I am in the process of buying a new car and I want to fit a rack on it for my bikes. Are there any issues that I need to be aware of for fitting a rack to a car, or rather are their any factors that would make it impossible to fit a rack to a car? That would be a deal breaker for me.
Sharing own experience with several racks, either used as bought and even homemade.
I can divide them in three categories:
More adequate for small cars (i.e. not so tall) for reach issues. Also, they work better with lighter bikes (Road bikes, XC bikes or the like). I wouldn't fit a heavy DH bike in a roof rack, it's heavy to lift up to the roof. Also if the car is too tall, the operation is likely to get difficult. In My experience, the roof rack would work fine if the car's roof is at your shoulder's height, above that, it gets too difficult.
There are two kinds: the ones that hold the whole bike or the ones that hold the bike by its fork. Either one has the advantage of easily accepting odd shaped bikes, as they usually have a rail in which the rear wheel fits.
If the whole bike type, they have a rail for the front wheel and a post that holds the bike upright. When sturdy enough they can handle heavy bikes like the DH ones.
The fork type requires you to remove the front wheel completely and put the fork in a hitch that has the same shape and dimensions as your wheel's axle. This of course works better if you have a quick release front axle, and along having to take your bike apart every time, you risk loosing axle nuts or springs. Also, you need the rack to have the adecuate hitch for your bike's front axle: road and XC hubs are different, All Mountain or DH bikes usually have thru axle type. However, they hold the bike very secure.
A useful advantage of the roof rack is that it is unobtrusive for most doors, so you have full access to your car without having to remove bikes. Also, they can be left on vehicle as it doesn't increase overall length, so is not a problem for tight parking and other slow maneuver. (Unless under a low garage or bridge).
Other advantage is that they usually can accommodate more bikes than other types. For example, I used to fit 3 XC bikes on top of a small car without protruding outside the roof. Another example: the support cars in Tour d France...
Better for bigger cars that are more likely to have adequate mounting points for the towing bar (what the hitch is bolted to), as this is the only mounting point unlike other rack types that have several mounting points.
This type is more likely to hold the bike by it's tires and have a post that holds the bike upright, so you don't have to disassemble the bike anytime just to transport it.
They are usually limited to three or four bikes.
Consider that they increase overall car length but can be left on vehicle. Also, in order to be sturdy enough they usually are heavy therefore difficult to install/remove by just one person. If they are too low they can hit the ground in certain situations. In some cars it will block the rear door, even when the bikes are not in the rack. Some can be folded up to be left in the vehicle when not in use.
These are very goo options for DH or AM bikes that use to be heavy, because this kind of rack does not require you to lift the bike too high. They are also useful for oddly shaped bikes, as most DH or XC frames can be.
Therese light racks are easy to install/remove by one person, and are specially adequate for lighter bikes. Every maker of these will claim they are universally compatible with any car, however, this is not true, some are better for sedans, some for hatchbacks. For sedans they can interfere or damage a spoiler. For Hatchbacks they can interfere with rear window wiper.
This rack type is better suited for straight top tube bikes and they can be hardly fitted with some full suspension bikes or any other bike that doesn't have a diamond shaped frame (there are temporary addaptors that are fitted between the seatpost and the stem post for this purpose.). They also grab the bike by its frame, so they can damage paint and can also be an issue for carbon frames.
They are usually limited to two or three bikes, and they better be light ones. Some people mount them in the hood too. (it funny to see a car with two bikes attached a each end)
They don't add too much to the overall length of the vehicle and can be left on when not in use. Most designs allow access to the trunk/rear door when bikes are not on them.
If they fit too low can let bike hit the ground in certain circumstances.
There are a variety that fits attached to the rear mounted spare wheel, these are not compatible with harcovers for the spare.
Other options you may consider are pickup trucks which exist in many different sizes and you may find one that fit all your needs (besides bike transport) They offer huge flexibility and carry capacity. Personally this happens to be my most recent circumstance (did not acquire the pickup because of the bikes) but is also the most comfortable one. I can carry from just one bike up to seven plus driver, riders and gear (my pickup is medium sized, not one of the biggest).
Another option can be a small trailer for bike carrying. This can be fitted to almost any vehicle, as a bike towing trailer will not bear too much weight. However it may need to be custom made /installed and it is more complicated to drive a car with a trailer attached. Nonetheless, a custom made bike carrying trailer, if well designed, can be very comfortable to use.
Finally: Consider the type of bike you are going to carry, and your other needs (Me for example, use the car for bike carrying just 2 days a week). Ease of use of course will make your biking journeys more enjoyable, so, congratulations for considering it! ;)
You will not be able to fit a roof rack unless the car type is designed to allow for rack fitting, but in general all car manufacturers state this. Either they have rails which allow for rack fitting, or they already have part of the rack inbuilt.
As an example, the drainage channels that many cars have down each side of the roof are often designed to take either manufacturer brand bars or some of the generic roof bars on the market. Look at the car manufacturer's website, or speak to the salesman. Often you can get the bars cheap or free if you take them as part of the package when you buy a car.
For racks that fit on the back, you may need to look at the documentation from the rack manufacturer - they will give lists of the vehicles their rack can fit to.
Also consider when purchasing a car, the size of your boot. Bike racks are great and I have used a generic one that clips to the back of your boot door a number of times, but mainly only for longer journeys where the boot and or seat space is needed. Depending on the size/type of car and amount of people/bikes you are transporting most of the time you can get away with shoving the bike in the boot with the occasional quick release of your front wheel. (This saves time and effort when going on a ride.)
I have managed to fit a bike rack like this to a pretty small car (nissan micra), anything with a boot that is more vertical and has slight space between the top of the boot door and the car roof will work!
You have two choices - many manufacturers have their own branded racks, in which case, as you're buying new, you might want to try to get the sales rep to throw in a set at no extra cost.
Possibly a better thought is to have a target brand and model of rack in mind.
For instance, I have a Thule set, which works by having two bars straddling the roof of the car, with the bike racks bridging between the bars. The bars attach to the car with model-specific 'feet' which are easily disengaged from the bars. So it is possible to use the same bars and racks (and boxes and so on) on different cars, just by removing the feet and replacing them with alternatives. (I've loaned my bars and racks to friends in this way.)
All you need to make sure of here is that the model-specific options are available for your car - and the manufacturer's website should help with that. Indeed, the rep who sold me my most recent purchase was able to give me the Thule part number!
If there are practical reasons why a roof set up isn't going to work for a particular model (e.g. it's an open top) then there are alternatives around rear-mounted racks (although many of these are dependent on a tow hook).
I say visit yakima and thule websites, and use their tools to see what and how their racks work. Im sure you have a short lost of cars you are interested in. The great thing about yakima and thule is that its fairly easy to change cars in the future with a small mount change.
I have had the same rails and crossbars on 4 cars and each car change is generally less than a $60 change in clips, and i usually ebay the old ones.
2 door cars, and cars with built in factory rails also make it tough to fit some racks, or the cross bars end up too close and have stability issues.
In my opinion, roof racks are the best. They are strong, they can carry quite a lot, and they hold everything out of the way. I have a roof rack on my Mazda 6 wagon and carry bikes, skis, kayaks, and plenty of other stuff.
I find it best to get a vehicle with the factory rails, then get Yakima/Thule towers and crossbars. Few sedans have factory rails, but many SUVs, vans, and wagons do.
The big downside with the roof is you must make sure everything is off before you pull into the garage, unless you enjoy the crunch sounds.
I once did what you're considering - I chose one vehicle over another primarily because the latter wouldn't take a roof rack. In hindsight, it may have been the right choice, but I was also unhappy with the result. I was choosing between two small four-door sedans, and in both cases the rack required extenders to reach far enough back for mounting the trays.
Depending on the type of vehicle, you should ask yourself a few questions:
In my case, I used various components of a Yakima rack system across several SUVs, a large minivan, and a small sedan, for 15 years or so. Today, I have a hitch-receiver rack mounted on the rear of a Jeep Cherokee, and it carries 4 bikes nicely and safely. But I still like roof racks :-)