Silly road test of new Trek speed concept on CN

[Hitchey]

"In fact, it’s the fastest aero bike we’ve ever ridden, and it shaved over a minute off our previous personal best at our local weekday time trial series."

I feel that in a widely read site like CN, it's highly suspect and irresponsible to print a review that opens with a statement that's as ridiculous as the one above in the opening paragraph of the test of the trek speed concept.

To state that a frame alone shaved over a minute off the time of a 10 mile time trial is pure rubbish.

The author states that the same wheels were used in the other rides. He also states that the same course had been ridden under both favorable and unfavorable wind conditions. If he had stated that there was an exceptionally good tailwind that day and he had been training a lot more, or that his position was very poor on the other tt bikes he previously rode the course on, it might make it a little more believable.

If we were to assume that the weather conditions and other factors were as favorable as possible to this particular day, and he states that he had ridden this course under favorable conditions, then the difference in wattage required to take a minute off of a 10 mi TT would be in the neighborhood of 40 watts.

For a frame to provide a 40W advantage is pure rubbish, unless he had been riding a box previously.

It's unfortunate that people are led to believe that if you go out and buy this trek speed concept, you will take completely unrealistic times off of your best previous times on the same course.

One would think that CN would ensure that tests that are posted on the site and potentially read by so many, would be more responsible than to state that a mere switch to a brand X or Y, where the only apparent or substantial difference is the frame, would result in so much increase in performance such as in the TT mentioned.

 

[Michielveedeebee]

"In fact, it’s the fastest aero bike we’ve ever ridden, and it shaved over a minute off our previous personal best at our local weekday time trial series."

I feel that in a widely read site like CN, it's highly suspect and irresponsible to print a review that opens with a statement that's as ridiculous as the one above in the opening paragraph of the test of the trek speed concept.

To state that a frame alone shaved over a minute off the time of a 10 mile time trial is pure rubbish.

The author states that the same wheels were used in the other rides. He also states that the same course had been ridden under both favorable and unfavorable wind conditions. If he had stated that there was an exceptionally good tailwind that day and he had been training a lot more, or that his position was very poor on the other tt bikes he previously rode the course on, it might make it a little more believable.

If we were to assume that the weather conditions and other factors were as favorable as possible to this particular day, and he states that he had ridden this course under favorable conditions, then the difference in wattage required to take a minute off of a 10 mi TT would be in the neighborhood of 40 watts.

For a frame to provide a 40W advantage is pure rubbish, unless he had been riding a box previously.

It's unfortunate that people are led to believe that if you go out and buy this trek speed concept, you will take completely unrealistic times off of your best previous times on the same course.

One would think that CN would ensure that tests that are posted on the site and potentially read by so many, would be more responsible than to state that a mere switch to a brand X or Y, where the only apparent or substantial difference is the frame, would result in so much increase in performance such as in the TT mentioned.

+1, you're damn right

 

[llebpmacds]

I disagree with you. The author clearly recognizes that the test is flawed (see the quoted section below) but that doesn't change his impression. The statement about "extremely fast nights" seems to indicate that the Speed Concept was ridden on a "normal" night. He criticizes the bike and offers that it "must be a consideration for those in the market for an aero bike". He rode faster on the SC than on any other bike, I don't think this is irresponsible at all.

Dave


Quoting:
"While this comparison is completely unscientific and the results are influenced by wildly different wind and weather conditions, equipment variables (we did use the same wheels as previously – a set of Zipp 999s), not to mention the test rider’s fitness, we have to attribute at least a portion of our saved time to Trek’s engineering team.

What is undisputable is that we’ve ridden this same race in horribly slow conditions as well as on extremely fast nights with the wind at out back and never gone this quickly."

 

[Black-Balled]

Hitchey! I hereby repossess your H and demand a B replace it.

WTF? The article clearly says, "...have to attribute at least a portion of our saved time to Trek’s engineering team...".

 

[usedtobefast]

i think the OP has a hidden agenda. the review was clear in all matters,imo.

 

[TarmacExpert]

the difference in wattage required to take a minute off of a 10 mi TT would be in the neighborhood of 40 watts.

The difference in power to improve by 1 minute is entirely dependent on how fast you are, and your CdA/Crr. To get down from 24 minutes to 23 minutes, say, only needs an increase of 26W for my CdA/Crr combination. If they were a 26 minute rider, they'd only need another 19W to get down to 25 minutes.

 

[Hitchey]

While I can read clearly that your/other posters's dissenting opinions are correct in stating that the author wrote:
"While this comparison is completely unscientific and the results are influenced by wildly different wind and weather conditions, equipment variables (we did use the same wheels as previously – a set of Zipp 999s), not to mention the test rider’s fitness, we have to attribute at least a portion of our saved time to Trek’s engineering team."

Umm, well no kidding. Of course he COULD attribute a PORTION of the improvement to the bike, but to make the statement as he did in the first paragraph that the bike took over a minute off of a 10 mi TT just because of a frame?

He also contradicts himself and discredits his first paragraph's key point by writing the paragraph to which I quote above and to which the dissenters to my post refer to.

The author begins his review and simply states in the very first paragraph that the bike took over 1 minute off of his TT time on the same course. That is complete rubbish, and I stand by that.

As I stated, unless he was riding a card board box before or had a very poor position, there is no way a frame accounts for a 30-40 watt decrease in drag, which is about the increase in wattage he would need to take over 1 minute off a 10 mile TT. The differences between an aerodynamically poor and inexpensive TT frame versus a cervelo P4, for example, might be 10 watts, and that is being extremely generous.

A cat 1 rider, based on a chart I have originally on cervelo's website, will take approx 43 secs off a 40K tt by going from a std road to aero frame. A recreational rider, could take 1 min 10 secs off of his 40K tt by doing the same. If we take the largest time improvement, based on a recreational rider, which by the way the author does not appear to be, with an average speed of almost 26 mph on the rolling course, he would only gain 1 min 10 sec on a course almost 2.5 times as long at 24 miles. I would estimate that the avg power he generated on his 10.4 mile course is in the area of 300-330 watts for roughly 23 minutes. Not many recreational riders can TT at that wattage, so the actual improvement could be far less.

If the author were to say that his threshold increased 30-40 watts over the last year, which is entirely possible, and he was fresh that day and was excited because someone gave him a new trek speed concept to test and then write an article about, I could buy that.

The numbers from wind tunnels and power files and tests are there in cyberspace for anyone to see. You don't have to believe me.

It simply strikes me that someone, an editor, anyone, that actually rides a bike at CN would read the article and say, whoa there cowboy, a minute off a 10 mile TT? We are going to be rich.....

Or........ Let's trim the review a wee bit- unless there is a hidden agenda?

b itchey......

The difference in power to improve by 1 minute is entirely dependent on how fast you are, and your CdA/Crr. To get down from 24 minutes to 23 minutes, say, only needs an increase of 26W for my CdA/Crr combination. If they were a 26 minute rider, they'd only need another 19W to get down to 25 minutes.

I looked up a couple of athletes power files on a flat TT course to arrive at my initial wattage estimate difference for the minute. Let us know what you think the decrease in CdA, from one aero frame to another might be and the difference in a best case scenario that a .000_ decrease in the CdA would then increase the speed over a 10.4 mile TT.
thanks

 

[the big ring]

I agree with OP - disclaimers are boring and mostly ignored, you read the other 99% of the article where it is claimed the bike is 1 minute quicker.

Stick a power meter on it and you get much more objective info.

 

[TarmacExpert]

The differences between an aerodynamically poor and inexpensive TT frame versus a cervelo P4, for example, might be 10 watts, and that is being extremely generous.

I don't have a link to where it is on the web, as I just have the copy I saved to my hard drive, but I have a chart of the drag of various TT bikes, and a P4 is over 20W faster than several other TT bikes. For a slowish rider, this would take a big chunk of a minute off their 10 mile TT time.

And some anecdotal evidence - in a 10 mile TT not that long ago I was 5 seconds faster than female national champion Julia Shaw. At the national 10 three weeks later, she rode a P4 for the first time, and went 89 seconds faster than me, despite me putting out 3W more power than when I was 5 secs faster than her three weeks earlier. Either she improved her power output a lot in the space of three weeks, or the P4 made a considerable difference.

 

[TarmacExpert]

Let us know what you think the decrease in CdA, from one aero frame to another might be and the difference in a best case scenario that a .000_ decrease in the CdA would then increase the speed over a 10.4 mile TT.
thanks

Unfortunately the data are in grams of drag, but at zero yaw, the Orbea Oro is around 810g and the P4 575g. The difference is greater at non-zero yaw. So the difference between those two is 235g, approximating to 23.5W less power required at the same speed.

So, best case for time difference: Suppose temperature 16C, pressure 1020hPa, total mass of bike+rider 80Kg, CdA 0.20, Crr 0.004.

Suppose they take 26 minutes to ride a 10 mile TT with the above values. That would require 167W. An extra 23.5W would get their time down to 24:45, saving 75 seconds.

 

[Hitchey]

I don't have a link to where it is on the web, as I just have the copy I saved to my hard drive, but I have a chart of the drag of various TT bikes, and a P4 is over 20W faster than several other TT bikes. For a slowish rider, this would take a big chunk of a minute off their 10 mile TT time.

And some anecdotal evidence - in a 10 mile TT not that long ago I was 5 seconds faster than female national champion Julia Shaw. At the national 10 three weeks later, she rode a P4 for the first time, and went 89 seconds faster than me, despite me putting out 3W more power than when I was 5 secs faster than her three weeks earlier. Either she improved her power output a lot in the space of three weeks, or the P4 made a considerable difference.

Not likely that she would be peaking for a national event 3 weeks early would she?
I don't dispute that the P4 could have been faster than whatever she was riding the first TT when you were quicker. Since you appear to train with power, do you know what her volume/intensity load was at the time of the first TT? She could have gone into the first TT with a high TSS score for a little overloading and then tapered for nats. Just throwing that out there.

For argument's sake, I used to ride brand x's TT bike, which is accepted as one of the more aero brands. I now ride brand y, (both brands have pro tour teams on them) even though the edges are visibly not as aero, but I go faster on brand y because it fits me just a little better, having slightly different geometry.

Unfortunately the data are in grams of drag, but at zero yaw, the Orbea Oro is around 810g and the P4 575g. The difference is greater at non-zero yaw. So the difference between those two is 235g, approximating to 23.5W less power required at the same speed.

So, best case for time difference: Suppose temperature 16C, pressure 1020hPa, total mass of bike+rider 80Kg, CdA 0.20, Crr 0.004.

Suppose they take 26 minutes to ride a 10 mile TT with the above values. That would require 167W. An extra 23.5W would get their time down to 24:45, saving 75 seconds.

Think about what you're proposing here. You're proposing that it requires only 167 watts to ride at 26 mph. Is that at 39,000 feet altitude downhill on a 4% grade? Is there a rider and wheels on that model?

A rider accounts for over 80% of the drag. Wheels are about 10%. Helmet, a few percent, FRAME, a few percent.

 

[the big ring]

...
And some anecdotal evidence - in a 10 mile TT not that long ago I was 5 seconds faster than female national champion Julia Shaw. At the national 10 three weeks later, she rode a P4 for the first time, and went 89 seconds faster than me, despite me putting out 3W more power than when I was 5 secs faster than her three weeks earlier. Either she improved her power output a lot in the space of three weeks, or the P4 made a considerable difference.

THREE WEEKS!!?

Welcome to some very basic training terms, eg: OVERLOADING, FATIGUE, PEAKING, TAPERING, NATIONAL and GOAL EVENT.

Good grief.

(What Hitchey said).

 

[the big ring]

...
For argument's sake, I used to ride brand x's TT bike, which is accepted as one of the more aero brands. I now ride brand y, (both brands have pro tour teams on them) even though the edges are visibly not as aero, but I go faster on brand y because it fits me just a little better, having slightly different geometry.

I think it's well within the realms of doability for CN to have "Intro to TT bike" link at the top of any TT bike review, that discusses critical aspects of TT bike selection, one of which is bike-fit. No mention of this is made in the article, and I agree 100%: bike fit and resultant CdA are critical in TT rider performance.

 

[TarmacExpert]

Think about what you're proposing here. You're proposing that it requires only 167 watts to ride at 26 mph.

No, to ride at 23mph, which is what it takes to do a 10 in 26 mins. I told you what parameters I was using, that is the power it takes to ride at that speed with those parameters.

 

[TarmacExpert]

Welcome to some very basic training terms, eg: OVERLOADING, FATIGUE, PEAKING, TAPERING, NATIONAL and GOAL EVENT

According to Andrew Coggan, 3% improvement is about all you can expect from a well executed taper. It's nowhere near enough to account for the difference.

 

[Hitchey]

tarmacexpert, You're still saying that it takes 167 watts to ride at 23 mph and 200 watts to ride at 26 mph. You might want to modify your calculation model as it takes a lot more than 200 watts to ride at a steady 26 mph without a tailwind or a downhill, or below 39,000 feet. Your "theoretical" model needs some "reality" based modifications.

You're also not getting it regarding the overloading/taper/peak. Neither you nor I know exactly what the training load was in the first TT and how much lower the power was than during the TT at nationals. It's not just about the 3%. Power is a lot more than 3% difference when fatigued and overloaded. Go ride your bike and report back with a power file.

 

[the big ring]

According to Andrew Coggan, 3% improvement is about all you can expect from a well executed taper. It's nowhere near enough to account for the difference.

FWIW, I experienced a 12% increase in TT specific power over 5 minute durations, simply from racing (on the drops) 3 times a week for 4 weeks. And this was before my taper.

You are kidding yourself severely if you think you understand all the variables differentiating the 2 performances between yourself and a national champion.

You are also severely mistaken if you think someone tapers for 3 weeks for a 10 mile event, or that they will only gain 3% improvement from one performance to the next, based on Dr Coggan's "research" or studies, when they do not account for fatigue when racing before / after, etc, etc.

For all you know she could have been hungover in the first TT.

 

[TarmacExpert]

tarmacexpert, You're still saying that it takes 167 watts to ride at 23 mph and 200 watts to ride at 26 mph. You might want to modify your calculation model as it takes a lot more than 200 watts to ride at a steady 26 mph without a tailwind or a downhill, or below 39,000 feet. Your "theoretical" model needs some "reality" based modifications.

That is how much power it takes if you have a CdA of 0.20 plus the other parameters. Most people aren't that aero, that's why you think it takes more than that, but there are some people who are actually more aero than that, and they would need even less power to do those speeds. (edit: I'm not sure where you got the 200W/26mph from, I didn't say that, and it isn't correct, it would take more like 229W even with a CdA of .20. 167W for 23mph with CdA of .20 is correct, though).

I've just re-read the article (I originally read it almost a week ago when it was on bikeradar), and I see he did actually give the exact times for the 10.4 mile TT, so we can get a better estimate of the extra power needed. You're looking at somewhere around 30W extra power needed. 27W to 34W for CdA extremes of .20 to .25.

Look, I agree the article is poor in that it clearly would have been much better if they had power data for the rides. But I think you're underestimating how much time can be saved by a frame. It's not uncommon to have such disbelief, e.g. look at the reaction to this thread where many people simply refused to believe that the two frames in question could differ by 2 minutes over 40k:
http://forum.slowtwitch.com/cgi-bin...183;page=1;sb=post_latest_reply;so=ASC;mh=25;

 

[Hitchey]

I read some info on the post. It's very long and there are as many dissenting opinions on that thread, as there is agreement. The bottom line is that it says going from a p2k to a p3c saves 2 min in a 40k TT and 10 or so minutes in a ironman leg. I disagree with the time gains that test claims.

I was lucky to have been a fly on the wall at a low speed wind tunnel test with Cervelo a few years ago when they were testing the P4 in prototype stage. They had several other makes of frames there to test and I had a chance to see a lot of info for the competition. The data I saw that day as well as real world numbers do not support your position. The test you reference is a multiple of what Cervelo claims for aero gains on their frames.

thanks for the info though.

 

[karlboss]

Don't worry guys, it's a matter of time before some independent magazine throws all the new gen tt bikes into a wind tunnel and gives you your answers. One minute is clearly BS purely on the frame. We have pro riders to watch and I didn't see any of them dump huge chunks (3min over 40km) of time when they jumped aboard a speed concept.

 

[Moose McKnuckles]

But is it laterally stiff yet vertically compliant?

 

[usedtobefast]

But is it laterally stiff yet vertically compliant?

absolutely...and it tastes great and is less filling

 

[biker jk]

But is it laterally stiff yet vertically compliant?

That's priceless. Exactly what just about every bike review says. The CN review of the Speed Concept just perpetuates the marketing BS which is all too common in bike reviews.