Best Upgrade for a TRI Bike - (Page 3)

NateC - 2007-11-02 12:18 PM

You aerospace degree isn't helping you when it comes to making a decent comparison.

Consider the R&D budgets, intended purposes, and production costs of Formula 1 cars or fighter jets, vs. a 747 or Honda Civic.

A Honda Civic is limited in terms of aerodynamics, not due to the fact that it's bound to be a slower car but because of the fact that it's meant to haul people and belongings from one place to another and it needs to be made affordable to the general public. Taking the design of the Civic into the wind tunnel for the extensive testing and tweaking that an F1 car would go through is an argument of diminishing marginal returns for the manufacturer. The car may get better gas mileage but it then becomes unaffordable to more and more members of the general public.

.. BLAH BLAH BLAH

amiine - 2007-11-01 2:02 PM

I was going to post a lengthy reply about some of your opinions, but after reading your paragraphs about the aero-helmet and aero-wheels I figured it was going to be pointless. According to you, next week I should expect to avg 27-28 mph for 56 Mi with my cool LG rocket helmet and my disc/tri spoke wheel combo, YAY!

ranger5oh - 2007-11-02 11:13 AM

Fact of the matter is, aero wheels and and a helmet will not make a 15mph rider average 17-19mph as you have stated.

I dont disagree that aero wheels and helmets can offer a benefit, in fact I ride on them everyday. I just think you have severely overstated the benefit of the wheels and helmet... especially for slower riders.

NateC - 2007-11-02 12:47 PM

You make an excellent point. It's all true and if I would have known that my suggestions would be so attacked, I would have reconsidered making that statement as it's very anecdotal.

The point that I was trying to make (I must be careful now that I'm under a microscope), is that as far as BIKE UPGRADES go, my opinion and experience is that FITTING, THEN AERO COMPONENTS are the best bang for the buck.

A powermeter is only a data collection device that requires effort to learn to use and upkeep properly and a coach is not cycling specific. A good coach will help everything tremendously, but it comes at quite a significant expense.

D.Z. - 2007-11-02 1:17 PM Wow Jorge, that's a pretty unprofessional response on BEGINNER Triathlete.

dgunthert - 2007-11-01 12:00 PM



This is going to be harsh, but is absolutely not directed at you: The guy at the bike shop is a complete moron.

First, the location of your knee in relation to the spindle doesn't mean a damn thing, especially on a tri bike. What matters is the hip/torso and torso/arm angles that are established by your position. Those angles should be consistent regardless of how low you go in front. Check Dan Empfield's articles on fit at slowtwitch.com. They make it pretty clear why the whole knee over the spindle thing is useless.

Second, the idea that aero wheels aren't worth it unless you can average 24-25 mph displays even more ignorance than the fit issue. It is true that wind resistance increases exponentially with speed and that aero savings will result in a greater percentage savings the faster you go. However, actual net savings will actually be higher for slower speed riders.

wheel.

dgunthert - 2007-11-02 5:57 PM

I didn't misquote the article or mislead anyone about it. I certainly didn't misquote you and would very much like to know why you think I did. I did say that having the knee over the spindle didn't mean anything and pointed to a very respected source to back that up.

I never claimed that what I wrote about knee/spindle relationship was a quote from the article. What I attempted to imply was that if you understood the basics of what Dan espouses (including in the article you linked to), that's the inevitable conclusion.

Here's one of the most recent versions of Dan's fit article (there's another version, but it's broken up into 10 different parts):
http://www.slowtwitch.com/mainheadings/techctr/bikefit06.html

If you would like an exact quote from it:
"You can also see from the photo that "knee over pedal spindle (KOPS) can be thrown out the window for this application (tri bike fit) because Swedish pro triathlete Jonas Colting (pictured) is riding a very steep position (80 degrees or thereabouts), and his knee is going to be well in front of the pedal spindle."

You'll also notice regarding the letter you mention that he completely ignores the question the guy asks because the knee/spindle position is irrelevant to proper fit. By the way, the guy in the letter was on a tri bike (Litespeed), and Dan used it as an example of someone who might be better off using a slacker, road bike geometry. Still doesn't have anything to do with knee/spindle.

That's not to say that in fitting an aero position on a road bike, your knee won't end up over the spindle. The point is that it doesn't mean anything if it does or does not.

So, no, your tech was not correct in what he did with your knee placement if it didn't come as a simple byproduct of the rest of the fit process. The fact that he even mentioned it to you makes it seem like that it was an end unto itself. If it came as a byproduct of the rest of the fit process, there's no reason to even refer to it because it's meaningless. It's kind of like saying, "I had to change the seat position in my car. It turns out my knee was too far behind the gear shift." The gear shift has nothing to do with properly adjusting the seat, so why even mention it as a reference point? If I misinterpreted what took place, I sincerely apologize for that.

I won't retract the statement that the tech is a moron, though, based solely on his comment about wheels. Check the results of a few local tri's. Regardless of the distance, you'll likely find that that 24-25 mph would put you close to the top of your AG and well up amongst the pros. Saying you need to be there before you think about getting aero wheels is ignorant. Whether or not their worth the investment is a personal question. But even at lower speeds and very high yaw angles, they'll perform, at worst, the same as a non-aero rim. That's a generalized statement, by the way, and not necessarily true for every single rim at every wind speed and yaw angle. Hopefully, the rest of this conversation has at least convinced you of that.