School of Rack | Car Roof Top Carriers vs Rear Mount Carriers Information Article

It’s no secret that car racks make life easier when it comes to transporting bicycles, boats, skis and snowboards, all types of gear and luggage, and numerous other things that you’d rather not share interior space with. What isn’t always obvious is where on the vehicle a specific item is best carried. With bicycles, skis & snowboards, cargo boxes and gear baskets, you have the option of transporting them either on the roof or the rear of the vehicle. Both of these applications come with pros and cons, and making a decision will boil down to a compromise between these pros and cons based on an individual user’s priorities. In certain cases, the vehicle itself will determine the choice for you, as some vehicles don’t have a fit option for the rear while other vehicles don’t have an option for the roof.

Roof Attachments
Roof attachments, like bike, kayak, canoe, surfboard, ski-snowboard and cargo-luggage carriers, mount to a pair of crossbars that run across the vehicle's rooftop from side to side (luggage roof bags and the Thule Snowcat ski carrier can mount to vehicles with just factory side rails). Some vehicles come with pre-installed factory crossbars and some vehicles come without them. In the case of vehicles with factory crossbars, many attachments, like kayak carriers, ski carriers, cargo carriers and certain bike carriers, can be mounted directly to the crossbars while other attachments require the use of special factory rack bar adapters. Some gear carriers, like upright mount bike racks (transports bicycle with both wheels on) and fork mount bike racks (transports bicycle with the front wheel removed) can only be mounted to Thule or Yakima crossbars. For cars without factory crossbars, a roof rack base system must first be installed before any attachments can be used. Once a base system is installed however, there are no restrictions. You are free to attach any carrier—ski, bike, boat, cargo box, etc.—you want.

Pros:

• Security: Roof mounted carriers are generally the safest and most secure way to carry your gear, especially when concerning bikes. With the exception of the newer, premium platform style hitch carriers, bikes are less likely to get scratched and/or stolen when mounted on the roof. On a roof system, bikes are held securely in individual trays, eliminating the worry of the bikes banging together, and when locked down, bikes are harder to steal, as opposed to bikes held in strap down car trunk racks.
• Protection: Gear is less vulnerable when carried on the roof. There are far fewer hazards that can cause damage up above than on the ground level. Your bike will fare much better slamming into a bug while cruising down the interstate than it would slamming into a fire hydrant while backing up.
• Profile: Carrying bicycles on the roof will retain the overall length of the vehicle. You have a better chance of squeezing into that tight parking spot than you would with a rear mount cargo box, gear basket, or bike rack sticking out.
• Capacity: You can simply carry more gear with a roof top system. The roof boxes and baskets are larger and therefore have a higher capacity. You can also carry more bikes than a rear system, provided your vehicle can handle the weight. With longer crossbars, you can safely carry six or more bicycles.

Cons:

• Low Over-Hangs: A roof system with gear attached presents the problem when height clearance is questionable, so the driver must be cautious when driving into parking garages or any other space with a low roof.
• Decreased gas mileage: Although this varies between vehicles, and can be somewhat mitigated with a wind fairing, your gas gauge will fall a bit faster than it would with a rear mounted rack. In recent years, however, car rack manufacturers have invested heavily in muanufacturing very aerodynamic gear carriers, especially cargo boxes, which can noticeably decrease your fuel costs.
• Bug Splatter: During certain times of the year, and especially on longer trips, your bikes will become covered with dead bugs, which aside from being gross, can stick to your frame like cement. There are products available to protect your bikes from insect assault, but they can be a hassle to deal with. Generally, the issue of bug splatter is easily overcome with a quick wipe down of equipment after transport.
• Lifting Equipment Over Your Head: Obviously, to get gear onto the roof of your vehicle, you are required to do some lifting. For some folks, hoisting heavy objects, such as bicycles, over their head can be difficult. The use of a small stepladder or a wheel step certainly can help, but will still require more lifting than a rear system would.
• Cost: Roof systems can be more expensive, especially when you need to first purchase a multi-purpose base rack system. If you want to carry three bikes, for example, you can do so with a car trunk rack inexpensively, whereas on a car with a naked roof, it will cost much more for a multi-purpose base rack system and each bike carrier.
• Installation: You’ll need to set aside more time/beverages to install a roof system than you would with a rear system.

Rear Mounted Attachments
Cargo boxes and cargo baskets, which started out as rooftop specific carriers, are now available in hitch-mounted versions. Rear ski & snowboard carriers, which attach to existing hitch bike racks, are also fairly new. Rear mounted bike racks, however, have been around for a long time, and are broken down into three main types: Trunk mounted, which attach with hooks and straps to the rear of the vehicle, spare tire mounted, which attach to the spare tire, and hitch mounted which attach to either a 1-1/4" or 2" receiver hitch.

Pros:

• Easier Access: Rear mounted boxes, baskets, and ski and bike carriers are easier to load and unload as minimal lifting is required.
• Affordability: Rear-mounted racks are a generally a less expensive alternative to roof racks, especially when carrying multiple bikes.
• Ease of Installation: Rear mounted racks, especially hitch mounted carriers, are easier and less time consuming to install.
• Versatility: Many rear carriers can move easily between different vehicles.

Cons:

• Damage to Vehicle: Because strap down bike racks are attached with hooks and straps, the pads that contact the vehicle are more likely to drift than roof systems and can result in cosmetic damage to the vehicle. The extent of this damage is usually chipped paint or scuffing, which can be minimized by wiping dirt away from where the pads make contact and by making sure the straps are tight.
• Inconvenient Access to Trunk: In certain cases, the trunk or rear hatch cannot be opened without first adjusting or removing gear on the rear mount rack. And in some instances removing the rack itself is required to access the vehicle's trunk or rear hatch. However, manufacturers have done a great job of engineering rear mount bike racks, cargo boxes and gear baskets that conveniently swing away or fold down to allow for access to the rear of the vehicle.
• Rear Wiper Issue: For most wagons, hatchbacks, and SUVs, the top support arm of a strap down bike rack rests against the glass, interfering with the rear wiper. The biggest issue is not so much losing the use of the rear wiper, rather the damage that can be caused to the wiper motor if the wiper is turned on and left on.
• Vulnerabilility: Gear is more vulnerable to damage from ground level hazards, such as careless drivers who rear end you and telephone poles that refuse to get out of the way when you are backing up. Models of bike carriers without anti-sway cradles allow the bikes to bang together, especially on bumpy roads.
• Road Grime: Because of the proximity to the road, dirt and grime can more easily cover your skis, snowboards, bikes, or luggage gear.

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