Dilemma...upgrade current bike, or get new one???

The most important thing is your training.

Then comes your position on the bike. Make sure you're optimized there.

Next, in order of $/time saved:

* Aero helmet.
* Aero wheels.
* Aero frameset.

Could you benefit from a "more aero" frame? Possibly. But if you don't have the big things covered, it'll be polishing a turd.

The Kilo is very capable of getting the big things covered, especially if you ride steep. Dan Empfield knew a thing or two when he designed it.

Worth it is always one of those things that you need to determine for yourself.

i know this isn't what you want to hear, but 10 times out of 10, the engine trumps the rig.

Pretty much the most money for the least amount of speed. You already have a TT bike, it's not like you're coming from a mountain bike. Unless of course it's the wrong size (my first bike problem).

I'm running an old P2-SL and it's still way more bike than I can take advantage of. 

He lives in PA, I heartily disagree with "weight is almost entirely meaningless" when he's probably climbing hills.  As for the 30s over 40km, that sounds completely unscientific, based on what?

Anyway, to the OP.  If you're averaging 18mph in a sprint, even with some hills I think there is probably a lot of room for improvement given the fact that your bike isn't awful.  IMO keep training and you'll notice upgraded parts a lot more when you're averaging 22+.

Agree 100% that engine is WAY more important than the bike. Assuming bike is fit is decent.

And every analysis I've seen suggests weight is essentially meaningless on TT/tri's (with rare point-to-point uphill courses).  On a rolling loop course, extra energy expended pedaling weight uphill is mostly reclaimed coming back downhill.

One other thing to consider is your tires.  Difference between all-season & higher-end race tire can be significant.

   I do actually ride a lot of hills around here in PA.  I just did a sprint tri last weekend (18 mile bike portion, total elevation gain: 1942 ft, average slope: 3.9%, max slope: 16%) and I do think less weight could help me some.  I finished with an average of 18 mph so 59:30 something like that. 

   I did my first bike only race a few weeks back (46 miles) on a really hilly course also and I averaged 19 mph.  I chalk that one up to the fact that I could draft.  That is why I wonder if aerodynamics is my issue. 

   Yes, I am also a big believer that the "engine" is the most important thing; but what I am asking is...if I AM going to spend some money, then where would it be better spent?  Start with new frame? or lighten/aerodynamic up my current bike?  I am also considering an aero helmet and a tri suit.

Ok, where is the data that you're getting these numbers from?  Before every hilly tri, there is always some post on ST about "should I ride my road bike", some guy named Lance has been asked quite often, and Escape from Alcatraz was filled with road bikes this year.

Now if by "numbers" you mean data for pro's where they figure out weight penalty vs. aero penalty at 25mph, I agree.  But for mere mortals, air isn't as big of a deal as gravity.

I found that this is a pretty good summary on weight vs aerodynamics

http://en.wikipedia.org/wiki/Bicycle_performance

Basically saying that for every pound of weight you reduce on yourself or your bike, you'll climb a 7.5% hill .06 mph faster.  And this does not take into account that as a lighter rider/bike, you will descend slower.

That is a cool site, but I don't really know what to compare it to.  I've never been able to find useful aerodynamic data comparing bikes for anything less than 25mph.  Obviously 7.5% is one heck of a hill so that's throwing a wrench in it, but I suspect a few lbs helping .1 mph isn't much different than a small drag difference at 15mph.

I took a few physics classes in college, enough to realize that I'm not an expert but there is a point where a bunch of math formulas don't precisely jive with the real world.  Just like how in highschool they teach you that the coefficient of friction has nothing to do with surface area, and yet nobody builds dragsters with honda civic tires.  In the same way, nobody I know rides a steel bike because some formulas say it's not much different and you regain so much speed on the way down. 

I made a calculator, you're right assuming 130watts and a 5% grade you're talking .05 mph difference in 2 lbs.  I still say there is more to it, according to that, weight is useless and lightweight wheels even more so.  We basically should all go back to 1989 and use steel bikes with bondo for aero, and carbon fiber wheels are a giant waste of money. 

On the other hand, I bought my wife a lighter bike a few years ago, it's in no way aero and she made a huge improvement, probably 2mph, and the old tires were fine.  I guess I'll just disagree.

You could...and probably not see much difference.  Just look at the new FLO wheels that have come out.  They are pretty much the heaviest set of wheels you can buy...heavier than most training wheels (they actually are just training wheels with carbon fairings molded on), but from their testing, they are extremely aero, and people are buying them up before they can even be made.  People do not desire carbon aero wheels because they are light...they desire them because they are aero.

Lightweight carbon climbing wheels...you could make an argument there, but they are designed for climbing.  The reward is not much, but seconds matter for some people.

You could do a simple test yourself.  Take an extra full water bottle with you on your next ride.  That should weigh about 2 pounds.  See if you notice any difference in speed.  I seriously doubt that over time, and many tests, you'll average 2 mph slower.

Well that settles it...Where is your data... besides n=1 that you are basing the conclusions on?

 Weight is just weight. It is very easy to figure out how much work it takes to get it up. It's not a lot. It is also recoverable... heavier wheels just means more energy to put in to get them spinning... but more energy returned upon slowing. The heavier you are going down hill, the faster you go. So it is not that much of a penalty on rollers or circular courses. Only point to point going up hill as was mentioned. Air resistence is exponential, and not recoverable.

As to the OP... just like has been said, unless your frame does not fit you, you are not going to see any real improvements. Dropping one pound from a decent frame is hard to do.. and it will not gain you much.... you could probably drop one pound just by putting your bike on a diet.... cut off all excess tubing from seat post, stem, handlebars. Look at what you put in your seat bag, take off anything not used.

Overall it is difficult to justify upgrading a lot of components... eaisier just to buy another bike. If you have a special frame you want for special reason it is easy to buy the frame and swap over all your stuff. I have done it for really good frames and then upgraded stuff as I needed it. Wheels are easy because you can take them with you, but the ROI is terrible... yes more aero, but you can buy a really good complete bike for the money. I don't see how you are going to make huge improvements and take off large chunks of time with the bike you have now as a starting point. Not that you can't improve what you have, but I doubt you will see it on the clock.

After more thought, the thing that I was missing last night was perspective.  sure 2 lbs may be less than a tenth of a mph when the combination is 190lbs, but that makes some sense as it isn't much overall.  The instance with my wife, is a whole lot less than 190lbs total, and the bike gain was more than 2lbs.  Again perspective.

The problem with the idea that "weight doesn't matter in a tri" is when you stare at complicated formulas, you forget simple ones.  F=M*A.  To say that "weight doesn't matter" is basically saying that bikes don't obey physics.  If you add mass, you have to add force to obtain the same speed.  

As for the lightweight wheels, that makes sense in a computer or on a pro that keeps a constant 25mph pace the entire way.  Again, perspective, most people on BT don't do that, they constantly accelerate and slow down.  Given a limited amount of power available at one time, that is why you don't want heavy wheels 

I'll concede that 2-5 lbs overall is small, even while climbing, as we aren't all 120lb riders.  However, where is the data that aero is such a big deal at 15mph?  I've searched and I'm willing to bet that the "small" gains that weight gives you are comperable. 

As others have said.. The only time weight is a real issue in triathlon is if it is a real hilly course.  I ride a litespeed Saber which isnt very aero but it is comfortable and gets me in a great aero position which in my opinion is more important. I wear an aero helmet and usually rent a set of Zipp wheels for races. 

I get passed by people all day long on old steel frames who are just beasts on the bike.  That convinces me more than anything that there is no replacement for good training. You cant buy your way fast. 

I guess you can call it big or small... but air gives 4 times the resistance at 15 mph than at 7.5 mph. 30 mph would be 16 times the resistance at 7.5 mph. Are you trying to argue that 2 lbs has anywhere near that effect?

Heavy wheels are nothing more than fly wheels. If you have ever switched to very light wheels, you can feel how easy they are to spin up... and how quickly they loose momentum.

Physics work just fine for bikes.

You're the one who's calling everything incorrect, by all means show me any test that discusses anything aero at 15mph.  I myself don't know how to calculate CdA for a given bike, mostly because it's dependent on velocity unless you want to get into more math than I can actually do.

I recognize that mass is in your equation, obviously.  My point is you can't say "weight is irrelevent" it isn't.  I'm not talking about microacceleration.  I'm talking about how in the real world people are constantly fluctuating speed and just like a flywheel when you force a human's engine to work harder, it has a negative affect on the rider.

It's nice that people can throw around simple math that says you gain maybe .02 seconds by losing a lb in an hour and yet "aero x is worth 20 seconds in a 40km TT" completely disregarding that everything is relative in aerodynamics.

Enough with the road bikes are good for hilly courses, the OP has a TT up a hill listed in his races.

CdA is a constant. It doesn't change with velocity. It changes with things like position alterations, or equipment swapping.

Weight does not have precisely zero effect, but at the very least, one should be able to see that it's much less relevant than aerodynamic drag with the values being discussed.

I love a good physics debate.

To the OP, as noted by most, you are much better off 'investing' in aerodynamics.  You are the greatest source of drag on the bike, so making sure you are in the most effective position is the most 'valuable'.  After that, it's generally the things on you and the bike (clothes, wheels, helmet, bottles, etc.).  Many of those can be accomplished for relatively little monetary investment.  Tires & tubes, though not specifically for aerodynamic purposes for the most part, are also sources of 'total drag' which can be optimized.  Finally, there is the frame.  Shane's number is not unreasonable from data I have seen.  But, given the monetary investment needed to make that incremental savings, I'd generaly recommend that as only a final aero-step.  After all of that, then you can start trimming weight on your components (as long as that doesn't sacrifice aerodynamics).

Of course, new bikes are cool.  So I could recommend one just on that basis.