Test aerycs Explore 40: The gravel wheelset with hookless rims offers solid technology and low weight at a reasonable price. With three different rim depths, you can also weigh up lightweight construction and aerodynamics.
Wheel manufacturer aerycs continues to expand its product range. Those looking for a wheelset for a gravel bike now have four models to choose from: The Alutrek offers modern technology for under €400, weighing around 1.600 grams, with a 22 mm internal rim width, tubeless rims, and DT Swiss hubs. Almost 400 grams lighter and four times as expensive is the Mudflow, featuring rims manufactured in Germany. In between are the GCX Terra , now with a 24 mm internal hooked rim, and the Explore, which is virtually indistinguishable from the GCX in appearance. Its distinguishing feature lies within: This wheelset uses hookless rims, a technology that often requires explanation.
Hookless rims with optimal tire fit
Hookless rims, once called "straight side", are by no means new - in earlier times they were the problem-free standard on everyday and touring bikes. Hook rims were developed for narrow racing tires that were ridden at high pressure; the rim flange protruding inwards prevented the tire from being pushed over the edge of the rim. Rims without rim flanges are now back in fashion, as they offer advantages in several respects: Firstly, carbon rims of this type are easier to manufacture, which of course pleases the manufacturers. Then hookless rims support the tire a little wider, giving it a better aerodynamic shape. And finally, experience shows that tubeless assembly generally works better with hookless rims.
Any disadvantages? No - but ONLY tubeless tires can be mounted (but preferably with a tube); you also have to adhere EXACTLY to the wheel and tire manufacturer's specifications regarding tire width and tire pressure. This isn't a major problem with a gravel bike, though - given the 25 mm inner width, you'll mainly ride this wheelset with tires from 40 mm upwards. Aerycs also allows comparatively narrow 28s, so this wheelset is also suitable for racing bikes. Given an outer rim width of 31 mm, however, we would recommend fitting at least a 30 tire, which should then harmonize perfectly with the rim aerodynamically.
Three rim profiles – lighter or more aerodynamic
Speaking of which: With 39 mm deep rims with a U-profile and flat spokes, the Explore 40 for 1.049 euros is also good against the wind. If you think this aspect is less important, you can also get the wheelset with 30 mm deep rims and save almost 100 grams in weight and a few euros; the Explore 50 is further aerodynamically optimized, is a few grams heavier and a little more expensive.
The hub set is always the same, a DT Swiss 350 with tension spokes and a toothed disc freewheel that engages in 10° increments. It's not a super-fine material, but it's extremely tried and tested - the bearings last a long time and the freewheel body can be removed by hand if a different model is to be fitted (for example when changing from Shimano HG to SRAM XDR). The tension spokes, which ensure optimal power transmission and long durability, have also proven themselves. While DT Swiss wheels occasionally make noise due to spokes rubbing against each other, the aerycs wheelset rolls inaudibly - probably due to higher spoke tension.
Particularly easy tire mounting
Before heading off-road, we put on the fast Schwalbe G-One RS, which can be easily pushed over the edge of the rim and pop into shape without a compressor or assembly fluid - so much for hookless tires. To seal the tires, every aerycs wheel set comes with a MilKit sealing milk set, which consists of milk, special valves and a syringe with a long, flexible nozzle. This makes filling the sealant very easy and clean, and normal valves can also be used. However, the sealing milk has to be rather thin - versions with large latex particles cannot be pushed through the tube.
In use, the aerycs Explore 40 impresses with its all-round positive characteristics. Its low weight makes it easy to handle when pedaling and accelerates quickly; the wheels feel stiff and, of course, the sound of the DT freewheel is a feast for the ears. There isn't much more to say about the riding experience, but the weight should of course be mentioned at the end: the test sample weighs 1.515 grams with tubeless rim tape and without valves (v. 706 / h. 809 g), which is a bit more than stated, but within the tolerance of +/- 5% also stated by aerycs. So the Explore 40 is impressive in this respect too.
Back to the beginning: Who should choose the Explore and who should choose the GCX Terra? The slightly better tire fit speaks for the Hookless, although this is not really noticeable in practice, while the GCX has a slightly higher pressure resistance. If you only want to use the wheelset on a gravel bike and occasionally mount other tires, the Explore might be a better choice - they are both very good wheelsets for a reasonable price.