Why (really) is a tri bike better Part II?

Triathlon Forum
1

Hello folks and sorry for taking the title. There sure is a lot of debate about this subject and one that I truly have an opinion about. However, I would like to present to those valiant members of Slowtwitch an impromptu study on the benefits of the design of the “tri” bike. What we will have when we are done is some anecdotal evidence, not supported by a university or research facility, which will highlight the advantages of the aero position for you as a triathlete.

To be apart of this study, you need to own a tri bike and a road race bike. Hopefully you will have been set up effectively on both bikes. Your tri bike has you steeper than your road bike. You will also need a heart rate monitor. As far as power goes, I do not believe that it will be that vital because we are not trying to gage power efforts in either position. We need a standard to hold and it should be speed at a particular effort level. This effort needs to remain constant between both bike rides. That is, when you submit your data to me there should not be a large deviation between the rides in terms of effort. I realize that there are other factors such as wind, rain, hail, stop lights, dogs, hydration etc. I think that carrying the study for at least 4 weeks should give us some good averages and minimize the influence of those variables.

There are going to be exceptions however; there always will be. The question will remain as to whether the exception becomes the norm. And, do the benefits of the tri bike have any advantage over a road bike for ST’ers participating in swim/bike/run events?

Tell me what you think and if you would like to give this a go. I did this last year with a 24 mile route and I was kind of stunned with my own findings.

Scheme:

Use cursory data i.e. heart rate, average heart rate, average speed, time, distance etc. to evaluate a predetermined route riding your Triathlon bike and your road race bike. Which bike is faster at that energy level and does that efficiency translate into quicker running splits.

Method:

Choose a route you know well at least 20 miles long…can be longer if you want. At the end of the ride note your average HR, speed, distance, time, etc. This does not need to be an all out effort. It is not a time trial or a race pace effort. It can be but then you may not want to do it 2x in the same week.

· Ride your road race bike first then run up to 5k off the bike – save your data.

· Take a couple days and then use your Triathlon bike on the same route and run up to 5k off the bike. The intensity and route should be the constants here – save your data.

· Take notes on the pertinent data: pace, time, HR, distance, how you feel and recovery. Use a 10 point scale with 10 = great and well recovered.

· Repeat this for 4 weeks consecutive weeks (we can go longer if necessary), email your data to me so I can compile the results and look at some statistical significance. You can email me weekly if you like.

(I can create an excel sheet that you can put your data into if you like so that all the variables are included.)

Results:

I will compile the results and post at the end of the four week period.

2

In a word, aerodynamics.

3

I think that is the understood part of the equation.

There seemed to be a lot of skepticism on the part of a good number of posters as to the validity and reliability of the studies that questioned the benefit of a steep angled bike for a triathlon vs. a traditional road race bike. I just thought it would be fun to compile a pseudo experiment and give some data back to what we came up with thats all.

4

The steeper angle allows the hip angle to be more open when the torso is low, allowing the rider to be more aerodynamic with a less closed hip angle.

I used to ride a 74 degree seat angle, but now run a 78 degree.

5

I’m not so certain of that…

http://www.biketechreview.com/performance/faster.htm

6

I agree with Kraig, faster is faster

I also agree, more aero is faster … if the balance between power, comfort and aerodynamics is optimal

In my case, forward is faster … I know this for fact

In others, maybe not … no such thing as cookie cutter fitting … each rider is unique

7

Hey folks,

While I appreciate the exchange of ideas, it is not the intent of this post to re-hash the argument, rather to look to our own experiences on both bikes during the next four weeks and come up with some individual data which I can then analyze and come up with a result for ST.

I thought the project might be fun and give us some ideas on where the advantages help us out.

Thanks,

Michael

8

And, just to clarify, no clip-on aero bars on the road bike? Just standard drops, right?

9

Yes the road bike must be set up to ride as a road bike no clip-ons.

Michael

10

How come? It seems to me that everyone accepts the aero advantages of a tri bike, and the real controversy is whether or not the tri bikes steeper angle makes running off the bike easier.

11

Uh, why? Wouldn’t you want to test if you could use a road bike effectively as a TT bike for tris? Seems like you should have it set up however you would race a tri on it. (Or what he said above…I’m too slow)

12

That is the very reason why I proposed this impromptu study. If done properly, we should have some great data to make some great correlations.

Michael

13

Not exactly a scientific study, but here’s my story.

I ride 3-4 times a week with a tri-training partner. Most days we are pretty even. He is faster than me in windy conditions (more power output), and I am a better climber.

Yesterday, we had two changes. 1. He put his Zipp 404’s on (Felt B2), and 2. I rode my road machine (around 75 degrees, standard drop bars with 19mm rims).

During the first few miles he road my slip, and all was merry, cruising along at ~22mph with a bit of a head/cross wind. After 4 miles or so, he pulled out of our little train and just LEFT my sorry ass. We’re talking about sustained 2-3mph faster than me for the next 10 miles. I powered, I got lower, etc, but there was nothing I could do to reel him back in.

Then the bastard flatted. Bwahahaha!
You can bet I’m going order that new BB for my tribike today so that embarrasment doesn’t happen again.

Chris

14

another way to do this would be do the ride on a trainer to isolate the geometry as the only change and eliminate the change in drag. that way I don’t have to ride my tri bike in the rain.

15

I tried something very similar to this proposed experiment back in high school for the science fair. I set up a set course and rode it 3 times in 3 different positions; hoods, drops and full aero tuck. This was all done on a Scott DH bar. The results I got were what you would expect, drops were faster than hoods, and aero pos. was faster than drops.

However, if what we are really looking at here is seat angles, then eliminating clip-ons on a road bike would defeat the purpose IMO. Of course you are going to be faster in an aero tuck. I think what you are looking for is if we feel better on the run following the “time trial”. What is the final expectation that you are looking for?? That seat tube angle matters a great deal?? If so, then all other factors should be the same. And since no one can control Mother Nature, then everything else should be as similar as possible.

Just my .02 cents.

Ken

16

Hey John,

Great question! The idea is not to see if a road bike serves as a tri bike with the proper tweaking. I have created that frankenbeast several times (not ideal in my opinion). It does get the person in the position. Whether the frame of a road bike is ideal for that creation is another topic, I believe. The question deals with the seat tube angle and the benefits both during the ride and as you begin to run. Does the steep angle offer more advantage on the bike course and does that advantage pay dividends on the run portion?

In my time at a previous bike shop I was always asked why would I want a tri bike? It’s is such a one dimentional creature. Couldn’t I just use a road bike with clip-ons? So, last summer I did this very test with my road race bike and my TT bike. I did it for about 8 weeks and came up with some very interesting results…It would interesting to see if others on ST have similar results. Hence, the set up of the experiment.

Does that make sense?

Michael

17

Yes, but you said no clip-ons for the road bike. It seems you want to test if you should use a (potentially) bastardized raod bike set-up over a specially designed TT bike. Not a standard road set-up versus a TT bike. If I can get into an aerodynamic position on my road bike and not suffer for it on the run versus the TT bike, why buy one?

18

What were your very interesting results?

19

Ok Mikey – I am going to test but it has to wait a little bit because I am finish up a big week of training and going into a rest week – so in two weeks I will start a test.

BUT it will be a little different.

  1. I live right by the Velodrome in Marymoor – I am going to conduct my test in the Velodrome – this will eliminate any stop light factors, etc. etc.

  2. Bikes – Road - Specialized S-works - Tri - Quintana Roo Caliente.

  3. I am going to use the Same wheels and same tires.

  4. I am going to use my aerobars on the road bike.

The run will be inside the velodrome also.

Should be interesting since I will be riding a bicycle purchased from Triumph Multisport !!! Do I get my money back if my S-works is faster ???

20

Hi John,

If I can set up a road bike to ride like a triathlon bike which I can, then what is the purpose of doing this? We are talking about frame geometry. The reason why this was suggested is because there are those who believe there is no run gain from the position. And while one can set up a road race bike to ride with a similar geometry to that of a tri bike, we are hampered by some fundamental construction issues such as the head tube. Nevertheless, the idea of using either a road race bike with clip-ons during your event will still have different effects to your outcome. However, for the task at hand, I am not concerned about using clip-ons on your road bike without changing the angle of the seat post. If however, you would like to use clip-ons please do. I can set up another category for the experiment.

Your last question is a good question. If the same position is attainable, why would there be a market for a “tri-bike”. I would contend that you may come close to an “ideal” position but it will not be the same position that a true steep angled bike will give you.

Michael