alto's carbon clincher shootout test

[glepore]

Yeah, I raced cars and motorcycles in the past, know how to corner. But roads aren't closed, as pointed out above traffic exists (also ask anyone who's done a popular fondo) and at 58 with a previous SCI I'm not anxious to go down again at 60kph. In an ideal situation I wouldn't overheat a carbon clincher, but I'd like to be freed of the concern. Wise choices now are tubies (lighter anyway) or alu clinchers (not much aero penalty anymore).

[C36]

. Wise choices now are tubies (lighter anyway) or alu clinchers (not much aero penalty anymore).

For high-mountain in unknown conditions I couldn't agree more. You just don't have ANY way to assess the rim situation.




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[AJS914]

I know two different experienced racers who have melted farsports rims. Carbon clinchers are simply a problematic product unless you are a flat lander.

[wheelbuilder]

I know two different experienced racers who have melted farsports rims. Carbon clinchers are simply a problematic product unless you are a flat lander.

Not sure I agree completely. Although Farsports isn't exactly a top-tier rim, I think the ability of the rider comes into play here. I have quite a few decent descents here in California and dont worry about my carbon clinchers at all under normal conditions. If I get stuck behind a car however, It does enter my mind and I will pull over until the descent is clear. Agreed that I should not have to take that into consideration and be free to brake as much and for as long as I want, but it is what it is. Inexperienced Fondo riders who must have carbon for the looks and cache but drag their rear brake throughout the entirety of the descent should not be on them in the first place. They should get disc.

[TobinHatesYou]

Everyone should get disc. FTFY.

[ichobi]

If you need to drag brake until the rim melts, even with alloy rims you will blowout the inner tube which is probably even more scary. On descent that i cant go down fast with lots of traffic i simply stop for either cars to clear or rim to get cooler. There is no prize to be won at the bottom of the hill, much less at the hospital.


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[TiCass]

Everyone should get disc. FTFY.

What makes you think a disc wheel could survive that test?

[glam2deaf]

Everyone should get disc. FTFY.

What makes you think a disc wheel could survive that test?

Why would you be performing that test on a disc rim?

[spartan]

the founder of alto answered most of the question raised on this thread at bike rumor's comment section

fyi i did not know this. cool


We have always been very open regarding our manufacturing. All of our metal working is done in Sarasota, Florida. This includes hubs, hub internals, and rim molds. The rim molds and the resin are then shipped to Topkey for construction, and rims are shipped back to us for assembly. I worked closely with Topkey while designing frames at Cannondale, and there simply aren’t any facilities in North America that can replicate what their equipment can do. Trust me, I’ve looked! Haha. I’m not sure who else Topkey manufactures for, but it’s likely that they make a large majority of the frame and rims in the industry. There aren’t that many composites factories in the world that can put out quality work, so many of the brands work with the same facilities.

https://www.bikerumor.com/2017/12/08/al ... rake-test/

[ergott]

So if they are using the same carbon as other companies how do they explain their results? Is their brake surface textured or smooth?

[TobinHatesYou]

So if they are using the same carbon as other companies how do they explain their results? Is their brake surface textured or smooth?

I think their vague official answer is proprietary resin and layup.

[Marin]

If you aren't real-world comparing stopping distances ( = energy conversion) the whole test is meaningless.

They should at least slow down a heavy drum, or brake against a known motor power.

[glepore]

They claim that they have proprietary resin, additives, and that their brake surface is filament wound. Would like to know more about that, trying to figure how you do that without winding the whole rim.

All this said, they're at least one ride report from a user on another forum (who seems to have lots of high end kit) that claims that they're nice wheels and "freakishly stiff".

[TiCass]

Everyone should get disc. FTFY.

What makes you think a disc wheel could survive that test?

Why would you be performing that test on a disc rim?

Since we're into overkill tests, why not doing it with disc wheel?
We already know 140mm rotor experiences heat build-up related issues. So how safe are we with a front 160mm rotor. Seems legit to ask.

[BobbySweeting]

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.