When it comes to road cycling, aerodynamic efficiency has been the main frontier of development in bikes, helmets, wheels, and kit for the last decade. With gravel riding hitting the big time in the last few years, the aero revolution has found its way into the gravel sector.

Wheel brands Zipp, Hunt, and Parcours have all brought out gravel-specific aero wheels with the goal of saving minutes over the duration of events such as the Unbound 200, which is 200 miles long. Kit companies have also come out with gravel-specific jerseys and skinsuits looking to do the same.

This wheelset has been designed specifically around the use of 40-45mm tyres with the rim, and at the racing speeds of high-level gravel racers, around 35kph. The FKT wheels have been designed with the Panaracer Gravelking X1 tyre so that the tyre shape and tread and rim profile complement each other to improve aerodynamics. Parcours state that this new wheelset is as fast compared to the previous gravel wheelset, as a rear disc wheel is to a shallow section climbing wheel.

Admittedly 48kph is a fast speed on the road let alone gravel, so it is not the most relevant piece of data for the everyday rider. A saving of similar magnitude was seen between the FKT wheelset with Panaracer Gravelking X1 and different tyres on the same rim, showing the importance of a tyre working with the rim when it comes to aerodynamics. This is said to equate to a saving of 6min 17sec over the course of the 2024 Unbound 200 mile race, or the difference from 1st to 4th in this year’s race.

Speaking to Cycling Weekly, Parcours founder Dov Tate argued that aerodynamic savings were still tangible at 25kph, a speed much more applicable for the majority of us over shorter distances and less extreme terrains. At this pace, he says, the Parcours FKT wheel would still save 3.7w over a box section shallow alloy wheel. When paired with the GravelKing X1 40mm tyre, this saving increases to 5.8w – that’s compared with a slower 40mm tyre.

“No,” said Johnson, “Mtb tyres are faster for most gravel courses. I’ve tested it and others are coming to the same conclusion after testing as well. This is partially because lightweight mtb tyres can use a thinner casing than most gravel tyres without increasing the puncture risk because the volume of the tire is so much higher. A thinner casing generally means less rolling resistance. In both road and Mtb racing tyres have continued to get wider. Gravel is a relatively new discipline of cycling and we’ll likely see the same thing happen.”

“Your body will always create the majority of your aero drag so aero clothing is super important,” Johnson says. “At Unbound this year I wore Rule 28’s new gravel suit which takes their road race skin suit and adds a sleeve for a hydration bladder on the back. We already found that adding a hydration pack to my body was more aero and this takes that idea and improves on it both in terms of comfort/heat management and aerodynamics.”

Aerodynamics gains are also difficult to extrapolate to lower speeds. Although we know the drag increases at a cubic rate, the way a wheel rim interacts with the air changes the proportional watt savings. For example, Wheel A and Wheel B may perform exactly the same at 40kph, but wheel A is comparatively faster at 45kph and Wheel B faster at 35kph. We can’t just say that a 4w saving at 30kph equates to a 1w saving at 20kph compared to a different wheel. This is where more relevant consumer testing and data is required.

However, when speed reduces, so too does the wheel inertia. This is important to consider as a heavier wheel can hold its speed better at higher speeds due to its own inertia keeping it rolling. This also makes it harder to get the wheel up to speed at lower inertia, and on steep climbs at low speeds, this can be particularly noticeable and hard to accelerate. So that weight penalty may be worth it for faster riders, but for riders traveling at lower speeds and tackling steeper inclines, it may be more of a hindrance.

There are some benefits however that can help us as much as the pros. For longer events like the Unbound 200, us mere mortals will take longer to complete them. This means we need more fluids and fuelling, so new aero gravel attire with inbuilt storage holds some big benefits. Whereas a hydration pack can cause irritation when riding, a hydration bladder fitted into a skinsuit will be both more secure and more comfortable. While a cargo base layer with a bottle or ice at the front is also highly practical.

Source link

Is aero important when riding gravel?

Fourteenth World Title for Marianne Vos with Gravel Worlds win

Is Lotte Kopecky’s bog-standard Specialized Crux proof that you don’t need wide tires and fancy suspension systems for gravel racing?

Lachlan Morton sets Staggering World Record

Donate

Privacy Policy

Related posts