This is from Thule's website and will help you in your selection process. Unsure of how you should carrier your bikes on your car? We can help you make the right choice for your needs.
Your 1st step is to know how many bikes you need to carry and what vehicle you will carry them on.
Next we will describe the different areas you can mount bikes – read each section to determine which mount best suits your needs.
Roof carriers (Mounting with a roof system or to your vehicle pre-existing factory rack system) have many advantages. Roof systems offer the most options and can usually carry many bikes (up to 4 or more in most cases). These systems will mount to either your vehicle doors or your factory rack and can carry up to the limit for your car – the instruction will give your specific limits. Beyond bike options, roof system can allow you to carry other item, such as luggage boxes, skis, boats, ect. While providing the most flexibility and options, roof systems will costs more, can take more time to mount, and you’ll need to watch out for low garage heights!
Main Advantages: Options, Flexability
Trunk carriers offer easy bike access and can usually carry up to 3 bikes. These carriers will mount with straps to your vehicle hatch and/or trunk – the instruction will give your specific mounting hints. Because of their size and the fact they are designed only for bikes, trunk racks are lower in cost and can move easily between different vehicles . You’ll need to look for additional options if you need to carry more than 3 bikes or need a place for other skis, boats, etc
Main Advantages: Lower price, portability
Hitch carriers (Mounting to a receiver or step bumper system). Hitch systems require a receiver hitch on your vehicle – the size and type can be determined by a local hitch dealer. Once you have a hitch on your vehicle, you can mount a Thule bike carrier, add a ski adapter, or use a hitch cargo box. Hitch carriers offer easy access, locking security, and easy installation and removal. Systems are available for up to five bikes and cargo systems up to 13 cubic feet. Systems are available that allow easy access to your hatch or rear vehicle compartment. Systems are limited to the hitch systems capacity.
Main Advantages: Access, Security
Truck carriers (Mounting to truckbed). Truck systems adapt to the pickup truck bed and can be mounted on a truck rack system or pickup bike mount. These system utilize pickbed space and offer options for items beyond bikes – The Bedrider system carries two to four bikes.
Main Advantages: Access