BTR Deluxe Bike Bag Phone Holder, Phone Mount & Waterproof Rain Cover GEN 5

While handy for touring or commutes where you just can't be without your phone, the BTR Deluxe Bike Bag & Phone Mount is too bulky for enthusiastic riders – plus it's either waterproof or transparent, but not both.

• Pros: Straps fit any frame, solidly built
• Cons: Interferes with pedalling, not fully waterproof, can slump sideways

The BTR Deluxe's five straps seem excessive; it has three underneath and two on the front for a full-on death grip along all 22cm of its length. The variety of strap lengths and fixing types (Velcro, shock cord and webbing) mean it should fit around any frame, though.

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The overcooked theme continues inside, with two strongly elasticated clip-together straps to keep your banana from breaking loose in transit, plus a large plastic key hook. Your phone is secured beneath the (effective) touchscreen-compatible window with a combination of fabric, Velcro and elastic. Should you ever turn your bike upside down and shake it with the zip undone, these will all prove useful.

The textured straps are a good idea, but their tenacity is undermined by the bag's bottom being shiny, so the whole thing can still slip. The pack is prone to slowly settling to one side or the other, especially under the high-up weight of a phone.

With phones getting so big, the BTR is inevitably wide enough to be cumbersome. My knees brushed it while seated until I adapted, but I personally found it impossible to avoid when stood up – I ended up rubbing it with my legs so hard it was like I was trying to make fire. It is not your friend on hard climbs, and won't please racy riders.

It's also a disappointment that its raison d'être – along with your phone screen – disappears in heavy rain. The zips might be waterproof, but the rest is just showerproof, so for full protection you're forced to slip on the elasticated (and Velcro-strapped, because safety first) rain cover. Which is black. Turns out black is a bad colour for a window, so say goodbye to using your phone. The rubber headphone port remains uncovered, however, so at least you can still hear its lonely bleeps.

If you're gently commuting or touring and only rarely get out of the saddle, this pack could prove handy. BTR doesn't give an internal volume, but our Medium version is exactly the right size and shape for a pint glass (don't ask how I found out), so easily accepts tools, a packable jacket, snacks and a phone. The Large is 0.5cm wider and 2cm longer, and swallows today's tray-sized mobiles.

There are slimmer and less intrusive top-tube bags available, although many – such as Zefal's reliable, £34 Z Race and the £47 Apidura Expedition – are a lot more expensive. Also, many don't cater specifically to phones, with Deuter's £15 Energy Bag being a good (but not waterproof) example of basic design.

> Beginner's guide to carrying stuff on your bike

In practice, there are better ways to carry luggage (such as saddle or frame bags) that don't restrict your movement, plus better, lighter ways to carry phones, such as bar mounts. These also sit further forward for better visibility – it's a long look away from the road to find the BTR Deluxe – while phone pouches are both waterproof/and/ transparent, if you can imagine such technology.

For gentle touring, the Deluxe will get the job done without letting you down, and the price is good. But it won't convince more energetic riders that the underlying idea of combining phone displays with luggage is the magic bullet. If it is, it's one that hits you in the kneecaps.

Verdict

Belt-and-braces design can't rescue the flawed concept, but can keep relaxed riders happy