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K-Edge HMS Max XL Combo Mount



Great mount, but equally good alternatives are available at less than half the price
Holds a Karoo 2 securely
GoPro mount works well for a front light
Slightly fiddly to install
Need an additional adapter to mount a front light

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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The K-Edge Hammerhead Max XL Combo Mount is designed for, and approved by, Hammerhead to mount your Karoo 2 out front of your stem, with a GoPro-style mount below the computer mounting point for a front light or camera. It looks sleek, is made from aluminium and held my Karoo 2 solidly, and a light below it securely. It's rather expensive, though.

Yet to decide on a GPS unit? Check out our guide to the best cycling computers – including the Hammerhead Karoo 2.

This Hammerhead mount is CNC machined from aluminium in Boise, Idaho, and looks and feels like a premium product. K-Edge is very specific about payloads: on top you're allowed 123g (ie a Karoo 2) and below, you're good for 242g.

I like this style of out-front mount with GoPro underneath. I think it's the perfect place to mount a small front light like the Ravemen CR450.

2023 K-EDGE HMS Max XL Combo Mount - 3.jpg

The mount isn't hard to install. It's designed for 31.8mm handlebars but comes with a shim for smaller diameters. The clamping part is hinged, and goes around the handlebar easily, and you tighten it up with a 3mm hex key, accessed from below.

2023 K-EDGE HMS Max XL Mount - 1.jpg

On the one hand, this looks neat as the bolt isn't visible; on the other, if you're swapping it frequently, access from the top (like you get with the Bar Fly 4 Max I've been using for ages) would be easier, less faffy, and my preferred option.

If you also want to mount a front light made by Niterider, K-Edge sells an adapter separately to make this a cinch. If you want to use a front light from a different brand, though, you'll need to go adapter hunting as it's not universal – unlike the adapter you get with the Bar Fly.


Once installed, the mount sits out front with the Hammerhead aligned with the top of the bar. For maximum aero. I think.

K-edge HMS Max XL - Karoo level with Handlebars.JPG

You can get a spacer kit if the alignment doesn't work out quite right on your setup, but on mine it sits just right. This spacer kit also comes with a spare Karoo insert – the one part that could potentially wear out – so as that is replaceable, this mount should last a long time.

My Karoo 2 was held solid during the testing period, and the front light that I mounted below didn't complain either, though I did need an adapter to mount it. It would have been nice to see some sort of generic adapter included, like you get with the Bar Fly (see above).

K-edge HMS Max XL - Karoo and Front Light combination.JPG

This mount places the Karoo 2 with enough space between the stem and the charging port that you can get some USB-C cables in there. This is important if you're planning any rides that will take more than about eight hours as you'll need to charge your Karoo 2 on the go. I had to buy a charging cable from Amazon that fits in that space.

K-edge HMS Max XL - Charging Cable.JPG

You can also get a K-Edge Hammerhead Mount without the GoPro mounting, if you want to spend a bit less and are not bothered about being able to hang something underneath. For completeness, you can also get a Boost Stem Mount option, as shown below.

2023 K-EDGE HMS Boost Stem Mount - 1.jpg


Like I said above, I like this style of head unit mount; I've been using a Bar Fly 4 Max for this purpose for ages, so I was interested to see how the K-Edge compared.

The Bar Fly is less than half the price (it costs £33), is 7g lighter, and does exactly the same thing (including having enough space for a charging cable). But it's made from plastic and doesn't use the Karoo 2-specific mount; I've been using it with a quarter-turn Garmin adapter.

To mount a front light below the computer on the K-Edge you need another adapter, while the one the Bar Fly 4 Max comes with is universal, making the K-edge even more expensive for this use case.

So, can I honestly say that you should spend £89.99 on the K-Edge? Well, it looks better than the Bar Fly, and it has the Karoo 2-specific mount. It's up to you whether that's worth spending nearly three times the money.

And there are cheaper options still if you don't want the GoPro mount. Hammerhead's own mount is £40, and if you're happy to go with the Garmin-style quarter-turn adapter that your Karoo came with then the Lifeline Out Front GPS Computer Mount can be had for £10.49 on Wiggle at the moment, down from £14.99.


This K-Edge Hammerhead mount works well, and does everything you'd want it to do. The sticking point is the cost, as other options are available at less than half the price. It's up to you whether you want to spend more for the Karoo 2-specific mount and the sleek looks; I'd find it hard to justify.


Great mount, but equally good alternatives are available at less than half the price test report

Make and model: K-Edge HMS Max XL Combo Mount

Size tested: Karoo 2

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?

K-Edge says: "The strongest K-EDGE mount on the market featuring the Hammerhead Mounting System for your Karoo 2 computer. Designed as a rock-solid platform for your Hammerhead computer in the on-center, out-front, and aero position with a mount for your camera or light underneath. Chosen by the best, year after year, when quality, performance, and craftsmanship matter."

Tell us some more about the technical aspects of the product?

K-Edge lists these attributes (specs):

CNC Machined Aluminum

Weight- 63g

Combo (computer on top – light or camera underneath)

Hammerhead approved replaceable computer insert

Anodized Black with laser-etched logos

Made in-house, Boise, Idaho USA

Lifetime Guarantee against material or manufacture defects. Damages due to abuse or crashing excluded.


Hammerhead Karoo 2 Cycling Computer

Combo (GoPro style light/camera interface) adapter compatible (K13-580-BLK included)

Payload Capacity- Top - 123g (example: Karoo 2) / Bottom 242g (example: NiteRider 1800 or Cycliq FLY12 light/camera)

Rate the product for quality of construction:
Rate the product for performance:
Rate the product for durability:
Rate the product for weight (if applicable)
Rate the product for value:

Tell us how the product performed overall when used for its designed purpose

It holds my Karoo solid.

Tell us what you particularly liked about the product

Not sure there is anything to particularly like about a computer mount. It works.

Tell us what you particularly disliked about the product

The mounting bolt is accessed from the bottom, which can make mounting a bit fiddly with gear cables and brake hoses in the way.

How does the price compare to that of similar products in the market, including ones recently tested on

It's much more expensive than other options.

Did you enjoy using the product? Yes

Would you consider buying the product? Probably not, I'd go for a cheaper option.

Would you recommend the product to a friend? Maybe

Use this box to explain your overall score

This mount works very well, there's really nothing much to complain about. I would have preferred to see the tightening bolt accessed from the top rather than the bottom, as it makes it a lot less fiddly to swap between bikes, and it would also be nice to see a generic front light mounting adapter included or even available separately. Those two changes, combined with a more reasonable price, would have resulted in a higher score, but as it is I'd still say it's good, and a 7.

Overall rating: 7/10

About the tester

Age: 44  Height: 1.78m  Weight: 77kg

I usually ride: All of them!  My best bike is: Ribble Endurance SL disc

I've been riding for: Over 20 years  I ride: Most days  I would class myself as: Expert

I regularly do the following types of riding: cyclo cross, commuting, touring, club rides, mtb, Zwift

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Secret_squirrel | 5 months ago

If you want a good looking good quality Alu mount I can recommend this one for £19.99.  Garmin + Gopro.  So just need to use the Karoo adapter.

You could kit out 4 bikes for the same price.

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