alto's carbon clincher shootout test

Discuss light weight issues concerning road bikes & parts.
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jlok
Posts: 502
Joined: Tue Jun 30, 2015 3:30 am

by jlok

ergott wrote:
Flrider wrote:!

Image
Still waiting for clarification on this. How could these rims be of a proprietary mold made in the USA, sent to Taiwan and manage to be exactly the same as the Pacenti rim?


Also waiting for an answer to my question about brake surface texture. Things are just not adding up and that should concern anyone relying on this test result.



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better get a screen capture of that statement...
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BobbySweeting
Posts: 37
Joined: Tue Apr 25, 2017 5:37 am

by BobbySweeting

Regarding the rim profiles of our disc brake models: again, I refer you to our website video showing the machine shop in Sarasota where we cut our hubs and rim molds. We launched this model at Interbike as a proprietary high pressure hookless system, and now Pacenti has launched a similar model. He hasn't done anything wrong because we have no patents on this particular design, it is just a similar system. Enve also makes a deep, hookless disc brake model that is very similar to this. There are only so many ways to do it so that the tire doesn't come off, haha.

I'm also shocked that, after launching a new resin system that has all but eliminated the risk of heat buildup in carbon clinchers, that anyone could possibly think we were just buying open mold products from Asia. Alto is operated solely by engineers (and investors) and owns multiple design patents -- we have everything we need to design and manufacture from the ground up. I'm not sure what else we have to do to prove ourselves, haha.

Can you please ask your brake surface texture question again? I'm sorry, I haven't been on the forum in a while and I must have missed it. Thank you!

basilic
Posts: 660
Joined: Wed Jan 05, 2011 8:05 am
Location: Geneva, Switzerland

by basilic

TobinHatesYou wrote:
I bought some
Tobin, would you measure the height and width?
at least sort that out

TobinHatesYou
Posts: 1194
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

basilic wrote:
TobinHatesYou wrote:
I bought some
Tobin, would you measure the height and width?
at least sort that out
When my tires need to be replaced I'll whip out the calipers. I have the CCX40s though and not the 52s.

phm8147
Posts: 25
Joined: Mon Dec 11, 2017 11:39 am

by phm8147

Wow.. Roval

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kavitator
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Location: Slovenia---that forest land

by kavitator

[quote="spartan"]why even bother. your test is not realistic. constant speed should be closer to 35-40km/hr brake load set at 4-5kg.


When cornering at 30km/h there is little heat on brake track

"Killers" of carbon rims are steep and sharp corners - i dont think you will have more than 20km/h in that corners

joejack951
Posts: 364
Joined: Fri Feb 18, 2005 6:50 pm
Location: Wilmington, DE

by joejack951

BobbySweeting wrote:owns multiple design patents
Do you really mean 'design' patents, as in a patent that only covers the appearance of something? Or do you have utility patents and on what specifically? Just curious.

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

by BobbySweeting

JoeJack951 - It is both, actually. I say "design" because it's more readily understood. The first is on the rear hub geometry, specifically the ratio between the drive and non-drive flange and how it relates to spoke bracing angles. The second is on the axle system and bearing enclosure, specifically the self extracting mechanism of the plug design.

BigPoser
Posts: 104
Joined: Tue Oct 21, 2014 11:42 pm

by BigPoser

coachboyd wrote:Most testing protocols are set between 12 and 16kph. It's not necessarily monitoring the speed, it's monitoring the braking force and temperature.

Kevin at Knight Composites has a lot of information about this and the ISO standards for testing. I need to look into the iso stuff more but I know those tests are run at 12.5 kph

Maybe I'm new, but testing a brake track at 12.5 kph, which is less that 8 mph, makes no sense to me whatsoever. Doesn't it take more force to stop a wheel traveling at 30kph when compared to 12.5kph? Who the hell goes down a mountain road at less than 8 mph?

coachboyd
in the industry
Posts: 52
Joined: Wed Dec 30, 2009 12:31 pm

by coachboyd

BigPoser wrote:
coachboyd wrote:Most testing protocols are set between 12 and 16kph. It's not necessarily monitoring the speed, it's monitoring the braking force and temperature.

Kevin at Knight Composites has a lot of information about this and the ISO standards for testing. I need to look into the iso stuff more but I know those tests are run at 12.5 kph

Maybe I'm new, but testing a brake track at 12.5 kph, which is less that 8 mph, makes no sense to me whatsoever. Doesn't it take more force to stop a wheel traveling at 30kph when compared to 12.5kph? Who the hell goes down a mountain road at less than 8 mph?
If you are going down a steep hill and having to hold the brakes which is going to cause you to hold the brakes harder? Going 12.5kph or 30kph?
But even still, the testing that is done is concentrated around holding a set speed and monitoring the brake forces and heat levels at that speed.

In terms of what people actually do coming down a mountain, it's a lot more hitting the brakes really hard, letting off them, and doing that over and over.

That is why doing this test repeatedly is a better indication of braking forces.
https://www.youtube.com/watch?v=BdwbGyYh0_k
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apctjb
Posts: 59
Joined: Mon Oct 30, 2017 11:27 pm

by apctjb

That is why doing this test repeatedly is a better indication of braking forces.
https://www.youtube.com/watch?v=BdwbGyYh0_k
Nice video,; can you clarify the purpose of the test? Clearly it shows that the brakes are able to stop the wheel from spinning. Where you measuring force applied, time to stop and rim temperature, etc.

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

by BobbySweeting

The testing protocol at slower speeds is not realistic, and a force balance isn't being taken into consideration.

For example: Fb (brake force) = Fg (net gravitational force) = (m)(g)sin(theta) at constant speed down a hill. For a 12% gradient (7 degrees) and 80kg rider, this is 95.64 N. At 50km/hr, Work = Fv = (95.64N)(13.89 m/s) = 1328 Watts (664 watts per rim). This doesn't take into account reduction for air resistance, mind you. But if you allow 140kg+ riders on your wheels then you are looking at over 1000 watts per rim to get down a hill at a constant speed, even at 40km/hr. The ISO standard, in my opinion, needs to be revised slightly to reflect more "worst case scenario" situations, not average situations.

And please remember, this is not trying to validate our test video as "real world" because it was not. It was very extreme. I'm simply making a point about more stringent testing protocols in general.

antonioiglesius
Posts: 257
Joined: Sat Oct 15, 2016 9:08 pm

by antonioiglesius

BobbySweeting wrote:And please remember, this is not trying to validate our test video as "real world" because it was not. It was very extreme. I'm simply making a point about more stringent testing protocols in general.
I'm sorry but personally, I'm much more interested in real world scenarios and not extremes, which has the dangerous effect of skewing people's opinions the wrong way.

Fiery
Posts: 412
Joined: Sat Mar 16, 2013 9:21 am

by Fiery

BobbySweeting wrote:The testing protocol at slower speeds is not realistic, and a force balance isn't being taken into consideration.

For example: Fb (brake force) = Fg (net gravitational force) = (m)(g)sin(theta) at constant speed down a hill. For a 12% gradient (7 degrees) and 80kg rider, this is 95.64 N. At 50km/hr, Work = Fv = (95.64N)(13.89 m/s) = 1328 Watts (664 watts per rim). This doesn't take into account reduction for air resistance, mind you. But if you allow 140kg+ riders on your wheels then you are looking at over 1000 watts per rim to get down a hill at a constant speed, even at 40km/hr. The ISO standard, in my opinion, needs to be revised slightly to reflect more "worst case scenario" situations, not average situations.

And please remember, this is not trying to validate our test video as "real world" because it was not. It was very extreme. I'm simply making a point about more stringent testing protocols in general.
How can you judge the slower speed protocols if you don't know the input force accelerating the wheel?

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

by BobbySweeting

Can you please clarify what you mean when you say "the input force accelerating the wheel." When you're coasting down hill the input force is that of gravity (effected by mass and the slope of the ground), and the brake force is equal to it when you are at constant velocity.

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