Do Zinc Caster Wedges Break? (Ask What's Under Them)
Do zinc caster wedges break? Only when the load concentrates on one spot — usually a Z-block or H-block spacer. Here's what actually matters.
Chris Ludwig
11/1/20261 min read
The most common objection we hear about zinc caster wedges isn't about price — it's "won't zinc break?" Fair question from anyone who's seen a wedge fail. But the wedge material is rarely the real story. What matters is what's sitting under it.
A caster wedge lives between the axle and the leaf spring, and its whole job is to take load. Our HD wedges are die-cast Zamak 5 zinc alloy — a hard, dense alloy made for exactly this kind of compressive load. In a flat, even stack, zinc holds up fine for the life of the alignment.
Wedges break when the load stops being even. The culprit we see is the Z-block or H-block spacer: those stepped spacers concentrate the whole load onto one narrow spot on the wedge instead of spreading it across the face. Put a focused load like that on any wedge — zinc or aluminum — and something eventually gives.
That's the part the aluminum-wedge pitch skips. Switching to aluminum doesn't fix a concentrated load; it just moves the failure point. The actual fix is a flat spacer plate under the wedge, which spreads the load back across the full face. We don't stock the plates, but we can get them for you drop-shipped.
So the zinc-versus-aluminum debate asks the wrong question. Ask what's under the wedge instead. If the stack is flat, zinc does the job at a fraction of the price — and ours have one more advantage: they're the only slotted break-away wedges on the market, so the bolt never has to come all the way out to swap one.
Order by part number: 43-951 through 43-958, half a degree through 4 degrees, six to a box. Call or text 469-215-7730.