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TECH NEWS

Hunt’s new SUB50 Limitless Aero Disc wheels offer “aero superiority and class-beating performance to weight”

With hookless rims, carbon spokes and a new ratchet hub, this is “the ultimate all-around mid-depth wheel system for riders unwilling to compromise”, says the UK brand

Hunt has introduced a new SUB50 Limitless Aero Disc wheelset which, it says, is the fastest road race option out there in a depth of up to 50mm when fitted with either 30mm or 28mm tyres. With front- and rear-specific hookless rim profiles, the option of unidirectional carbon spokes, and a new ratchet hub design, the complete wheelset weighs as little as 1,380g, Hunt claims, while improving on the aero performance of its previous 48 Limitless wheels. 

2024 Hunt SUB50 Limitless bike action - 1 (1)

“Compared to relevant wheels in the mid-depth category, the SUB50 Limitless aerodynamically outperforms the relevant competitor wheels up to and including 50mm in depth when mounted with modern 30mm tyres, and performs similarly to significantly deeper wheels tested,” says Hunt. “When aerodynamic drag-to-weight and aerodynamic drag-to-depth ratios are considered, the SUB50 significantly outperforms [competitors].”

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Hunt says that when it was launched in 2019, its 48 Limitless Aero Disc was “the world’s fastest road disc brake wheelset up to 50mm in depth”. Since then, though, the deeper Roval Rapide II has come along (the front rim is 51mm deep, the rear is 60mm deep) and has a slight aerodynamic advantage over the 48 Limitless, and brands like Vision and Enve have widened the external width of their wheels to 32mm and above.

Plus, there has been a move towards hookless (also called tubeless straight side, or TSS) tech in the road wheel market over the past few years, with some aerodynamic and weight benefits, while the 48 Limitless has hooked rims, so Hunt felt the need to update its offering.

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Hunt says that the SUB50 Limitless, the result of a three-year development project, is “an all-round racing wheelset with drag characteristics among the very best wheels available and a low weight and wide measured tyre profile characteristics that make it excellent for any racing condition, including mountains, cobbles and crosswinds”.

2024 Hunt SUB50 Limitless bike action - 1

It says the SUB50 Limitless offers performance benefits relating to four key metrics: aerodynamic efficiency, aerodynamic stability, weight, and tyre shape. We’ll take a look at each in turn. 

Before we start, it’s worth pointing out that although we’ve seen these wheels, we’ve yet to use them, so we’re reporting Hunt’s tech claims rather than telling you about our own ride experience.

Improved aero efficiency 

Hunt says that to maximise aero efficiency, it focused on “creating the most efficient rim profile for managing clean airflow at the front of the bike”. 

After looking at possible profiles using CFD (computational fluid dynamics), and testing the most promising shapes in the GST wind tunnel in Immenstaad, Germany, it opted for a front rim that was 49.5mm deep and 34mm at its widest point. 

2024 Hunt SUB50 Limitless - 24

“Since the rear wheel encounters heavily disturbed airflow affected by the front of the bike and rider, the engineering team saw an opportunity to minimise material in the rear wheel without negatively affecting system aerodynamics,” says Hunt.

Again using CFD and wind tunnel testing, Hunt decided on a rear rim that’s 49.5mm deep, like the front, but considerably narrower at a maximum width of 30mm.

2024 Hunt SUB50 Limitless - 23

We’ve seen other wheel brands, such as Roval, pair a shallower front rim with a deeper rear rim to reduce drag without affecting handling, but Hunt says its design offers “ample stability and predictability” (more on that in a sec), so it can maximise aero benefits by going for equal depths.

If you want to know precise details about Hunt’s rim profiles and the data and reasoning behind them, we’d direct you to the white paper that accompanies this launch. 

Hunt took its wheelset to the wind tunnel and compared the aero performance with that of key competitors: Roval Rapide CLX II, Enve 4.5 SES, Princeton Peak 4550, Zipp 454 NSW, Zipp 303 S.

2024 Hunt SUB50 Limitless wind tunnel - 1

With both 28mm and 30mm tyres fitted, Hunt found that the SUB50 had the third lowest aero drag behind the Roval Rapide and Enve 4.5 SES at 45km/h (28mph) – the difference was always less than 1W – but those rivals have deeper rims and are heavier (the Enve 4.5 has rim depths of 50mm at the front, and 56mm at the rear). The Roval Rapide has a claimed wheelset weight of 1,520g while the Enve 4.5 has a claimed weight of 1,511g, compared with 1,380g for the SUB50. Incidentally, the first-generation Roval Rapides were much lighter than the ones that Hunt used in their testing, but they were only suitable for non-tubeless tyres.

“Of wheelsets of a similar depth, the SUB50 stands out clearly from the rest of the sample, having a much more efficient profile for the depth of rim, and with drag numbers close to or exceeding the deeper wheels in the test,” says Hunt.

“With a 28mm tyre, the SUB50 and the Zipp 454 NSW have the lowest drag compared to the wheelset’s weight. This provides versatility: pure aerodynamic performance among the very best tested while also being some of the lightest all-round wheels available.”

Compared with its own 48 Limitless, Hunt says the SUB50 fitted with a 28mm tyre requires 1.4W less to maintain a speed of 45km/h (28mph). 

Of course, all of the data quoted here – and in the white paper – is Hunt's own. Although it was collected by Ernst Pfeiffer at the GST wind tunnel, Hunt gets to decide what it releases, so check out the white paper yourself and see what you make of it. 

Stable performance

Hunt says that the SUB50 Limitless Aero’s stability is all part of its speed story because your ability to predict how the wheel will behave as the wind changes allows you to ride faster. Essentially, you want a front wheel where the steering force you experience in a crosswind is minimised to ensure stable handling. 

2024 Hunt SUB50 Limitless steering moment comparison 28mm tyre - 1

“Predictability through variable wind conditions allows riders to comfortably stay in a low, aero position on the bike for longer, which can have a considerable impact on efficiency and expended energy throughout a long road stage or classics race,” says Hunt. 

“This stability is attributed to the wide radius at the rims’ spoke bed, which achieves more consistent and controlled stall conditions, shown on the steering moment co-efficient graph as lower fluctuations around the stall points. Steering moment co-efficient is proportional to side force on the rim.”

If that’s all getting a bit technical, in simple performance terms, stalling means instability. Again, if you want to know why Hunt went for the precise rim profiles it chose, all of the details are contained in its white paper.

2024 Hunt SUB50 Limitless wind tunnel - 2

Hunt says, “The SUB50, Rapid and Enve wheelsets [fitted with 28mm tyres] share a similar behaviour to each other with lower steering moments up to around 10° yaw, but they do not experience stall until around 16°. This later stall achieves lower average drag and a more predictable change in steering moment as the wind conditions change – albeit with a higher overall steering moment at the highest yaw angles.”

With 30mm tyres fitted, Hunt says, “The SUB50 shows the smoothest behaviour through the stall point which should ensure predictable handling at all yaw angles.”

Reducing the weight

The lightest SUB50 Limitless wheelsets are 130g less than the previous 48 Limitless. Hunt claims a weight of 1,380g per pair for the models with carbon spokes, and we weighed them at 1,382g – so near enough – complete with rim tape, in the road.cc office when Hunt came a-calling.

It’s not one factor that has led to this weight loss; Hunt has been cutting the grams across various wheel components.

For a start, the rims are hookless (more on that below) and that saves a small amount of weight. Hunt first offered road hookless wheels way back in 2016. However, the number of hookless-compatible tyres available at the time was limited, and Hunt eventually updated those wheels to hooked rims. 

2024 Hunt SUB50 Limitless - 5

Now, though, ETRTO guidelines mean that variances between tyre and wheel manufacturers have reduced, and there are more tyre options out there, so hookless rims are back on the agenda. It looks like they're here to stay this time.

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Hunt also says that recent advancements in composite lay-up capabilities have allowed it “to achieve previously unreachable strength-to-weight ratios in the construction of these new, wide rim shapes, resulting in lighter rim weights”.

Beyond the rims, Hunt uses its existing TaperLock unidirectional (UD) carbon fibre spoke tech for its SUB50 Limitless wheelset (a steel-spoked version is available too). This means the spokes are held mechanically, with no bonding, and can be trued like normal steel spokes.

“The UD carbon spokes offer 6% greater lateral responsiveness compared to steel spoke equivalents with significantly less weight (2.7g per spoke), allowing the design team to reduce the number of spokes used in the system,” says Hunt.

On the carbon-spoked wheels, Hunt goes for 18 spokes at the front and 20 at the rear (full spec details are down below). It says that carbon-fibre spokes also reduce high-frequency vibration to smooth the ride and reduce fatigue.

Hunt has also introduced a new double ratchet hub system at the rear, with a 40-tooth drive ring that’s said to offer “increased engagement surface area while using less shell materials relative to pawl-based systems”. 

2024 Hunt SUB50 Limitless - 10

The hub shell is made using 6066 aluminium alloy, with a 7075-T6 alloy axle and freehub body with a ceramic-reinforced coating designed to protect against gouging. The carbon spoke version of the Hunt H_Ratchet DBL hubset weighs a claimed 332g.

“Reliably offering 9-degree engagement, the system is designed for high torque load and easy servicing, with tool-free end cap removal and double-sealed main hub bearings,” says Hunt. 

2024 Hunt SUB50 Limitless - 15

While the Enve SES 4.5 and Roval Rapide wheels offer marginally less drag, Hunt believes that the SUB50’s lower weight – saving 131g and 140g, respectively, according to manufacturers’ claimed weights – provides a significant advantage, as do the lower rim depths and the wider measured widths for a given tyre.

Going hookless... again

Hunt has made the SUB50 Limitless Aero rims hookless, as mentioned above, with an internal rim width of 23mm. The wheels are said to be optimised for both 28mm and 30mm tyres. 

> What’s the difference between hooked and hookless and which is better for you? 

2024 Hunt SUB50 Limitless - 7

“Hookless rim technology allows [us] to slightly reduce rim weight, improve manufacturing consistency, and improve aerodynamics at the tyre-to-rim interface by reducing the ‘lightbulb’ effect that inwardly protruded hooks have on the tyre profile,” says Hunt. “A wider hookless bead profile also helps reduce the chance of pinch flats, due to the blunt, flattened profile.”

The previous 48 Limitless wheels were optimised for 28mm tyres but Hunt feels that the market is moving wider still, hence a focus on 30mm tyres too.

“If rims are correctly optimised for wider tyres, the aerodynamic differences between wider and narrower tyres will be reduced and may be eliminated altogether, especially at higher yaw angles where the aerodynamic performance is more dependent on overall rim shape than frontal area,” says Hunt. 

“The wider internal rim width allows riders to take advantage of the rolling resistance benefits that come with wider tyres on all road conditions, but especially on rougher racing surfaces and cobbles.”

Specs and prices

Hunt is offering its SUB50 Limitless Aero wheels in these three versions:
 
Hunt SUB50 Limitless Aero Disc UD Carbon Spoke, CeramicSpeed Bearings
Weight: 1,380g per pair
Internal rim width: 23.0mm
External rim width: 34.2mm front, 30mm rear
Spokes: TaperLock UD Carbon, 18 front, 20 rear
Hubs: Hunt H_Ratchet DBL, 40T, 9° engagement
Bearings: CeramicSpeed, double-sealed
Price: £2,289
 
Hunt SUB50 Limitless Aero Disc UD Carbon Spoke, Stainless Steel Bearings
Weight:
1,380g per pair
Internal rim width: 23.0mm
External rim width: 34.2mm front, 30mm rear
Spokes: TaperLock UD Carbon, 18 front, 20 rear
Hubs: Hunt H_Ratchet DBL, 40T, 9° engagement
Bearings: Double-sealed stainless steel cartridge
Price: £1,849 

Hunt SUB50 Limitless Aero Disc Steel Spoke, Stainless Steel Bearings
Weight:
1,428g per pair
Internal rim width: 23.0mm
External rim width: 34.2mm front, 30mm rear
Spokes: Pillar Wing 20 Elliptical Aero, 20 front, 24 rear
Hubs: Hunt H_Ratchet DBL, 40T, 9° engagement
Bearings: Double-sealed stainless steel cartridge
Pricing: £1,479

The first delivery of Hunt SUB50 Limitless Aero Disc wheelsets is available for pre-order now in limited quantities. Most stock will arrive with riders in late February, with CeramicSpeed wheelsets coming in late April.

For more info, including Hunt’s white paper, head over to www.huntbikewheels.com

Mat has been in cycling media since 1996, on titles including BikeRadar, Total Bike, Total Mountain Bike, What Mountain Bike and Mountain Biking UK, and he has been editor of 220 Triathlon and Cycling Plus. Mat has been road.cc technical editor for over a decade, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a winner of the Cycling Media Award for Specialist Online Writer. Now over 50, he's riding road and gravel bikes most days for fun and fitness rather than training for competitions.

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23 comments

Avatar
PeterF01 | 4 months ago
1 like

Yet more uber-hyped marketing speil from the Taiwanese Pillar spokes sub-brand.

You can buy far superior yet cheaper wheelsets direct from Alibaba that just perform without all the UK's marketing office's tech spin for the ill-informed.

I believe Hambini is working on an in-depth expose of the 'reality' of the brand. Stay tuned......

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Cyclo1964 | 4 months ago
1 like

Got to be honest I cannot quite see the point of carbon spokes 🤷

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Secret_squirrel replied to Cyclo1964 | 4 months ago
0 likes

Less Weight innit?

More seriously why not?  Steel is traditional but carbon and alu disc wheels have been a thing for years - plastic even on Raleigh burners.

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KDee replied to Secret_squirrel | 4 months ago
0 likes

Skyway Tuff 2 in 700c please!

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Cyclo1964 replied to Secret_squirrel | 4 months ago
0 likes

Spinergy rev x was a roaring success.

 

Avatar
Simon E replied to Secret_squirrel | 4 months ago
2 likes

Secret_squirrel wrote:

Less Weight innit?

More seriously why not?  Steel is traditional but carbon and alu disc wheels have been a thing for years - plastic even on Raleigh burners.

More money.

If they break it can apparently be more serious. I wouldn't rush to go hookless either, I'd prefer to wait and see if it has genuine real-world benefits. After all, it took a while for carbon rim-brake wheels to be consistently reliable.

A spoke does a different job to that of a rim.

Avatar
msackman replied to Cyclo1964 | 4 months ago
5 likes

Quite. They don't stretch like steel does. This may make it easier to get the spokes up to very high tension, and make the wheel very stiff, but:
a) this means ever more reliance on the tyre only to provide any suspension
b) a small impact on the rim (e.g. you hit a stone) can lead to much more significant detensioning of the wheel than with steel spokes. This can be dangerous.

And hookless rims are just unsafe. Far too many cases of tyres blowing off anywhere near the rated pressure limit. Personally, I wouldn't touch them with a barge-pole.

Avatar
Psi Squared | 4 months ago
0 likes

A counterpoint to Hunt's claim that hookless has aero and weight benefits comes from SwissSide and their aero engineers who say that hookless has no real aero benefit and that the main benefit of hookless is that it's cheaper to manufacture.

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OnYerBike replied to Psi Squared | 4 months ago
0 likes

Hookless isn't just "cheaper" to manufacture, it's easier to manufacture to high tolerance and with less waste than a hooked rim. There's more detail on various articles/podcasts on the subject, including road.cc's own coverage.

All of which should trickle down to customers, making hookless wheelsets more affordable and more sustainable than hooked wheelsets, even if the aero performance was identical. (It should be noted that, as per the article linked above, Zipp agree with Hunt that hookless does provide aero benefits).

Avatar
mark1a | 4 months ago
1 like

I never thought I'd see Hunt launch a wheelset that make my Roval Rapide CLIIs and CL50s look like a bargain.

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wickedstealthy | 4 months ago
1 like

Hookless meh. Running Reserve 52/63 hooked 34 wide weighing 1440gr with cx ray spokes. Using 28mm Pirelli's with tpu tubes the system weight is at least 100gr lighter for higher wheels. All those tubeless tires weigh at least 80/90gr more then their tubed siblings. Add 40gr per tire sealant and you see +200gr difference. Also tire thread on tubeless is far less and wear out much quicker. I run them 4.2/4.4 bar on tpu tubes. Tpu has been proven to have almost equal rr then tubeless and that for tires with a lot more thread ! 

Avatar
60kg lean keen ... replied to wickedstealthy | 4 months ago
1 like

Is Hookless the new press fit? Press fit was sold as as the great futrure of BBs,  we know now where that rabbit hole led us, right back to the place it began.

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mctrials23 replied to 60kg lean keen climbing machine | 4 months ago
2 likes

Press fit is objectively better than threaded. The issue is manufacturers are incapable of operating to remotely good tolerances. Press fit is lighter, easy to install and remove and doesn't suffer from some of the other issues that comes from bonding metal to things like carbon. Unfortunately these benefits are eclipsed when manufacturers cant make round holes that align between the two halves of a BB shell. 

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Secret_squirrel replied to mctrials23 | 4 months ago
2 likes

I think you mean subjectively better.  Its only objectively better under lab conditions (eg manufacturing tolerances rarely found in real world mass production.)

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LookAhead replied to mctrials23 | 4 months ago
2 likes

mctrials23 wrote:

Press fit is objectively better than threaded. The issue is manufacturers are incapable of operating to remotely good tolerances. 

I think you mean theoretically better. Something can't be said to be objectively better in a practical application if it doesn't work in real world conditions.

Avatar
60kg lean keen ... replied to mctrials23 | 4 months ago
1 like

You have just answered my quesion, yes the bofins can feed us there lab data that shows hookless as a viable option with benefits, but when I am going at 40kph I want to be sure that the people who made my wheel and the tyre have done a proper job, so that I can be sure the tyre stays put and I dont end up face down on the deck!!!

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Backladder replied to 60kg lean keen climbing machine | 4 months ago
0 likes

60kg lean keen climbing machine wrote:

Is Hookless the new press fit? Press fit was sold as as the great futrure of BBs,  we know now where that rabbit hole led us, right back to the place it began.

No, hookless is the old threaded BB, hookless was around long before hooked rims became available and unfortunately it seems to be coming back just because it is cheaper to manufacture rather than it being better. So we've already gone full circle on this, time to advocate for tubulars again!

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Secret_squirrel replied to wickedstealthy | 4 months ago
0 likes

wickedstealthy wrote:

 Also tire thread on tubeless is far less and wear out much quicker. 

Please provide evidence for higher wear/less tread.

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Miller replied to Secret_squirrel | 4 months ago
0 likes
Secret_squirrel wrote:

wickedstealthy wrote:

 Also tire thread on tubeless is far less and wear out much quicker. 

Please provide evidence for higher wear/less tread.

Well, they can't because it's not true. I can't wear the damn things out! Still using a pair of GP5K TL 28s I bought for the 2019 Ride London. They are many thousand of km down the line, and quite tatty, but still great tyres.

Avatar
check12 | 4 months ago
0 likes

Fitting 28mm tyres to all tested wheel sets then surprise surprise their 28/30mm optimised wheels come out top. Fit 25s to all sets and test them, also test the dtswiss arc 1100/1400 wheels with a 25/23mm tyre and let's see who comes out top. 

Avatar
wycombewheeler replied to check12 | 4 months ago
4 likes

check12 wrote:

Fitting 28mm tyres to all tested wheel sets then surprise surprise their 28/30mm optimised wheels come out top. Fit 25s to all sets and test them, also test the dtswiss arc 1100/1400 wheels with a 25/23mm tyre and let's see who comes out top. 

why run 25mm tyres on UK roads? the surfaces are so bad.

Avatar
Secret_squirrel replied to wycombewheeler | 4 months ago
0 likes

wycombewheeler wrote:

why run 25mm tyres on UK roads? the surfaces are so bad.

Precisely.  Only masochists would run 23's these days.  Not even the pro's do.

Avatar
I love my bike replied to wycombewheeler | 4 months ago
0 likes

It does depend on how much you weigh. A 50kg rider has different needs to a 100kg rider.

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