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The Just Riding Along Mahi Mahi 40 carbon disc wheels aim to be a do-it-all choice. They're very light and stiff, with a 40mm rim depth to help make them fast as well. You would expect this to come at a cost, and while the £850 rrp certainly doesn't make them cheap, they're more affordable than most of the competition, and offer extra customisation as well.
All Mahi Mahi wheels are handbuilt to order. The options include three different rim depths – 30mm, 40mm and 50mm – and hubs that can cater for all axle widths, cassette types and disc mounts imaginable. Sapim CX-Ray spokes are used as standard, but there is the option of brass or aluminium nipples, a choice of 11 colours and also many different decal options, with no extra lead time. The lead time is currently five days for all in-stock components, which is impressive for a full custom, handbuilt wheelset.
Our test wheels have 40mm-deep rims with straight-pull Centerlock hubs, 12mm thru-axles, bright green nipples, and gloss black decals.
Just Riding Along is a British company based in Yorkshire that's been at the forefront of tubeless tyre use for almost two decades, initially as a website providing useful information about converting to tubeless, then moving on to create Wheel Milk, a tubeless sealant it still makes to this day. No surprise, then, that the Mahi Mahi and the majority of the JRA range are tubeless compatible.
Fitting tubeless tyres can be difficult depending on the tyre/rim combination, so it was very pleasing to find that several different tubeless road and gravel tyres fitted onto these rims with ease, without feeling like I was in a wrestling match. At the most, a single tyre lever was needed, which is encouraging – if you had to remove a tyre while out riding it should still be possible. I also tried the wheels with non-tubeless tyres and they fitted with ease, too.
The 22mm internal rim width is wider than the majority of wheels currently available that are aimed at road bikes, and the result is that most tyres will be wider. A pair of 25mm Vittoria Corsa (non-tubeless) tyres measured 29mm at their widest point. The increased width is said to offer better aerodynamics because of the cleaner transition from tyre to rim, and the wider profile means you can run lower pressures for extra comfort.
I tested the wheels with several different tyres, both tubeless and tubed, and at a range of pressures. JRA says they're suitable for running tyres up to 100psi, which should be enough to satisfy most riders, although JRA does recommend running lower pressures. I tested them with tubed tyres at 80psi and tubeless down to 70psi and had no issues with the tyre seating. The pressure used will ultimately be a personal choice, but with recommended pressures from 60-80psi it is encouraging for anyone looking to run lower pressures but fearing the risk of burping or unseating a tyre.
The overwhelming initial impression is how responsive and laterally stiff the wheelset feels under acceleration, making starts at traffic lights and junctions all the more enjoyable. The stiffness on offer is particularly impressive given the low weight.
At 1,490g for the pair when weighed with rim tape fitted, it makes them a competitor for almost any other wheelset for weight regardless of price. They're 130g lighter and £250 cheaper than the Fulcrum Wind 40 disc brake wheels, for example. And though they're 19g heavier (but £20 less) than the Scribe Aero Wide+ 40-D (claimed 1,471g and £870), and Hunt's 4050 wheelset is cheaper and lighter at £789 and a claimed 1,458g, neither offers the customisation possibilities of the JRA.
The low overall weight of the Mahi Mahi wheelset is achieved without sacrificing performance: 24 Sapim CX-Ray bladed spokes are laced two-cross front and rear, and a Shimano freehub with 'Anti-Bite' steel splines prevents cassette wear from teeth digging in, which can be an issue on alloy cassette bodies. Multiple freehub options are available when building, including Shimano, SRAM XD, XD-R and Campagnolo.
The Just Riding Along-branded hubs are made by Bitex, a large and reputable company that makes many OE hubs. The bearings are extremely smooth front and rear and there is not a hint of play or drag, even after several thousand kilometres of testing. The 6-pawl, 48-point engagement freehub gives instant drive, and I had no issues with reliability of the freehub or bearing design.
The wheels also stayed perfectly true throughout testing, with no need to reach for a spoke key, and while the use of aluminium spoke nipples may not be everyone's preference, they help keep the weight low. You can, of course, have brass spoke nipples should you wish.
Aerodynamics is quite subjective without a wind tunnel, and JRA doesn't make any specific claims for the Mahi Mahi wheels, but they feel at least as fast as other wheels of similar depth used on the same bike. I rode them in all weathers, including on very windy days, and the performance in sidewinds is very good. In stronger winds you can feel the sideways pressure, but it is never sudden and they don't snatch as some older V-shaped rims have a tendency to at times. Even if JRA had offered aerodynamic data it would be impossible to verify in real world conditions, but the stiffness and low weight help make them feel fast.
The Mahi Mahi wheels are rated for both road and gravel riding and over several thousand kilometres I have used them on a wide range of surfaces, including extremely rough off-road tracks. They've had several big knocks but have remained true throughout.
As a gravel wheelset I tested them with tyres up to 43mm wide – this gives a good tyre profile, with the internal rim width supporting them on rougher terrain and at lower pressures.
Riding off-road, the lateral stiffness is evident and having taken them down a few tracks that are more mountain bike trail than gravel they have proven capable, holding a line at all times. Can a wheelset be too stiff? For some people a little lateral movement might at times be beneficial, but given the intended purpose of the Mahi Mahi wheelset, designed for faster riding, they achieve the goal.
Some might see them as overkill for a gravel bike wheelset, but they could be ideal for the increasing number of gravel races and longer distance events emerging. You could also swap them between a road and gravel bike, if you have both types of bike.
Overall, these are impressively lightweight and extremely responsive carbon wheels with on and off-road capability. Installing tubeless tyres is easy, and they're a competitive price.
Extremely impressive lightweight and responsive carbon wheels with on and off-road capability, at a competitive price
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road.cc test report
Make and model: Just Riding Along Mahi Mahi 40 wheelset
Size tested: 700C, 40mm deep
Tell us what the wheel 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?
JRA says: "The Mahi Mahi disk wheels offer a perfect balance of light weight and power-saving aerodynamic profile. Our in-house hand-built quality, high performance hubs and Sapim CX-Ray spokes add up to an unbeatable wheelset for racing or all-round riding, on or off-road."
Throughout testing, on and off-road, the wheelset lived up the claims and was trouble-free.
Tell us some more about the technical aspects of the wheel?
The Mahi Mahi disk range also has options for rim depths from 30mm to 80mm for riders looking for either lighter weight, or greater aero benefits.
A disk-specific design allows for optimised aerodynamics while the low weight is an important part of the lively, responsive feel and streamlined performance of these wheels in all weather conditions. As with all our wheels they are handbuilt by us in our York workshop for perfect build quality every time and customisation through our choice of hubs and spoke nipples for the perfect fit with your bike.
The rim width is a massive 22mm internal, 30.5mm external optimised for best aerodynamic performance with tyres measuring around 25-27mm. The width allows for lower tyre pressures without increasing rolling resistance – we recommend 60-80psi for most riders.
The Mahi Mahi disk rim is the result of 3 years' development with our rim supplier including several iterations of rim design to perfect the tubeless fit. With 15 years' experience of building tubeless wheels it was important for us to use a rim which offers easy tubeless inflation and maximum tyre security as well as strength. The result is a semi-hooked sidewall design which fits tubed or tubeless tyres securely and easily and offers greater impact resistance than a standard hooked bead. Unlike hookless bead rims, the semi-hook bead is suitable for running tyre pressures up to 100psi with 25mm tubeless tyres (though we recommend lower pressure for better ride quality)
Long term reliability, strength and meticulous attention to detail is standard on every wheelset we build. At the heart of this is our JRA hubs, with variants to fit any bike but all sharing the same light weight, ultra smooth and durable TPI bearings and reliable 6-pawl double-sealed 48-point freehub design. Building all wheels by hand in-house means quality control is built-in to every wheel with each component being checked as the wheel is built so we can achieve very close to zero returns.
30mm rims are our lightest weight wheelset with good aerodynamic performance. These wheels are light for hill climbing but roll fast on the flat too.
40mm seems to be the sweet spot for most riders and with a weight of just 1433g per pair and almost totally unaffected by side-winds we recommend them for anyone.
50mm wheels are very fast with great aerodynamic performance at the expense of a bit more weight. These are the deepest rims normally used on standard road bikes.
Weight 1500 g
internal rim width
external rim width
front lacing pattern
rear lacing pattern
The wheels are laced with equal tension throughout and after several thousand kilometres of riding, which has included some rougher terrain, they are still perfectly true.
Extremely impressive lateral stiffness, especially considering the lightweight design. Off-road, for some riders they're potentially too stiff, but I'd say they're excellent for their intended use.
No issues at all in several thousand km, mostly road but also off-road use.
The value is impressive, being cheaper than most other wheels of a similar specification (weight/rim height and design). Two competitors are Hunt's 4050 wheelset, £789 and a claimed 1458g, and Scribe's Aero Wide+ 42 Carbon disc wheelset: £870 and a claimed 1,471g. These don't offer as many customisable options as the JRA Mahi Mahi wheelset, though.
Did the wheels stay true? Any issues with spoke tension?
Perfectly true after several thousand kilometres of mixed riding. No issues or problems at all.
How easy did you find it to fit tyres?
Tubeless tyres in particular were great, at the most, requiring one tyre lever. Compared to some road tubeless wheels and tyres they're excellent.
How did the wheel extras (eg skewers and rim tape) perform?
Tubeless rim tape and optional tubeless valves are cleanly fitted and functioned well throughout testing.
Tell us how the wheel performed overall when used for its designed purpose
They're designed to offer a mix of lightweight and aerodynamic benefits, which are evident in use. As JRA is a big proponent of tubeless technology it is no surprise that installing tyres was very easy.
Tell us what you particularly liked about the wheel
Exceptional stiffness under acceleration, and the ease of tubeless tyre installation. It is also reassuring to have a wheelset that is recommended and tested for both road and gravel terrain. The wide internal rim design makes what is otherwise a reasonably narrow tyre into a wider and, in theory, faster shape.
Tell us what you particularly disliked about the wheel
How does the price compare to that of similar products in the market, including ones recently tested on road.cc?
They are £60 more and slightly heavier than Hunt's 4050s (1,458g, £789), and £20 less and 19g more than Scribe's Aero Wide+ 42 (1,471g, £870), but £250 cheaper and 130g lighter than the Fulcrum Wind 40 disc brake wheels. Specialized's Roval CLX 50 Discs are lighter (1,410g pair) but not as laterally stiff and not suggested for off-road use – and will set you back another £1,000...
Did you enjoy using the wheel? Yes
Would you consider buying the wheel? Yes
Would you recommend the wheel to a friend? Yes
Use this box to explain your overall score
Up-to-date rim design with customisable spec and price that makes them excellent value for money, plus impressive stiffness, lightweight design and easy tubeless tyre installation. An excellent package.
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.