Buying a Roof Bag-The 7 fatal mistakes to avoid

Car Roof bags are the practical and cheaper alternative a bulky and expensive car roof box and choosing a roof bag should be easy right? Sure you can wander into your local auto retailer and choose between the two they have on the shelf or you can go online and google one or buy one of the many on sale at Amazon or Walmart. The problem is with so many to choose from where do you start? I bought my first car roof bag and it lasted a few months before I then had to buy another and another and another only six months after that! Hopefully I can help you avoid wasting your cash and buying the right bag for you first time round.  In this article we are going to discuss the biggest mistakes to avoid when choosing a roof bag.

Buying for the wrong reasons

Why are you buying a roof bag? Most people are looking to buy a cargo bag for their vehicle to create extra storage space for their journeys. Car roof bags are perfect for temporary trips but lets delve into this in more detail. Here are three key questions you should ask yourself before you buy:

1. What’s my budget? Most Quality roof cargo bags are in the $60-100 price range when compared to a roof box at $200-900 + the cost of racks they are extremely good value.

2. How often am I going to use it? If the answer is every day or even every week then maybe a roof box is a better answer for you. Roof bags are designed for temporary fit, they are brilliant for journeys or roadtrips where you can take the bag off in seconds and carry it to your vacation home/tent/college etc. If however you are going to be loading it up every day to go to the store or use it for work then I wouldn’t buy a roof bag.

3. What am I going to be carrying? Although you can carry pretty much anything in a roof bag, they are perfect for large, bulky and soft items such as bedding, tents, clothing, towels, dog beds etc. If you are using it to carry logs for your wood burner you might want to reconsider. Sharp and heavy items are not a great idea for a roof bag and even the strongest, toughest bags can be punctured or ripped by sharp items. Also you need to consider the roof load bearing capacity of your vehicle (you can check this with your dealer or in your vehicle handbook) as you dont want to damage your roof with too much weight.

OK, so you have run a mental check list and answered the key questions on buying a roof bag, so what else do you need to avoid when choosing your luggage roof bag?

Not measuring your vehicle

Before you hit the stores or buy online go get your measuring tape! Car roof bags come in all different sizes and it can get quite confusing so the first thing you need to know is how big your roof space is. Measure the width and length of your vehicle roof top. The bag must be smaller than this space for it to fit. You don’t want to buy a bag that’s going to overhang as it’s unsafe and could come off! If you have a roof rack does it move or is it fixed? If it’s fixed, measure the space in between the cross rails as this is where you want to fit your bag. You can fit it on top of the rack as well but its best to fit in between the rails. Likewise if you have roof rails on the sides of your roof measure inside those rails as again this is where your roof bag sits. It’s worth noting that most bags can be fitted onto a roof either lengthways or sideways but you will need to check with the manufacturer. So if you have a Truck with a small roof space and you are thinking of fitting a roof bag to it remember to check first before buying.

I don’t have roof bars/ roof rails/ cross rails on my car

This is the biggest mistake people make when choosing a roof bag. You need to ensure the bag you buy works with the vehicle you own:

Do you have a roof rack? If so, pretty much all roof bags will work with your vehicle providing it fits in the space.

Do you have roof rails? Again, nearly all roof bags will work for you. Make sure you can fit a strap undeneath your roof rail and its not a solid rail. If it is a solid rail then buy a bag that can be used without rails.

Do you have no roof rails and no rack? If not, don’t worry there are one or two great bags available that work for cars or vehicles without roof racks or rails. They come with their owne special straps for attaching to the roof but MOST BAGS WON”T WORK for your vehicle. Check out our list of suitable car roof bags without roof rack that I recommend.

It’s not waterproof

How big a deal is this? Well even if you live in the Sunshine state and you are only popping down to Grandmas 5 miles down the road, wouldn’t you prefer everything to be dry when you get there? Most Car roof bag manufacturers describe their bags as water resistant but some bags are as close to waterproof as you’ll get. I always advise people to keep their belongings in a refuse sack before filling their roof bag anyway just to be on the safe side but there are some really waterproof bags available and I would always buy one of those first before considering others. Features to look for as standard include Storm Flaps, waterproof seamed zip and in some of the better bags, electronically heat welded seams. These are the most waterproof roof bags available

It’s not big enough or it’s too big

Most bags are described in either cubic feet or in litre capacity. Small roof bags are in the range of 200-300 litres or 9-10 cubic feet and they still fit loads of stuff in! Larger bags are 400-500 litres or 15-18 cubic feet and they can easily fit a fully grown man inside (I know cause I tried!) so for larger loads with 3+ suitcases go a for a larger bag. Even a smaller cargo bag can fit loads of kit in and don’t compare to roof boxes as roof boxes are rigid and funny shaped they are awkward to load whereas a cargo bag will eat your extra kit and a couple of kids too! (Please note I don’t condone travelling with kids in your roof bag…Unless they are really noisy like mine!)

I didn’t buy any accessories or I bought straps etc that I don’t need

Most Cargo Bag manufacturers would love to sell you some extra kit, some of it is really useful and essential and some is a waste of money. Here’s the lowdown on exactly what you will need:

For cars with racks or rails you just need a bag and roof mat

For cars without racks or rails you need a bag, roof mat and securing straps to fit the chassis of your car (They normally either fit through your doors and lock together under your roof or they attach to the metal frame of your roof like a aftermarket roof rack.

I would consider a roof mat to be essential as even though most roof bags are pretty soft it only takes one caught strap or even a grain of sand under the bag to scratch your roof so buy a roof mat or buy a bag that comes with a roof mat for extra protection.

It’s not strong enough/secure enough

This should probably be the biggest consideration of yours when you buy a roof bag. Make sure its well reviewed and tough as old boots. Trust me as I know from experience, you do not want your roof bag splitting or coming apart at the seams whilst you are crusing at 70 on the freeway! Don’t buy cheap, crappy roof bags! They are dangerous and at best you will only lose alll your belongings, the worst case scenario doesnt bear thinking about. I have reviewed the best selling roof bags available on the market and also compared them to one or two chaep bags to show you the difference.


I love Cargo Roof Bags! I think if you buy the right one and avoid the mistakes in this article you can get thousands of happy, stress free miles out of it. They are cheap to buy, fit loads of stuff in and I love clipping it on and off my car in seconds then rolling it up and stuffing it away after my journey. So much less hassle and cost than a great big roof box that takes up half of my garage for 48 weeks of the year! I hope you have enjoyed this post and I look forward to reading your comments!


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