B70 versus XTerra - My experience
by, December 9th, 2008 at 12:00 PM (801 Views)
Swam at the Long Beach meet this weekend and had some decent swims. I used both the Xterra and B70 for different races.
Had a life time personal best (50 back) in the B70 (age group record at the top end of the age group). But, the suit has unraveled after a few swims (26, 5'8", 175). The elastic around the neck is exposed! I'll post a picture on my blog.
If there is a B70 rep reading this, do you have an exchange policy? You might learn something about quality control by doing a failure analysis; e.g., where to reinforce seams, etc.
My M-size Xterra, apparently made of the same material, did not fit correctly. I purchased a knee or farmer john suit. I expected that the band around the knee would be reinforced by elastic. Instead, it was loose and not snug. I don't think it would provide the desired effect of minimizing laminar turbulence. I noticed that other male swimmers also had the same issue with their suit.
I also found that the Xterra felt like it let water into the suit during the maximum velocity portions of the race - at the start and after the turns. I felt water rushing into the suit and it felt like it "gushed" all the way down from neck to knee - a cool wave of water. This may or may not have had a physical effect, but it clearly broke my concentration. I did not have the same issue with the B70.
Question: why do these suits have to be so tight?
I hypothesize that the suits have two effects: 1) minimizing laminar flow resistance and 2) increasing buoyancy (my subjective opinion and mentioned in other forum posts).
If the hypothesis is true, I believe that the optimum suit would be snug or tight enough to minimize laminar flow (and prevent water intake) while not leaving welts and constricting inhalation. Also, maximizing the amount of material should increase subjective buoyancy.
I also hypothesize that the recommended suit size (extra-tight) places undue stress on the seams of the suits and reduces the expected life of the suit. After examining the rubber coating of both the Xterra and B70, I believe that the material may be more resilient than lycra, but unfortunately, we as consumers, have no independent testing capability and have to rely on ancedotal forum reports.
Personally, I like these suits. I would like them to last longer and I believe that if they could be better designed that they would capture a greater share of the market.
How many suits can be worn in competition? There were unsubstantiated rumours of record setting performances attained through the use of multiple suits. I suppose that anyone that could physically wear more than one of these extra tight suits deserves some kind of award, but if the buoyancy hypothesis is correct, the use of multiple suits poses ethical if not legal questions.