Size and dimension charts look simple, but a surprising number of fitting problems trace back to a chart being read slightly wrong rather than the part itself being incorrect.
Know which dimension is which before you measure. Leg width (the flat dimension across the gear), mounting hole spacing (centre-to-centre distance between bolt holes), and axle diameter are three genuinely different measurements that are easy to confuse if a chart isn’t labelled clearly — always measure your own model against the chart’s stated reference points, not just against a general size description.
Check units carefully, especially with parts sourced internationally. Metric and imperial measurements mixed on the same chart, or a chart using a different convention than you’re used to, is a common source of small but real fitting errors — a millimetre-to-inch mix-up on axle diameter, for instance, is a classic and entirely avoidable mistake.
“Compatible with” claims should be checked against your specific model, not just its general class. Two models nominally in the same size bracket can have genuinely different mounting layouts even from the same manufacturer’s range — a chart listing broad compatibility is a helpful starting point, not a guarantee that skips the need to check your own model’s specific dimensions.
When measuring your own model for comparison, measure the actual mounting points, not the fuselage’s outer dimensions. It sounds obvious written down, but it’s an easy mistake to make when working quickly — the number that matters is where the bolts actually go, not how wide the fuselage looks from outside.
If a chart’s dimensions and your own measurements don’t quite agree, trust your own measurements and get in touch before ordering — it’s far easier to double-check a measurement or ask a question up front than to deal with a return because a chart was read slightly wrong.
You can browse our 20-35cc Carbon Fibre Undercarriage for Petrol / Gas / Nitro models. to see this in practice.