Zefal Z Adventure C4 frame bag

The Zefal Z Adventure C4 frame bag is very spacious and well put together, with lots of good points. And one really bad point, which undoes a lot of the other good work here.

For more options, check out our guide to the best bikepacking bags.

This C4 bag – the biggest in the range – is a big old thing with a 4.2-litre capacity. In spite of that it should fit in a decent range of frames; my Tripster ATR (pictured) is a 60cm, but there's space at the back, and it'll also work with head tubes a lot shorter than mine. Riders with small frames will probably need to look further down the range, though.

The bag is made from heavy-duty 600D polyester that gives the bag plenty of structure and means it doesn't flap about when it's not full. You attach it to your bike using the four hook-and-loop straps supplied, and there are a good number of mounting points so you can tailor the fit to your bike. The bag wasn't sufficiently deep at the head tube that I could fit a strap around the down tube on my bike, but despite that it's very stable in use.

The full-length zip is described as 'water repellant' and the bag's waterproofing rating is IPX4 which realistically means it's very unlikely water will get inside in use. The zip has a nice hood at the end so it's better sealed when closed, and it's easy to open and close with one hand.

Inside is basically one big compartment, with a small zipped enclosure and a hanger for your keys. I managed to fit plenty of stuff in it; a phone, a battery for charging stuff, an insulated gilet, a bag of sweets, some headphones, a wallet and my keys didn't fill it up. With the long zip it's easy to get stuff on the go, and because the bag is pretty sturdy it doesn't flap open too much so you're unlikely to lose anything if you do want to access it when riding.

So far so good, and now on to the main issue. The Adventure C4 bag is made by welding the two sides onto the central frame of the bag and this leaves an exposed edge at the top. This isn't the narrowest bag at 65mm (all three sizes are the same width), which isn't an issue in itself and helps to make it more usable, but it means that sometimes you catch your legs on the bag, and the bit you catch them on is not smooth.

This may not be an issue for you, depending on how big your legs are, and what your riding style is. But I used this bag on a 400km audax and my legs were pretty sore at the end from the exposed edges catching my skin. Two days later and they've scabbed up a bit, which means they were actually rubbed raw. If you were doing multi-day rides in shorts, you would likely not enjoy the experience.

It's an annoying flaw in an otherwise really good bag, and it's also easily fixable: all it needs is some kind of second layer over the top of that join, and only halfway along the top where your legs might rub. I've used some high-strength tape on this one; it's still a hard corner but it doesn't catch you like the exposed seam does.

And I've done that really because I want to keep the Adventure C4 on the bike, because in nearly every other aspect it's a very likeable bag. But I do find it hard to understand how this bag went through the entire development and prototyping process without someone saying, 'those edges are going to scratch your thighs up a treat'. Because that's literally the first thing I said when I saw it.

Value & conclusion

In terms of value, less than £50 for a big, waterproof bag that's easy to use is pretty good. Ortlieb will charge you £115 for its 4L Frame-Pack (tested by off-road.cc in 2020), and the Brooks Scape, which Hollis tested in 2021, is £89.99.

It might be worth waiting for version two of this bag, though, unless you fancy hacking it yourself, or you don't think the thigh rub will be an issue for you.

Verdict

Solidly built bag that's easy to use and waterproof, but can rub your legs raw on longer rides