Roof Boxes Buying Guide

We hope these pages will help you to make an informed choice about which roof box will suit you best.

• How to decide:  Think about “shape” as well as price and features
• Different shapes for different purposes - more information
• Our 90 day exchange scheme
• Brands and quality overview: Atera, Calix, Hapro, INNO, KAMEI, Thule
• Are all box volumes believable? Length and width are what really matters
• Box features you can't really see, the most important ones:
  - Safety
  - Security
  - Materials
  - Waterproofing
• Box features – the most visible ones:
  - Locking systems
  - Gas struts or spring struts
  - Box to bar fitting systems
  - Dual side opening
  - Styling and streamlining
  - Different finishes
• Our star scoring system
• You need roof bars
• Steel bars or aluminium bars?
• FAQs (not covered elsewhere)
• Roof box accessories

The decision about which roof box to buy should mainly be influenced by what basic shape of box is appropriate for your requirements, which means most importantly “What width of box?” followed by “What length of box?”

It's usually quite easy to decide which shape of box to go for.  Rule 1:  If you want to carry other things on the roof as well as the box, either now or later, choose a box which leaves space on the roof bars.  That's obvious.  Narrow or Medium-width boxes will suit people who want the flexibility to carry bikes, windsurfers, or kayaks.  Rule 2:  If you need to carry long items over 2 metres, you'll need a long box, whatever the width.  Also obvious!

Even if you don't have particularly long things to carry, it's likely that a long box will suit you best if it's for use by a family of four or five people. Long medium-width and Long full-width boxes are by far and away our most popular 'family flexible' boxes. There'll usually be space on the roof bars for at least one bike carrier, especially if you use T-track aluminium aerobars (which allow the full length of the bars to be used for load carrying), and you choose the type of roof bars which stick out beyond the roof bar 'feet'.

“Long boxes” will almost certainly be longer than your car roof and will stick out over the windscreen, but "So what?" - you won't notice the box when you're in the car.

There's no such thing as a particular box for a particular car, but it makes sense to be able to open your tailgate fully, making sure that any tailgate spoiler doesn't hit the back of the box, so there are some boxes which aren't suitable for particular cars. Sometimes the positioning of the roof bars on the car roof will require some boxes to be fitted in an unsatisfactory position; we'll tell you about these bad combinations whenever we have this information.

Price is important but bear in mind that a roof box should be expected to last for many family holidays and weekends away; it should give many years of solid and reliable service. We don't stock any of the really cheap boxes because there are real doubts about their safety and build quality.

Here are some other 'Rules of thumb' where boxes are fitted to 118cm or 120cm aluminium T-slot roof bars: There'll be space on a long medium-width box for 2 bike carriers, and space on a long full-width box for 1 bike carrier. Mid-length medium-width boxes are usually big enough for a family of 4, leaving room for up to 2 bike carriers. Note that 3 bikes can usually be fitted on the back of the car, or 4 on a tow bar carrier.

Narrow roof boxes (up to 60cm wide)
People usually need to choose narrow boxes if they want to leave space on the roof of a standard width vehicle for a kayak, or for two or three bike carriers.

Medium-width roof boxes (up to 75cm wide)
These boxes are significantly easier than full-width boxes for one reasonably strong person to lift and to move around safely, not only because they are usually much lighter, but also because you can get hold of them from both sides. Depending on what type of roof bars you are using, you should also be able to carry at least one bike on the roof, often two bikes.

These are our most popular family boxes, because of the flexibility they offer.

There's a filter on the medium-width roof box lists for mid-length boxes and for long boxes.

Full-width roof boxes (up to 95cm wide)
Wide roof boxes impose limitations on what else you can carry on the roof. There will usually be roof bar space for one bike carrier, depending on the length of the roof bars and whether you use T-track aluminium bars.

There's a filter on the full-width category for short boxes and for long boxes.

Long full-width boxes are always very bulky and awkward for one person to move on their own, and they can be significantly more difficult to store.

All our roof box customers are included in our unique 90 day exchange scheme. Basically, if you think you have chosen the wrong box, having had the opportunity to use it, we'll change it for another.

Most of our new customers have never used a roof box before, and roof boxes are definitely a product that people only start thinking about when they think they might buy one. We really want you to buy a suitable box first time out, but if you don't, then “No worries”, you can exchange it.

Roof boxes are our specialist subject and we know from experience which boxes will last the pace over many years, and which ones often don't, regardless of the manufacturers' guarantees. We're therefore confident about our comments, recommendations and star ratings. If you buy from us (and we hope you will!) you may well be buying a roof box brand that you haven't heard of before; no worries!

Atera, Germany's premier car racks manufacturer, has its boxes made for them by Hapro. We stock the full Casar range (it is the same as Hapro's premium Trivor range but with a different style of lid). These are top quality boxes, with a unique opening handle for easy opening, and a pull to shut closing system, separate from the locking system.

Calix is Sweden's specialist box manufacturer, making boxes for car manufacturers as well as their own-branded range. Calix branded boxes are made by the CalixKlippan subsidiary Autoform in Malung, in the Dalarna region of Sweden. We include them because of their innovative designs and engineering, notably the double skin, low profile NORDIC LOADER.

Hapro (Holland) is one of the three major manufacturers in the European market, together with KAMEI and Thule. Their Roady range is markedly better than cheap supermarket ranges, and their Traxer range is designed to beat mid-market Thule ranges in quality and price.

INNO is Japan's premier car racks manufacturer, part of the Car Mate group who are listed on the Tokyo stock exchange.

Their boxes are technically very advanced, using SPM moulding technology for the box bases - they come out lighter, stiffer and stronger than conventional vacuum forming - and all fittings are of the highest quality.

KAMEI is Germany's roof box specialist, based in Wolfsburg. Thinking about the volume manufacturers, they make the best quality boxes on the worldwide market, no doubt at all, using specialist plastics and taking a 'no compromise' attitude to design that sets the engineering aspects of their boxes above the demands of the marketing people. There are three ranges: top quality (Oyster, Fosco), mid to top (Delphin, 330, 510), and mid-market (Husky), a cheaper range which still meets all the same safety criteria as the rest of the range. KAMEI supplies many car manufacturers with own branded roof boxes, including Mercedes-Benz and Volkswagen.

Thule is the world's dominant car rack systems manufacturer; their boxes are widely sold in the UK so you'll see plenty of them about. They have 3 main box ranges - economy (Force XT, Ocean, Pacific, Touring), mid to top (Motion XT), and top quality (Vector).

We make no apologies for being very opinionated about roof boxes. Profit margins are thin at the best of times, thanks in large part to the freight costs, and sorting out problems 2 or 3 years up the line (e.g. jammed locks or broken struts) always leaves us with an overall loss, as well as being a hassle for our customers.

At the premium end The Roof Box Company is proud to be stocking the best boxes available anywhere. Atera Casar and KAMEI Fosco and Oyster are the best quality followed equally by the Hapro Traxer and KAMEI Delphin boxes.

Don't take too much notice of manufacturers' estimates of capacity (litres). A few extra centimetres of height can make a huge difference to the nominal capacity of a roof box, but will probably make no difference to its real world usefulness, particularly if the box lid has pronounced styling. Anyway, the lower the box the less is the wind resistance. You are likely to put one layer of soft bags along the base of the box, and then coats and flatter objects on top of them; no box on the market will be deep enough for two layers of soft bags. So, “Length and width are the most important measures of usefulness”.

Unless indicated otherwise, all the boxes we sell will accommodate several sets of golf clubs, or a decent sized tent and sleeping bags etc. Many customers ask whether their child's buggy will fit in the roof box. The answer is that “It depends” - the size of the wheels being the usual problem. Don't forget that it's likely to be a lot easier to put the buggy in the back of the car, and use the roof box for other items. Hard suitcases, especially large ones, are not usually suitable for use in roof boxes; soft bags are always more appropriate.

It's also a matter of fact that some manufacturers tend to exaggerate roof box capacities. KAMEI tends to underestimate, Thule tends to overestimate. The pictures below show (L to R) a 480 litre Thule box and, in the middle, a 330 litre KAMEI box (the box on the right is no longer available). In each case the roof box is the full size of its carton - you'll see that the length and the width of the 480 and 330 litre boxes are almost the same, and you'd find that each box would hold the same quantity of bags, coats and boots. So, again, we recommend that you focus on the length and the width.

Boxes are on the face of it very simple products - two bits of plastic joined together with hinges, struts and locks. Many manufacturers source these raw materials from the same European suppliers.

Safety
You tend to get what you pay for with roof boxes, and you certainly do when you make the jump from boxes below £175 to those above. Bearing in mind that roof boxes are European made, so labour costs will be similar, it's a good rule of thumb that the cheaper the box, the thinner the material will be, and the less robust and secure the box will be. Most families use roof boxes for a number of years, and with £50 or so being the difference between an adequate product and a good one, and maybe £100 the difference between an adequate box and a very good one, it does make sense to trade up market.

All the boxes we sell have been subjected to thorough crash-testing, meeting ISO standards - if you're looking at other brands, including supermarket brands, ask the safety questions!

If you're likely to be carrying skis, keep an eye out for boxes with a “safety nose”, an additional internal energy-absorbing barrier that's designed to stop skis bursting through the front of a box in a high energy collision.

Security
We know of boxes where the front and rear hinges are too far from the ends of the box, the plastic is too thin, and it's easy enough to lift up either end and look in - some are so weak that you can get your arm in and pull stuff out. You can be sure that all the boxes we sell have well designed locking systems.

Materials
The thickness and quality of plastic makes a significant difference to overall box quality. Boxes are subjected to huge forces at speed, and thinner plastic boxes - the ones that feel like 'eggshell' - tend to rattle a bit after prolonged use, as the rivets may compress the thin plastic and move about. This isn't a problem with thicker plastic / heavier boxes.

Unless stated, all the boxes we sell are made from various types of UV-protected ABS plastic, and they are fully recyclable.

Waterproofing
Waterproofing is usually down to the quality of the moulding, the length of the overlap between lid and base, and the system for covering the roof bar fixing slots or holes in the base.

Locking systems
Central locking sounds smart, but it often makes roof boxes more difficult to close!

This is because most central locking systems require a centrally located key to be turned and, at the same time, both the front and the rear of the box to be properly closed. This seems simple enough but will become a three handed operation (two people!) if there is bulky gear in the box, holding up the lid - even soft coats can cause this problem - or if the base is sagging, either because it's weak or the box has been loaded incorrectly with too much weight at the front or at the back.

KAMEI's central locking system is different; you unlock the box with a quarter key turn, but you don't have to touch the key when locking it - you just pull the box shut until you hear a click which shows that all three locking points have engaged, at which point the key can be removed. Their Husky and Delphin range uses push button locks at each end, allowing you to lock first one end, then the other.

The Atera Casar, INNO boxes and Thule Motion XTs also have a pull shut to lock system.

Gas struts or spring struts
Calix and KAMEI use hydraulic struts to hold up the lid, the technology that holds up your vehicle tailgate, making for a particularly smooth opening and closing system. Other boxes use spring assisted struts. This is not a big deal either way.

Box to bar fitting systems
Our experience is that all boxes are almost as quick and easy to fit to roof bars, whether or not they have 'quick fit' systems. Marketing people make a big deal about their quick fitting systems, but in truth some of these are bulky and take up too much space in the box; the lower profile the fittings, the better.

It can certainly be awkward to fit U bolts to full-width single-side opening boxes - you have to stretch a long way to the hinge side fittings - but it's not a problem with any of the boxes we sell. The KAMEI Husky and Delphin boxes have special grippers which hold their U bolts in place before the butterfly nuts are attached, so the U bolts won't fall back onto the car roof; they also include T-track adapters for aluminium bars.

Hapro and Thule use rubber-covered claw style grippers that fit around all the bars we sell, tightened with a few turns of a twist wheel; the best of these include a torque system which prevents over-tightening and ensures that the tension on the bars is at the optimum. The downside of gripper systems is that they should not be used in the area of the roof bar feet; both Hapro and Thule sell T-track adapters as an accessory, to give complete flexibility about where the roof box is positioned on the bars - which is important if you are also carrying bikes on the roof.

KAMEI's Fosco and Oyster boxes include their ultra-low-profile ClickFix system, by some way the fastest fitting system on the market, suitable for T-track aluminium bars only.

It's worth noting that many people leave their box permanently fixed to the roof bars, storing the two together, perhaps using a roof box hoist to pull the whole lot into their garage roof space, so fitting time is irrelevant. And also ask yourself the question, “If I take my box on holiday 3 times a year, and the slower but often lower profile U bolt fittings take an extra 2 minutes to fit each time, does this really make much difference?”

Better quality boxes have adjustable fitting systems which accommodate unusual roof bar centres, which saves the hassle of drilling extra holes.

Dual side opening
Dual side opening, the ability to open a box either from the left side or from the right side, is particularly useful on full-width boxes, particularly when used on tall vehicles, but is of less benefit on narrower boxes as for ease of access these boxes really need to be on one side of the car or the other, and cannot then be reached from the other side. Placing a box in the middle of the car might look tidier but unless it's a wide box you'll always end up having to stretch, balancing on the door sill and at risk of straining your back.

Rear-opening boxes allow access from three sides of the box at once, depending of course on the height and width of the car.

Styling and streamlining
Quality boxes should be almost silent in use. Boxes mounted too close to the roof are likely to generate a whistling noise at high speeds, so you'll find that roof bars lift them at least 10cm clear of the car roof.

The sections of roof bars not covered with a roof box tend to make most noise; if you are buying a top quality box it makes sense to buy into the latest low drag / low noise technology, so choose Atera aero-profile bars, CRUZ Airo bars, Thule WingBars or Yakima Whispbars.

Roof boxes are always fitted to a set of roof bars, a set of steel or aluminium bars going across the car, from one side to the other. Cars with factory-fitted longitudinal roof-rails will still need a set of roof bars going from rail to rail.

Apart from the KAMEI Fosco and Oyster boxes, which only fit into T-track slots, any brand of roof box can be fitted to any brand of roof bars, whether these roof bars are supplied by us or by a car dealer.

Of course we would like to sell you both the box and the roof bars, but there is more to it than this. The problem is that some dealer supplied bars are neat looking but surprisingly impractical, being too weirdly shaped to accommodate anything except for a roof box; for example, you might not be able to find bike carriers that fit to them.

It's also fair to mention that some dealer-supplied 'Original Equipment' bars are just own-badged Atera or Thule bars.

If you like the look of roof bars with closed ends, in other words with no bar ends sticking out beyond the mountings (we call these “through bars”) then you need to be looking to see whether there are CRUZ Airo Fuse, Thule WingBar Edge or Yakima flush bars available for your vehicle.

Flush bars will always be shorter than through bars, which is likely to prevent you from carrying bikes on the roof at the same time as a roof box.

Aluminium bars not only look smarter than steel bars, but nowadays most of them are low noise / low drag, so you won't get the Middle C background hum, sometimes intrusively loud, associated with square-edged steel bars.

Aluminium bars also allow you to carry more on the roof, thanks to the 'T-track' slots which run full length of the bars, designed to accommodate special adapters.

Apart from noise, the likely problem with steel bars is that the bar to vehicle fixings are likely to be in just the wrong place for your combination of roof box and bike carrier fixings (U bolts or claw grippers), which wrap around the bars. This is why you can almost always carry a wider load on T-track aluminium bars than you can carry on steel bars.

If you already have aluminium bars, or decide to order them from our site, please also be sure to order the appropriate T-track roof box adapters! These are included as standard in some roof boxes, but are a vital accessory for others.

Most quality roof bar manufacturers have now followed Yakima's lead and produce low noise roof bars. As well as Yakima Whispbar, look out for Thule WingBars, Atera aero-profile bars - Atera is the best of the German car rack system brands - and the much cheaper but nonetheless excellent CRUZ bars, made in Spain.

Customers tend to ask the same sort of questions if they haven't used a roof box before. Here are some frequently asked questions, and answers:

Do I need anything else apart from roof bars and a roof box?
No. A set of box to standard bar fittings is included with every roof box we sell, as is a set of straps to keep luggage in place. When a box is locked it can't be removed from the bars because the fittings that hold it to the roof bars are tightened up inside the box, and the box will be locked.

Which side is Left hand opening and which side is Right hand opening?
Left hand opening boxes open on the passenger side of a standard UK right hand drive car, the 'nearside'. Right hand opening means 'driver's side', 'offside'.

I have a full-length box and it seems to overhang the bars a long way. Is this OK
Yes. These boxes are designed so that approximately one third hangs out behind the rear bar, one third is supported by the roof bars, and one third overhangs the front bar.

We have a wide range of roof box accessories, including specially designed roof box bags, internal lamps, storage devices, and protective covers. Accessories that are designed for specific boxes are shown only on the relevant product pages, more general accessories are listed at Roof Boxes / Accessories.