not to be snarky or unhelpful... but there are literally hundreds of posts addressing this. Please do a search.

Not to be even more snarky, but what the #$%&$ is the point of this post?

IMO - TT bike alone - maybe 0.5 - 1.5 mph, depending on how aero you can get on the Tarmac.

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Well I believe in God, and the only thing that scares me is Keyser Soze

I'd say the point is to help the OP access the information quicker and more thoroughly than waiting for replies. Folks who know the answer (not me) might get answer fatique if it is a common question.

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Aaron Bales
Lansing Triathlon Team

OR possibly be helpful and directing them to somehting like this http://forum.slowtwitch.com/...improvement;#2848352

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Well I believe in God, and the only thing that scares me is Keyser Soze

The point is I don't want to spend $3000 for a half a mile per hour. I can find a less expensive way to save 2 minutes. Now, if we're talking 2-4 MPH on the bike and a faster run split on fresher legs, it's a different scenario. Thanks.

I don't think there's any way to know without having some idea of what kind of position you have on your current bike with the aerobars, etc. Moving to a faster bike (frame) probably is worth no more than .5mph in itself, but the big advantage of a TT bike is the geometry and the position it allows you to acheive. If your current bike is preventing you from getting in a good TT position, then you'll probably see a pretty significant speed gain. If you've already got yourself dialed in to perfection (perhaps with a ffwd seatpost and a negative rise stem) than you probably will only see modest gains by moving to a TT bike (although you'll probably end up with a bike that handles better in the aero position).

Well your line of reasoning is sound in my estimation, but the numbers might be more like $1500-$2000 for 1-3mph, and possibly a faster run split on "fresher" legs. I found that when I switched to a tri-specific bike, there was also a subtle and very subjective difference for me that made it worthwhile. I just "felt more like a triathlete", and I really liked that.

Perhaps do the $/mph improvement based on 1 mph and if you actually got more all the better.

My tri bike only cost $700...

=)

For most people the speedup will be around 1 to 2mph, but it really depends how aero a tri bike you get, how aero your road bike was, what your position is like on each and so on.

If you want to get lower than your current road bike allows, then a tri bike will be a nice speedup, if you don't, it may not be worth bothering with.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

It depends on what your position on this road bike with clip-ons really looks like compared to what you would achieve on a TT bike.
Have any pictures?

IMO - TT bike alone - maybe 0.5 - 1.5 mph, depending on how aero you can get on the Tarmac.

No chance... he already has aerobars, aero helmet, and a disc cover. 0.25 mph max... unless he gets other equipment.

interesting thread.... I'm in a similar quandary.....I've had the roadie "fit" at the local fit place..... forward post, aero's and a negative stem. wheel cover, aero helmet, bla bla bla.... not sure if I want to spend 3k on a tri bike, or get a killer wheel set and change from road bars to a base bar with brakes and end shifters...... If the speed pick up is only .5 to 1 mph, I should be able to find that just getting better on the bike.

Background,
3 months into this sport, 3 sprints , 1 oly under my belt, 48yrs old went from 238 to right at 200lbs in those 3 months, ave 3-4mph less on the bike than the elite winners for those races.


I'm thinking wheels....

I'll answer this with some direct experience of four races of a friend of mine:

Bikes:
Custom Serotta steel roadie with clip-ons, slacker seat angle -- 2009
Look 576TT -- 2010

Races 1/2 IM and IM 2009 to 2010:

2009 1/2: 2:47 @ 20.1
2010 1/2: 2:52 @ 19.5

Same course, very similar training, similar weather.

2009 full IM: 5:46 @ 19.4
2010 full IM: 6:14 @ 18.0

Same course, similar training, hotter weather 2009, cooler 2010.

Ooops. Results with a TT may vary.

How long were you riding you serotta? i`m just asking because if riding a relaxed angled bike for more than a couple of years have an effect when you switch to a steeper angled frameset even if you train for year on the new frame. i just switched back to a tri bike again after a year of riding a road bike and i was never able to pedal as fast on the tri-bike (same fitness level but was on a tri bike for around 15 yrs) when i was on the road frame nor feel as comfy on the roady even if i was fitted on it correctly.

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"Pain is NOT temporary,you remember every bit of it"

Not my bike, but I think the road Serotta was 2005-2009, switch to the Look this season (7-months of riding time). Train on both about equally.

I`ve been on the tri bike for almost 2 months since the switch and my hard trainer rides now feel better, i stopped riding for a month when i made the switch because i had to wait for a part for the tri bike but the moment i rode it, it felt as if i just rode it the other day. i`ll be able to test next month when i do a 40k ITT on a course i did last year on the road bike.

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"Pain is NOT temporary,you remember every bit of it"

http://www.specialized.com/...research%20FINAL.pdf

So what would you do w/ your old bike if you got a new TT/Tri bike? Do you already have another "rain"/road bike? If not, the answer (unless you live in an apt the size of a broom closet) is almost always MORE BIKES!!! Yes, get the new bike -- whether it's 1mph faster or 3mph, so what... It's good either way, and then you can convert your Tarmac back to everyday roadie use for group rides, foul weather, or whatever. It's always useful to have a spare bike for training if the other one has a flat or some last-minute issue and you want to ride NOW, or you can leave one set up on the trainer so you can squeeze in some extra indoor workouts more often during the winter without having to swap the bike between inside/outside repeatedly, etc. Add that multiple-tool training advantage to whatever aero gains you get from the new bike, and you will be that much faster.

I used my road bike, a 2001 Litespeed Sienna, for tri's for quite a while. Even with the seatpost adapted and clip ons, I am far more comfortable and feel like I deliver more power with less effort in the aero position on my tri bike (Felt B12). Obviously the best thing you can do is to ride a TT bike if you have not had the opportunity. It would be worth a bit of travel to do so if you don't have demo ops at home.

This post gets a little more to the overall advantage of tri geometry. As another poster said search this forum, you will learn if you read. I'll also assume you've read this first: http://www.slowtwitch.com/...techctr/bikefit.html. I'm responding because STers did for me when I had a lot of initial questions, so folks shouldn't be snarky out there - just ignore the thread if you want to.

As for my personal experience, a tri specific geometry helped immensely. Money was less of an issue, fit was my goal. With a proper fit on a tri-specific bike I not only improved my speed by 3-4mph (HIM), I was also much more comfortable on and then off the bike for the run. That comfort for my upper and lower body provided gains in my running speed. 2009 HIM with road bike (clip-ons and not a good fit) to 2010 same HIM with tri bike, I shaved 45min off my PB. It was worth every penny to me... but that's just me.

I'm thinking wheels....

The rear is fine with a disc cover. Don't know what you have on the front... something with a decent depth (like 25mm+) and minimal aero steel spokes would be good enough.

You might have more to gain by getting good tires and using latex tubes.

Unless you are itching to spend money, I'd advise waiting awhile on getting new expensive stuff. When you've neared the limit of your athletic ability and/or have the podium in site, then a few 10ths of a mph might be worth it.

As for my personal experience, a tri specific geometry helped immensely. Money was less of an issue, fit was my goal. With a proper fit on a tri-specific bike I not only improved my speed by 3-4mph (HIM), I was also much more comfortable on and then off the bike for the run.

3-4 mph by changing your position and bike?! I'd need to see a before-after of those setups.

I've been doing weekly TTs Apr-Sept for 4 years. First year I rode my road bike with clip-ons... no other aero anything. Next year I got a full TT bike, disc rear 80mm front, fast tires and latex tubes, skinsuit and aero helmet. The speed increase was 0.8 mph on the same power. Oddly, if I look at common Crr and CdA estimates of what all these changes would have done for me, then 0.8 mph is about right. No mystery there.

If the OP's position is screwed up then he doesn't need a new bike to fix it... and the aero benefits of getting a TT bike would be pretty small.

latex tubes lighter? I'm running Michelin race 3's on Easton vista rims.... what would you recommend for an up grade on the wheels?

I really don't want to spent the the xtra, already going to buy a new ride for the g-friend to replace her crap steel framed bike....