Profile has just introduced three new aero road bike wheels, each with a profile specific to the type of riding that particular depth might see. Called 38TwentyFour, 58TwentyFour and 78TwentyFour, the numerals represent the depth with all three getting a 24mm wide brake track.
The aerodynamics were done with CFD based on course data from Kona’s Ironman triathlon. They looked at wind speeds and angles to figure how that averages out over the course, then plotted that into the wheel design. Why Kona? Because if you’re gonna pick a race where performance needs to be at its best, Kona’s it. It can also have some of the windiest conditions…
They admit the aero savings are going to be different for different levels of riders, whether that’s based on distance or speed.
Each size has its own shape tailored to the likely usage. 38’s get a rounded “V” shape with straight brake tracks. The 58’s have a straight brake track with flatter sides but a rounded nose. The 78’s have a more bulbous shape and non parallel brake track.
Tech wise, the carbon is a proprietary prepreg with a 220°C Tg resin to handle braking heat. That lets a fair amount of heat to go into the brake track, which allows for better braking, so they had to develop their own brake pad that’s a bit softer. They’ll wear a bit quicker, but Mark Vandermolen (head of product development) says the performance is similar to alloy rims.
The manufacturing process uses an automated layup for the brake track and tire bed to provide more uniformity and compaction, then the rest of the rim is laid up by hand and it’s all cured together as one piece.
The spoke nipple bed has an alloy insert at the nose for better strength, more even tension and better seating.
They’re hand built with Sapim CX Ray spokes. They’re UCI approved and EN tested, and available as tubulars (no 38, yet) and clinchers. Weights are:
- 38 clincher – 660g F / 818g R
- 58 clincher – 730g F / 900g R
- 78 clincher – 830g F / 990g R
- 58 tubular – 624g F / 739g R
- 78 tubular – 700g F / 875g R