by iflyadesk on Sat Aug 15, 2020 2:18 am

Of course, $12k (+ 10% tax) is a lot of money, so it forced me to use my cerebral cortex instead of just my limbic system. As an engineer, I'm always suspicious of dimensonless charts. But they are making claims that can be backed by numbers we have (thanks to Tour Magazine). So, I created my own "aeroness vs lightness" chart for bikes that I could find Tour Mag data. It's only as good as the data, and it doesn't take things like seat post stiffness into consideration (which I find very important -> hated my 2016 Giant Propel because it beat the hell out of me), but it's something to look at and chat about regardless.

AUG 18, 2020 EDIT: Added rim brake bikes, a guess at model years, fixed some errors, removed the link to Google Sheets because Excel is so much better at labeling and breaking out series.

AUG 23, 2020 EDIT: I think one way to better capture the "right tradeoffs" is to make the slope of the lines on the chart match the equivalent lightness vs aeroness based on a model.

AUG 27, 2020 EDIT: I just realized the original chart from Specialized included the Venge Vias and 1st Gen Venge but my chart did not, so I figured I should add them for completeness.

I was not a Tour Mag reader in Feb 2015 so I totally missed this explanation of their model and how they determine tradeoff between light and aero:

So roughly translating that model to my chart, I've added one set of lines to show a 100km race with 500m of elevation (~270g per W) and another set of lines to show a 100km race with 2000m of elevation (~70g per W). They are assuming 85kg for the rider, bike, and kit. My personal calculations in this thread trying to figure out the weight-to-aero tradeoff for multiple accelerations in a flat crit were roughly 100g per W so that falls in between these two. I think maybe these are solid "bounding conditions." The tradeoff between lightness and aeroness likely falls on or between these two slopes for any given race.

As you can see, the 2015 Venge and Venge Vias (both rim and disc) do not really fall at the same places on my chart based on Tour Mag data. "Aeroness" could be slightly different based on differences in testing protocols between Tour and Specialized but weight is pretty straightforward. It's amazing that in 2015 you could get a top-of-the-line 6.7kg S-Works Venge for 7300 EUR. My, how times have changed. It would seem to me that bikes really haven't gotten lighter or more aero in the last six model years. What they (as an industry) have done is managed to stay pretty close to the "lightness vs aeroness efficient frontier" while providing us with better ride quality, disc brakes, electronic shifting, and easier serviceability.

SEP 2, 2020 EDIT: Updates include: • a couple new bikes • several fixes of "fat finger errors" on my part • align all the year make and model labels on the edges of the chart • made rim brake dot looks like a rim, disc brake dot looks like a disc — pretty proud of myself for that idea, lol • updated "Watts at 45kph" to include the air resistance of upper body and rolling resistance of tires to give a more realistic representation of the percent marginal gains at play here • made the lines for 500m and 2000m climbining in 100km represent time-to-complete for 75kg rider at 200W average • removed 2021 Trek Madone SLR because it was Mad Petersen's personal bike, a size 58cm with 28mm front tire and different handlebars... all things that make it unfairly slower and heavier than every other bike tested and was causing confusion

SEP 27, 2020 EDIT: Added more bikes

OCT 16, 2020 EDIT: Added more bikes

OCT 26, 2023 EDIT: Added new bikes since 2020. Removed all Rim brake bikes. Surely by now we can all agree the aero bikes of 2014-2016 with their proprietary rim brakes didn't work, couldn't be fixed when they broke, and were terribly stiff and uncomfortable so we can just move on now and pretend like they never existed.

OCT 31, 2023 EDIT: Added a BUNCH of new bikes thanks to PFoxy's personal collection of Tour Mag data.

Worldwide:

And here it is filtered down to bikes available in the USA (to the best of my knowledge):

Retired: 2022 Tarmac SL7 7.0kg | 2022 Crux 6.6kg | 2020 Crestone 11.7kg | 2021 Epic 10.0kg | 2022 Ripmo 14.0kg | 2015 Propel Advanced SL 7.0kg | 2018 Stigmata 6.8kg | 2018 Madone 7.1kg | 2018 Aeroad Disc 7.1kg | Switch SS 5.9kg