oxologic

I have seen pretty nice time trial bikes around, namely the Trek Team Time Trial Bike and the Cannondale Ironman series, especially Ironman 2000. I don't plan to get a time trial bike as yet. I was wondering like whether there is any difference in the aerodynamics. It seems like the Trek time trial bike is very state-of-the-art and seems to be the most aerodynamic. Is there any studies that compare the aerodynamics of these bikes. Just looking around actually, so anyone please share their views, especially those with time trial bikes.

MichaelW

The bike account for about 10% of the total aerodynamic drag, and most of that is on the wheels. TT bikes are about putting the rider into an aerodynamic position. Any fancy frame profiles or whatever are really about marketing.

~LongRider~

Cervelo makes some pretty cool TT bikes.

LSR

I think from talking to some of the Tri guys around here that the Cervelo P3 is considered to be the best in their circles.

~LongRider~

Here's a resemblence of one.


Follow the link.

https://www.cervelo.com/images/2002/2003-p3-full.jpg

vovk25

For me this is The One:

Guest

vovk- which Pinarello is this? It's a sweet lookin' bike, dood!

Ajay213

Actually riding "normally" the bike accounts for 25% of the drag, the body 75%, by making your body as aero as possible (skin suit, position, fancy helmet, etc) the numbers get closer to 50/50 between body and bike.

The generally accepted order of importance is;
1. Position - being aero on TT style bars
2. Wheels - Disc rear and aero front (like a tri-spoke) will make a good 2-3 minute difference on a 25 mile high paced ride.
3. Frame - An aero fram can make a good 1-2 minute difference over that same 25 miles

For some "general" information check out;
https://www.slowtwitch.com/mainheadin...tubeshape.html
https://www.slowtwitch.com/mainheadin...frametube.html
https://www.princeton.edu/~asmits/Bic...ycle_aero.html
https://www.cervelo.com/qa/article5.html

The Trek TT bike was designed in a wind tunnel and is generally considered one of the fastest UCI legal frames. Other frames like Softrides (beam bikes, something without the normal double triangle) can be quite a bit faster than a standard frame. However I have yet to see a comparison between various "aero" frames.

Andrew

vovk25

I have forgoten to post the name fo the bike. That sweet thing is a Pinarello Montello .

Here in Fassa colors:

Guest

Drool... drooooooool...

Dang, that's a nice bike!

MichaelW

Even if all that sleek carbon is just marketing, it works for me.

pointyhead

And its only $9000.00 USD for the privilege to own one.

vovk25

$9000.00 USD for frame only. A complete bike would cost round $15000.00 USD.

itschris

I"m pretty involved in the Triathlon scene, so I may be able to give you some insight. The better performers I see in the races ride all brands, but you do see a lot of Quintana Roo, Cervelo, Kestral, and Softride, usually the higher end models. But there are some very fine bikes in those line ups at 2K range. Watching some of the pro races and other elite events, you will see the P3, but also I've begun to notice more Felts. Craig Walton, one of the fasted pros rides a Felt DA750. I've had a chance to ride around on one at a recent race and I thought it pretty incredible. But you even see some of their less expensive Felt frames, the TT and B2, which I have also heard great things about. You may want to give them a look. Any of the top manufacturers though make great frames. Calfee makes a carbon tri frame but I have not heard or seen much about it. I've talked to one person who had one, and he said he wouldn't ride anything else, however.

pointyhead

Hey, vov, check out this link.

Hi-Tech Bikes

Complete bike 9K.

deliriou5

The cannondale Ironman series is not a road racing time trial bike.... it is a triathlon bike. This means that the seat tube is much steeper (around 78 degrees) than traditional road bikes. A time trial bike will on the other hand will usually have a traditional seat tube angle (around 74). Note how on the pics of the Pinarello above, as fancy as it looks, at its core it still looks like a regular road bike.

The reason Tri bikes come with steeper seat tubes is because this position allows the rider to conserve his quad muscles for the run after the bike.

Ajay213

Well a "tri-geometry" also will have a shorter top tube which will allow us mere mortals ride on a set of aero bars without being to stretched out. If you look at the Trek TT it comes in 3 sizes, so you may find it hard to fit on the bike (especially considering that most one-piece aero bars have integrated stems as well).

The pro's can't ride "tri-geometry" because of those UCI rules, I guess the question is would they ride them if they could.

Andrew

vadimivich

The pro's don't ride Tri position bikes for the simple reason they aren't as fast. Tri bikes trade less quad stress for slightly less power output. In a bike race, where you don't have to run afterwords, a slacker seat tube angle (73-75) will allow you to put more power down, which is why most professional TT bikes use a slightly more standard geometry.

There's no UCI regulation on frame angles ... they just can't use Softrides or anything that isn't a traditional triangle frameshape

Ajay213

There are no regulations on angles, but there are regulations on the setup of the bike. For instance;

1.3.013
The peak of the saddle shall be a minimum of 5 cm to the rear of a vertical plane passing through
the bottom bracket spindle1). This restriction shall not be applied to the bicycle ridden by a rider in a
track sprint event, keirin, 500 metres or 1 kilometre time trials; however, in no circumstances shall
the peak of the saddle extend in front of a vertical line passing through the bottom bracket spindle.

Just from that there is no way to ride with a steep geometry seat tube. Granted you could ride a 78degree, but you would have to set the seat back so far (plus probably need to use a set back seat post) that the overall "true" angle would be back to a "road" dimension (probably around 75 degrees or so, which is still pretty steep). There are also rules on length of saddle, height of BB, length of bike, distance from front axle to BB, etc.

As to the rest, I dunno. I rarely see speed come up when comparing the frames and I haven't ridden enough "tri" bikes to tell, so I'll take you guys word on it

Andrew

Ajay213

This is interesting reading;

https://www.slowtwitch.com/mainheadin...seatangle.html

Basically talks about the performance differences between steep and shallow seat tube angles. Basically saying what you guys mentioned, that the steep angle helps out with the run (by a large margin), but it also helps out with the bike ride itself (but not by much of a difference).

Andrew

lowracer1

I use this for time trials when they let me.

https://wisil.recumbents.com/wisil/ra...rit/Racer3.jpg

deliriou5

lowracer: how fast can you go in that thing?

oxologic

Interesting. I never knew that there was a difference between a time trial road bike and a triathlon time trial bike. Really interesting, yah, I can understand the reason for less quad stress since there's the running section after the cycling.

Does anyone have any studies between the various time-trial frames? I know it makes very little difference, but there should be a slight difference. Please link if there's any.