Hello everybody,
For years I have tried to improve my position on the bike. Not only so that I look cooler and more professional, but also because it saves a few seconds. The big advantage is that you get these seconds for free and without any additional training!
I started on an old GDR steel racing bike with a top tube gearshift. I don't know who heard that before, but it must have been Jan Ullrich's father. My four gears ranged from hellishly difficult to impossible to pedal J In slow motion, I tortured my way up the mountains with it. My first aerodynamic improvement was a “20 Euro” time trial attachment. Of course, this was far too short and after a few kilometers my forearms, which were resting on the pads, hurt a lot.
Fortunately, those times are over and today I have gained a few more experiences in this regard. My knowledge of aerodynamics is based solely on experience and what I have read.
Seat tube angle and saddle position
This determines a lot, namely the necessary length and the possible position of the time trial attachment. The standard seat tube position on a normal racing bike is 73 degrees. This is the best all-round position, as it is in this position that you can develop the most strength and, best of all, crank up the mountains. In the end, there is no reason to change this position, except that at a larger angle (e.g. 78 degrees) you can "slide" a long way forward on the bike and thus lower the time trial attachment, i.e. the wind - (Front) surface of the body minimized. Although the possible power development decreases, the speed increases because the wind resistance is reduced.
The faster you can ride a bike, the greater the effect, of course.
My experience in this regard is that I can still crank well with an angle of 78 degrees and still have enough leeway in the front of the cockpit. Personally, I wouldn't go any further forward, as the muscular strain then moves towards the rear thigh, on which you naturally have much less strength than on the front.
The nose of the saddle is horizontal until it slopes slightly forward. But only slightly. If the saddle nose goes too far down, the permanent pressure on the legs increases because you are less “sitting” on the saddle. I prefer normal saddles, without a wider nose, as is common with Tria saddles. It's probably a matter of taste, but for me it's more comfortable and I don't squeeze my E… while driving.
Essay
With the attachment you can tease out the lion's share of the free time. This must be the right length. Determine the saddle position beforehand. The forearms should rest on the pads just before the elbows. The upper arm to forearm angle should be 90 degrees. Otherwise the pressure on the shoulders when driving will be too great, they will start to hurt and you will cramp.
Not like that…
The depth of the attachment determines the position of the upper body on the bike. The deeper the better. But only up to a certain limit. The upper body should be as horizontal as possible. Otherwise the angle between the upper and lower body will be too small and the possible power development will be minimized too much.
I advise against tilting the extension arms downwards, on the contrary, the extension arms can be inclined "upwards". This brings the shoulders closer together and minimizes the frontal area. When the arms are tilted down, the shoulders diverge and thus become wider.
not like that…
Impellers
A costly factor, which, however, can have a big impact. In my opinion, this is where the second greatest potential for time saved lies. Even if individual newspaper reports bring out dubious results. The windshield is the most aerodynamic, it's just that physically. However, this also weighs more than flank wheels and really only brings something from around 35km / average per hour. Especially on routes prone to cross winds and lighter (weaker) drivers, you have to consider the use. Flank wheels are probably the best compromise. Here, however, beware of "soft" wheels, this is becoming increasingly important, especially for riders over 75kg. If the wheels are too soft, too much energy is simply lost. You can easily test whether your wheels are too soft:
Place a passenger directly behind you and step hard on the pedals as you step out of the saddle. "Soft" wheels give way to the side and the rear rider can see that clearly. "How is the distance between the wheel and the brake pads?"
These wheels are less critical at the front, as there are no tensile forces acting there as on the rear wheel. Personally, I have a combination of a soft front wheel (for financial reasons) and a rear disc.
Aero helmet
Much more important than the brand of the helmet is the seat of the helmet. Ideally, the long nose rests on the back. Then a perfectly streamlined surface is created, the greater the distance between the helmet nose and the back, the more this "surface" is disturbed by air turbulence.
If you use an aero helmet, you should also be careful not to look down too often. Then the wind resistance is greater than with a normal helmet.
additional
The leg position when descending should always be horizontal, so do not let one foot down and the other “hang” up, this increases the resistance.
Aerotrink systems mainly prevent the inconvenient grip on the drinking bottle while driving. From a purely aerodynamic point of view, it is negligible whether the bottle is installed in the front or in the drinking bottle container.
Place changing items, etc .. behind the saddle, but not too high! This disturbs the "wind bubble" that wanders down the back of the helmet and finally leaves the rider at the saddle. It is better to put the change of clothes a little lower, slightly below the height of the buttocks.
So, these are my experiences that I have gained over my competition time. There is one thing that should not be forgotten in all these considerations. The perfect position is of little use if you can't drive it. Comfort plays an increasingly important role, especially on longer journeys!
Aerodynamic positions also require good torso stability, otherwise you will get back pain faster than you think.
How are your experiences with it?
I like to keep learning !!
Skin clean
krelli
Hi Krelli,
first of all I wanted to say what cool and interesting blogs you always write! Unfortunately too little;)
But wanted to know what kind of bike or wheels you ride. Equipment etc. And do you also train with the Tria bike or with a normal racing bike?
MfG Tobi
Hey Tobi,
the picture below is my current equipment. So I was out and about in Zurich last year. Vuelta at the front and an FIR lens at the back (I got it pretty cheap 😉
Bike is Cervelo P2C 2007 version, re-import (was also cheaper). You see, I'm a poor little sausage without a big budget. But I'm still super satisfied with my equipment!
For training, however, I almost exclusively use my normal racing bike, without an aero attachment. Training with the others is harder. So from May I start to train with the competition bike to get used to the position.
How about you with the basic camp, I'm happy that everything is going so well ...
What is your Roth preparation actually doing?
Many greetings
Michael
Hey, thank you for the reply!
But I'm afraid you're mistaking me for another Tobi: D
I don't even dream of Roth;)
MfG Tobi
all right Tobi 2 🙂
No problem, why don't you dream of Roth ???
Yeah, good question.
It's just way too far away.
Of course you dream about it, but it is just too early to risk a half-serious thought about it. My "triathlon career" only started in November 08 :)
Do you have Hawaii in mind for this year?
Hey Tobi II,
All right, then you're right, don't stress yourself, especially at the beginning. I would definitely not recommend the LD to start with, it just slows you down. First try to build up basic speed, especially on the short distances. You can always acquire stamina later without any problems. The other way around, unfortunately, the whole thing doesn't work so well.
Roth under 9 hours has to be enough as a goal this year. Hawaii is great, of course, but also very expensive 🙁
greetings
krelli
Hey, that's how I imagined it would be.
I can well imagine that Hawaii is expensive, of course that you can't do that indefinitely every year.
greeting
Tobi
Hello Michael,
just the right blog! I'm tinkering a bit with the position and am mainly considering buying new wheels. I bought the Felt B2 last year and rode the 40mm aluminum factory rims for the first year. Now I'm wondering what the right investment is. You may know someone who has had experience with the following rims:
Mavic Cosmic Carbone Premium
Grammo Viper
Planet X wheels
It also depends on the best price (performance) ratio, so zips are not included 😉
I am careful about the windshield, because of its susceptibility to wind ... Or would you prefer a station wagon with a windshield at the back and, if necessary, switch to the factory bike? What do you think?
greetings
Dennis
Hi Dennis,
mmhh, the Cosmic are generally good choices. Unfortunately, I don't know the Grammo Viper. From the Planet-X things I think that they are quite soft, but if you weigh less than 75kg, that should be possible.
In case of doubt, better not to use a disc, you have to be sure of that. Otherwise you will panic every time the wind is announced for the competition day 🙂 believe me, I've already experienced it myself.
Well, I can only reach 75kg in winter. And only if everything is crammed in for Christmas 😉
I have to think twice about it and then probably hit it in the week after my training camp. It's just a lot of money and it needs to be invested correctly and convincingly!