Publishing the bill of materials

We published the complete bill of materials with the first car. Several people told us it would destroy the parts business. Here is what actually happened.

Parts revenue went up

Independent garages started ordering from us, because they could finally identify the right part without guessing or calling. We lost the margin on captive customers and gained volume from people who previously would not touch the car at all.

The unexpected effect

Suppliers began listing their own part numbers against ours, which means an owner in year twelve can buy a wheel bearing from the company that made it. We expected to mind this more than we do.

What it costs

Publishing a BOM means you cannot quietly substitute a cheaper component mid-year. Every change is visible. That discipline is genuinely expensive and it is the part we would warn others about.