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PostPosted: Tue Feb 24, 2015 5:20 am 
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Here's a plot of Tour Magazine's frameset mass rating plotted versus frameset mass from the 2015.03 tests. These include 4 super-light bikes (Emonda, RCA, Vial Evo, and Rose X-Lite) of which the Rose isn't so super-life, and 8 additional budget road bikes.

Image

The weird thing is the super-light bikes were given all a 1 rating (two of the points are coincident since the RCA and the Vial Evo tied). The gap between the Emonda and the Rose X-Lite really deserves a score difference. The regression is around 0.003 points per gram, or 1 point per 333 grams. and the difference is around half this.

The result is the Rose won the test.

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Posted: Tue Feb 24, 2015 5:20 am 


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PostPosted: Tue Feb 24, 2015 10:52 am 
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Hardly surprising as the Rose complete bike with premium parts costs little more than some framesets.


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PostPosted: Tue Feb 24, 2015 11:35 am 
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It is really amusing the fact you can buy two bikestore superbikes such as Rose X-lite for aprox the price of one RCA frameset.

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PostPosted: Tue Feb 24, 2015 11:43 am 
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DJ, I guess I don't follow what your are pointing out here.
Tour never tests using just one factor (like mass) as their 'end all be all' score influence.
They usually provide a description of how they ranked the frames at the beginning of each testing article - weighting based on value, finish, weight, tested stiffness, etc.
Altering the fators can provide some nice play room so that a Rose wins that particular test.
Are you just looking at the individual scores provided for the Mass category?


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PostPosted: Tue Feb 24, 2015 1:11 pm 
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not surprising that they twist and turn the exact points distribution so that the frame/bike wins the test whose brand has the most commercials in the magazine.
the aero test in the february issue was a good read and showed intresting facts,but canyon aero bike as test winners,on the magazine cover,in the magazine as title picture for the aero test story and several detail shots smell a bit awkward to me...


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PostPosted: Tue Feb 24, 2015 1:55 pm 
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I agree with Simon, Tour mag is always playing favorites. Cue Thomas Dolby.


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PostPosted: Tue Feb 24, 2015 3:45 pm 
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I understand absolutely nothing, which cross is what bike??


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PostPosted: Tue Feb 24, 2015 4:36 pm 
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Assuming the lower the Tour magazine rank, the better, lower number (0-1) the better. Then based on your regression picture it appears mass of the frame is what is being rated. Very simple and straightforward criteria. Lighter=better. Heavier=worse. Nothing bad about this. Unless they state or imply other factors such as handling, comfort, components are being used to rate the bikes. But as long as the magazine and readers know weight is the deciding criteria, its fine.


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PostPosted: Tue Feb 24, 2015 5:25 pm 
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kgt wrote:
It is really amusing the fact you can buy two bikestore superbikes such as Rose X-lite for aprox the price of one RCA frameset.

Says the man who champions Cipollini frames in another thread :roll: :roll:


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PostPosted: Tue Feb 24, 2015 6:44 pm 
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if weight was the only criterion then all bikes would lie on the line. They don't, so there have to be some other criteria at work. But the high correlation indicates that weight is the most significant factor, either directly or indirectly (i.e. this one handles bumps better because it has less unsprung weight).

But putting many subjective variables on a graph like this is highly suspect in any event.


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PostPosted: Tue Feb 24, 2015 7:02 pm 
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Hmmm.... everyone seemed to miss my point.

The Rose is the 3rd cross from the left (crosses go: Emonda, then RCA and Evo Vial sharing the next cross, then the Rose). My point is that despite the fact the Rose and Emonda differ substantially in mass, they were all rated 1.0, so the weight difference counted for exactly zero. If they had just used a formula (like my regression) converting mass to rating then the Emonda would have gotten credit for being lightest. As it was it got credit only for being lighter than the entry level bikes (8 points to the right of the first 3, which are really 4, because the AX and the RCA are the same mass).

I don't argue lightness should be everything, but it should at least count for something..

I need to read the English language version of the article since I bought the print edition in German which I don't read.

I want to read the aero bike test in 2015.02. In the past, they've used a formula in their aero bike comparisons which actually favors non-aero bike. So the least aero bike wins.

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PostPosted: Tue Feb 24, 2015 8:05 pm 
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simon wrote:
not surprising that they twist and turn the exact points distribution so that the frame/bike wins the test whose brand has the most commercials in the magazine.
the aero test in the february issue was a good read and showed intresting facts,but canyon aero bike as test winners,on the magazine cover,in the magazine as title picture for the aero test story and several detail shots smell a bit awkward to me...


And or the manufacturer builds bike to win tests. I used to subscribe to the German Bike and it always seemed like the German bikes came out on top. Never read test like that anymore though as I personally bikes are much more than testing numbers.


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PostPosted: Tue Feb 24, 2015 8:11 pm 
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Here's another possibility. Tour could be using a mass to mass score converter which roughly speaking is a horizontal line with value 1 for everything below 1150g (or so), and then goes up roughly linearly for mass above 1150g. That would basically be saying that once the mass gets down to 1150g, that's low enough, and it doesn't really matter how much lower it is. However, in reality, the actual scoring formula appears to be based on binning of the mass.

What in effect has been done is to bin the masses into a given score. As long as no there is no instance in which frameset A has mass less than frameset B, but has a higher score, then it can be argued that the scoring is not inconsistent, and really comes down to what mass values are established for lower and upper bounds on each of the bins. The plotted values do not violate this criterion, and therefore are not inherently inconsistent.

As to why Tour might have such a formula? Perhaps, as some posters have said, Tour decided on the formula (the binning lower and upper bounds) so that preferred bikes (due to advertising or whatever) win.


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PostPosted: Tue Feb 24, 2015 8:28 pm 
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Binning is the key thing. No reason to bin at all.

On the "mass X is good enough" argument -- silly, of course. It's all small compared to body mass anyway. A gram saved is worth a gram, whether that's from 650 grams or 1650 grams.

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Posted: Tue Feb 24, 2015 8:28 pm 


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PostPosted: Tue Feb 24, 2015 10:01 pm 
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Someone asked this above already, but still not clear to me. Is the rating overall, or for the weight?

Assuming it is overall rating, is there much point in a regression of a single component, leaving out all the other independent contributing factors?

Am I just not getting it?

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