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The Altura Vortex 2 is a lightweight frame pack with fantastic weatherproofing. If you don't care about downtube bottle mounts or your bike is very tall, its performance is superb – but for many frames it's an awkward depth for frame bosses.

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The Vortex 2 is made from a light and relatively thin polyester that stood up to some heavy weather in testing. The material itself is waterproof, and all seams are sealed for extra protection.

There's a cable port near the front, but it's protected under a strip of velcro and about the only way water is getting through is by actual submersion.

The zip is unusual – it's like a heavy-duty version of a zip-lock food bag – and I was initially sceptical about its strength and durability, my fears proved unfounded. Even when I purposely overloaded the pack to strain it, I had no issues.

It has a little more friction than a regular zip but it works fine, helped by the long zip puller that is easy to grab. There's a big zip garage to stop it rubbing on your knees as you ride, too.

That thin fabric means the pack does need to be packed well, because it bows out easily. Neatly filled the Vortex 2 is around 10cm wide – wider than some.

The pack has attachment points on all sides and five across the top, which should let you avoid clashing with pretty much any cable stops. You get three on each of the other edges too, even along bottom edge.

All straps are good quality Velcro and removable, which is helpful – fitting longer, shorter or (way down the line) less worn-out ones takes seconds.

Altura claims the pack is either half or full-size, depending on the size of your frame, and  unless you have a very large bike the Vortex 2's 24cm depth will block the water bottle mounts, while leaving a large open space that's difficult to fill.

It's pictured here on a 52cm Ritchey Outback, where it made good use of the upper space within the frame. There's only one size available and in reality, it is more of a half to three-quarter pack.

At £70 the pricing is competitive – it's cheaper than most alternatives, such as the Bontrager Adventure frame bag at £80 or the Ortlieb Frame-Pack Toptube at £105.

The material performance from the pack certainly doesn't feel budget though, and it has a good zip – it stood up to some very wet conditions when testing. The size might be an issue, however, if you like your water bottle on your down tube.

• www.altura.co.uk

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