By the way PD measures it's 143. By the way PIA recommends measuring it's bigger. So when your comparing sizes between PD and other manufacturers your not comparing numbers obtained in the same way. This is why PD reserves seem to pack bigger.
I am aware of that, and it's quite disturbing that manufacturers can't get together and use the established standards of the association they are members of.
The point I'm trying to make, and the problem I've delt with in gear sales for a long time is that people see things like the words "flys big" and hear about measuring differences and make decisions about sizing that they might not have made before. This problem extends much furthur than PD's measuring system, but it's a problem.
On that chart, is there any reason why a Triathlon 175 has a 382 cu in volume while a Triathlon 160 has a 419?
Probably a great question. I did not put it topgether but it just flat out might be a mistake.. Parta-Gear does note this at the bottom:
CAUTION: PARA-GEAR has no control over these statistics. For general comparison only. Volume and size figures could vary 20% ±. This volume chart has been put together from many sources using various methods of measurements. Figures in lighter type furnished by PARACHUTE INDUSTRY ASSOCIATION. Figures in bold type come from many sources. THESE STATISTICS, THEREFORE, SHOULD BE CONSIDERED ONLY TO BE APPROXIMATE VOLUMES. Special thanks to Sandy Reid.
A large 160 could easily be bigger than a small 175. And depending on who did the measurment and where the volume can vary with the same canopy. There is larger variation in volume measurement than area measuement.
My experience has been that the PIA numbers are closer to container mfr. numbers.
I only trust numbers published by container manufacturers, because they are the ones who get stuck with re-building a container if the canopies don't fit. For example, back in the mid-1990s, Gelvenor (South Africa) made a batch of ZP fabric that weighed 20% more than American or British-made fabric. This resulted in a batch of Triathlons that packed considerably bulkier than earlier Triathlons. It drove container manufacturers to drink until they figured out the source of the problem.