What Fits on Roof Bars? Bikes, Skis, Kayaks, Boxes and Ladders

Quick answer: Roof bars are a base. Almost every roof accessory — bike carrier, ski carrier, roof box, kayak cradle, ladder clamp, load stop — mounts onto the bars rather than onto the car. What determines compatibility is the bar's profile and whether it has a T-track channel, not the make of the vehicle underneath.

Why does the bar profile matter more than the car?

Once bars are fitted, the vehicle is no longer part of the equation. An accessory clamps to the bar, so the question becomes whether that clamp fits that bar's cross-section.

There are two mounting mechanisms in general use. U-bolt clamps wrap around the outside of the bar and tighten underneath — these work on almost any bar of a suitable width. T-track fittings slide into a channel running along the top of the bar and lock in place with a bolt.

T-track is the stronger and tidier of the two, and it is the standard for load stops and ladder clamps. If your bars have a visible slot along the top face, they accept T-track accessories.

What do I need to carry bikes?

A roof-mounted bike carrier holds one bicycle upright by its frame or fork and clamps to both bars. Carry two bikes by fitting two carriers side by side.

Weight is the limiting factor. A typical adult bicycle weighs 10 to 15 kg and the carrier adds 3 to 5 kg. Two bikes plus two carriers plus the bars themselves approaches 45 kg, which sits within the 75 kg dynamic rating of standard aluminium bars but leaves less margin than most people assume.

Lockable carriers secure the bike to the carrier and the carrier to the bar. Both locks matter: an unlocked carrier can be removed complete with the bike.

Remember the height. A car with a bike on the roof is typically 2.5 to 2.8 metres tall, which exceeds many multi-storey car park and drive-through height limits.

What do I need to carry skis and snowboards?

A ski carrier is a pair of clamping arms with rubber jaws that grip skis or boards flat across both roof bars. Sliding carriers extend outward from the roof so the equipment can be loaded without reaching over the vehicle.

Capacity is quoted in pairs of skis or number of boards. A 75 cm carrier typically holds four pairs of skis or two snowboards; a 90 cm carrier holds the same count with more clearance for wide powder skis and bindings.

Ski carriers are universal fitment. They clamp to the bar, not the vehicle, so a carrier bought for one car transfers to another when the bars change.

Fit skis with the tips pointing rearward. This reduces lift and keeps snow and grit off the windscreen of the vehicle behind.

What do I need to carry a kayak or canoe?

Kayaks are carried either flat on the bars with straps, or on a J-cradle that holds the hull on its side. J-cradles free up roof width so two kayaks fit where one would otherwise sit flat.

Bar spacing matters more here than for any other accessory. Bars set too close together allow the hull to pivot; a spacing of at least 70 cm is normal, and four-bar van racks handle long sea kayaks better than two-bar car sets.

Always use bow and stern lines to the vehicle's towing eyes in addition to the roof straps. A kayak generates significant lift at motorway speed.

What do I need to carry a roof box?

Roof boxes mount directly to the bars with U-bolts or T-track fittings supplied with the box. Most modern boxes accept both.

Check three measurements before buying: the box's minimum and maximum bar spacing, the maximum bar width it will clamp to, and the combined weight of box plus contents against the bar's dynamic rating. A 15 kg box with 40 kg of luggage plus 5 kg of bars totals 60 kg — inside a 75 kg limit, but not by much.

Boxes also affect boot access on hatchbacks and estates when opened. Rear-opening boxes should be positioned far enough forward that the tailgate clears them.

What do I need to carry ladders and long loads?

Ladders need two accessories: load stops to prevent sideways movement, and ladder clamps to hold the ladder down and lock it in place. Both require T-track bars.

Load stops are adjustable blocks that bolt into the T-track and form a barrier at each end of the load. A four-pack covers both sides of two bars. They are equally useful for pipes, conduit and rolled materials.

Lockable ladder clamps accept a padlock and are the standard theft deterrent for trade vehicles parked overnight. Sold in pairs.

For loads longer than the vehicle, four-bar van racks provide more support points and reduce flexing. A rear roller makes single-handed loading practical.

Do I need to remove accessories when not in use?

Empty bars and carriers still generate drag and noise. Removing them improves fuel consumption and eliminates wind whistle.

Where the accessory is left fitted, check the clamps at the same interval as the bars themselves — after the first 50 miles following fitting, then periodically.

Frequently asked questions

Will a bike carrier from my old car fit my new bars? Usually yes. Carriers clamp to the bar, so compatibility depends on bar width and profile rather than the vehicle.

How do I know if my bars have a T-track? Look along the top face of the bar. A continuous slot running the length of the bar is a T-track. A smooth closed top is not.

Can I fit accessories to bare-roof bars? Yes. The mounting method at the roof does not affect what can be carried on top, only the total weight allowance.

How much weight can I carry in total? Axenture aluminium bars are rated at 75 kg dynamic and 150 kg static. The figure includes bars, accessory and load. The vehicle handbook may specify a lower roof limit, which then takes precedence.

Do roof accessories affect insurance? Permanently fitted racks on commercial vehicles should be declared. Removable carriers generally do not require notification, but policies vary.

Compatibility summary