As a fellow automotive IA, I was on the front lines of this scaling problem. Which asks a larger question, why does everything have to be on the same hub?

Why does a vehicle brand have to organize all the vehicle lines within the same site? It’s logical from a business point of view but too risky to make everything tiered and cumbersome to navigate. The hard part is getting the user experience to match the branding of the vehicle versus the car manufacturer’s holistic brand version of one site fits all.

Car organization should remain at the database level abstracted to the user. Keep the site simple and emphasize a “strong center” which is focused on supporting the user’s interests during the research phase.

Create an engaging (shell) introduction on determining who your user is, invest in an interaction model that is smart, easy and helps users frame guided factors on comparing and evaluating vehicle particulars, if they want more choices they’ll opt for it. Add behind the scenes business logic when referral sites push them to your site. So many ways to drive content into how a site should be organized.

From there you can anticipate and measure these preference-paths into scenarios that inform what categories match users interests. Get crazy and tell these big company cultures to hub it out, bitch!