Tri, road, or tweener?

If you visit our Triathlon Reader Forum, you'll find folks just like you agonizing over whether to buy the new Cervelo tri bike or the Orbea; or whether to buy the new Specialized or have a custom Elite built; and so on. But for you — as for those posing these queries — this might be jumping the gun. Ought you to be considering a tri bike at all?

Just about everything written on Slowtwitch on the subject of bike fit, applies to tri bike fit. But not every bike that is ridden, or ought to be ridden, in a triathlon is a "tri bike."

But wait! Certainly a mountain bike is the best bike for a mountain bike race; a cross bike is best for a cyclocross race; you wouldn't enter a road race on anything but a road race bike; if it's a triathlon, shouldn't you be on a tri bike? Maybe, maybe not.

There are two questions we'll seek to answer here: How do you know whether you'll be better outfitted for racing triathlons on a tri bike versus a road bike? And what about that position that's been called the "multisport" position, or the "tweener" position — that is to say, a morphing of road and tri?

A "tri bike," according to Slowtwitchers, is a bike built around the idea of aerobars, that is, it's a frameset and eventual complete bike designed with aerobars in mind. By "aerobars" I'm referring to that construct containing armrests and extensions. Our bedrock concept relies on the view that this is more than just an accessory or component: rather, that it turns a bike into a sort of "front recumbent," because you rest the top half of your body skeletally on the front of the bike.

Imagine laying face down on a massage table, versus maintaining yourself in the push-up position, up, with arms locked. Yes, that's a stark analogy, and certainly overstates the "rest" afforded by a tri bike versus the upper body muscular "stress" of riding a road bike. Nevertheless, we believe this ability to "rest" your upper body on the front of the bike — displacing your weight skeletally on the front and rear of the bike, versus only on the rear of a typical road race bike — affects just about all aspects of how a bike built for this position ought to be designed.

Riding your bike in comfort, like laying on a massage table, sounds pretty appealing, doesn't it? But think about what riding with a flatter bike for a long time "comfortably" means: you also may be riding with your weight not on the fat of your rear for a long time, rather on a part of your anatomy less well suited for weight displacement; and you may be riding with your head craned forward for a long time (you look down when getting a massage; imagine the stress on your neck if looking straight ahead while getting your hour-long massage). For these reasons, riding a tri bike might not be optimal for you — you may (perish the thought) be better off riding triathlons on a road race bike.

The first decision you must make, even with the full knowledge that triathlon is the intended use, is whether a tri bike is the best bike for you. This isn't straightforward. The simplest determiner is this: Can you, and will you, ride in the "aero" position for virtually the entire bike leg of the race?

But it's not necessarily easy to answer this question. Even if you'd like to ride in this fashion, and intend to, perhaps you don't know if you can until you're fitted properly, and atop the equipment that suits you best.

I realize it's a little like asking you if you can ride 6 hours comfortably on a horse. It's hard to know this without first being fitted to a saddle; and on a saddle that suits your anatomy; riding a horse that suits you; and having enough hours in the saddle to make a judgment. How will you know whether you can ride 6 hours in the saddle comfortably without first making a mountain of investment in horses, saddles, and training?

These hurdles notwithstanding, there are clues upon which you may rely.


A tri bike is the inferior style whenever you're out of the aero position. Whenever you brake, corner, descend, sprint, or do anything with your hands in the pursuit bars, you'd be better off if you were on a road race bike in that moment. The reason tri bikes are used by the best athletes is that those moments are relatively brief as a percentage of the entire ride.

- So, the first, truest thing you can say about this decision between road and tri is this: If you know, irrespective of anything you might learn here or elsewhere, that you're destined to spend a third, or half, or two-thirds of your racing miles out of the aero position and on the pursuit bars, you'll probably be both faster and more comfortable on a road race bike set up as a road race bike, even though it's a triathlon you're racing in.

- At the risk of putting too fine a point on it, are you slow? And is that just relatively slow, or absolutely, dog, slow? The slower you are, the less weight is on your pedals, the more weight is on your saddle, and the more pain you're likely to endure while in the aero position. There is no sin in riding a road race bike, set up as a road race bike, in a triathlon. Road race bikes are fast, even those with no aero bars. They're almost as fast as tri bikes. So, riding a road bike, road geometry, in a road position, with road shift/braker levers on a road handlebar, is not a bad option. It is certainly better than riding a tri bike, with a mountain of spacers on a tiny stem, uncomfortably.

- Are you carrying 40 more pounds than your ideal weight? A tri bike might be in your future, but it's questionable whether it's in your present. The extra weight coming down on your tender regions, and the lack of flexibility and "room" at the top of the pedal stroke, means the tri bike you'd buy now would be slower than the road bike you'd choose (even in a no-draft triathlon). Furthermore, the tri bike you'd buy now would probably be different than the tri bike you'd choose were you to wait until you were closer to your ideal weight.

- Are you a congenitally bad bike handler? If you're not going to get much better at handling, and you're constantly in and out of the aero position, and you're swervy and slow, you're probably slower on a tri bike than you would be on a road race bike, and you're more of a danger to yourself and others.

There is no sin if you find yourself in one or more of the above categories. In fact, if a road race bike is your best bike, you'll no doubt find yourself riding past lots of tri bike riders in races. This, because you're on "your" best bike; and because you're riding against a lot of riders who're not on "their" best bikes.

What about putting an aerobar onto a road race bike? If you're in the three categories listed above, I'd say don't do it. If you won't ride a tri bike comfortably and confidently in the aero position, you probably aren't going to ride any bike that way. Those who do ride with aerobars on road bikes are usually best off with the sorts of "shorty" bars ITU racers prefer. But I have "rules" that govern their best use, and they generally revolve around not messing up the good available riding positions on your road race bike.


When I first started riding with aero bars, immediately after they came out more than 20 years ago, I just slapped them on my road bike. That's what we all did. There were no tri bikes. But two things were obvious to most of us: the position we found ourselves in was too stretched out; and we were uncomfortably low in front, constricting our hips, that is, it was hard to generate power at the top of the pedal stroke.

So, I shortened the stem and raised the bars. At that point in the evolution of my riding position, I was sitting back in my "road" seat angle, and the saddle and the aero bar armrests were at about the same elevation. I looked like a sail, but I could ride the bike reasonably comfortably.

In my personal bio-chronology, this narrative has so far advanced you about 6 months, taking you from Spring of 1987 to Fall of 1987. At this point I've got a road bike, set up at a road seat angle, but with full aero bars. I'm halfway between road and tri. I'm Missing Link Man.

Plenty of those who're fitting triathletes today stopped their learning and evolving right there, at that point. This is still how they fit their charges. Is this a viable position? Let's assume for a moment that it is and, assuming it is, what bike geometry best fits this tweener position? There are two sorts of geometries that represent a bit of a convergence, and that is the road race bike as I described it in the paragraph above, and the "tri" bike built with a shallow seat angle and a tall head tube. If you're a bike designer and you craft your tri bike's geometry this way, you're making something very much like a road bike. When looking at our stack and reach tables, tri bikes that have short reaches and tall stacks are built in this fashion, that is, they are "narrow and tall" (described on the graphic above) instead of "long and low." (shown on the graphic below).

Would I ride faster on a bike outfitted like this — the way my aerobars were outfitted on my road bike in 1987 — or on a road race bike, set up like a road bike, with no aerobars at all (or perhaps with shorty bars)? Were it a flat, featureless course, I suspect it would be a wash. The body positions are similar, featuring the same angle of my torso into the wind, and the same biomechanics. The value in a pure road race bike is in the various positions available to you (hoods with straight arms, hoods with forearms parallel to the ground; hoods out of the saddle; tops; drops). Offsetting this is some potential aerodynamic value to you in the tweener position if you are set up narrow.

Back to 1987: As I rode this bike month after month I found that I instinctively wanted two things: a lower position with a flatter bike; combined with the ability to ride with my trunk further forward. This is the evolution in which many triathletes of the time found themselves engaged.

After another six months of moving the stem and saddle and aerobars, it became apparent to me that a new frame design was indicated. This 12 months — mid 87 to mid 88 — this was the period during which the R&D (you might say) for the "tri bike" occurred.


- You're a candidate for the "tri bike" if you find yourself going through the same sort of evolution I went through two decades ago. You continually find yourself wanting a shorter cockpit; you're moving forward to the nose of the saddle and wishing you could move further forward still; and you find yourself wishing your bars were lower (commensurate with moving your saddle forward). This is your body telling you what my body was telling me — and what the bodies of dozens of pro athletes back in the 80s were telling them.

- If you're fit and trim and reasonably coordinated you're part of the two-thirds of the triathlon world who will find themselves faster on a tri bike (properly designed, built and set up) than on a road race bike.

- Speed is king to you, and you're willing to go through the process of investigating how it is to generate more speed. For a lot of people, speed is not the priority. Just know that if it is a priority, speed through tri bike riding is not easily won. As you ride with your seat angle steeper and and your back flatter, your choice of saddle, aerobars, bike frame, your training and racing bike apparel, your technique, your cadence, all narrow in their utility — your available choice in what you use and how you ride tightens. While 50 different saddles might be acceptable on your road bike, only 1 or 2 might work for your steep-angled tri position. You'll have to ferret them out. You have to be willing to engage in this process.


I've been deliberately opaque on the utility of the tweener position. Of course you can tell that I have a personal dislike for it, because it was an early stage in my evolution to what ended up being a position with which I ride with much greater satisfaction. I might chalk this up to my idiosyncratic self, were it not for the parallels between my self-discovered position and that discovered by most of the world's best pros from that time until this.

Accordingly, my view of the tweener position is that it's underpowered and slow. Bringing a tweener position to a triathlon is like bringing a knife to a gunfight.

But for those who aren't prepared, for whatever reason, to take the full advantage the aerobar and the aero position affords, what's the best set up? A tweener aero position, or a standard road position? I favor the standard road, for several reasons, namely...

There is no aero bar made today that mounts on a road bike, with the saddle, road bar, and shifters all in their proper road configs, that places the road bar in its proper spatial relationship fore/aft while granting the rider an appropriately short cockpit distance. In other words, if you just mount the aero bar on your properly set up road bike, you'll be too stretched out. If you shorten the cockpit, you'll have ruined your road bike contact points.

The alternative is to do a full tri front end to your tweener outfitted bike. It sort of works. But I remain unimpressed. I'd rather just have a proper road bike underneath me.

That established, I will not have convinced many riders and fitters out there, and the tweener positioned will still be employed. Knowing this, I offer two takeaways about this tweener position. First, if you must resort to this, don't try to do it with a Cervelo P3. "Long and low" tri bikes are just not made for the tweener. Best to just use a standard road bike; failing that a tri bike that's built narrow and tall. (There is a confluence in bike design, where narrow and tall tri bikes "look" geometrically like road bikes, as suggested by the yellow rectangle in the graphic adjacent.)

Second, as stated three paragraphs up, a full tri bar on a properly positioned road bike with STI shifters guarantees either your tri position will be bad; or your hoods position will be bad. Full tri bars go together with pursuit bars, bar-end shifters, plug in brake levers. If you must put an aero bar on a road front end (road bars, STI, et al), the shorty bar best complements it. I would take more comfort stating this, and leaving it lie, were there a really good shorty bar currently made. Regrettably, there is not. When there is, I'll write about it, and until then we'll all have to make due mounting less-than-perfect shorties on our road bikes, or mounting no aerobars at all on them.


As you might by now divine, I'm an agnostic about the tweener position. It's not right for me; and it's not right for most tri bikes; but it might be right under certain conditions, on certain bikes, for certain people, with all the qualifiers and mitigators contained above. The truest thing I can say is that there is a "tri position" that generates and delivers all the blessings and benefits of the aerobar, and when you read about "tri bike fit" on the pages of Slowtwitch it is this position about which we write. True, this tri position lives inside of a range of shallow seat angles to steep, but in the context of true tri positions when we say shallow we mean 77° and when we say steep we mean 81°, with 79° dead nuts center.

Best, then, for you the user to ask yourself whether you're a candidate for the sort of "tri position" that conforms to our idea of best practices. If you are such a candidate, then you can pass through the door of Cervelo tri, Felt tri, and so forth. If you're not a candidate, there's no shame in that. It's just that you'll be unhappy with most of the better selling "tri" bikes, and if you're dead set on a tri bike anyway you're better off choosing one that matches your riding style. (narrow and tall, ridden with a shallower seat angle and taller front end, and with a full tri set up, in something closer to our Slowtwitch-described tweener position). Or (and maybe better yet) simply choose a standard road race bike. Heck, my favorite style of bike to ride on a day to day basis is a road race bike. These bikes are fine, and it may be the bike on which you'll most happily, powerfully, and comfortably race your triathlons.