How Giant attempted to reinvent the wheel with CADEX, a name it pinched from some 35 years ago in its history
For 2020 Giant has brought back an old name, but with some radical new tech that is set to improve your ride
CADEX is a name resurrected by Giant Bicycles from way back in 1985. It was the model designation used to name the first ‘volume production’ carbon-fibre road bike. That means Giant has 35 years of experience in manipulating the black stuff we all take for granted today. For 2020, however, CADEX is a series of high-end, professional-level components that as soon as racing resumes, you’ll see on the bikes of the Giant-sponsored CCC team and its leader Greg Van Avermaet. The world of carbon road wheels is a busy one, with established brands such as Zipp, ENVE, Reynolds, Mavic, Lightweight, DT Swiss and Fulcrum all offering great products. Then there is a raft of up-and-coming brands, such as Roval, Bontrager, 3T, Vision and Hunt all vying for our upgrade cash.
CADEX, however, is doing something a little different with both the design and construction of its new hoops. The rim itself is 42mm deep with a (slender by modern standards) 23mm outer width and a 19.4mm inner. Those dimensions mark the 42s as a purist road wheel and are designed to work optimally with 25mm and 28mm tyres. So far, so normal, but the internals of the rim are cleverly designed to be hookless.
Off the hook
A hook on a rim is designed to ‘catch’ and hold the bead of a tyre, ensuring proper retention. The hookless design (much like on a car or motorbike tyre) relies on the air pressure itself forcing an air-tight seal. It’s pretty much how tubeless systems work best and the 42s are absolutely no exception. These are the least troublesome road tubeless wheels we’ve ever tried. Mavic’s hookless design on its gravel wheels is just as hassle-free but this is the best we’ve seen for slender road rubber.
The downside of the CADEX range is that because it is so new, the approved tyres list (found on the CADEX website) only really includes Giant and CADEX products, although Giant assures us that this list will grow as soon as they’ve had a chance to fully test other tyres. Thankfully, the CADEX 28c tyres we fitted are excellent: compliant, tough and the slick pattern works well in adverse (rainy) conditions, too.
The carbon fibre layup of the rim is very well considered, and the carbon is mapped out with absolute precision, so more material is used to reinforce key areas (spoke beds, hookless rim sidewalls) and things get more minimal where extra material isn’t required, resulting in a strong, yet light rim.
Built to race
The construction is where things get very interesting, and everything on the wheel is manufactured in-house (Giant has its own wheel-building factory). It’s here that CADEX has used bladed, carbon fibre spokes. We’ve seen carbon spokes before, but that usually involves spokes bonded to hub and rim, which saves heaps of weight but makes home servicing and repairs impossible. The 42s’ spokes, however, are more traditional in a straight-pull design. The spokes can be adjusted too. The external part of the nipple is fixed with a male thread on its end with the internal part sitting in the rim bed with a female thread. You adjust spoke tension from in the rim bed: the external spoke nipple has flat sections so it can be held in place by a spoke key while you rotate the adjustable part.
The carbon-fibre spokes were wind-tunnel developed and are aerodynamically shaped for the direction the wheel is going in. Under testing CADEX claims that these spokes alone offer a one to two-watt advantage in drag reduction over a DT Swiss Aerolite. It’s not just about aerodynamics, either: the construction method, which uses uni-directional long filament fibres with three ‘strings’ of 64 filaments making up the composition, adds massively to the tensile strength. The metal ends of the spokes aren’t bonded as you’d expect, but are introduced into the construction before the spokes’ carbon is cured, so they are effectively ‘cooked’ into place. This makes for a spoke that’s 45 per cent lighter than a steel spoke.
The advantage of these spokes is two-fold: it means a big reduction in weight and the carbon spokes are much stiffer laterally than metal. The bare wheels tip the scales at an impressive 1327g; with tubeless valves and tubeless tape fitted that rises to 1430g (620g front including tubeless valve and tape, 810g rear including tubeless valve and tape). By comparison, bare Zipp 303s weigh 1480g a pair (£2406 a pair) and ENVE’s bare 3.4 AR Disc on Chris King hubs weigh 1436g (from £2800 a pair). At 335g for the 28c tyre, with 2oz of sealant that’s usually recommended adding another 56g, it all results in a very light wheel package and it’s this, and the feel of the wheels, that you experience out on the road.
In the hub
The spokes are also laced into the hubs differently using CADEX’s DBL system (see p99). The hub is a first for CADEX/Giant as it's designed from the ground up inhouse. In the past, Giant’s wheels have always featured internals by DT Swiss (like a huge number of other brands’ wheels). The new freehub features a 30t ratchet with hardened steel faces on both sides (for longevity)
and sprung on one side for even engagement. The freehub seems to have been designed for the demands of powerful racers as it’s capable of taking 35 per cent more load than the 18t ratchet found on DT Swiss’ 240 hubs. Giant tested a range of bearings and settled on a steel, high-precision set throughout. In every benchmark test it found the hubset to have 69 per cent less roll-resistance than the 240. Giant tells us that the bearing sizes are available from Ceramic Speed should you want to upgrade.
On the road
The 42s are among the laterally stiffest wheels we’ve ever tried. They feel as if they just want to go straight. Drop your shoulders and lay the back into a corner and on exit the bike just wants to stand up straight and forge ahead. At first it feels somewhat odd and it took a few hours of riding to ‘get’ the feel. Although when it clicks, the 42s are a devastatingly rapid set of wheels. Oddly, they don’t make the ride any harder or harsher. It’s claimed that the carbon-bladed spokes actually offer better high frequency vibration damping than traditional metal spokes, although judging that when they’re rolling on 28c tubeless tyres is really something for a forensic lab and not Wiltshire tarmac.
The lack of mass becomes most telling when you get to the hills. A light set of wheels is a boon to any climbing task, but combine lightness with the resolute solidity of the 42s and it’s an incredible feeling: as if every ounce of your energy is finding its way to the tyres’ contact patch to push you upwards with every pedal stroke. I’ve ridden plenty of light wheelsets before, but these are different. With the lack of lateral flex they just feel so efficient. They are very cleverly designed and built and that translates into real-world performance and, surely, that’s exactly what you want.
At what price?
At £1099 (F) and £1399 (R) CADEX has priced the 42s at the premium end, between Zipp’s 303 Firecrest and ENVE’s SEC AR. It includes everything to set up the wheels, plus bags. They come with a two-year unlimited warranty and a five-year free crash replacement scheme with the wheels’ original owner.
SPOKE SENSE What is DBL technology?
Giant developed a new wheel-lacing technology that aims to improve wheel stiffness and durability. It’s called Dynamic Balance Lacing, or DBL. A standard, crossspoked wheel subjects the spokes to forces when moving as a standard wheel uses uniform spokes and uniform tension. Giant’s research showed that, under load, a forwardfacing spoke loses tension as it’s effectively being ‘pushed’, while a rearward facing spoke is pulled and put under masses of tension. This push-pull effect is what leads to spoke failures, wheel buckling and tension loss.
Giant’s solution is uneven spoke lengths so when the push-pull effect happens the wheel tensions up evenly, which puts less stress on the wheel system with vastly improved reliability. On disc wheels DBL is used on both sides of the rear wheel and on the disc side of the front to balance forces from braking too.
Giant say this tech has only just arrived on its carbon wheels because it's a complex problem with more than 27 different configurations needing to be tried and tested. That, and because the spokes are of different lengths and tensions, means they can’t be mass-produced by machine, so each has to be built by hand, using a DT Swiss Tensiometer at every stage.
The system is tested with forces up to 2000 watts of rider input. DBL technology isn’t just reserved for the CADEX wheel range, however, as Giant has introduced it across its carbon wheel line, including on our Endurance Bike of the Year – the Giant Defy.
MATERIAL MATTERS Carbon vs stainless steel
Ultra-lightweight: The CADEX carbon spoke (2.6g) is 45 per cent or approximately 2g lighter than the same length DT Swiss Aerolite spoke (4.6g). CADEX 42 Disc Tubeless Wheel System with 45 spokes (21 F and 24 R) is 90g lighter than if it was built with the DT Aerolite spokes. This is weight that the rider needs to move to go forward. The result is a livelier or snappier feel. Carbon is also better at damping or reducing overall road vibration, which helps to provide a smoother, more compliant ride feel.
Transmission Stiffness: CADEX carbon spokes, combined with Dynamic Balance Lacing technology results in greater overall transmission stiffness for maximum power transfer. Giant claims that its testing shows a 20.5 per cent improvement in transmission stiffness vs the Zipp 303 NSW.
Lateral Stiffness: CADEX carbon spokes combined with DBL and Precision Reinforced Carbon Layup technologies boosts lateral stiffness to allow the bike to track more accurately while cornering and be more stable while sprinting. Testing shows a 26.9 per cent improvement vs the Zipp 303 NSW.
VERDICT CADEX 42 Disc Wheels £1099 (F) £1399 (R)
The CADEX 42s are a genuine innovation and the wheel is a true ‘system’ in that everything is designed to work together as it’s not an assembly of off-theshelf parts. The result does offer a genuine performance benefit for the end user. Sadly, that doesn’t come cheap, but these are not the most expensive carbon wheel upgrades you can find. We’d highly recommend them to anyone looking to shave some weight and improve their ride. For non-disc users the rim-brake version is even lighter at just 1260g with the same DBL technology. If these are just too pricey DBL has already trickled down through Giant’s carbon wheel range so the reliability of the system is available to riders with less deep pockets.