Quad Lock Stem Cap Mount

The Quad Lock Stem Cap Mount adds another smart on-bike phone-mounting option to Quad’s line-up, offering an alternative place to mount your phone to reduce bar clutter. It’s secure, reliable and very easy to set up and use, but not cheap by the time you’ve bought the corresponding Quad Lock case for your phone, and added at least a screen protector to shield it from sweat and other nasties. It will undoubtedly last you years, and ensure your phone will never go anywhere during your rides.

The Quad Lock system has been a favourite for plenty of cyclists, motorcyclists and drivers since the early 2010s as a premium and very secure phone mounting solution. If you switch to it from a stretchy, rubbery thing or similar cheaper yet inferior phone holder, it’s unlikely you’ll be going back after giving Quad Lock a go.

Just push down on the mount, twist the back of your phone into it, and turn until it stops. It would require a ridiculous amount of force for the phone to dislodge from a Quad Lock mount, and of the few reported failures online most are from motorcyclists. Quad Lock offers a vibration dampener to lessen the impact on a phone when motorbiking over rough terrain, but even on very tricky trails, pedal cyclists needn’t worry.

You do have to buy in so to speak, as the Stem Cap Mount plus Quad Lock’s classic and out-front mounts will only work with Quad Lock cases, which are priced at around £25.99 each. You’ll be pleased to know there are cases for almost any smartphone currently available, and unless you don’t like the look of it then you can just keep it on the back of your phone when off the bike too.

Paired with a screen protector, my phone has the front and back covered at all times, and it’s ready to attach to my bike when I need it for navigation, or stopping to catch up on what I’ve missed at road.cc when I’ve snuck out for too long at lunchtime. Quad Lock does say that some screen protectors won’t be compatible with its cases if there is too much overhang at the edges, but of course there’s a Quad Lock tempered glass screen protector in loads of sizes for that (£11.99). Luckily mine from the local phone shop bossman worked fine, so I didn’t need to buy another.

Before I get into fitting and using it, it’s worth going over what bikes and components the Stem Cap Mount will work for. There are two versions: the standard which I have, and the Stem Cap Mount Adjustable (£39.99). The standard suits common stem angles between +15° or -15°, covering the stems of most road, hybrid and gravel bikes, while the adjustable one has a hinge that can make it sit above stems that are angled up to 55°, more suitable for mountain bikes.

For the mount to fit under your stem cap, it will need to have a modern standard, round diameter of 28.6mm (1 1/8in). This covers most road, gravel and hybrid bikes, but it’s worth checking the diameter of the stem if your bike is decades old, and anything with a quill stem won’t work. Some of the latest aero road bikes also won’t be compatible, such as the Cervélo S5 and Colnago Y1RS, because they don’t use standard-sized round spacers and top caps for you to fit the mount underneath. Plenty of flashy bikes and integrated bars still use the 1 1/8in standard though.

Quad Lock says the main advantage of its Stem Cap Mount is that it declutters your handlebar. If you prefer to use your phone and bike computer simultaneously, or just want to use your phone for navigation occasionally, it might not be possible to attach both Quad Lock’s Out-Front mount and your bike computer if both are chunky units, and it will look a bit messy.

You can attach the standard Quad Lock mount secured with O-rings around a stem, but arguably the ‘aircraft-grade’ aluminium Stem Cap Mount that bolts firmly under your stem cap is even more secure, and a bit cleaner. I’m still a V1 Wahoo Elemnt Bolt user, and as the mapping on this is just basic turn-by-turn, I always use my phone for proper navigation when I need it. The Stem Cap mount means I can mount my phone, computer and a front light, all on my integrated Black Inc. barstem.

Set-up

Setting up the Stem Cap Mount requires one small extra step over Quad Lock’s others mounts, as you need to remove the top cap on your stem. Once that’s done you put the Stem Cap Mount on, ensuring it sits above your fork steerer, and put your stem cap on top of it, tightening it back up to the recommended 4Nm to secure the mount. Quad Lock also supplies a 3mm and 5mm spacer so you can tweak the fit, and the mount is dual-sided so you can angle it down if your have a slammed stem, or up for the rest of us who prefer to avoid regular visits to the chiropractor. The lever to attach and release your phone can be arranged any way you like, and your phone will lock into place vertically or horizontally.

Riding

Riding with my Samsung S23 attached via the Stem Cap Mount, I had absolutely full confidence that my phone wasn’t going to budge at all times, even when bouncing over some rough backroads. Although I wouldn’t recommend it in most circumstances, it is perfectly possible to operate your phone while riding, as the screen and all buttons are accessible.

There’s little more to say about the security of the Quad Lock system and the robustness of the Stem Cap Mount, there’s little to improve on here. What I did find was that with my phone mounted at my stem cap, and therefore right underneath me, was that my phone did collect a bit of moisture after some time in the saddle when I’d started to get a sweat on. I am a heavy sweater so this might not apply to all, and most riders using their phone for navigation won’t be on intense training rides; but in the middle of summer I’m generally a sweaty sight to behold, even when pedalling gently. My phone screen was protected, but I can anticipate that on really hot summer rides I might saturate it so much that I’d need to give it a wipe to use the touchscreen properly (apologies if you’re eating while reading this).

The other moisture-related issue – and this applies to all Quad Lock bike mounts – is that it’s less good when it rains. Quad Lock does have its Rain Poncho (£15.99) available in lots of sizes for bad weather, although this plus a screen protector can make it difficult to use the touch screen, and they can steam up. My budget, improvised solution was to cut a hole in the back of a very cheap universal case, and I find I can still operate the touchscreen of my phone this way. A rain cover will also stop mud, crud and grit getting in, so it’s almost essential unless you only ever plan to put your phone on your bike on dry days.

Value

As I’ve already mentioned, if you’re new to Quad Lock you’ll also have to factor in the cost of a Quad Lock phone case, and perhaps another screen protector. Luckily my screen protector worked with the Quad Lock case, so I’d be looking at £55.98 if I was happy to continue using my improvised rain cover, or another £15.99 on top to upgrade to Quad Lock’s Poncho.

Of the similar recommended products in our reviews archive, you’ll pay less for the clever (£39.95) Loop Micro Mount that also mounts to the stem, and uses a sliding mechanism to secure your phone so there’s no need for a case.

Fidlock’s Vacuum phone case + base is the same price as Quad Lock and offers similar levels of versatility, while you’ll pay £90 for the Peak Design Everyday Case and out-front mount (£90). 

We haven’t reviewed SP Connect’s mounts, but they’re also around the same price as Quad Lock. I found a near-copycat stem cap on Amazon for £19.99 but Quad Lock’s pricing is middling enough to suggest it certainly isn’t charging a big premium compared to most of the competition.

Conclusion

Overall, I think the Stem Cap mount is another successful Quad Lock product in its huge range of options for mounting your phone to your bike. Nothing else beats the Quad Lock system for versatility and the sheer number of devices it will work with, and for ease of use it’s also among the very best. I wasn’t super keen on my phone being right underneath me, so would always recommend protecting your screen before heading out for a ride with your phone attached to the Stem Cap Mount.

Verdict

Another super-secure and versatile Quad Lock phone mounting solution that reduces handlebar clutter

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