Just keep the required information to a useful minimum.
Allow the posting of Optional information.

Required: Name (please enter at least the first name you normally use)
Required: Username/Nickname (the username/nickname you use in the Forum)
Optional: Email Address
Optional: City or County or Parish or Region (where you live)
Required: State or Province
Required: Country
Required: Year, Make & Model of your truck (multiple entries allowed)
Optional: one or more URLs that "points to" your truck(s) (photo, website, etc)