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 Post subject: Re: 700 Gram frame
PostPosted: Sat Oct 06, 2012 9:16 pm 
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Not that I know anything about it (but since when has that been a prequalifyer for posting on this forum) but I believe bench testing as a method to evaluate the frame is mostly if not 100% useless, as opposed to bench testing to confirm it has the MINIMUM strength /stifness to be at least safe, whereby hanging a great f** off weight off the bottom and subjecting it to cyclical testing isnt a bad idea. I think the point of some of the framebuilding great and good in this thread is that many of the less than say 750 grm "artesan" frames would fail at this first, lowest common denominator, hurdle.


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 Post subject: Re: 700 Gram frame
Posted: Sat Oct 06, 2012 9:16 pm 


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 Post subject: Re: 700 Gram frame
PostPosted: Sat Oct 06, 2012 9:31 pm 
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Bench testing has it's place, just like wind tunnel testing does... The trick is getting relative info. Without it, what ever the score is winds up beinh useless, but if you get numbers from a single frame you've been happy with and then get numbers from other frames under the same test, you'll at least have some basic info to use comparing your own bike to others.

scores sometimes dont translate well to ride quality, in fact I think the "Komfort" section of a couple of tests have been pretty damn poor. Frame deflection just doesnt translate well to ride in some cases.

But having the info is usually better than not having it, especially if it's relative to things you know.


Another case that needs clearing is in ride tests that dont use the same wheels, tires and tire pressures... Riding the Cervelo and BMC pretty much had to take place on the same hoops and rubber (and past that, the same hoops and rubber you use every day) or you honestly dont have a good indicator of the ride quality of either bike relative to what you ride or to each other. BUT your take away for each isnt without value, just like the takeaway info from bench testing isn't without value...

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Last edited by CharlesM on Mon Oct 08, 2012 4:19 am, edited 1 time in total.

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 Post subject: Re: 700 Gram frame
PostPosted: Sat Oct 06, 2012 10:42 pm 
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Totally agree with you Charles. (incidentally, believe it or not, the reason I didn't like the Cervelo wasn't the ride quality, but the fact that, in my perception at least, the noise from the drivetrain echo'd through the frame and made quite a racket!! :shock: )

Leviathan, what makes you think that these sub 750 gram frames will fail the tests?


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 Post subject: Re: 700 Gram frame
PostPosted: Sun Oct 07, 2012 12:57 am 
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I think what you want from you bike i.e. comfort, stiffness, aero etc etc are things that are individual to the bike and what the customer wants but testing should be done so that we know our bike is not going to fail in some way . Then we can have confidence in our purchase. It would be good if when a new frame or part is made , it is taken straight out on the road and given a serious hammering. We have had some top end bikes fail on these pages and more than once the same problem cropping up on a frame or part. I just don't know if you can believe some of the claims made . There is no better way to test a bike ,get it on the road and ride it .


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 Post subject: Re: 700 Gram frame
PostPosted: Sun Oct 07, 2012 2:37 am 
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artray wrote:
We have had some top end bikes fail on these pages


that can be said of any frame though, it's not specific to 'top end' frames. We're doing quite a number of repairs that are, for want of a better description, declined warranty claims.

I think testing to make sure a bike meets certain standard citeria, such as the British Standards is a good idea from a safety point of view, but I'm not sure that someone I don't know, giving the bike a good hammering, would inspire me with any more confidence than lab testing. An independent journalist riding then reporting would be a good idea, but that more or less happens in cycling magazines now anyway, that's assuming they're independent?


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 Post subject: Re: 700 Gram frame
PostPosted: Sun Oct 07, 2012 5:44 am 
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Lab testing like EN and Zedler does not actually represent YOU but representing numbers that cannot be dimmed by feel or expectations.

If you are a serious buyer and felt both a frame X and frame Y was ridig similar but the frame X is 50 gram lighter but the lab tests said it was 50% less stiff in BB area or what your preference is.

I would bet you let it grow for a week and buying frame Y instead.

If no lab tests, what comparison do you have, a frame Z is compared to what? it sure rides good but against what and WHY it rides good?
Then it´s free for assumptions.

If you go in frame building in detail, you will believe there´s a place for lab testing as ALL serious manufacturers do it!, in a way or another way!.

I do EN test on my road handlebar and bar combo, not failed at 500N at 230mm from center, that´s TOUGH, the EN test consists of 1000N (98,2 KG), from 230mm off center on the handlebar.

Lab tests is a must combined with real world testing just because of two things as I see.

1. Safety, a 1500W sprinter should use it as a 150 kg rider if mentioned a weight limit or watt limit.

2. Fine tune the layup and testing over again, how can you increase stiffness AND save weight?

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 Post subject: Re: 700 Gram frame
PostPosted: Sun Oct 07, 2012 5:52 am 
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stephen@fibre-lyte wrote:
artray wrote:
We have had some top end bikes fail on these pages

I think testing to make sure a bike meets certain standard citeria, such as the British Standards is a good idea from a safety point of view, but I'm not sure that someone I don't know, giving the bike a good hammering, would inspire me with any more confidence than lab testing. An independent journalist riding then reporting would be a good idea, but that more or less happens in cycling magazines now anyway, that's assuming they're independent?


A good hammering is a assumption, a preference who differs from me and you, sir Chris Hoy can do a good workout of the BB area that will never be exceeded by us mortals, if he written in his test protocol the frame X have a stiff BB area and you write the frame X have a noodly BB area.

Who should I believe? that´s my point, all of us thinks different, that´s the problem.
A bike rides great by a sum of all parts, not the frame only.

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 Post subject: Re: 700 Gram frame
PostPosted: Sun Oct 07, 2012 10:59 am 
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Mattias, in most aspects I agree with you, but my problem with testing is what does it actually tell the customer? If there was a full explanation of the testing procedure along with the actual test then the customer could make their own mind up about the validity of the test. For instance, the handlebar test you talk about, that sounds like a beam test i.e. put a weight at 230mm and see if it snaps. That tells you nothing about torsional forces. Plus, you say that the test is 1000N which is only 100kg. How would a typical cyclist interpret that? What I'm trying to suggest is that lab testing is needed as PART of how to compare bikes, but not as the only way and the tests also need to be explained more so that the consumer understands what the comparison relates to.


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 Post subject: Re: 700 Gram frame
PostPosted: Sun Oct 07, 2012 11:11 am 
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Stephen: you are correct, EN testing is mostly for safety and roadworthiness.
But can also be used to see IF your product hold up compared to a product which weighs more.

Schmolke does EN tests to ensure their products are safe.

The particular handlebar test I did, 50 kg on a 230mm from center of handlebar is a LOT of force, don´t read numbers and assume, think about the requirements a 80 gram stem and a 130 gram road handlebar must withstand to pass double that.

For more detailed tests, in fact bicycle industry has very few standard tests that ALL can use besides EN, Zedler has one but you need to take your product there and letting them test your product and give you numbers, then compare to others that they have tested.

Rider preferences are personal, I love my Cannondale Super Six Himod, as I like to ride a A2J Rolo, have only ridden it a couple of hundreds meters with standard shoes but without chamois so I could feel how well it dampened the road vibrations compared to out of saddle stiffness.

I have ridden too expensive bikes from early 90s and I know roughly how a bike should handle, not an expert here.

My opinion is:

A frame is a part of a bike, as part of a bike it should be treated so, lab testing gives you a part of a picture, your rider preference give you the rest resulting a full picture.
For me lab testing together with finish INSIDE the bike give me the most part of picture, then I ride it to feel if my assumtion was right.
The outside of a frame is easy to fix to a good finish, the inside isn´t, I´ve seen my fair share of 10s grams of glue blobs and 10s grams of bondo and so on in for other invisible joints.

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 Post subject: Re: 700 Gram frame
PostPosted: Sun Oct 07, 2012 12:54 pm 
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Mattias Hellöre wrote:
50 kg on a 230mm from center of handlebar is a LOT of force, don´t read numbers and assume, think about the requirements a 80 gram stem and a 130 gram road handlebar must withstand to pass double that.


50kg is a lot of force, but it needs to be somehow related to the 'typical' rider. For example, how much force does the 'typical' rider put through the bars? If I wasn't an engineer, I could look at that number and think 'well, if I sit on the bars, I weigh 75kg so I'd snap them, so how strong in reality are they?'. Of course you wouldn't sit on the bars, but do you see what I mean, that the testing needs to be explained relative to how much force a 'typical' rider would use.

Mattias Hellöre wrote:
For me lab testing together with finish INSIDE the bike give me the most part of picture, then I ride it to feel if my assumtion was right.
The outside of a frame is easy to fix to a good finish, the inside isn´t, I´ve seen my fair share of 10s grams of glue blobs and 10s grams of bondo and so on in for other invisible joints.


That's a fair comment, for you personally. We've seen our fair share of badly manufactured frames that have been sent for repair and you can tell a fair amount from the inside of the tubes, but only if you know carbon fibre. Plus, as you're aware, there are many variations of carbon fibre and many different layups, so two well manufactured frames can have totally different characteristics. Unidirectional tubing (the current fashion for the 'naked' look) is great in a beam test such as what you talked about but not so great in torsion. Bearing in mind the twist effect at the bottom bracket, a beam type test has no real validity (in my opinion) in comparing frames.


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 Post subject: Re: 700 Gram frame
PostPosted: Sun Oct 07, 2012 3:39 pm 
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http://www.youtube.com/watch?v=lrjId0-K-Ts
Pinarello testing frames.

http://www.youtube.com/watch?v=X1mPd97x6r4
Roundtail FEA.

http://www.youtube.com/watch?feature=endscreen&v=dNDub_EyUDg&NR=1
Simple jig testing.


A small number of tests that are available for public through youtube.

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 Post subject: Re: 700 Gram frame
PostPosted: Mon Oct 08, 2012 3:59 am 
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Just to clarify my post, I said "a few" of the super light frames are "unlikely" to pass the tests, which is more of a speculation. So not saying "most super light frames" will fail. In fact, offerings from major brands are typically tested quite extensively, partially because they also take the most abuse in use or assembly.

A word on standard tests --- true they do not 100% reflect the actual forces from a cyclist, but they tend to be a bit overly stringent just to be safe. Plus commercial practicality and uniformity makes them the desirable way to test frames. IMHO, they are much harder than having one or two 120lb (or 160lb) riders reporting no breakage after 3000 miles. My comment on assuming a heavy rider is a loose way of saying the tests impose substantial loads on the frames, so I'm in full agreement that a light rider could be powerful and hard on his equipment.


stephen@fibre-lyte wrote:
I'd be curious to know what exactly the standards are and what makes you think that most super light frames won't pass them? You could be right, but an explanation of the details would help. I've always pointed out that I think a rider weight limit should only be a guide. The forces through a frame are related to the power being put through it. I remember pk0r's power output was far higher than mine yet he's 20kg lighter!!

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