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T1 First Wave Concept 5 Wetsuit – 2 Pieces Better Than 1?

By Zachary Crumbo for

De Soto 1st Wave Concept 5
De Soto 1st Wave Concept 5

My name is Zachary, and I am not a swimmer.

Swimming as a function of time
The swimming continuum

First off, a little history:  I’ve been participating (not competing) in the sport of triathlon for a little over 5 years, coming from a background of competitive sports, all of which were conducted entirely on dry land.  I am fond of pointing out that where I grew up, the closest lap pool was a 1.5 hour drive away, and even though I’ve been perfectly comfortable in the water longer than I’ve been walking, it wasn’t until I was well into my twenties that I considered doing tris and “Swimming” (as opposed to “swimming”).  When I first started at (coincidentally, a few months before I did my first triathlon), I was blissfully unaware of the notion of fast swimmers.  All I was trying to do was physically survive the swim leg, so that I might have a shot at physically surviving the rest of the event.  Working at a company where the CEO is a multiple Kona qualifier, and my immediate supervisor and two people I shared a desk with have since gone pro, your perspective gets a little off.  After completing my first Half-Iron distance race, a co-worker asked what my splits were.  After I refused to name my swim split, he threw out a joke time that was supposed to represent something so slow as to be considered laughable.  It was about 5 minutes faster than what I did.  In the intervening years, I’ve completed many more races, and even managed to podium a few times.  I say this not to brag but to show you where I’m coming from in reviewing the T1 Concept 5 from De Soto Sport – a run-of-the-mill age grouper who has clawed his way up from laughably slow to respectably mediocre.

2-Piece suits in a 1-Piece world

The T1 series of wetsuits from De Soto inhabit a unique space in the wetsuit world.  As the only major 2-piece player in an industry dominated by 1-piece suits, they face a unique set of challenges from potential customers.  Are they harder to get on?  Slower to come off? What (if anything) are you giving up?  The answers, respectively, are no, no, and nothing (aside from a potential learning curve).

De Soto Sport is a triathlon original and a pioneer in our sport.  The founder, Emilio De Soto, is an accomplished amateur triathlete who has consistently delivered innovations in materials and construction that are now industry standards. Triathlon-specific equipment exists to solve very specific (and unique) problems inherent in multi-sport activities, and has a history of “mad-scientist” types who have worked in labs and garages to create the innovations that eventually work their way to the forefront of what has become a multi-billion dollar industry.  Triathlon wetsuits are a perfect example of this process – tri-specific wetsuits exist to solve a few basic problems, and they all face the same set of design challenges.

Wetsuit Problems
Lack of wetsuit flexibility can be problematic. The author in his first open-water swim.

The Problems with Swimming

• That water is cold
• I’m a lousy swimmer

The Problems with Wetsuits

• Swimmers need excellent range of motion, and wetsuits restrict it
• Ill-fitting wetsuits make everything the worst

Wetsuits solve the swimming problems in several ways – the first one being the most obvious.  Just about any wetsuit, regardless of design and materials, will help keep you warm.  They trap a thin layer of water between you and the suit.  You warm up that water with your body heat, and you stay comfortable.  The way wetsuits help you with the second problem is just a bit more complicated, but the gist of is that they float your body higher in the water.  The less of you that’s in the water, the faster you’re going to swim.

The problems that come up in wetsuit design (and the reason why they now run up to $1200), is that a wetsuit that’s just designed to keep you warm isn’t necessarily easy to move in.  1-Piece companies have many variations on a similar theme – variations in neoprene thickness from 1mm to 5mm, with the thinnest, most flexible rubber going around the shoulders and arms, and the thickest rubber going to where it will keep in the most warmth and float the parts of your body that most want to sink.  All of them do an excellent job for most athletes, but all of them need to design for an ideal body type, one that doesn’t necessarily align with your particular needs.  If, like me, you were born with disproportionate leg and torso lengths, or disproportionate upper and lower body mass, finding a 1-Piece suit that works can be a challenge.

If you don’t get that ideal fit, then instead of solving those swimming problems, a wetsuit can compound them.  Too tight, and your range of motion will be severely restricted, you can have trouble breathing, and have painful chafing (all of these issues can make an already stressful and chaotic swim leg completely unbearable).  This is why fit is so crucial in finding your wetsuit (and why we recommend calling in for advice if you have any questions on it).

The 2-Piece Answer

Building wetsuits in 2-Pieces has a few obvious advantages:  for the disproportionate athlete, you don’t have to compromise on sizing.  You get a perfect size for your upper and lower body.  Another advantage has to do with complexity – in order to isolate the parts of your body that need mobility from the bulk of the suit, 1-Piece manufacturers go to heroic lengths with materials and construction to achieve that goal.  By having a top unconnected to the bottom, you automatically have more mobility, and can thereby achieve the same goal without resorting to ultra thin, ultra-flexible (and ultra-fragile) shoulder and arm pieces and complex patterning, stitching and construction.

But Does it Float?

Yes, It floats
Yes, it floats

So how does the 2-Piece design perform in real-world use?  To answer this question I used it as I trained for and completed IRONMAN Coeur D’Alene – what would be my 2nd full-distance tri (following an identical training plan), but my first experience with the T1 series of suits.

As an employee of, I’ve had the opportunity to swim in a huge range of suits, so why is this my first experience with the T1?  Laziness, primarily.  I found a suit that worked for me a few years back, and have stuck with it.  I am a creature of habit – if it ain’t broke, don’t fix it and all of that.  But there were a few issues I’ve always had with my beloved one-piece (very tough to get on, and unless the neck was closed perfectly, was subject to serious chafing) and  was curious to see if De Soto could solve them.  Additionally, I was (as always) looking to shave some time off my PR, and though my bike and run legs were much fatter targets for reducing my time, De Soto offers a “fastest swim guarantee,” which I just had to try out for myself.
Materials and Construction

De Soto has moved from petroleum-based neoprene to Limeston-based


I swam in the T1 First Wave Concept 5 Pullover and the T1 First Wave Bibjohn.  That mouthful signifies a few things:  “First Wave” is the company’s high-end line of suits – they are made with more flexible (and more expensive) neoprene and boast an SCS (Super Composite Skin) coating that makes the rubber slip more easily through the water and more resistant to fingernails.  While most wetsuit companies use Yamamoto petroleum-based neoprene, De Soto has moved to what they call “GreenGoma” Limestone-based rubber, which they claim offers superior stretch, buoyancy, and durability.  And while they could use the move away from petroleum to be the entire basis of a “greenwashing” campaign, they are thankfully completely upfront about the environmental impacts coming from the mining and production of this type of neoprene – the company literature describes this as a step in the right direction (and one of several present in the suit’s design) along the path of making wetsuit that has a smaller environmental impact.

Concept 5 Forearm Panel Vs. Traditional
Concept 5 Forearm Panel Vs. Traditional Forearm

The concept in “Concept 5” refers to the arms of the suit.  A few years ago, De Soto produced a suit that was so fast it was outlawed – the infamous Water Rover.  The governing bodies of triathlon changed the rules to negate the advantage the Water Rover had given, but De Soto seems to have learned some lessons from the experience that they are carrying forward with their completely legal suits.  The key feature of the now-illegal suit was a full 10mm of neoprene in strategic areas.  The additional rubber floated people even higher in the water, but the inclusion of the ultra-thick rubber on the forearms of the suit did something else:  it made for a physically larger “paddle” attached to a swimmer’s arm.

The Concept 5 doesn’t go nearly as far as the Water Rover did – but it goes right up to the now-mandated maximum thickness of 5mm to provide a similar (if smaller) advantage to a swimmer’s pull.

Dry-Land Usage

Putting on
The 2-piece design allows for a simple process

Even after years of practice, getting into a wetsuit remains a challenge.  Considering that it’s more important to get out of a suit quickly than it is to get into one, most designers err on the side of speedy exits.  That’s great in T1, but can be a bummer if you don’t have a buddy around to help shoehorn you in.  The T1 is hands-down the easiest wetsuit to get into that I’ve ever tried.  What is generally (for me) an endurance event in itself became a trivial matter.  All of my rituals and tricks were largely unnecessary – the suit just goes on easy.  It’s still important to line everything up correctly, but the 2-pieces and (most significantly) the lack of a full-length zipper meant that I didn’t have to wander the beach hoping to find someone who could zip me up without ripping my fancy wetsuit.

In the Water

In the water with the Concept 5
In the water with the Concept 5

So how does it swim?   The novel design does come with a few peculiarities: the lack of a full-length zipper means the neck has no adjustability.  This is not necessarily a bad thing, as it can take work to get the neck closure perfectly aligned to avoid chafing.  With the T1, you have one size only – for me, that size was a tiny bit small, so I had to make certain I used enough Body Glide to make sure I didn’t chafe.  The only other strange thing was getting used to the torso being unconnected from the legs when you stretch your arms in front of you – you get so used to the tugging sensation that when it’s gone you feel like the top is riding up.  After checking several times into my first swim, however, I was assured this was not the case and eventually just got used to it.

As for the Concept 5’s signature feature – I was initially unconvinced.  I had a hard time deciding whether the increased volume in my forearms was actually going to make my pull stronger, or if the added buoyancy of the thicker rubber was just going to make it harder to submerge my arm: adding to the difficulty without actually increasing my speed.  My training swims didn’t do much to clear up the confusion; I felt like I was working harder, but I didn’t have any apples-to-apples data to compare swim times.  The closest I could come would be race day, where I was hoping for comparable conditions to my last Ironman.

Removing the Suit
Suit Removal is quick and easy

Coming Off

Getting out of the suit is equally simple as getting in:  there is a learning curve dealing with two pieces, and at first you can feel like you’re juggling and losing track of things.   After a few practice sessions, and figuring out that you just need to take the top off over your head in one motion, I was just as fast, if not faster, than with my beloved 1-piece.

Race Day Cometh

Race morning came with the usual nervousness and flurry of activity.  It was a genuine comfort to know how easy it would be to get into my suit, and that I could focus on what I was going to need to do to get through the 140.6 miles of the day.

During the swim, the suit did exactly what I needed it to do.  It kept me warm and safe, and helped float me in the water and achieve a much faster swim than I could do without it.  I never once felt held back by it, or chafed by it.  I barely noticed it at all – perhaps the highest compliment I could give.

Coming out of the water at Coeur D'alene

The other race-related question I had was about my transition time:  would the design differences that made the suit go on so much easier make for a longer transition?  The answer was in my time again:  I was 3 minutes faster in T1 this time around.  How much of that is attributable to my wetsuit is open to debate, but one thing is for certain:  it didn’t slow me down.

As for the apples-to-apples comparison I was hoping for?  I was fortunate to have calm weather and a relatively clear path in the swim (equal to my previous IM), so it was as close a comparison I could hope for without doing the swim twice in a row with my other suit.  As I came out of the water and saw that I had dropped 5 minutes off my previous swim time, I guess I had my answer.  And did I incur any extra fatigue due to my faster time?  Not so much:  I also managed to drop over 30 minutes from my bike time that day.

Final Thoughts

De Soto makes quality gear and will stand up for their product – you will find no more passionate a defender of the T1 line wetsuits, and they go so far as to guarantee your fastest swim or your money back.  That’s a pretty aggressive guarantee, but in my case it certainly worked out.  Obviously my “experiment” had some design problems that my wife (the scientist) would take issue with, but for two races of equal length in similar conditions with an identical training plan, the data is good enough for me.  I swam faster in the T1 – and that solid swim set me up for a great overall day where I took over an hour off my total time.

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