Not every fuselage matches a standard gear width exactly, and that’s more common than you’d think — even within a single “size class” of model, mounting widths vary between manufacturers and even between different production runs of the same kit.
The good news is that carbon fibre undercarriages are generally straightforward to adapt in width, provided you approach it methodically. Many two-part gear designs are specifically made this way — manufacturers intend for the centre section to be trimmed or a section removed, then the two halves bolted back together at a narrower span, which is a well-established and structurally sound method rather than a workaround.
A few practical points if you’re trimming gear to fit:
Mark your cut line carefully and double-check the measurement twice before cutting once — carbon fibre offcuts aren’t reusable if you get it wrong.
Use a fine-toothed blade suited to composite materials, and always cut with adequate dust extraction or outdoors with a mask — carbon fibre dust is an irritant you don’t want to breathe or get in your eyes.
Deburr and lightly seal any freshly cut edge, since a bare cut edge is more vulnerable to moisture ingress and fibre fraying at the exposed layers than the factory-finished parts of the leg.
Re-drill mounting holes rather than trying to reuse factory-positioned holes that no longer line up after trimming — it’s a five-minute job and avoids putting unnecessary stress on a hole that’s now in the wrong place relative to the new span.
If you’re at all unsure whether your specific gear is designed to be trimmed this way, check the product description or ask before cutting — some designs are genuinely not meant to be shortened, and attempting it risks compromising the structural integrity of the leg.
Our EXTRA 300 100CC Carbon Fibre undercarriage is a good illustration of the kind of fit and finish to look for.