Friday, August 29, 2014

Tour magazine sub-800 gram frame test: comparing measured frame mass to claimed

Previously I reported on the Tour Magazine test of "frames under 800 grams" published in the December 2013 edition of the magazine, and summarized on-line.

In the article, they weighed the frame, fork, and bearings from a series of light & expensive bikes. They also bent them, measuring the stiffness characteristics. They then calculate a rating based on these and some other minor factors (warranty, quality of finish).

But it's interesting to compare these weights to what is claimed by the manufacturer. Those aren't listed in the article. The focus of Tour isn't to investigate the dishonesty of bike companies. Rather it's to determine the truth.

Claimed weight is a tricky business. Only Cervelo is totally clear in the matter, publishing a lot minimum, average, and maximum for each size of the RCa frame in their White Paper on the bike. Obviously bigger frames tend to weigh more. If I'm buying a 56-cm frame, I don't care about the mass of a 48-cm frame. If one company sells a 52 cm frame as their small bike, and another a 48, do I take the latter because they can claim a lower number for their smallest bike?

Then there's painted versus unpainted. Some people like to sand the paint off their bikes. But for most, the unpainted mass is irrelevant. Sure, if I'm getting a white bike, which might be relatively heavier, I don't care how good Trek's "vapor coat" is. I want to compare, for example, Cannondale's white to Trek's white. But in general it's more honest to publish the lightest painted bike sold. Key question: would stripping the paint void the warranty? If yes, don't tell me the weight of the unpainted frame.

Then there's the issue of hardware. I'm okay with leaving off the bottle cage bolts, since I can easily ride the bike without those. But the derailleur hanger? Err... no. That stays. And it's not as if I can just go and swap a heavy hanger for a light one, something I can do with bottle bolts.

Let's go through the bikes...

  1. Cannondale SuperSix Evo Black: Google had a cached page from Cannondale claiming "under 700 grams", although the 2015 page has no claim. So I used 695.
  2. Cervélo RCA: I took their reported average for 56 cm frames (see table above). The high for this size was 696.
  3. Corratec Mauro Sannino Prima: "starting at 680 grams." This is a custom bike, which adds a lot of potential variability.
  4. Focus Izalco Max 0.0: I got 750 grams from a dealer.
  5. Neil Pryde Bura SL: There's a big fat "710 grams" on their web page.
  6. Pasculli Altissimo: This is another custom bike. But unlike Corratec, these guys just say "680".
  7. Simplon Pavo 3 Ultra: I got 740 grams off their web page.
  8. Trek Madone 7.9 H1: I got 725 grams from a Jan 2013 VeloNews article (down from 750 grams in 2012).

Only Cervelo was a size-specific mass. The others were all just a single quoted number.

Here's the result:

image

Amazingly Simplon came in well under the claimed weight. All others were over. I was surprised Cervelo was over. Trek, Focus, and Cannondale are each around 50-60 grams over claimed. The two custom frames were 100 grams over claimed, but I'll cut the custom builders some slack, since they tune stiffness. The Bora came in 90 grams over claimed.

The result is you can't put much faith in claimed mass, comparing different manufacturers. Trek, Cannondale, and Focus each seem to be mutually consistent in how low they are. This is likely because they are referencing a small frame, and Tour measures relatively large 56-58 cm frames. For the customs, you need to say what you want: if you want light, and don't care about stiff, you need to say that. Neil Pryde is the one which is most clearly off target.

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