Darkhorse delivered a set of SLF 36c wheels decorated with their standard white decal package. They also offer a stealth decal pack, if you'd like to keep an element of surprise in your back pocket come race day.
SLF range improvements
Much of the development to the SLF range has been in improving the construction of the rims. A few of the main features include the use of an EPS moulding system which achieves a greater pressure in the moulding process. The result is a better bond between the layers of carbon and less chance of air gaps. Another key improvement has been the development of a proprietary high-temperature resin which allows the rims to be cured at 220°C. This process improves the brake surface's heat resistance and braking performance. The construction of the tyre bead has also been adapted using a machine to wrap the carbon which is then CNC cut to create a more uniform and balanced rim.
The SLF series rims have been made a little wider measuring 24mm to better accommodate larger volume tyres. Darkhorse Wheels has kept a U-shaped profile for aerodynamic efficiency, especially in crosswinds. As mentioned above, the set we tested is the 36c model with a 36mm rim depth. Darkhorse also offer a 60mm/88mm front and rear combination as well as a 50mm option and a full disc rear wheel as part of their SLF range.
All Darkhorse wheelsets go through the necessary rigorous impact, braking, tyre pressure, and spoke tension testing to be approved by the UCI. The improvements to the construction of their wheels have also allowed them to bump up the rider weight limit to 110kg, as well as giving them the confidence to offer a 2-year warranty.
As with all Darkhorse wheelsets, the hubs are the tried and tested Bitex hubs which make use of a patented 6-pawl freebody. Bitex has made further improvements with a new anti-bite system which integrates stainless steel splines on the body for better resistance to wear from the cassette.
During the long-term test period, the hubs were reliable with no unreasonable sign of bearing wear. After around eight months of use, some play developed but this quickly remedied by tightening the axle bolt. The anti-bite system was not flawless with evident damage made to the aluminium freehub body by the cassette on some of the unprotected splines. The anti-bite feature did, however, prevent the cassette from embedding itself into the hub body allowing for quick and painless removable and re-application of the cassette even with the existing damage.
Rim: High modulus full carbon clincher
Rim dimension: 36mm high 24mm OD wide.
Weight: 1380 grams
Hubs: Bitex RAR9 , RAF10
Spokes: Sapim CX-Ray 24 rear, 20 front
Nipples: Sapim secure lock nipples
Max Tyre pressure: 120 psi
Rider weight limit: 110kg
Pricing: R13,995.00 (currently on sale). More information here.
On the Road
Over the test year, the Darkhorse SLF 36c wheelset was ridden in a number of configurations. They graced five bikes: a Scott Addict, Swift Attack, Cannondale SuperSix EVO, Specialized Tarmac, and an aluminium Silverback Salice. Tyre choices included Specialized Turbo Cotton (24c), Maxxis Dolomites (25c), Vittoria Rubino Pro (25c), and Specialized Turbo (28c).
Weighing in under 1,400 grams, the Darkhorse wheels are competitively light. Replacing the largely mid-range aluminium stock wheels on the test bikes made them noticeably lighter. The result was an instant and fast acceleration from standstill and out of corners. The hubs also played their part with quick engagement and no lag in the pick-up. For the majority of test riders, the wheels proved themselves to be stiff without being overly harsh, even under the hardest of acceleration and all-out efforts. Only our most powerful rider experienced the tiniest of flexing during hard climbing efforts. It was not picked up by feedback through the bike to the rider, but through the sound of rubbing brake blocks (which were very closely aligned).
Stopping performance has historically been the Achilles heel of the carbon wheel. From our experience, it seems Darkhorse has taken the lessons learned across the industry and applied them to the SLF range. The Darkhorse wheels offered comparably good stopping power with a positive feel through the lever. There were no signs of heat build-up and the resultant brake fade on downhill blasts. Braking on carbon rims in the wet is never an ideal situation and the Darkhorses suffer from unpredictable grabbing power in the wet where, more (admittedly) expensive wheels, may fair better.
Across the spectrum of test bikes, the Darkhorse wheels proved to be a worthy upgrade reducing weight and feeling faster. Most interesting was applying the wheels to the entry-level Silverback Salice with an aluminium frame. Once the (frankly) terrible stock wheels had been replaced the bike was transformed. Weight, stiffness, and aerodynamic gains all worked together to make the bike noticeably faster in a straight line and in the turns.
How well did they last?
As mentioned above, the wheels were handed around the office for over a year. They were fitted to a variety of bikes with a number of tyre changes. Unfortunately, we lost track of how many kilometres the wheels travelled but at all times they were fitted to an actively ridden road bike (even through winter).
Before returning the wheels to Darkhorse, we put them on a truing stand to check how well they had fared. As it turned out, they did very well with hardly any deviation from their original state. The only maintenance needed was a tightening on the rear hub after noticing free-body play. This was a quick fix and the problem did not appear again. Inspecting the spokes there was no sign of damage or corrosion on the nipples.
A rim brake hoop can be considered a consumable as the braking surface will eventually wear through. Some of us might never reach this stage but more active (and hard braking) riders will be able to attest to this. After the year-long test period, the Darkhorse rims show only a slight sign of wear and tear on the braking surface, and are fit for many more miles of smooth braking.
If you are looking to upgrade your current wheels, you have every reason to look at the offerings from Darkhorse Wheels as they tick all the boxes at a reasonable price point with all the features you can expect from a high-end carbon wheel. Over the year of testing, durability is good and the requirement for maintenance has been low.