Over 30 years of racing experience has taught Xlab what works and what is just marketing hype. Xlab has produced what they feel are the best race wheels for the money today. Here are the facts:
- Narrow 19mm Rim Width
When time trialing, your front tire should be 19mm to reduce frontal area and improve aerodynamics. Consequently we made the rim width 19mm for a perfect fit with 19mm Tufo or 19mm Continental tires. For use on the rear where frontal area is less of a concern, 21mm tires also fit great on all Xlab Wheels.
- Optimum 50mm Rim Depth
When you add a 19mm tire to the rim, the total aerodynamic length becomes 69mm. At bicycle speeds the ratio (aspect ratio) of rim width to aerodynamic length should be at least 3.0. With a 19mm tire the Xlab wheel ratio is 3.6 and with a 23mm tire the ratio is 3.2. You may see deeper rims on the market, remember that deeper rims mean added weight, more side area to be affected by side winds with minimal increase in speed. Rather than going deeper, we concentrated on the best aerodynamic profile for a bicycle rim, which in our opinion is 50mm.
- Proven Aerodynamic Shape
The Xlab staff knows what works with aerodynamic and hydrodynamic shapes with winning experience from trans-Atlantic racing yachts, vertical take-off aircraft and multiple Ironman World Championship wins. True aerofoil shapes have a NACA designation. They are clean shapes optimized for the speed the vehicle will be traveling at. You ideally want a continuous smooth gentle change in shape from the maximum thickness to the trailing edge. You want the air to stay laminar. If there are bumps or recesses the air will breakaway and cause turbulence (drag), remember air prefers clean shapes. The Xlab rim shape is one of the few optimized for bicycle speeds.
- Super Low Surface Friction
After taking care of frontal area (only 19mm.) and the shape of the aerofoil, the next challenge is reducing surface friction. The smoother the surface, the lower the friction. Xlab has now developed a lightweight high gloss finish for its wheels, greatly reducing friction compared with others wheels. Also see the Xlab Fast Finish surface treatment, a two-part process that cleans off the molding compound left on carbon products and then seals at a molecular level, dramatically reducing skin friction.
- Interlocking Clincher Rim
It has always been difficult for wheel manufactures to bond aluminum rims to carbon fiber. Xlab has a unique Interlocking Rim Technology (IRT) which has a mechanical interlocking connection to prevent the rim from coming loose. It is slightly heavier but Xlab thinks your safety is paramount.
- Designed for High Spoke Tension
Xlab has found that an aluminum ring inside the rim provides more consistency as a bed for the nipples than carbon fiber. Carbon fiber is a hand laid process and Xlab uses high spoke tensions for great lateral stiffness when cornering, so a really solid nipple base is key if you want to avoid constant wheel turning.
- Rider Weight Limit
This wheel is designed to have a maximum rider weight of 180 pounds.
Lacing & Spokes
- Aero Wheel Lacing Pattern
It is essential to use radial lacing on the front wheel because the wheel is fully exposed to the wind and radial lacing reduces aerodynamic drag. For the rear wheel, which carries 55% of your weight, it is essential to have a strong wheel with comfort for the long haul. Consequently Xlab use spokes two-crossed for more lateral strength and comfort on the rear.
- Why 18 spokes front and 24 rear
Because of this number of spokes, Xlab can permit riders up to 200lbs on their wheels. Remember, Xlab uses spokes with high tension and unique rims and hubs resulting in some of the strongest and most reliable wheels on the market today.