Which front wheel works best
The best all round wheel up front is a wheel that performs well through a wide range of yaw angles, the angle of the wind combined with the speed of forward motion. The rim needs to be deep enough to perform aerodynamically but not so deep as to compromise handling at higher yaw angles, time spent even thinking about staying to your chosen line is time lost against the watch, as focus is needed at all times.
We recommend our 50 or 60mm deep rimmed front options as the best overall wheel averaged out over all conditions. It’s wide 26.5mm profile with rounded trailing edge provides excellent handling characteristics and superior real world, aerodynamic performance. Our 86mm deep front wheels have the potential to be faster but only in very calm conditions or low yaw angles. Don’t fall into the trap that deeper means faster just because lots of top riders use the deepest wheels. The faster you can ride into any given wind the lower the yaw angle you create. At 30mph + the top riders can use any depth of wheel because the yaw angle will be very low and therefore fast.
Yaw angle answered
Yaw angle is the actual effective angle that the wind reacts with a rider during forward motion. A direct head wind = 0 degrees regardless of wind speed where as even a 90 degree direct crosswind will have an actual angle of attack much smaller as the rider cuts through it. As the riders speed varies so does the yaw angle despite the wind speed remaining constant. Therefore a rider typically has to overcome an average yaw angle of between 5 and 17 degrees.
Is a Disc always faster?
In our opinion a disc wheel is always the faster choice for the rear, regardless of wind angle. However, a 86mm deep section may be favourable over a disc if average speeds are below 24mph like for ironman competitions or when courses are particularly hilly. There are typically no handling issues when using a disc as it is fixed in position with the majority of the riders weight over it, unlike the front wheel which pivots freely.
Why use wider rims?
Almost all of our wheels have been designed to use tyres of between 23mm to 25mm in width, as it has now been proven without doubt that they are faster at the speeds encountered by cyclists. This is due in part to there lower rolling resistance compared to traditional 20mm tyres over almost all road surfaces. The rougher a roads surface the greater a tyres rolling resistance will be. A narrower tyre has to distort more out of shape than a wider tyre, creating greater rolling resistance. All of our wheels rims are just over 26.5mm at there widest, regardless of depth and have a blunter rounded trailing edge. This allows the use of wider tyres without a combined resulting, tyre/rim lightbulb shape, which is bad news aerodynamically. A cross section through our tyre/rim profile reveals a more equally balanced shape which gives unsurpassed handling properties and enhanced aerodynamic performance in overall conditions. These are characteristics that more traditional narrow V shaped rims haven’t been able to achieve.
Clinchers or Tubulars. Which is best for me?
Most experienced racing cyclists would agree that traditionally tubulars have been regarded as the faster of the two, but in recent years pressure has been on manufactures to produce equivalent performing clincher tyres, some now having performance equalling rolling resistance. Clinchers are more practical in terms of changing a puncture and cheaper to run as they often need only a new inner tube after a puncture, where as a tubular tyre is usually discarded at great cost. The penalty paid by using clinchers is their weight compared to tubulars. This weight penalty applies to the actual wheel rims also, resulting in a combined wheel/tyre penalty of around 300g + per pair. This wont make much difference over flat terrain in time trials or most triathlons but in a hilly time trial or road race with more climbing and accelerating involved, tubulars are likely to be a better choice. Therefore your typical event will determine which is best for you.
How much tyre pressure?
In the past time trialists simply inflated their tyres to the maximum psi printed on the side wall of the tyre and a bit for good measure. We now know that this is actually slower as the tyre skips over the surface and stops conforming to the surface of the road, thus losing traction. The most efficient pressure is likely to be between 100 and 120 psi for clincher tyres and approximately 10 psi more for tubular tyres. If you would class yourself as a lighter rider you’re ideal psi will be nearer 100 and vice versa for a heavier rider. Its not an exact science as air temperature changes and excessive braking can change the tyre pressure continuously during your ride.
Are these wheels serviceable?
Our wheels can be serviced just like any other spoked wheel. Our deep front and rear wheels have sensible externally seated spoke nipples, making the wheel easy to true, if necessary. The bearings are all replaceable and can be easily upgraded to ceramic, if you wish. We do recommend that any wheel maintenance be carried out by an experienced bicycle shop mechanic.
Will wider rims fit my bike?
Almost all frames will have more than enough clearance for our wheels between the chainstays. If you have any doubts, simply take a measurement between the stays. Our wheels have a maximum width of 26.5mm which starts just below the braking surface. It is likely that the only change that you will have to make is to widen your brake block slightly. Check our individual models data for detailed dimensions of all our wheels profiles