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PostPosted: Thu Jul 04, 2013 10:50 pm 
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Lol. Can't help myself........looks like the noodles in this case were in your body. Congratulations on the weight loss. Great to hear that your issue is solved.

Sent from my SGH-I747M using Tapatalk 4 Beta


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PostPosted: Thu Jul 04, 2013 11:15 pm 
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Location: Los Angeles
Permon wrote:
So, I do believe that majority of guys riding size 54 (considering them smaller, less powerfull) feels R5 as super stiff bike.


Weight nor height of the rider does not have a correlation to their power output. Sorry.
There are short guys who ride 48s and barely crack 130lbs who can put out more power than a rider who uses a 56 and stands over 200lbs. Yes the world does have a general bias to people who are taller (business, relationships, etc:.) which often acts blind to the person's actual capabilities, but that bias does not necessarily carry any veracity. To paraphrase what a person might actually learn about human behaviour if you study it enough: "People are idiots."

I will not call you an idiot, even though you said that people could, but assuming a correlation between the size of a rider and their power output is a bit shortsighted, if not naïve.

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Posted: Thu Jul 04, 2013 11:15 pm 


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PostPosted: Thu Jul 04, 2013 11:26 pm 
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Posts: 447
OK, lets talk about averages. :smartass:
Does Your ideas still work? I doubt it.

If there are 2 guys:
- a little one riding size 48
- a bigger/heavier one riding size 56

Both of them make the route of a certain distance in the same time.... please, could You tell me who aplied significantly more power to get to finish at the same time?

Yes, teh bigger one. A the bigger puts more power to pedals, handebars etc..... frameset and all components (chainrings, chain, wheels ....) have to take care of much more power.

It explains the change in behaving of my frameset.....now, I am 11kg ligher, I put less power to ride the bike the same speeds.


Last edited by Permon on Fri Jul 05, 2013 12:31 pm, edited 2 times in total.

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PostPosted: Thu Jul 04, 2013 11:33 pm 
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Ok, let's talk about assumptions.
You start off with a blanket statement without any specifics, I countered with "no correlation."
Then you throw in a specific scenario? That isn't a blanket statement, that's specific.

Power over what distance?

You are assuming they finish at the same time.
You are assuming they are of the same capability.
You are assuming a lot which you take for granted (such as the variability of humanity).
You are assuming a correlation of height (~frame size) to weight and capability.

You know what they say about assumptions?

Here, let me break your scenario:
Rider 1: Short guy... say Purito... plenty of power, yet small.
Rider 2: Tall guy. Guess what? Just because he's tall does not mean he puts out the same power. Heck, he might not be as strong of a rider nor experienced?

So with your original statement, just because Purito rides a smaller frame he will always have less power than any rider on a bigger frame?
Bullocks.

There. No assumptions of anything specific: they could be any rider. Therefore countering your argument of "frame size correlates to power" general statement.

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Last edited by prendrefeu on Thu Jul 04, 2013 11:38 pm, edited 1 time in total.

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PostPosted: Thu Jul 04, 2013 11:37 pm 
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Lets make it simple.
Larger frame size .... the stronger it is to be.

I am sure, You agree.
(all frame producers knows it and use this knowledge in engineering)..... even Cervelo when they were engineering RCA size 58 :mrgreen: What a pitty, they did not use the knowledge in the range of 48-56 :P


Last edited by Permon on Fri Jul 05, 2013 12:32 pm, edited 1 time in total.

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PostPosted: Thu Jul 04, 2013 11:39 pm 
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You're still ignoring a defense of your original statement - that the frame size of the rider correlates to THEIR power output.

So if you see two identical builds up against a cafe wall, one of them size 48 and the other a 56, without seeing who is riding which bike, you are assuming that the person with the smaller frame puts out less power than the taller riders? Again, naïve and shortsighted. Let's go for a ride sometime, I'll wait for you at the top.

And please, is it really necessary to quote the post immediately above yours? A bit inefficient.

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PostPosted: Fri Jul 05, 2013 10:07 am 
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prendrefeu wrote:
that the frame size of the rider correlates to THEIR power output.


In GENERAL, YES. That is a matter of fact. Otherwise You would assume that taller/heavier riders are slower than the small one!

prendrefeu wrote:
So if you see two identical builds up against a cafe wall, one of them size 48 and the other a 56, without seeing who is riding which bike, you are assuming that the person with the smaller frame puts out less power than the taller riders? Again, naïve and shortsighted.


YES, that is exactly what each frame manufacturer has to consider.

prendrefeu wrote:

Let's go for a ride sometime, I'll wait for you at the top.


Funny, You never met me, and You are so sure, You drop me :mrgreen:
Even if You droped me, I could have used SO MUCH more power to get up the hill than You!
Just becasue, I could be heavier than You (to get more weight up the hill = more power to do it in a certain time.....)
Even if You get up there 5minutes earlier and I ll be 150kg, YES, I would be the one who put MUCH MORE POWER to the bike (absolute numbers, not watt/kg)

We live in a World which measures cycling performance in TIME, the sooner You are at the finish line, the better You are. Right?
So, who uses more power to get to the finish line wheel to wheel considering Purito and Greipel???
Yes, Greipel.

And one more thing.....if You are taller... the frameset tubes are longer, Your arms and legs are longer. You need MORE material to deal with it.
Simple as it is. :wink:

Lets stop this discussion....this thread is about RCA.


Last edited by Permon on Fri Jul 05, 2013 12:19 pm, edited 2 times in total.

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PostPosted: Fri Jul 05, 2013 10:29 am 
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Location: UK
Permon, you just need to let it go.

Your R5 is a noodle thread was a joke.

I'm sure you're not a Troll but some of your comments come across as if you are one.


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PostPosted: Fri Jul 05, 2013 11:37 am 
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in the industry

Joined: Fri Apr 29, 2011 8:32 pm
Posts: 29
Hi Permon,

Good observation - the rider's characteristics have a lot to do with how a bicycle feels.

Regarding the uneven steps in weight from one size to the next, a lot of the change in weight has little to do with stiffness, and more to do with strength. As top and down tube get farther apart, they are better positioned to brace against loads coming in through the head tube. This affects the frames' frontal strength differently for different frame sizes. There are other examples as well (seat tube cluster, etc.).

This is related to the well-known engineering principle called the "size effect" (http://en.wikipedia.org/wiki/Size_effec ... l_strength).

But this natural phenomenon also corrupted by the legal requirement to meet the "same" strength standard, regardless of size. Which explains why the smaller sizes don't get lighter as quickly - they have less leverage but must be just as strong.

These effects show up mostly with highly engineered frames, where we approach the limits. It doesn't happen as much with metal frames. Cut off some tube, lose some weight.

Cheers,

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Senior Advanced R&D Engineer at Vroomen.White.Design
http://www.cervelo.com
http://www.bbright.net/


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PostPosted: Fri Jul 05, 2013 12:23 pm 
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Damon, thank You for the explanation.
I was really wondering why those differences in weights across the sizes are so small. :idea:

It is great that You/Cervélo write comments to webs like WW. :thumbup:


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PostPosted: Fri Jul 05, 2013 6:59 pm 
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Permon, you're welcome. Thank you for the good question. May I use your question on our web site? Some day I would like to post it in our "Ask the Engineers" pages:

http://www.cervelo.com/en/engineering/a ... neers.html

Is it okay with you?

Thanks,
Damon

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Senior Advanced R&D Engineer at Vroomen.White.Design
http://www.cervelo.com
http://www.bbright.net/


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PostPosted: Fri Jul 05, 2013 10:35 pm 
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Damon, my pleasure. Use whatever You want.

P.S. by accident I was reading those 3 articles in the section "Ask The Engineers" on cervelo.com this Tuesday :-)
Looking forward for the upcomming articles. Very usefull to get some "insider" information.
GREAT JOB You do! :thumbup:


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PostPosted: Fri Jul 05, 2013 11:55 pm 
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Thanks Permon! Not sure when you might see it, but keep a look out. ;-)

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Senior Advanced R&D Engineer at Vroomen.White.Design
http://www.cervelo.com
http://www.bbright.net/


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PostPosted: Mon Jul 15, 2013 1:11 pm 
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Joined: Mon Jun 23, 2008 8:52 am
Posts: 447
prendrefeu wrote:
You're still ignoring a defense of your original statement - that the frame size of the rider correlates to THEIR power output.

So if you see two identical builds up against a cafe wall, one of them size 48 and the other a 56, without seeing who is riding which bike, you are assuming that the person with the smaller frame puts out less power than the taller riders? Again, naïve and shortsighted. Let's go for a ride sometime, I'll wait for you at the top.

And please, is it really necessary to quote the post immediately above yours? A bit inefficient.


Something for You, Specialized has news for 2014:

"All the Tarmac and Roubaix bikes get SL4 size-specific engineering, which recently only applied to the top models.
The technology means that each frame size gets its own shapes, layups, seatstays, chainstays, forks and bearings. The thinking is that a smaller rider has different needs to a taller rider; a 49cm bike shouldn’t be as stiff as a 61cm one."


More here: http://www.bikeradar.com/road/news/arti ... ils-37862/" onclick="window.open(this.href);return false;

But I guess You are smarter than producers and will keep on telling me, that 48 size frame has to carry the same load as size 61 :mrgreen:
Maybe Specialized should hire You....their egineering team made a real big mistake in engineering 2014 model range :welcome: You go and tell them! :smartass:


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PostPosted: Mon Jul 15, 2013 2:57 pm 
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Location: Los Angeles
Permon. I won't call you daft, but I will ask if you have a reading comprehension difficulty.

Please, go back and read the arguments between us. WHERE did I state that the frames should be designed equally between sizes?
You have a complete misunderstanding here of the difference between the power output of a rider and the forces a rider's body puts upon a frame. Do you know the difference? Apparently not because you are still trying to claim the same argument against me.

And, again, there is no direct correlation between the size of the rider (as judged by their chosen frame size) and their power output if you are judging purely on the size of the frame without looking at the rider. Your statement is as naïve as someone stating that they can judge a person's intelligence by whether they are wearing corrective lenses or not because they need to strain their eyes to see.

Basic physics tells us that larger objects exert different forces upon an object compared to smaller ones (in this case, a frame). No shit, Sherlock. That's basic secondary school physics. NO ONE is disagreeing with you there. That's not what I'm questioning. If there are different forces on a frame the frame needs different designs and layups. Yep. That does not mean that the taller rider will necessarily, outright, without-question-all-the-time put out more power than the smaller rider. Do you know the difference?

Now, I've stated here in this very post and in every single post leading up to this what - exactly - am I questioning from your original statement. Please go back and read it. I'll wait. In the meantime, pulling up references which refer to FORCES and not POWER output is just making you seem like you have reading comprehension difficulties.

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Posted: Mon Jul 15, 2013 2:57 pm 


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