Dimples, rugosity, compression, solar load: go-faster cycle clothing gets more technical

In July, the blazers of FINA, swimming’s governing body, banned Speedo’s polyurethane swimming suits despite having okayed them in June. Cycling’s UCI also has a slew of rules on go-faster clothing but, despite being poked and prodded in the above ‘weapons of mass acceleration’ spoof from Pearl Izumi, the gnomes of Aigle have yet to come down hard on those companies breaching the clothing rules.

There are lots of ways of making cycle clothes faster – dimples; placing seams away from the airflow; fabric rugosity (ie roughness); body-mapping (ie designing clothes with athletes’ muscle groups in mind); trapping air around the upper arm; wire inserts under jerseys to aid air-flow – some of which are allowed by UCI, some of which are banned, but not routinely enforced.

Given their propensity for pristine, UCI tech wonks may soon turn their focus on fabrics and could one day ban a lot of the clothing innovations that have been trickling down to you and I over the last three to four years.

“After months of research and development, Castelli created a jersey that features a new aero-slippery fabric, a wrinkle-free fit, and critical areas of dimpled material. In the wind tunnel, the Split Second jersey delivered a CxA drag coefficient of 0.359 compared to 0.377 for a standard Castelli jersey. In a zero cross-wind environment, this computes into a savings of 15 watts. And across various cross-wind measurements, the average savings was 13.8 watts – which equates to a 58 seconds savings over 40 kilometers at an approximate pace of 25 mph.”
Castelli press release, 2006

And not just dimpled fabrics, the UCI doesn’t like anything that smacks of “performance enhancement.” I have it on good authority that at one meeting to discuss clothing rules, the UCI seriously wanted to ban materials which wick moisture as this helps cooling and thus aids performance. It was carefully explained to them that banning wicking materials, which are now commonplace in all sports, would be like banning composite frames (hang on, I shouldn’t have said that, don’t want to give the buggers ideas).

It would be cruel to imply that some UCI types hanker after the type of woolen cycle shorts that would weigh twice as much when wet as when dry but what was good enough for Eddy Merckx in 1970 should be good enough for us now often seems to be the guiding principle behind the UCI’s tech regulations.

However, as Jason Rance, vice-president of marketing at Speedo International, pointed out in July, preventing sports equipment companies from innovating is point blank stupid.

“In order to get rid of the wrong of having wetsuits in the pool you’re actually going to take back innovation in the sport and throw the sport back two decades. My analogy would be next year at Wimbledon Federer and Nadal are about to start a game and you say, ‘Hang on a minute, mate. Give me your nice carbon graphite racquet, here’s a cane one from back in 1990. Have a good game.'”

Critics of the give-technology-free-rein approach point out that some performance-enhancing clothing isn’t just slippier through the water or air, it’s biomechanical cheating. ‘Compression’ clothing is getting a lot of attention right now and there are almost claims it’s another form of propulsion. For instance, Power Lycra “controls and reduces muscle vibration, maximizing power while reducing energy loss, muscle fatigue and the risk of cramps.” Sounds reasonable, but what about elastic-band exoskeletons? There are garments for elite cross-country skiers which use Thermoplastic urethane (TPU) bands to store and release energy upon movement.

adidas uses TPU ‘Powerweb technology’ on its cross-country ski suits. TPU bands “support the natural expansion and contraction of the musculoskeletal system while performing. They provide elastic support and performance enhancement of key muscle groups.”

Working on such garments for adidas was James Lamont of Scotland, now based in Germany. He used to work in the adidas Innovation Team but is now a freelance consultant. He has worked across many different sports, but his abiding interest is cycling.

I first met James in the early 1990s when he worked for Raw Experience of Edinburgh, the then importer of Clif Bars and other niche brands into the UK cycle trade. He often emails me with highly-technical critiques of so-called innovations in cycle clothing. Compression togs from well-known brands, for example, are often only minimally ‘compressive’ and mostly in the wrong places, he whispers in my online ear.

And when he tells me stuff, I tend to sit up and take notice because when it comes to go-faster fabrics, he’s the go-to guy. It was he who developed the adidas Ian Thorpe swim suit; he who led the research to make TPU bands for cross-county skiing; and he who married polyurethane to swimming suits. He’s also worked on go-faster cycle clothing for pro bike teams, including trying to ‘compress’ Jan Ullrich’s tummy legs.

Here’s his take on a bunch of the latest developments in bike clothing tech:

Aerodynamics is always key in cycling. A little more attention could be paid to specific riding positions, and not just for time trialling, also for long breakaways, chases at the front. In cycling there seems to be a fascination with surface drag, which relative to form drag is a tiny proportion of the drag load on a rider. We constantly see quotes for power savings or ‘gains’ which, as a percentage of the drag load from surface friction, effects are bigger than the total power lost by the drag factor they suggest they are dealing with.

The governing body rules have been very strict on clothing and footwear, and must always be respected, although this year some teams have been experimenting in early season races like the Tour of California with devices on clothing which are clearly against the spirit and the law of the regulations. Given the attention that the UCI has recently been giving once more to equipment, particularly aspect ratios and fairing, there are nevertheless still major steps which can be made in drag reduction.

I am still very surprised that very few people have looked at aerodynamics in the context of cooling, as they have say in braking systems in Formula One. This is a huge potential area to make improvements for performance and comfort. A little focus and exploration here could yield major benefits.

Colour makes a big difference in terms of solar load, we saw that clearly with teams changing jersey and short colour for the Tour de France this year. However, there are issues to do with opacity caused by water, particularly liquid sweat, which could be dealt with much better to deal better with heat load. There have been improvements in use of different fabric weights and constructions such as mesh, single jersey or mock eyelet, plus incorporation of stretch, even in wovens. However, placement of areas of lighter or more closed fabric is still an area which seems very old fashioned compared with work I have done on heat production and heat load on the body. This is an area of potentially big improvements.

Heat is a huge issue for riders as they become more tired over the course of the race. How they deal with heat load and heat stress has a big impact on performance. When a rider is producing 400 watts or more on a climb to stay with the leaders, given that even a top athlete’s body is only 25 percent efficient in energy conversion, the body is creating nearly 1600 watts, 1200 watts of which then is mostly lost as thermal energy. Combine this with external heat load, quite a remarkably high number of watts per square metre on the open road in the Alps in July directly from the sun, plus reflected and radiated heat from the external environment (Mont Ventoux’s final kilometers being one of the most striking examples of this later effect), there is a great amount of heat to be lost from the body through evaporation, radiation, convection and conduction, along with a large heat load from the external environment. Clearly, what is next to the skin, or major organ, to lose that excess heat generated internally and resist external heat load, that is the rider’s clothing, can have a big positive impact on performance.

It is great to see ideas like pre-cooling before the event, along with ice pack interventions during the race, but much can be done for the future in clothing. There are many solutions available in other industries and fields which can be incorporated.

In the high mountains, weight, or rather gravity, is of course a key issue, as I always see on my SRM power meter as I hit a climb. Garment weights are also approached rather peculiarly. As for much equipment (and I have always been a proponent of the idea of ‘clothing as equipment’), there is an obsession with weight. However, this is typically always looked at as a dry weight. We know from research, our own riding experience, and from watching top riders in the tour, that water as sweat is a major factor in weight. In fact, there are some quite counter-intuitive approaches to system weight of a rider’s outfit which could yield much lower weights in a race.

This has really become a huge trend in the past couple of years. Based on research first carried out in the early 1990s with athletes, it seems as though every team has a different sponsor providing a variety of products all making big performance improvement claims. We can see from riders’ SRM power meter data over the course of a grand tour, that for riders the challenge is to recover from each days’ efforts, and perhaps over three weeks try to delay the inevitable reduction in performance.

For recovery, compression garments offer great potential benefits. However, most products I have seen, both on the general market and supposedly custom made, offer very little compression, compromise freedom of movement and also do not have the correct compression graduation engineered into them. Most would seem to offer no more than a placebo effect. In addition, many garments I see being used are of very low compression force compared with the trained muscles of a professional cyclist, and in addition pay scant attention to the very specific body shapes of these athletes.

While this is disappointing, it leaves much scope for improvements to be made in the products and in maintaining rider performance for recovery, travel and warm-up. At least these are becoming more accepted in what can be a very conservative sport.

There has also been little attention to all the layers and components of what the rider wears, and although sponsor manufacturers would like us to buy only their products, there is still, in something key like heat load, very little thought going into clothing as a system. More of a systems approach in all the areas above could yield great benefits in terms of performance, comfort and also sensation.

As we saw in the stage Heinrich Hausler won, this can also be a big issue, and we saw one particular example in the late 90s of a German star who lost much time due to cold, wet conditions. With very low body fat (insulation) at peak condition for the Tour, high riding speeds (thus cooling rates) and also water from precipitation plus thrown up water from other riders wheels, we end up with big issues. Given that water conducts heat typically at least 26 times faster than dry air, the potential for heat loss and catastrophic loss of performance is huge. Combined with high power outputs (and thus necessary heat loss) up climbs, then inactivity and high speeds on descents, rapid cooling is a natural result.

This year I was struck by how poorly prepared in terms of clothing most teams were. This is an area in which pro riders, tied to sponsors product and the need to show logos and names, can actually be at a disadvantage to what amateur riders can buy and wear. There are a whole range of products which could also be built specifically for pro riders needs in an event like the Tour de France.

A version of this interview with James Lamont appeared on srm.de and is used here with permission.