Killer Instinct Crossbow Strings & Cables Replacement

Strings don't fail on a fixed schedule — they fail based on shots, storage, and care. Replace (or have a shop replace) when you see:

• Frayed or broken strands, especially near the end loops or cams.
• Serving separation — gaps or unraveling in the center serving where the bolt sits or where the string contacts the cams.
• Fuzzing that won't wax down, or a visibly stretched string that has cost you FPS.

As a rough rule, many hunters re-string every couple of seasons or after a few hundred shots, and immediately after any obvious damage. A worn string quietly steals speed long before it snaps, so a periodic replacement keeps your bolts hitting where your reticle says.

String and cable sets are cut to exact lengths for each cam system, so they are not interchangeable between models. To order correctly:

• Identify your exact model and year — e.g. Lethal 405, Ripper 415, Rapid 420, Logix 435 — since each may use a different string/cable length.
• Order the full set (string plus cables) if the cables show wear too; replacing only the string on stretched cables won't fully restore tune.
• Confirm the spec against your owner's manual or the OEM listing rather than eyeballing length.

Because X-Cam and other cam configurations vary across the lineup, matching the exact part is essential — see our strings and accessories pages, and keep spare parts for the field.

Two good paths:

• OEM replacement set — matched to factory spec and the simplest way to keep advertised performance and scope calibration. Best default choice.
• Custom aftermarket strings — can offer premium materials, colors, and durability, but must be built to your model's exact lengths. Only go custom with a reputable builder who has the correct specs.

Whichever you choose, replace string and cables as a set when both are worn, and re-check speed and zero afterward. Budget for the labor if you don't own a crossbow press — most models require one for safe installation.

Care extends string life dramatically:

• Wax regularly — apply string wax to the string body (not the center serving or cam contact points) every several shooting sessions and before storage. Rub it in until the strands look sealed.
• Don't over-serve or wax the serving — that's where the bolt and cams ride.
• Use a rail lube on the flight rail to reduce serving wear at the shot.
• Installation usually requires a crossbow press. Restringing a modern high-poundage crossbow without one is dangerous — if you're unsure, have a pro shop do it.
• After install, cycle the bow, re-check FPS, and re-sight your scope.

A crank draws the same string every cycle — pair a fresh string with your DSC crank for the most consistent speed.

A new string is a good moment to refresh the rest of the system:

• HYPR bolts — confirm zero with fresh bolts after re-stringing.
• Replacement parts — string stops, dampeners, and rail hardware wear alongside the string.
• Lumix scopes — re-calibrate to the restored FPS.

Comparing models before you invest in maintenance? See our best Killer Instinct crossbow guide and reviews.