38, 39, 40. These numbers do not reference European shoe sizes nor do they allude to a series of symphonies, instead these are the proletariat model numbers that correspond with Japanese rubber manufacturer Yamamoto’s lines of neoprene rubber. The fact of the matter is you may be able to find a tri-wetsuit that’s not made from Yamamoto neoprene, but it wouldn’t be easy. These ubiquitously used materials are pervasive within the majority of triathlon wetsuits found in today’s market and if you’re a triathlete you’ve more than likely heard the name and numbers thrown about alongside that sleek new wetsuit you’ve been eyeing.
You may wonder what the numbers mean and what significance, if any, they carry that makes these levels of neoprene best suited for triathlon wetsuits?
Yamamoto began producing wetsuit material in 1961 and have grown with the sport of triathlon ever since Dan Empfield’s pioneering work marrying the garment with the sport. Yamamoto’s rubber was chosen after the discovery of the unique properties that the rubber holds making it a perfect fit for triathlon specific garments. Yamamoto neoprene is a limestone sourced rubber and whose amazing properties include:
- Nitrogen gas blown rubber that augments the insulation of the wetsuit, making it warmer
- A 23% higher closed-cell structure than oil derived neoprene, making it more buoyant
- Maximum elongation of over 480%, whereas human skin stretches only up to 60 to 70%
- 95% water impermeable whereas oil derived standard is nearly 70%