alto's carbon clincher shootout test

Discuss light weight issues concerning road bikes & parts.
spartan
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Joined: Fri Sep 03, 2004 2:52 am

by spartan

another comparison test this time focusing on impact strength. :up:
I hope you include the same rim manufacturers as in the heat test that blew up the internet. look forward to test results.

happy holidays alto + ww community
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2017 Giant TCR Advanced SL 0 DI2 9150

spartan
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Joined: Fri Sep 03, 2004 2:52 am

by spartan

alto release another video on impact testing good but disappointed did not perform any comparative testing. curious on zipp/enve impact strength

https://www.youtube.com/watch?v=DOW092uOpLg&t=410s
Last edited by spartan on Fri Dec 22, 2017 4:27 pm, edited 1 time in total.
Current Rides:

2017 Giant TCR Advanced SL 0 DI2 9150

by Weenie


spartan
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Joined: Fri Sep 03, 2004 2:52 am

by spartan

boyd impact testing only went up to 95 joules vs alto at 225 joules.

https://www.youtube.com/watch?v=fFT6i8PS8XI
Current Rides:

2017 Giant TCR Advanced SL 0 DI2 9150

joejack951
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Location: Wilmington, DE

by joejack951

spartan wrote:
Fri Dec 22, 2017 4:26 pm
boyd impact testing only went up to 95 joules vs alto at 225 joules.

https://www.youtube.com/watch?v=fFT6i8PS8XI
Boyd also used real impact testing equipment. There appeared to be quite a bit of flex in the Alto setup which will serve to dissipate the impact energy. It was irritating to keep hearing 'joules of force' over and over again in the Boyd video. Kind of like 'pounds of pressure' that is so often repeated. Units are important, people! :D

BobbySweeting
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Joined: Tue Apr 25, 2017 5:37 am

by BobbySweeting

joejack951: Please keep in mind that our rims are tested twice (once at Topkey on a machine similar to the factory Boyd works with) and again in Sarasota to corroborate the results. Our new rims are tested to 250J before failure, but we expected the compromised rim to fail well below 220J!

At 40-105J our jig doesn't have any movement, other than the same slight side-to-side upright movement that you see in Boyd's video. It's just not that much energy into the rim. Once we got up over 150J the whole jig started to pop up of the ground after impact. The impact itself was at full force with no flex, but of course for every action there's an equal and opposite... In the future we may just bolt the jig into the ground to keep it from flying away at the higher energy tests, haha. But rest assured that this had no bearing on the test results. You can also check out a slow-mo video on our Instagram page, which is the 215J drop. Check out how much the rim deforms, it's intense!

antonioiglesius
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by antonioiglesius

BobbySweeting wrote:
Fri Dec 22, 2017 8:06 pm
our rims are tested twice (once at Topkey on a machine similar to the factory Boyd works with)
Can you post the test results from Topkey?

mag
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Joined: Thu Mar 16, 2017 12:23 pm

by mag

@BobbySweeting Since your rims provide less braking performance than most competitors in the braking test do you plan to improve on that somehow?

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ergott
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by ergott

Can you explain why the pitch the spokes resonate at changed several times during the test? It would seem to me something was different about the wheel in some of those replays.

BobbySweeting
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by BobbySweeting

antonio: I don't have a great video of their test at the moment, but when I visit next month I'll be sure to take one!

mag: Please keep in mind that the difference in lever pull to reach the same braking power as the Enve was roughly 0.3lbs. To meet and surpass the Bontrager it was 1.8lbs. These precise measurements can be taken in the lab, but you have to ask youself: would you be able to feel that difference? An average adult has a max grip strength of 100lbs, so when you modulate the brakes between 7lbs and 9lbs during braking, you will not notice this difference. As far as field testing goes, all of these rims would perform very similarly in braking power. Now, that's not to say that we aren't always looking to innovate and improve! We want to be the world leader in every category, period. We have no immediate plans to update our brake track because we have never had a customer that needed more braking power (or even mentioned anything other than how our brake performance was superior, since it doesn't heat up and pulsate), so there's no real need to change anything. But we'll continue to experiment with prototypes like we always do, and we'll keep innovating and improving! That process will never stop!

BobbySweeting
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by BobbySweeting

ergott: The pitch that the spokes resonate at.... are you referring to the impact sound? The metal-on-metal sound in some of the drops was actually coming from the front cylindrical weight on the angle brackets, as it was touching the mounting plate of the sled. That made for a loud "clanging" for sure, haha. The pitch also changed when we filled the sled with lead weights! We had to change that thing 3 times to continue adding weight, so that's probably the sound difference you're referring to. If you can be more specific about which replays you're referring to then I might be able to answer your question more accurately!

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ergott
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by ergott

There's a pronounced difference between 4th and 5th impact. Around the 13th impact it changed again. There are others in the video. The spokes ring after each impact. It's a very unique sound and it's not coming from the test rig.

antonioiglesius
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by antonioiglesius

BobbySweeting wrote:
Fri Dec 22, 2017 10:05 pm
antonio: I don't have a great video of their test at the moment, but when I visit next month I'll be sure to take one!
It doesn't have to be a video, just whatever it was they sent as test results. Text would do.

BobbySweeting
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by BobbySweeting

ergott: Ah I hear it now! That's our lack of continuity, haha. We tried to make it look like we did this all in one day, but it took 4 days. We stopped on the first day after the 4th drop so that we could edit the intro and make sure that the video was going to look proper before proceeding. You can probably tell by the way the video is framed, because it's a lot different on the 5th! We tried to make them the same, but we're not great film makers. My bet is that the way we had the room set up with the lights and equipment was different enough to where the lav mic was picking up different parts of the echo. That's a pretty small room that we film in, so the sound can be tricky.

Good ear! I never noticed how different it sounded until now.

antonio: Topkey runs an identical test to what you see in our video. That's why we do it this way! Our rims (rim brake, road/cx disc brake, and cross country mtb) see spoke pull through at 245-260J when they're brand new, and our enduro MTB rims at 285J. I have to take a video of the filament winding process for another forum goer, so I'll add this one to the list! Haha.

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ergott
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by ergott

No, the pitch is different. That's not explained by acoustics. It's a function of the tension and gauge of the spokes. Somehow the pitch went up about a semitone between the 4th and 5th drop.

After that pitch "reset" the tension drops gradually the next 10 drops. This is to be expected as a the spoke elbows conform more and bed into the flange. There can also be some amount of nipple bedding into the rim. This issue can be reduced in the building process by grabbing spoke pairs very tightly with both hands. That also stress relieves the spoke elbows.

It gets to a point there's little tension in the wheel. That lack of tension absorbs a lot of the energy that wouldn't normally dissipate. If you were to take a brand new wheel that is tensioned and skip to the last couple of drops I'm not sure they would fair as well.

by Weenie


antonioiglesius
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by antonioiglesius

BobbySweeting wrote:
Fri Dec 22, 2017 11:07 pm
antonio: Topkey runs an identical test to what you see in our video. That's why we do it this way! Our rims (rim brake, road/cx disc brake, and cross country mtb) see spoke pull through at 245-260J when they're brand new, and our enduro MTB rims at 285J. I have to take a video of the filament winding process for another forum goer, so I'll add this one to the list! Haha.
The video is not necessary, I'm only interested in Topkey's test result that matches yours.

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