
The Castelli Gear Backpack has been designed to be a commuting backpack option, while also having the right dimensions so it can be used as carry-on luggage on flights for a cycling getaway.
Construction
To fend off the elements as well as provide durability, Castelli's Gear Backpack uses a water and stain resistant exterior material. Water resistant zippers aim to boost the weather resistance. Maximum volume is claimed to be 26 litres capacity, while the dimensions of the pack are 56 x 35 x 15cm.

Internally there are three main compartments. The main body houses a padded laptop sleeve and mesh zip up mesh pocket. Compartment two uses another zip up interior pocket and a lanyard hook. The final compartment uses a side entrance for easier access to essentials. There is also a water bottle holder on the side externally. All of the interior materials are easy to wipe clean.

Additional features include external loops to attach lights or clip on a helmet. The large rear straps are designed to offer support across the shoulders while perforated rear panels aim to boost breathability. These main straps also feature attachment points for lights. There are both chest and waist clip straps for added security and improved weight distribution as well as small reflective details on the straps and front of the backpack.
The ride
For me, the key to a good backpack is just how much you can actually fit inside it. And 26 litres of storage is a good amount for a bag this size, if not class leading. However, it’s also about how accessible that space is and what you are packing. The main large body of the bag is the right size to be able to put a pair of cycling shoes right at the bottom while still piling up kit and clothing items on top of that for a long weekend away. The padded laptop bag is a great addition, which doesn’t add excessive bulk but does provide essential protection for an expensive item. It can however be a little hard to access if you really pack the bag fully.

The other main compartments are not as spacious, but the placement of zipped internal pockets help make valuables more easily accessible. For commuting to work, the size is easily spacious enough to put office shoes and clothes in the bag. The easy to wipe down interior is also great, ensuring that even if it does gets dirty, it’s easy to clean.
None of the pockets are easily accessible while wearing the backpack, save for the bottle holder. I do like how the zips all have tabs to make them straightforward to open and close even with gloves on.
I haven’t tested it in the rain to see how dry it keeps the contents, but I’ve used Castelli saddlebags with the same zip structure, and they are not fully waterproof. The water resistance and shower proofing is very good though.

Another important element is how comfortable a backpack is to wear. This is where the Castelli Backpack absolutely shines. Even when fully packed to over 20kg / 44lbs, the wide straps with their padded and perforated material are incredibly comfortable and spread the weight nicely over the shoulders and back. The sternum and hip straps aim to add further stability, but in practice I never found that I needed them, so comfortable and secure were the standard straps. I also found in warmer temperatures the perforated elements of the backpack did seem to help avoid excessive heat buildup.

I appreciate the amount of additional features this backpack has, helping make it suitable for commuting. On the straps and the face of the backpack it has attachment points for lights to be fitted. This is especially useful given the relative lack of reflective detailing on the bag. These clips can also be used to hang a helmet from when the commute turns from cycling to walking.
As mentioned previously, the internal zip pockets being positioned at the top of the compartments does make access to valuables nice and easy for the user. Something that is missing though is more of a 'clamshell' opening system. I found that when items were packed at the bottom of the bag, the rest of the contents needed to be removed to access them. With a clamshell design the bag can be opened out to grab specific contents and pack more effectively in my experience.
A huge plus point, especially with UK airlines cracking down on bag size and giving on the spot charges for bags that are too large, is that it fits within RyanAir and EasyJet carry-on bag size allowance. Indeed, I was slightly surprised that it fitted within the airline's size restrictions given how much I had packed for a flight to Spain.
Value & conclusion
In terms of price, £170 is certainly towards the more premium end for a cycling specific backpack. However, when assessing value for money, the Castelli bag performs pretty well. The 26-litre storage is a fair bit more than many of the backpacks featured in our best backpacks for cycling buyers guide, while the price is not much higher.
The CamelBak and Rapha options do feature either a clamshell design or larger opening for the main compartments, but availability nowadays for those models is scarce. Most competitors use a roll-top design which is even less practical for accessing contents at the bottom of the bag.
All told, the Castelli Gear Backpack is a very effective travel backpack that’s perfect for commuting or flying. Comfort and overall storage are the key highlights, while attachment points for lights are greatly appreciated along with its protection against showers. It does lack reflective detailing, and a clamshell design is better for access and packing, but it’s still a great option.