ordering.

Pro Tip from the Shop

If your trailer’s spring‑center measurement is anything other than standard, order loose pads. We can weld them for you for a small fee, or you can weld them yourself. It’s the best way to ensure your springs align perfectly with your hangers. For common widths, pre‑welded pads are the fastest route to a bolt‑in installation.

Trailer Parts Unlimited – 631 TX 75 N, Huntsville TX 77320
Exit 118 off I‑45, next to Pilot and Chicken Express
Pickup or shipping available