Hey guys! I'd like to clear up some of the questions that you may have.
First, the energy input into each rim is identical. It equates to the motor power, caliper force, brake pad material, and kinetic energy of the wheel (i.e. rotational speed). By keep the energy input identical and displaying wheel speed, everyone can understand the exact circumstances of each rim test in its entirety. You can also run the test by controlling rim speed and motor power, and varying/displaying the caliper force. This simply changes the amount of energy input into each rim, which we didn't think would offer a fair comparison of the actually resin and layup quality.
The brake pad selection must be controlled in order to accurately compare composite structures without introducing rogue variables. For example, the Enve rim may have gone 8 minutes with an Enve pad. We could then test a cheap eBay rim that comes with a cork pad, and it could run 9 minutes. Does this mean that the eBay rim has a better composites structure and resin? It's impossible to know. We would love to run the test again with brand specific pads in order to compare the results, so if anyone has another 9 rims to send us we will be happy to do it!
The increase in speed throughout the Alto test can also be seen towards the end of the Zipp and Enve tests. This is due to pad glassing, which is a property of the pad and not the rim. At sustained temperatures over 180 F, the bad builds up a film that causes you to lose braking power. If the other rims ran for 20 minutes you would see a similar increase in rim speed.
As far as braking power goes, you will note that in the phase 1 test all rims run within 0.8mph of each other for the first few minutes (prior to pad glassing). In phase 2, with a 9lb lever pull, the Alto rim runs a bit slower or identical to the other rims. Please keep some perspective here, as the average adult has a grip strength of over 100lb. A difference of 2lbs to modulate braking power would not be felt by the rider in a real world situation, and all of the rims in this test will feel nearly identical in terms of stopping power. These differences in wheel speed are interesting to note in the lab, but the differences aren't significant enough to be relevant to the user. Also note that, in the phase 2 test and at lower speeds, the Alto rim outperforms the other rims for reasons I will explain below.
For the reasons mentioned above, a lack of friction is why the Alto rims ran at a lower temperature. Many of the other rims actually ran lower, but failed prematurely. This temperature variance is due to the resin and construction process. We've been working for 8 months on various resin additives that would allow it to flow more readily through the matrix, filling voids and giving the material better conductive properties. We then filament wind the brake track to pull the fibers super tight and get even further compaction. The resin glass temp, additives, and filament winding process are why the Alto rim can dissipate heat at a faster rate while still maintaining its structural integrity. This is why you can run any carbon brake pad on our rims without voiding the 5 year warranty. There isn't a pad in the world that will cause damage to it.
I hope this helps to clear up some of these issues! There are MANY different way to run this test, and I hope this will be a good start for the industry. I also hope that other rim manufacturers will follow suit and do their own testing, perhaps with different criteria, and show the results to the world as we did. It's important.