Hunt Bike Wheels has announced its new 32 Aerodynamicist disc-brake wheelset with hookless rims, carbon spokes and a claimed weight of 1,213g.
Hunt describes the carbon fibre road wheels as “the first choice for big days in the mountains”, claiming the wheels offer the lowest possible rim weight for their strength and reliability.
The 32mm-deep wheels carry the British-based brand’s Aerodynamicist label, meaning the rim shape is optimised for aerodynamic performance.
It’s a hookless rim – a return to hookless for Hunt’s carbon road wheels after four years – with a 21mm internal width, designed for 28mm tubeless tyres. The wheelset also features Hunt’s new Sprint SLC hubs.
Pricing starts at £1,199 / $1,549 / €1,619. The wheels are available for pre-order with delivery expected to be in May.
Hookless rims for reduced weight
Hunt first started development into hookless rims, whereby the rim lacks the bead hooks that help retain conventional clincher tyres when inflated, in 2016.
At the time, the brand says it saw weight savings of 10-15g per rim when compared to equivalent hooked rims, as well as smoother airflow between the tyre and the rim, apparently reducing the wake behind the rim.
“A hookless rim design enables us to save 18g per rim,” says Hunt’s development engineer, Chris Colenso, of the new 32 Aerodynamicist design.
“This not only benefits overall weight but is located at the edge of the rim so results in reduced rotational mass.”
Hunt says this has helped reduce the weight of the final rims to 374g and 377g for the front and rear rims respectively (incidentally, Hunt's press photos show a 561g weight for the complete front wheel and 685g for the rear, for a real-world total of 1,246g).
Hookless rims also reduce waste in manufacturing, according to the brand, which is then passed onto the rider as a cost reduction.
The rims on these new wheels have an internal width of 21mm and an external width of 25mm, which Hunt says is optimised for 25mm-28mm tubeless tyres.
The truncated airfoil design and U-shape profile of the rim are also claimed to minimise drag, though there’s no aero data in the press material and Hunt offers far deeper and, in turn, more aerodynamic wheels than this (including the existing 44mm and 54mm-deep options in the Aerodynamicist range).
Tyre compatibility
Hookless rims have courted some controversy since the technology started to appear on the latest road bike wheels.
Zipp, with the 404 and 303 Firecrest, is among the brands to push hookless but others, including Campagnolo with its latest Bora Ultra WTO wheels, have stuck steadfastly to hooked rims.
It’s a subject we’ve covered in detail before but, in short, hookless road rims have been mired in compatibility issues and you need to make sure the tubeless tyres you’re using are compatible with a hookless design.
Hunt first used hookless rims on the 55 Carbon Wide Aero (in 2016-2017) and 30/50 Carbon Aero Disc (in 2016-2018) wheels but, with tyre compatibility limited, reverted those designed to hooked rims.
The company is confident about the future of hookless rims now, though, and hookless designs are making a return for Hunt.
“Fast forward to the present day, there are far more suitable tyre options for riders wishing to use hookless wheels,” according to Hunt.
“Additionally, with newer ETRTO (European Tyre and Rim Technical Organisation) guidelines, the variances between tyre and wheel manufacturers' ‘tubeless standards’ have been reduced, thus leading to a better-informed acceptance by some riders for running hookless on the road.”
Ultimately, Hunt says its 32 Aerodynamicist wheelset has a hookless rim profile that is “fully compliant” with those new ETRTO tubeless road guidelines, when used with hookless-compatible 25/28mm+ tyres at a maximum pressure of no more than 72psi (5 bar).
Serviceable carbon spokes
The Hunt 32 Aerodynamicist wheelset uses the company’s UD Carbon spokes, which we first saw in 2019, and again on the Hunt UD Carbon Spoke Disc wheelset in March 2020.
Using carbon spokes achieves a higher stiffness-to-weight ratio, according to Hunt, resulting in either improved responsiveness for a given weight or reduced mass without adverse effects on ride quality or performance.
"Due to the increased stiffness of a carbon spoke versus steel spoke, it is possible to engineer the right amount of lateral stiffness by reducing the spoke account accordingly,” says Colenso.
“Therefore, through using UD Carbon Spoke technology, it enables us to maintain lateral stiffness whilst reducing the system weight of the wheel and balancing the riding characteristics.”
Carbon spokes can raise concerns when it comes to maintenance, though. Carbon spokes are often bonded to the hub and rim, creating a single unit and making it difficult to true or repair a wheel compared to a steel spoke design.
Hunt’s TaperLock spoke technology is said to get around this problem, providing fully serviceable and tuneable carbon-spoked wheels.
The carbon spokes have a steel mandrel which is placed on the top of the spoke in the carbon bonding process.
When the wheel is assembled, you can then access an internal nipple threaded onto the mandrel to tension the spoke.
The result, Hunt says, is an improved lifespan for the wheelset but the company is also exploring the possibility of a steel-spoked version of the 32 Aerodynamicist.
New Sprint SLC hubs
Hunt’s new Sprint SLC hubs sit at the centre of the 32 Aerodynamicist wheelset.
The rear freehub is said to offer a 7.5-degree angle of engagement for enhanced power transfer.
Hunt also says it has chosen to use a leaf and pawl freehub rather than a ratchet system because this apparently offers improved engagement while avoiding any adverse impact on the reliability of the system.
Hunt’s global brand manager, Ollie Gray, says that while ease of maintenance is often cited as a benefit of ratchet systems, Hunt’s hubs are easy to take apart and service, even for “the most inexperienced of home mechanics”.
“The issues around ratchet reliability, once you go down to smaller angles of engagement, are prohibitive at the moment,” adds Gray.
“But technology is always evolving and improving, so I think it's important to keep an open mind. If the right option for riders in the future looks like a ratchet system, then we'll use it."
The hub shell is made from CNC-machined, cold-forged aluminium, said to save weight without compromising durability.
This means the new hubs have dropped in weight compared to the brand’s previous Sprint hubs, with a claimed weight of 95g for the front hub and 220g for the rear hub.
Hunt Wheels says we can expect to see the Sprint SLC hubs rolled out across its range in the coming months.
