Aero road bike vs Tri Bike, Need your WISDOM!

The benefits of a TT bike are really more about the aero position of the rider, than they are about the bike.  Sure, the bike is part of the equation - but it's the smaller part.  Getting your body out of the wind, and doing it in a way to keep your hip angle open so that you don't lose too much power is the trick of the TT bike.  Being in a roadie position on a really aero frame isn't nearly as good as being on a round tubed TT bike with a good body position.

I've got a decent carbon Orbea with full DuraAce.  I never ride it anymore since I got my Felt B10 with Di2.  Since with Di2 and dual position shifting, you can ride and shift on the hoods, or ride and shift on the aerobars.  So- your TT bike IS a road bike.

So- instead of getting one pimped out Aero Roadie, instead, get one pimped out Tri Bike.  !!!

x2

An aero road bike is probably going to be 0-0.1 mph faster than a traditional road bike.  And if a properly fitted TT bike is usually about 1-1.5 mph faster than a traditional road bike...so, you can do the math for yourself.  The TT bike is all about the way it positions the rider.  It's why a properly fitted aluminum P2SL will still be faster in a TT than a S5 with normal road bars.  The difference in frame aerodynamics is very minimal, but it can make a difference.

Some of the top sprinters will use an aero road bike for stages they expect to be a bunch finish because those minor aero advantages will make a difference...especially at top end speed.  But it's not like teams who have access to aero road bikes like the S5 or the AR1 are dropping everyone else with traditional road bikes because they are so much faster.  Weight isn't even an issue for pro riders either since they generally all have their bikes weigh in at the UCI minimum.

If your goal is to consolidate to just one bike, and you don't want a tri bike anymore, then an aero road bike with Di2 is a pretty sweet option.  But if your goal is to go as fast as possible over various types of riding, including tris...then it's probably not a wise decision.

I understand that not everyone is out there for speed and we do this for enjoyment...so go with what makes you happy and want to ride.

^^^  Chris makes a solid point here.

I'd go searching around the interwebs for a good deal on an ultegra Di2 setup and put in on whatever bike you ride more.  (then again, put it on whatever bike you want to ride more, as whatever has Di2 on it... you'll want to be on)

I have a tri bike and two road bikes.  My tri bike only gets ridden once a week and for races.  My less nice road bike stays permanently on my trainer.  My nice new road bike gets used for hill riding and more fun riding.

A nice road bike just rides better than a tri bike.  Tri bikes aren't generally super comfortable to ride.

If you just plan on doing triathlons then get a tri bike.

For those of us without budget constraints then having both makes sense. Each type of bike is better at something, so you can use the right tool for the job.

If you can only get one bike, then unless you are purely triathlon focused then a good road bike with aerobars is a safe bet. Sure its a compromises but that's what your budget forces. You can always add  a tri bike later as budget allows, and then still keep the road bike. Buying road first, tri second is very common.

Btw I went from Trek 2000 to Trek 5200, did my first Ironman on the 5200, then added a Cervelo P3C. It wasn't budget constraints that forced the order, more a dire to avoid being a poseur - the slow middle age guy on a superbike I could afford but didn't earn. Note this was back in the day when a tri bike was step 27 of being a triathletes, not step 3.

I think the gap is nearly identical.

The overwhelming majority (like 90%+) of the aero gains from the TT bike are not from the sexy aero tubing, but from the lower position of the rider in the aero position. 

It's so overwhelming that for pure speed considerations, I would take a round-tubed TT bike over a aero-framed road bike any day. I'd even go with the round tubed TT bike compared to the aeroframed road bike with attached aerobars unless you change the fit on the roadie so that it's setup identically to a pure TT bike (which means it'll be suboptimally fit more might not fit at all if you take the aerobars off, in which case you might as well have just bought a TT bike.)

The aero framed tubing consistently ranks as near the bottom in terms of aerodynamic time savings, and pretty much the absolute worst in terms of dollar/aero bang for the buck in pretty much every test out there. 

(Admission: I ride a Cervelo TT aeroframed bike but still feel the aero tube benefits are hugely overstated. The COSMETIC effect is awesome though, and to me well worth the additional cost! )

Again, it does depend on which you do more or value more. If you rarely race triathlons, but LOVE road cycling in all its forms, it wouldn't make as much sense if you had limited money for bike expenditures to spend it on a whole 2nd tribike that you might ride a few times a year. 

However, if you do expect to take triathlon at least semi seriously (you're not a one and doner, and hope to improve over time), the TT bike is the logical next purchase. You WILL use it and benefit from it if you keep at triathlon for more than a few months.

I do not think you should look at your trek 1000 as a limiter whatsoever. That bike, as well as the rest of the entry level bikes today, perform 98% as well in terms of speed as a $15k bike. You will NOT get significantly faster by just buying a new roadie, unfortuantely. (You wouldl if you were going from a mtn bike or non drop-bar bike to a road bike, but the Trek 1000 is already a drop-bar bike.)

We currently own

Speed Concept 7.5 (ultegra)

Cervelo P-2 (ultegra)

Madone 5.2 (ultegra)

Madone 5.9 (aero road bike, Ultegra Di2)

Scattante Race (carbon frame, ultegra)

There is no way anyone rides faster on the Aero roadie than they do on the TT bikes (my son and I ride same bikes)......position won't allow it....ok, he can beat me on the roadie when I'm on a TT bike....but I digress.  Likewise, the aero roadie is faster than the Scattante in crit races and draft legal triathlon because Di2 is badarse and when alot of shifting is involved for quick jumps, lots of corners, etc.....it's easier to get through the gears.  Maybe that's not the case for VERY experienced riders, but for us the electronic shifting is da bomb.

A TT bike is still a TT bike and a road bike, aero or not, is still a road bike.  An aero road bike is not, and will never be, a TT bike.

Just a word of caution that even with electronic shifting, a TT bike is NOT a road bike when you're on the horns. 

http://blog.rappstar.com/2014/04/why-triathletes-need-road-bike.html

Here's my two cents, if you can only have one and you like to ride a bike for things other than racing (commuting, groups, etc) then go with the aero road bike. TT bikes absolutely suck for commuting and blow for group rides. Now if commuting is every once in a while and you train predominantly solo (or with one or two other peeps) then go TT all the way. 

I watched a guy take an OA win in a HIM this past weekend with a Bianchi with clip ons, FWIW

On similar lines, Chrissie Wellington dominated her early tris with clipons on a roadie as well.