Maybe you’ve been considering running larger tires on your road bike. But what about those aerodynamics, right? Surely larger tires will be slower than smaller ones, at least in terms of aerodynamic drag? Maybe not – though it looks like a lot of that depends on the design of your wheels.

Parcours Strade carbon wheels are aerodynamically optimized for 28mm tires & affordable

The Strade is the newest wheelset from Parcours who are based out of the UK. Parcours offers a number of different wheels, but the Strade was purposely developed to provide optimal aerodynamics with a 28mm tire.

What does that mean? Well, over the span of 12 months working with Nottingham Trent University, Parcours took the design of the Strade from CFD iterations to the wind tunnel. Their findings led them to a different design front and rear with an external width of 32mm up front and just 30.5mm out back (even though both have an internal width of 22.5mm). The wheels also have different depths with 49mm up front and 54mm out back.

Parcours Strade carbon wheels are aerodynamically optimized for 28mm tires & affordable

According to their white paper, not only was the Strade Disc faster in the wind tunnel when compared with their 56mm deep Passista Rim Brake wheelset, but the Strada fitted with 28mm tires was the fastest overall. That should mean that not only are you getting the best set up in terms of aerodynamics, you should be getting a better ride quality as well, possibly with lower rolling resistance depending on the selected tires.

Parcours Strade carbon wheels are aerodynamically optimized for 28mm tires & affordable

Even more impressive, is that Parcours has done all of this testing and development, while keeping the price for a carbon wheelset down to just £999 (roughly $1,234).

Parcours Strade carbon wheels are aerodynamically optimized for 28mm tires & affordable

That includes their own alloy straight pull hub with EZO cartridge bearings and centerlock rotor mounts. Each wheel is built with 24 Sapim CX-Ray spokes with external nipples.

Parcours Strade carbon wheels are aerodynamically optimized for 28mm tires & affordable
Strade wheels shown on Parcours’ own Flanders frameset.

Out of the box, the rims come pre-taped and are tubeless ready, while the hubs are set up with Shimano/SRAM 11 speed freehubs, and 12mm thru axles front and rear with additional adapter kits and freehubs available. Claimed weight is 1,520g for the set, and orders placed now should start shipping in the middle of this month.

parcours.cc

13 COMMENTS

  1. Is that how they test their wheels? All alone? Last time I looked I seemed to notice that they are usually attached to a bike with a person on board, pedalling away. Any data doesn’t really mean much if the picture shown is how they obtain it.

    • Don’t disagree with you. Their data on overall drag may fall apart when you actually run the wheel between fork blades, where the air stack-up is worse with a 28mm tire than it is with a 25mm. Then again, we have mfgs bragging about the aero drag of gravel bikes & wheels, as if a 40mm tire with knobs isn’t throwing off a huge wake and drag.

    • This is actually something that we’ve discussed several times in the office and also in the wind tunnel. Whilst you’re right that no wheel will ever be ridden alone, introducing a frame to the test doesn’t necessarily replicate “real-world” riding either. You’d need to add a rider as well (given no bike is ridden without a person on board).

      The issue here is that the rider and position will add noise to any test. We’ve run some testing with a rider on a bike & can show that the difference between two wheels in some of our testing can be as small as 1% of the overall system drag. Unfortunately no test rider is able to maintain their position to an accuracy of +/- 1% drag. In order to test to this accuracy we have chosen to remove as much noise as possible, hence testing wheel-only.

      Additionally, we know there will be differences between frames as to how a wheel will interact with it. Whilst in an ideal world it would be great to test every wheel/frame combination, that’s not practically possible. Again, testing wheel-only removes this variable. I’d agree it’s not a perfect representation of real-world riding, but it does allow for more accurate measurement with a lower degree of uncertainty.

    • I can’t speak for how other brands go about their development, but the Strade rim profiles were the result of our real-world yaw angle measurement project in conjunction with NTU. We’re aiming to publish the full results of this study in the coming weeks, but as far as I’m aware it’s unique in the bike world in that we measured the yaw angle at two discrete points of the bike – the front wheel and rear wheel.

      The rim profiles have been independently optimised for the observed yaw conditions at each point, so if you were to swap the rims front -> rear / rear -> front you’d actually find they were measurably slower!

  2. Nice job positioning the smoke at the right location! Profile drag is magnified at the top against propulsive counterforces directed at the axle. And friction drag is also amplified by the upper surface wind speeds nearing twice the vehicle speed, plus any additional ground headwind. Your object should be to minimize power dissipation on the wheel, which is heavily concentrated at the top. Measuring lateral drag forces gives only an estimate of vehicle efficiency, ignoring power dissipated by vertical wheel surface motion.

    See US 10,502,656 for a more accurate method to measure vehicle efficiency inside a wind tunnel, using an unrestrained freely self-propelled vehicle instead. But don’t ask the A2 guys. They have little incentive to change.

  3. Hi Dov it is good to see that you are doing some confirmation testing. It would be a revelation for you guys in terms of increased performance if you were to build the same wheels using xtreme carbon AERO hubs and then do some comparison testing. if you are really pushing for increased performance this would be an interesting direction. Check out the Australian Patent AU2016218931 for their technology. faster is always better.

  4. It’s nice to see more options for wheels optimized around wide tires. Not everyone wants to spend big $$ on Enves especially in this economy.

    • It’s a valid thought/question, however in order to fully replicate rider interaction with the bike/wheels/airflow the dummy would need to be active and pedalling, which isn’t something that’s currently possible.

      You’d also need to be very precise in positioning a dummy across each and every run otherwise you’re still introducing another variable to the test. I don’t have any data to hand though that would show whether the noise from using a dummy would be greater or less than that from a rider, but I’d suggest it’s likely still greater than the resolution needed to examine the differences we’re looking at.

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