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Coach Steve being aero!

WHEEL CHOICES: Wheels have more impact on speed than any other component of your bike. Think of a fast rotating wheel as virtually solid, similar to the propeller of a airplane spinning at high speed. When a spoked wheel isn't moving plenty of air can pass through, but the faster it spins, the less air can pass through. In fact spokes create air turbulence and lots of drag. This is why fewer spokes and the shape of spokes can make a wheel faster. A disc creates a smooth laminar flow; much less turbulence.

The mass of a spinning wheel also has to be [re]accelerated many times during a race and this involves an increase of power output each time. This is why saving weight for wheels has more positive effect on speed than saving weight from your frame. The further the weight is from a wheel's hub, the more effect it has on acceleration, so the weight of the rim has more impact on acceleration than the weight of the hub.

For wheels to train on I choose by durability. For wheels to race on I spare no expense in getting the most aero, with light weight secondary. I ride clinchers for training, and tubulars for race day. Clinchers are more familiar; a separate tube inside and a tire that fits to the rim with a bead that is smaller than the outermost rim diameter. Tubulars have a tube 'sewn-up' inside and must be carefully glued to a rim.

I prefer tubulars on race day for their ability to conform to road surfaces. They have thinner and taller sidewalls so are more able to absorb road shock than clinchers. This is helpful on rough roads, for example on a rough corner a tubular will be better able to keep the rubber in contact with the road surface as it conforms to high and low spots.

For race wheels the size and speed of the athlete should impact wheel choice.

The taller the aero rim, the more affected it is by crosswinds. Light riders will have a proportionally tougher time controlling a disc wheel in a crosswind than a heavier rider. Even a deep rim wheel with spokes can be tough to control at times for medium to small riders. Front wheels have more effect on handling than rear. The 650c size is significantly easier to handle for lighter riders.

The advantages of aero wheels are proportional to speed. If your average race pace will be ~35kph or less, I don't recommend a disc. A disc wheel will have more mass to accelerate, and is typically heavier, slowing you down on climbs; it will use-up more energy than help for riders who don't develop serious watts. A heavier rider who can develop lots of power will always gain more advantage from a disc. The best all-round race wheels for most riders will be a light, deep composite rim wheel with few spokes.

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