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The Alpkit Stem Cell is designed to either behind or in front of your bar. Offering 1.8 litres of space and made from ripstop nylon, it's light and durable. It offers a useful amount of space and provides easy, one-handed access to essentials, although some riders might find it interferes with pedalling – and the way it closes is vulnerable to rain.
The VX21 fabric – a four-layer waterproof nylon coated with DWR – means this bag is pretty tough but very light at just 68g including all straps. This Regular version (there's a three litre XL for £2 more) is 15cm wide at the top and tapers to 7cm.
The whole thing's 21cm tall, not including the 7cm black 'extension tube' on top, though obviously you can't quite use all of that as length.
Fitting is very simple – one bit of velcro wraps either the stem or the handlebar, and one (optional) strap goes to the fork. The top strap has several attachment points on a webbing ladder, allowing you to tweak the fit.
The closure is a simple elasticated drawstring, and easy to use even one-handed on the go, but it inevitably leaves a hole that water can drain through. The drawstring is quite long, too, meaning the excess needs to be tucked away, though that's easy (if fiddly) to do.
This bag could especially suit bikepackers: the rounded shape suits things like mugs and gas canisters, which can often be tricky to fit neatly elsewhere on the bike.
With the Stem Cell mounted behind the bars, I found I had to slightly adjust the timing of pedal and frame swing to avoid my knee knocking the bag each time, but it very soon became fairly natural. The pack can also squash against the top tube and stop you turning the bars – it takes quite a severe angle thanks to the taper, so it's perfectly safe, but it can still irritate.
In general drop bar bikes are more affected, and pedalling out of the saddle on climbs makes knee contact worse. If you've got space behind your cables, mounting this bag ahead of the bars works better.
If that spot on your bike is already taken, though, the Stem Cell is neatly made from rugged fabrics, is a good shape for some traditionally awkward items, and is handy for keeping phones, snacks or tools close to hand. It's pretty stable too, but the closure wastes the waterproofing and needs a rethink, while the potential for knee-strikes is a little high on compact frames.
Handy extra storage for often-used items, but can clash with knees – and not waterproof
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road.cc test report
Make and model: Alpkit Stem Cell bikepacking bag
Size tested: Regular
Tell us what the product is for and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?
Alpkit says: "Stem Cell attaches to your bike's stem to provide easy-to-access storage space for the stuff that you'll need frequently during your ride. Placed well within reach when you're riding, it works well as a stand-alone bag for day riding or as a part of your cockpit setup on longer bikepacking adventures."
Tell us some more about the technical aspects of the product?
The company lists:
Stem-mounted storage that you can access as you ride
Made to last in the UK
Fully customisable (contact support [at] alpkit.com)
Made with waterproof and highly abrasion-resistant fabrics
Elasticated drawcord closure creates extension tube for maximum capacity
Bar-tacked webbing ladder for endless attachment points
Attaches to either side of stem
75 cm VELCRO® strap provided
25 Year Alpine Bond
Well made with good fabrics, although not waterproof.
Easy to open and use, but can interfere with pedalling – especially when out of the saddle.
Feels tough and likely to last. Comes with Alpkit's 25 year Alpine Bond, which offers repair or replacement.
Simple and light.
Can interfere with pedalling.
It's at the top end of the range for this kind of bag, though well made and (mostly) well-designed.
Tell us how the product performed overall when used for its designed purpose
Very well - unless it hits your knees.
Tell us what you particularly liked about the product
Stable and easy to use while riding.
Tell us what you particularly disliked about the product
It's not waterproof.
How does the price compare to that of similar products in the market, including ones recently tested on road.cc?
At £32.99 the Alpkit Stem Cell is priced fairly high, with the likes of PRO's Discover Food Pouch being £30, and the basic yet very similar BBB Bar Buddy costing considerably less at £18.95.
Did you enjoy using the product? Yes
Would you consider buying the product? If every other spot was full of luggage, yes
Would you recommend the product to a friend? Maybe
Use this box to explain your overall score
The Stem Cell is well made and neatly-shaped from quality fabrics, and it works well – especially if all your other mounting options are taken. The drawcord closure wastes the waterproof fabric, though, and it can clash with knees. The price is fair for the quality, but you can get cheaper bags that work nearly as well – this is good, but no more, and a seven.
About the tester
I usually ride: My best bike is: Cannondale SystemSix
I've been riding for: Over 20 years I ride: Every day I would class myself as: Expert
I regularly do the following types of riding: road racing, cyclo cross, sportives, mtb,
Matt is an endurance nut who loves big rides and big events. He's a former full-time racer and 24hr event specialist, but now is also happy riding off-road on gravel bikes or XC mountain bikes and exploring the mountains and hills of Mid Wales.