Test: The aerodynamic aluminium-carbon wheel set draws attention to itself with its relatively low price. Is the saving compared to a full carbon wheelset worth it?
"Strong, light, cheap - pick two" is the famous saying attributed to wheel expert Keith Bontrager. Most wheels are sufficiently "strong" these days, so we'll change the sentence a bit (and German it straight away): Aerodynamic, light, inexpensive - choose two.
Pretty much every wheel buyer is faced with this decision these days: If you want to own an aerodynamically optimised, light wheelset, you will definitely have to invest a four-digit sum, and full carbon rims are simply not available among them. However, one may wonder how easy “light enough” really is. If you want to cover longer distances at a consistently high speed - such as in triathlon - you don't have to pay attention to every gram and could also be happy with composite rims - they attract with significantly lower prices. Bontrager, Trek's component brand, shows how it's done with the Aeolus Comp 5 TLR: the supplier calls around 900 euros for this 50 mm wheelset, and the weight of 1.860 grams sounds quite acceptable in view of this price - that's worth a closer look View.
A special feature of composite rims of this type is that the carbon portion is merely a cover intended to optimize the aerodynamic properties. In addition to the weight of the load-bearing component, i.e. the aluminum rim, there is also the weight of the carbon cladding, so that the composite rim always has a weight disadvantage. With the present wheel set, this is of course limited, because the Aeolus Comp 5 TLR is likely to be based on a wheel set like the proven Bontrager Race TLR, which is indicated by the inner dimension of the rims of 17,5 mm. The stable, inexpensive aluminum wheel set, tried and tested at Velomotion for years on cross-country bikes, weighs around 1.750 grams - in view of the real 1.940 grams of the Aeolus (front 810/rear 1.130 g plus rim tape, etc.) one can speak of 100 grams per wheel , which are invested in better aerodynamics. Whereby the fairing is not everything: In addition, the wheel set is of course constructed with flat spokes, whereas the Race TLR (like its successor Paradigm TLR) is equipped with conventional round spokes. At this point, the wheel set can show an advantage over carbon wheels, because due to the design, the spoke nipples sit invisibly deep inside the aluminum rim. That looks pretty; However, it is difficult to judge what it brings in terms of aerodynamics, not least because of the holes on the inner edge of the rim. In addition, to center the tires, you have to disassemble them and use a long socket wrench. The 18 spokes in the front wheel are laid radially, while 24 spokes are crossed twice at the rear. In view of the rather simply designed hubs, classic cranked spokes are used, but this is not a functional disadvantage.
The connection between the aluminum rim and the carbon cladding is extremely clean. The transition is hardly noticeable, the gap between the two materials is extremely narrow, and the rims make a very high-quality impression. The rim width (17,5 mm), which is rather small by today's standards, is not a disadvantage in view of the intended use: If you pay attention to optimal aerodynamics, you will put on tires with a maximum width of 25 mm.
Bontrager is one of the pioneers of tubeless technology and of course also equips this wheelset with a corresponding rim well. The scope of delivery includes well-sealing valve inserts and the company's own tubeless rim rings, which are not practical here: they increase the diameter on the rim base so much that fitting the tire becomes a feat of strength - with the additional risk of not removing the tire from the rim later to get. However, you should keep the white rings: They are ideal for making a conventional rim tubeless-compatible.
With regular Tubeles rim tape, however, everything is very simple: the Conti 5000 TL seals immediately and permanently and can later be easily pulled off the rim. The rolling resistance-optimized tire is rather narrow and therefore fits perfectly with the Bontrager rim; However, it is not exactly super light either, which means that the ready-to-drive wheel set with spanner axles and cassette weighs just over three kilos. That's sobering - will it have a significant impact on handling?
The importance of wheel weight when accelerating tends to be overestimated, which can be seen when starting from a seated position. This is where the Aeolus Comp 5 TLR shows its good side with what feels like a high degree of rigidity: As usual, the bike moves forward and soon a comfortable cruising speed is reached. On the steep section when pedaling out of the saddle, the plus in mass - a whole pound more than the aluminum wheel set that is normally used - can already be felt: the wheel turns in a little more slowly and cannot be moved quite as easily under the driver.
Bontrager wheels are comfortably neutral in light winds and remain unobtrusive when a bend in the road changes the relative wind direction. Even when going downhill at high speed, the wind does not noticeably pull on the rims. On the other hand, it is not possible to say with certainty whether the 50 mm deep rims are faster on a bumpy course - the shape of the day and wind conditions are likely to be just as relevant here as the assumed advantages of the aero rims. In any case, the wheelset is very comfortable to drive and should be a good choice for anyone who wants to make progress aerodynamically.
But it can also be worth investing a little more, because Bontrager offers the Aeolus Pro 1.300 TLR for just 5 euros - a real full carbon wheelset that, according to the manufacturer, weighs around 150 grams less and also has the advantage of a 2 mm larger internal width offers, so is well suited for wider tires. In view of this in-house competitor, the Aeolus Comp can only point to the advantage of the aluminum braking surface - if it is one: On rainy days, water can penetrate through the already mentioned holes in the carbon lining, through which the spokes run it's just hard to get out. So this is not an aero wheel set for bad weather, the assumed better wet braking behavior of the aluminum flanks cannot serve as an argument.
And so it remains a question of price whether you choose the Bontrager Aeolus Pro 5 TLR - if you accept the higher weight in view of the probably good aerodynamics, you get a functional and top-quality wheelset, but not at the top when it comes to driving fun can play along.
