Fulcrum E-Racing 4 28´´ Disc Tubeless gravel wheel set

Aware of the constant growth in e-bikes, we have developed the first all-round wheel specifically for this market segment. We have a proven track record in the E-MTB world and we have applied this technical expertise to the latest evolution of current bikes and new way of cycling.

We began by developing a specific rim profile, with an inner rim width of 22 mm (ideal for tyres between 30 and 45 mm), special self-locking long head nipples and project-specific spokes. As we discovered when we developed the E-MTB wheels, the motor increases the load on the freewheel, which has to support greater torsional loads for longer periods too. This is where we focused our attention. Seeing as the freewheel body is the contact point where the drive force is transferred from the cassette to the wheel body, it is subject to higher stresses due to the increased power and jerks caused by the activation of the motor. This led us to use a tempered steel freewheel body, with specific internals, able to support a tensile strength greater than 30%. The results of lab analysis on the behaviour of the single pawls on cycles higher than a billion are clear: the life of cemented steel is estimated to be 2 times higher than Ergal models used for traditional road models.

Specifications:

- Tyre Type: 2-way Fit Ready (for Clincher And Tubeless)
- Tyre Size: 28´´
- Discipline: E-road / E-gravel
- Astm Categor: 2
- Weight: 1870 g
- Rim Material: Aluminium
- Rim Material Details: Aluminium
- Profile Height: Medium
- Rim Height: Front And Rear: 34 mm
- Rim Width: 27.1 mm
- Inner Rim Width(channel): 22 mm
- Tyre Width: From 25 Mm To 64 mm
- Braking System: Disc Brake
- Braking Surface/brakes Options: Afs
- Front Axle Compatibility: Hh12-100
- Rear Axle Compatibility: Hh12-142
- Front Wheel Spokes: 24 (16 Left - 8 Right)
- Rear Wheel Spokes: 24 (8 Left - 16 Right)
- Spokes: Material: Stainless Steel, Double Butted
- Spokes: Profile: Rounded, Straight Pull
- Nipples: Aluminium, Long Head
- Front Hub: Aluminium, Aluminium Flange
- Rear Hub: Aluminium, Aluminium Flange
- Bearings: Sealed Cartridge Bearings
- Others: Drp
- Weight Limit: 135 Kg (bike, Rider, Equipment And Luggage)
- Fwb Options: Hg - Xdr - Optional Campy N3w

Technology:

RDB™ Rim Dynamic Balance:
- The concept is simple and elegant: balance the weight of the gasket, with an item of similar weight placed on the exact opposite side.

AFS axle system™:
- The Axial Fixing System™ is the solution developed by Fulcrum® to fix the disc brake to the hub. The constraint granted by the butt area of the release mechanism, greater than in familiar standard ones, makes it possible to obtain greater structural rigidity and therefore more precise and powerful braking.

Asymmetric rim:
- The asymmetry is designed to improve rim tension, balancing the forces from brakes and sprocket cassette.

Reinforced head spokes:
- For the new E-Mtb Fulcrum range, only oversize spokes, with a specific reinforcement design on the heads, will be used: this makes it possible to have the best quality of response to stress both in terms of resistance and in terms of transfer of the propulsive power.
The technical refinement does not stop here. Changes were made to the profile too, which in some versions is variable.
An elaborate section, which varies from 2.2 mm of the head to 2/1.8mm in the thinnest point, makes it possible to save the very important grams without affecting performance.

Reinforced freehub system:
- Attention to detail was also paid to the freewheel body system, which is the point of junction and transfer of the driving force from the cogset to the wheel body.
The drastic increase of power and jerks, due to the intervention of the motor, made it necessary to use a freewheel body with tempered steel dedicated gears, which are able to withstand a breaking tension by 30% greater.
The laboratory analysis observed the behaviour of the individual ratchets on cycles greater than one billion of uses: the carburised steel ensures an estimated lifetime that is 4 times longer compared to the Ergal model used for the non-E-Mtb models.