The Wheel Thing

Don't take them for granted; your choice of wheels and tyres can make all the difference on race day


Posted: 18 November 2009

Your wheels and tyres can transform your bike from a cart horse into a thoroughbred, metaphorically speaking. Your bike's performance, acceleration, handling, comfort and ability to resist punctures depend on the choice you make. A set of tyres and wheels can cost anything from £100 to a dizzying £3,000, so there's plenty to choose from. And it's important to bear in mind that the most expensive is not always the
best. You have to know what's right for you and your bike.

Reinventing the wheel

Tri-spokes, disk-wheels, deep-section rims, ceramic hubs and bladed spokes - the number of wheels on the market can bewilder even the most technically minded triathlete. And if the options could leave you scratching your head, the potential cost could make you hyperventilate. A set of entry-level Easton EA50 wheels costs about £240, whereas a Zipp 1080 front wheel and Zipp Sub-9 rear disk-wheel would set you back, far back - about £2,470. They're beautiful, but you'd probably have to do a lot of explaining to loved ones when (or if) they found out how much you'd spent on wheels for your bike.

A standard racing-bike wheel such as the Easton EA50 looks like a bike wheel should look: it's round, it's made from metal and it has lots of spokes. These wheels, and others like them, are great, especially for training. They last for ages, they're light, comfortable, affordable and they can be repaired if something goes wrong. So you might wonder why you should pay more. Well, if you do, you'll get a lighter, more aerodynamic wheel with better bearings to help the wheels roll with less resistance. In other words, money can buy you more speed - but only if you spend it wisely.

The light touch

Wheels can be made lighter and faster in several ways. For example, you may have noticed that some bikes have lots of spokes, whereas others look like they have a few missing. Spinning spokes create drag, as you might expect, so wheels with a low number of spokes tend to be more aerodynamic. However, there are pros and cons to having fewer spokes. Some people feel that wheels with fewer spokes give a harsh ride quality and in some cases make the wheel too flexible. Other people swear by them - it's a matter of taste.

Another way of making a light, fast and, frankly, sleek-looking wheel is to use a carbon rim. Carbon is light and this means that the rim can be made deeper. This has the effect of shortening the spokes, so that the air around the wheel isn't churned up as much as usual and so the wheels slip more easily through the air. Known as deep-section carbon wheels, these are most commonly seen on the bikes of elite Ironman athletes such as Chrissie Wellington.

Carbon wheels can be taken one step further, to the disk wheel, which has no spokes. Disk wheels are light and super aerodynamic but they are not terribly useful when it comes to climbing or riding in crosswinds. They affect a bike's handling and people tend only to use them as a rear wheel. I've tried riding a bike with two disk wheels during a crosswind and, believe me, it's the worst go-faster idea I've ever had.

A better idea is to use a combination of a rear disk wheel and a deep-section carbon front wheel (with spokes), which can save you about one minute for every 25 miles, compared with standard spoked wheels. But if you want to save that time, be prepared to part with around £1,200.

Sometimes it's difficult to know how much to spend on wheels, when there are so many other things you could upgrade on your bike. The general feeling among cyclists is that, aside from the frame, your wheels are the most vital part of your bike. If you are happy with your bike frame, wheels would be the next thing to splash the cash on. The front wheel takes priority - being at the front means it takes the full force of the wind, so it needs to be as slipstreamed as possible. I competed for years with a £500 front wheel and a £100 rear wheel. It looked a bit odd, but it was the fastest combination I could afford. However, wheels are important to me. It's worthwhile doing some research and making the investment because they can transform your bike and your performance.


The spin doctor is in

Before you buy a set of wheels and tyres, consider your needs, the demands you'll be putting on your bike, and your budget

THE WHEEL DEAL

  • Reliability: Good wheels last for ages and are easy to maintain. However, it can be difficult to find spare parts for some wheels. Do your research.
  • Weight: Anything that rotates on a bike, such as the wheels, should be as light as possible to help conserve your energy. Lighter wheels help you to accelerate faster and climb easier.
  • Stiffness: If your wheels aren't stiff they will flex, causing you to lose power when you ride hard. However, if they are too stiff they may give a bumpy ride. If you're a large triathlete, choose very stiff wheels; if you're lighter you should choose something more forgiving.
  • Aerodynamics: Air resistance acts like an extra set of brakes, slowing you down despite your best efforts. Spinning wheels bear the brunt of that air resistance, so anything more aerodynamic will allow you to slip through the air unimpeded.
  • Low-resistance hub: Your bike wheels spin because of the well-oiled bearings inside the hub at the centre of the wheel. Pick up a wheel and spin it. A good hub will feel as if it wants to spin forever.

SMARTER TYRE

In the world of Formula 1, races can be won or lost as a result of tyre choice. The same can be said about triathlon, where punctures and tyre grip can make or break your race. As with running shoes, tyres have a limited lifespan. While worn-out old trainers might cause injuries, old tyres lead to punctures. Wear and tear makes it easier for sharp objects to pierce the tyre, straight through to your inner tube. The risk of punctures is also affected by the weather, so in the winter you should choose heavier, thicker-skinned tyres such as the Continental Ultra Gator Duraskin. During the summer, when punctures are rarer, you should swap to something lighter, faster and with more grip for racing and training, such as the Vittoria Diamante Pro Light.

DOUBLE UP

A rule of thumb to avoid punctures is to keep two sets of tyres, one for the winter and one for the summer, replacing them every year. When an old tyre has punctured twice in a month, I bin it and buy a new one, as the chances are that it will happen again. The back tyre wears out twice as fast as the front one, so swapping them over after a few months will help keep the wear-rate fairly even.

Tyres vary in price, from around £10 to £70. The more expensive variety feature layers of different materials, such as Kevlar, to maximise grip, reduce rolling resistance, shave off weight and resist punctures. Tyres are always something of a trade-off between weight, grip and puncture-proofing. I'd rather have a tyre that is unlikely to puncture mid-race, even if it means it's a bit heavier. You might decide that reducing weight is more important for you, and opt for a thinner, lighter tyre.

AIR SUPPLY

Simply choosing the right tyres isn't enough; you have to pump them up properly. Your tyre pressure affects grip, punctures and rolling resistance just as much as your choice of tyres. You should pump them up according to the road and weather conditions.

Firstly, make sure you have a proper track pump with a pressure gauge. A tyre pressure of around 8 bar or 110 psi is best for most racing and training rides. Letting out some air will give you better grip in the wet, but be aware that it may make you more prone to punctures. Harder tyre pressures, above 8 bar or 110 psi, may make you faster because of the lower rolling resistance, but only on smooth roads. A combination of hard tyres and bumpy roads can make for a teeth-rattling ride.

It takes mere minutes to make adjustments to your tyre pressure, but they could mean the difference between a puncture and a great race.


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