The Speed 25 is the latest range-topping disc brake climbing wheelset from Fulcrum and utilises a range of technologies to achieve peak performance, low weight and ease of use.
Testing reveals a set of road bike wheels with brilliant handling and performance that’s certainly geared towards climbing.
If you like to take on gradients more than anything else, the Speed 25s are worth your attention.
Fulcrum Speed 25 wheelset specifications and details
Fulcrum has fully embraced tubeless technology with the Speed 25 wheelset.
Its ‘MoMag’ system, which uses magnets to locate spoke nipples during construction, comes with claims of increased rim stiffness and reliability (more on this later).
Importantly, it makes tubeless setup very easy, with no rim tape required.
I fitted 700 x 30c Schwalbe Pro One and 700 x 28c Goodyear 4Seasons tyres to these wheels using Orange Seal sealant and an air-chamber equipped track pump. I had no issues with tyre seating or sealing.
The 21mm internal width of the Speed 25 wheels is right in the ‘Goldilocks zone’ for a modern road wheelset, and enables 28 to 30mm-wide tyres to inflate to a well-supported shape.
Fulcrum states these wheels are suitable for tyres ranging from 700 x 25-35c.
Many wheel brands have moved towards hookless rims, citing the benefit of a smoother transition from rim to tyre, resulting in improved aerodynamic efficiency (alongside cost and raw material savings). However, for the Speed 25s, Fulcrum has opted to maintain a hooked rim.
I am a fan of hookless rims and running tyres tubeless, and would have liked to have seen them here for their purported benefits with a climbing wheel such as this.
If you’re not familiar with the ‘hooked vs hookless’ debate, it’s worth catching up on the latest insight provided by the BikeRadar team.
However, some riders will certainly appreciate the freedom of tyre choice a hooked rim offers.
Fulcrum Speed 25 wheelset build
The Fulcrum Speed 25 wheelset utilises an asymmetrical rear rim built with a standard 2x lacing pattern, paired with a symmetrical front rim, which uses a 2:1 lacing pattern.
Both methods are intended to ensure a good balance of spoke tension from left to right and are not uncommon, although it’s unusual to see both utilised in the same wheelset.
Fulcrum claims maintaining a symmetrical front rim aids aerodynamic performance, though that’s unlikely to be a big performance-determining factor for a wheelset of this depth.
On inspecting spoke tension, I found the Speed 25 to be extremely well built and evenly tensioned, and this hasn’t changed despite plenty of use in pothole-riddled lanes.
On one occasion, I struck the rear wheel hard against a large hole submerged in a puddle and was impressed by how well the Speed 25s shrugged it off. I’ve dented aluminium rims and seen carbon rims fail in similar circumstances.
The Fulcrum Speed 25 rims appear to be very well finished, and their ‘DIMF’ (Direct In Mould Finish) keeps weight to a minimum by removing the need for any additional finishing processes or protective lacquers.
At this point, it’s worth further discussion of Fulcrum’s ‘Momag’ technology.
The Speed 25 features an undrilled rim bed, which means tape isn’t required for tubeless setup.
Fulcrum also claims it’s able to better optimise the carbon layup of the rim because it doesn’t have to account for the potentially damaging effects of drilling spoke holes.
As far as setup is concerned, this is great and makes life very easy, with no need to worry about the quality of your tubeless tape installation job.
The downside, however, is that the wheels are much more time-consuming to rebuild or repair. Each spoke nipple needs to be dragged around the inside of the rim using a magnet before finding either the valve or spoke hole.
Should your wheel need rebuilding, you can expect most mechanics to charge around double what you may pay for work on a more standard wheel, owing to the time required.
Fulcrum claims that its ceramic ‘USB’ (Ultra Smooth Bearings) are 50 per cent smoother than those of its competitors, but it’s worth noting it doesn’t provide data to specifically back this up.
The bearings feel smooth, as you would expect from a wheelset of this standard.
However, there’s a small amount of noticeable drag in the freehub, which manifests itself in the top of the chain becoming slack when backpedalling in a workstand.
This isn’t noticeable on the road, but suggests there’s more drag present here than in some other brands’ hubs I’ve been hands-on with before.
The freehub utilises a 36-tooth ratchet mechanism, resulting in a 10-degree engagement angle.
The hub’s axles are of a solid one-piece design, intended to promote stiffness.
Fulcrum has opted for standard double-butted, bladed straight-pull spokes, and chosen to build them in a non-interlaced orientation. This means no two spokes are touching.
In wheelsets with interlaced spokes, it’s possible for them to rub at their crosses and become noisy or damaged by fatigue. Not interlacing the spokes prevents this possibility, and Fulcrum claims it increases stiffness too.
The Fulcrum Speed 25s come with a pair of wheel bags, a build certificate, tubeless valves and a pair of small black logo stickers if the stock red isn’t your style.
Fulcrum Speed 25 wheelset ride impressions
Out on the road, there’s no escaping the light weight of the Speed 25 wheelset.
They accelerate brilliantly on the climbs, feeling stiff, responsive and quick to react to rider input. When out of the saddle and pushing hard, there’s no discernible flex or instability.
Riders looking for a climbing-specific wheelset without sacrificing the comfort and durability of wider tubeless tyres would be very happy with the Speed 25s.
When descending, the Speed 25s are sure-footed and confidence-inspiring. This is due in part to their relatively wide 21mm internal width, which supports the tyre and prevents any squirmy feeling, even when running lower tyre pressures.
The stiffness inherent in the Speed 25 wheelset’s design also plays a role here. Some particularly lightweight wheels can feel fragile and less assured at speed, but that isn’t the case.
It’s no surprise that flat-land aero performance isn’t where this wheelset shines.
I certainly felt as if I lost out on a few watts when cruising along at higher speeds on the flat versus a deeper rim, but riders looking to this kind of wheelset will be well aware of the trade-off.
A great positive to be drawn from the shallow rims is they’re very easy to handle in the worst of wind and weather – you don’t need to worry about being blown about on windy days.
Fulcrum claims to have aimed the Speed 25 at riders looking to challenge their best times uphill, and this certainly shows in the ride characteristics.
The majority of my testing took place on rough and dirty back lanes, and the ride quality of the Speed 25s shone through for this kind of riding, with the wheels feeling smooth and compliant.
While the Speed 25s would make a great all-round wheelset, they do carry a maximum system weight limit of 120kg.
At the extreme end of things, if you’re a larger rider, or perhaps wanting to press these wheels into a (road-bound) bikepacking trip, riding with any additional weight on the bike, I would suggest looking elsewhere.
Lack of crash replacement policy
Unfortunately, Fulcrum does not publicise a crash replacement policy at this time, which is disappointing in comparison to some of its rivals.
High-end wheel manufacturers such as ENVE, Reserve and Zipp offer limited lifetime warranties and crash replacements, as does popular value-driven brand Hunt.
In short, Fulcrum has some catching up to do in this area.
Fulcrum Speed 25 wheelset bottom line
Fulcrum has done a great job of producing a lightweight, agile and smooth-riding wheelset in the Speed 25.
Riders looking to focus on the climbs and drop a few grams at the expense of some aerodynamic performance will surely appreciate this wheelset.
I can also envisage this wheelset being a popular choice among more traditional riders looking for a classy look and feel from their bike, rather than focusing on aerodynamics.
|Price||br_price, 5, 3, Price, GBP £2000.00|
|Weight||br_weight, 5, 6, Weight, 1,336g (700c) – HG Freehub, including tubeless valves (1,285 claimed), Array, g|
|Brand||br_brand, 5, 10, Brand, Fulcrum|
|Features||br_Features, 11, 0, Features, Axle: 12mm Front and Rear
Additional features: ‘AFS’ external lock ring thread, XDR, N3W, and HG11 Freehub options, ‘2-way fit’ tube and tubeless compatibility
|Brake type||br_brakeTypeSimple, 11, 0, Brake type, Disc|
|Freehub||br_freehub, 11, 0, Freehub, HG|
|Rim depth||br_rimDepth, 11, 0, Rim depth, 26mm|
|Rim internal width||br_rimInternalWidth, 11, 0, Rim internal width, 21mm|
|Rim material||br_rimMaterial, 11, 0, Rim material, Carbon|
|Spoke count||br_spokeCountFront, 11, 0, Spoke count, 24 front, 24 rear|
|Spokes||br_spokes, 11, 0, Spokes, Stainless steel, double butted|
|Wheel size||br_wheelSize, 11, 0, Wheel size, 29in/700c|