You're insistent on this, you're kind of making me wonder whether I'm missing something. Let's take an extreme case: Wheel 1 has a Teflon coating, so it takes a huge amount of brake caliper force to yield an equivalent amount of actual braking. Wheel 2 is super sticky, so it requires far less brake caliper force. In your test, Wheel 1 is going to crush Wheel 2, because way less heat gets generated. But in the real world, a rider would have to brake way harder to achieve the same descent speeds on Wheel 1, so the test sheds no light on whether Wheel 1 would be more likely to make it down a given mountain. Someone suggested above that in the initial test results your wheels ran about 1 mph faster than other wheels. If that's true, your wheel is Wheel 1 in the example above, and your test tells me nothing about your wheel's ability to safety make it down mountain X. It might be safer, or it might be less safe, but we just don't know based on the test. Clearer?

That is quite clear. Please watch the test and you will see how the speed of our wheel in phase 1 and 2 compares with the others. For a 2 pound lever pull difference there is a large increase in brake force, bringing our wheel speed down to the 19.4mph range and slower than the other rims. Considering the average adult has a grip strength of over 100 pounds, we consider this difference to be inconsequential. I guess my point is that all of the rims are within 1mph of each other and the difference in lever load is 2 pounds (for phase 2, however Alto was the only rim to get there). All of the metrics that we measured were displayed so that everyone could see every piece of data in excruciating detail, but in our opinions the actually braking power between all of the rims should be considered even.

Okay, I actually watched the test.

On the first test, your wheel was consistently 0.5-1 mph faster than other wheels. In other words, your wheel generates less braking force at an equivalent caliper pressure, i.e. it brakes less well. The maximum temperature recorded was also lower than most of the other wheels, as one would expect based on that lesser braking observed. Interestingly, though, two of the wheels tested failed at lower temperatures than the one your wheel survived. Assuming temperature is being recorded accurately (it seemed to bounce around a surprising amount), that would seem to be a datapoint in your wheel's favor. Its survival of the first test is a less compelling datapoint, because it was generating less braking forces, so it's not an apples-to-apples comparison (your wheel requires the rider to squeeze the brakes harder to generate an equivalent descent speed than the wheels of all these competitors).

During the second test, with more brake caliper force, your wheel spun at about the same speed as the other wheels spun in the first test. This would seem to suggest that although your wheel requires more force to generate equivalent braking, it is in fact better able to survive under equivalent braking than the competitors. So it seems to me the crucial part of this test is a comparison between how the other wheels did in the first test and how your wheel did in the second test, and that part does seem to reflect well on the durability of your wheels (though not on their braking performance).

I'll be curious to hear others chime in on this, too.

Thanks man, I think that's very accurate. And please keep in mind that it is the same rim! We finished phase 1, replaced the brake pads, hung the heavier weight, and immediately started phase 2. We honestly wanted to do everything we could to blow up our rim, because we've never been able to do it. We got close at the end I think, but there was only a small bit of delamination at the edge of the track.

So you will give a no conditions warranty on any wheel damaged by heat?

but, no carbon clincher wheel brakes well to begin with. so, having a carbon clincher rim that can resist heat buildup and survive 20 minutes of brake dragging is...questionably useful.

i'm not saying i don't like carbon clincher wheels, i'm just saying that most carbon clincher wheel companies seem to be attempting to optimize the wrong thing.

an interesting test would be the test the brake track temperature under a realistic braking scenario. take a rider to a standard descent that is difficult for any brake track to manage (very steep, numerous slow switchbacks, etc) and figure out how the rider uses the brakes. then, take that information to the lab. nobody that knows what they're doing continuously drags their brakes like this test is doing.

That is correct. Our 2018 wheels have a 5 year warranty and you are welcome to use any carbon specific brake pad.

You’re right, we’d love to do 10 more iterations of this test! We don’t have unlimited time or money to do everything (we do have to run the business and sell wheels, after all), so we measured the cooling rate of each rim so that you could infer the results and see how they would perform while coming on and off the brakes.

But your test was flawed from the beginning. Don’t pull the “we don’t have time and money” argument. The test should have been designed correctly from the start.

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Thank you for the constructive input. As discussed previously, this test was designed correctly by our engineers, but there are many other way to conduct it. We’d do them all if we could. Perhaps another brand should conduct and publish tests such as this (and others), because it’s been 15 years of carbon clinchers with no data or regulation. I hope you can appreciate the investment that we’ve made to shed light on this issue for you and for our customers.

It’s a moot point because we’re all going to hydraulic discs pretty soon anyway.

fixed it for you. i appreciate that statement and the video in that context.

ETA - and I realize you're going to say, indignantly: "We didn't know the outcome of the test, so how could the test have been designed to - as you say - "sell wheels??"

Hopefully other manufacturers will follow our lead and design their own test (perhaps you could offer independent contractor services to help them?) so that customers can actually see how their products perform. It's important to differentiate the truth from the marketing, in our opinion. We will be the first in line to submit a rim, because the more data that can be collected the better. By the way, they're welcome to use any carbon brake pad when they test our rim, because it won't damage it in any way.

They all have their internal tests they do. Zipp and ENVE do plenty of in house testing. You are not the only company doing this. However, the rims and pads work together as a system. Your test is flawed.

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I'm extremely curious to understand what you mean when saying that the rims and pad "work together as a system." Pad density and caliper force create friction, which varies depending on the pad material, and releases heat. It is a mechanical system, not a chemical one. I'm hoping that you can explain how a Zipp brake pad reacts with a Zipp rim differently than it would with any other carbon rim. Simply saying "your test is flawed" because "they work as a system" is too vague for me to give a response to.

The material of the pad is designed according to manufacturer specs to generate a certain amount of heat under braking force. Am I wrong on this? Why is it that they only tell you to use their pads on their wheels? Different pads can generate more heat

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Enve Test

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They tell you to use their pad on their rim because a denser pad will generate more heat and damage the rim. This is why an open mold rim from China will come with cork pads... A real carbon pad will destroy them. It's the same logic, and has nothing to do with the chemical makeup of the rim or pad. My point is that, yes, an Enve pad likely runs cooler than a Black Prince pad because it is less dense (*I don't know this for sure, but am assuming), which means that an Enve pad will allow any rim (not just Enve) to run cooler and last longer in this test. Every pad generates a different amount of heat, but that difference is the same on any rim that you choose..

So if you test an Enve rim with an Enve pad, and a Zipp rim with a cork pad (let's just say that's what they spec, I know they don't) then the Zipp will blow Enve out of the water. But it would be impossible to know if the Zipp composite and resin were actually of a higher quality, because the the difference in the amount of heat generate by the pad material is massive.

We could run this test with any pad and the results would be the same, every rim would simply go up or down in duration by the same percentage. But by using the same pad on each rim we can accurately compare composite qualities.

I hope that helps to clarify this issue!

I suppose in a perfect world, maybe one uses proprietary pads for each rim, and designs the system to use constant input watts but modulate brake caliper pressure to achieve a constant wheel speed, and that would be an apples-to-apples comparison, i.e. it would tell me how rim A (paired with brake pads A) would compare to rim B (paired with brake pads B) at getting me safely down mountain X. But that would require a way more sophisticated test setup that could adjust brake caliper pressure to achieve a desired speed.

I suppose a cruder version could involve manually calibrating the brake caliper pressure to achieve a set wheel speed at the beginning of the test, and then letting things run. As the brake pad and rim were progressively affected by wear, wheel speed would start to deviate, but this would at least put the rims in the ballpark of each other, so it would be more of an apples-to-pears comparison, better than apples-to-oranges.

Zipp testing

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Yes, we've seen every brake track test on the internet because we searched high and low to find results! We wanted to know how our new rim development compared with others. Unfortunately they don't tell you anything... It's simply: "they're super safe because we test them, trust us. The resin is stable to a billion degrees." There is no regulation on this, and we never knew what was true and what wasn't. So we had no idea how our new rim would stack up in an apples-to-apples test. I know that many brands do their own internal testing, I just think the results should be published in a way that qualifies them by the UCI (or anyone) or actually shows the data so that the test can be replicated and proven. This is done for performance data like weight, aerodynamics, stiffness, etc, but never for braking or failure modes. That's why we did this.

You should know if an ENVE pad runs cooler if you are going to make a video calling out every big wheel manufacturer.

So if every pad generates different amount of heat and the brake track resins are tuned to a certain heat threshold based off the max heat generated by their brake track and brake pad...then once again your test is flawed.

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There is no standard test for aerodynamics except just use 30 mph.

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That is perfectly fine and reasonable! If someone uses a low quality resin and specs a cork pad, and the rim never fails, I think that's awesome for them. That's not what we were testing for. We wanted to see who had the highest quality resin and were testing specifically for failure points. Please re-read our disclaimer at the beginning of the video and it will be clear.

My high school physics is a little rusty, but is it possible for a brake pad to generate less heat while generating a given amount of braking force (not caliper pressure, but how much braking is actually happening)? If the braking energy wasn't being released as heat, as what would that energy be released? To put this differently, does a brake pad that generates less heat simply brake less well, i.e. is that how it achieves its lesser heat generation?