Both wheels utilise a hookless rim design, whereby the rim lacks a hook on the bead to hold the tyre. Hunt first started using the technology in 2016.

The brand says the use of hookless rims allowed it to save weight, bringing the rim weights down to a claimed 385g and 395g.

We were initially surprised to see the 10g weight difference between both rims and asked Hunt for further clarification. Hunt explained to BikeRadar that the carbon construction of the 25 Carbon Gravel Disc differs from the 40 in that it is built to be a sturdier and tougher rim.

Hunt also says hookless rims are more aerodynamic because they “enable a smoother transition of airflow between the tyre and the rim, and therefore reduce the wake behind the rim, resulting in lower system drag”.

Hunt also points out that the simpler manufacturing process results in less waste and a cost reduction, which can be passed to riders.

Hookless rims have caused controversy due to some tyre compatibility issues, and we’ve previously explored the subject in detail.

As you would expect from a hookless rim, they are compatible with tubeless tyres only. Not all tyre manufacturers support hookless rims, so you should check compatibility before running your chosen tyre.

The 25 Carbon Gravel Disc features a 33mm external rim width and a 26mm internal rim width. Hunt claims the wheelset weighs in at 1,380g.

Hunt says it has designed the wheel to offer versatility for the harshest and steepest days, and the wider rim offers more compliance.

The 40 Carbon Gravel Disc is a more race-oriented wheelset, featuring a narrower 30mm external rim width and a 25mm internal rim width. Despite having a 15mm deeper rim, the weight penalty is claimed to only be 3g because the claimed weight is 1,383g. Hunt says this wheelset is built to offer speed on the very fastest of courses.

We asked Hunt why it decided to use a narrower rim width on the 40. The brand explained this is to allow it to also make for a fast road wheel, because it can accept a 700x28mm tyre. Hunt says it doesn’t foresee riders using the 25 Carbon Gravel Disc on the road, from its market research.

Tyre clearances

Hunt

On the subject of tyre clearances, Hunt recommends tyres from 700x28mm upwards on the 40 Carbon Gravel Disc and from 700x35mm upwards on the 25 Carbon Gravel Disc. Both wheels can fit up to a maximum of 700x65mm rubber.

As the rim is hookless, a lower tyre pressure is typically required. Hunt says the maximum tyre pressure should not exceed 72.5psi.

Both rims are laced to the hub using Pillar Spoke Re-enforcement PSR XTRA spokes and are compatible with Centre-Lock disc rotors.

Hunt

New hubs

Both wheels feature a new hub called the ‘Sprint SL’. This is constructed from 6066 aluminium alloy. Hunt says this offers a greater strength-to-weight ratio than other alloys, with many cheaper hubs using a lower 6000 series aluminium.

Like all other Hunt wheels, the hubs spin on sealed-cartridge bearings by EZO Japan.

The new hubs are said to have an engagement rate of 7.5 degrees, with multi-point pawls running on a 48-tooth ratchet.

Many manufacturers are now moving to a ratchet spring design, pioneered by DT Swiss. Hunt says it has stuck to a conventional pawl system because it believes they are more reliable and just as easy to maintain.

The front hub is claimed to weigh in at 95g and the rear hub at 230g. Hunt says it will be using these new hubs on upcoming products and will also be using the hubs on current product lines.

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