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PostPosted: Mon Apr 01, 2013 8:39 pm 
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refthimos wrote:
Permon wrote:
btompkins0112 wrote:
NGMN wrote:
Can we agree once and for all that you seem to be talking about stability and not stiffness??


Yes.


Whatever we call it, is this a standard R5 behaviour?


Your video shows shimmy, or "speed wobble." It doesn't look like you are even going fast in that video, though hard to tell - which is surprising because IME speed wobble usually presents itself at speeds over 30mph, even more commonly at speeds over 40mph.



No, it is not a speed wobble. The shimmy behaviour shown by the video is a result of my action. (I did it on purpose by shaking my hands to show the instability/lack of stiffness of R5s headtube area....it is hard to do the same on Pinarello DOGMA...... :noidea: ).

So far I have not experienced any shimmy or speed wobble on the R5 during downhills.


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PostPosted: Mon Apr 01, 2013 8:47 pm 
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Is this an april fools thread? All I see in the video is a bike going like 10mph and a guy with ski gloves trying to shake the bars for some reason. This must be about the geo and maybe weight of the stem/bar headtube area of both bikes being much different. The light and "twitchy" feeling of the R5 vs the tank like cockpit of the dogma.

Good luck either way but I doubt the R5 is flexy.


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Posted: Mon Apr 01, 2013 8:47 pm 


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PostPosted: Mon Apr 01, 2013 8:52 pm 
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tinozee wrote:
Is this an april fools thread? All I see in the video is a bike going like 10mph and a guy with ski gloves trying to shake the bars for some reason. This must be about the geo and maybe weight of the stem/bar headtube are of both bikes being much different - the light feeling of the R5 vs the tank like cockpit of the dogma.

Good luck either way but I doubt the R5 is flexy.


Yeah, maybe You are right with the "april folls thread" :up:

The shaking of the bars was just a way to show what R5 does while Dogma does not.
The Dogma felt really STIFF and SOLID like a rock. The R5 does not give me the feeling. That is why I was searching for an advice.


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PostPosted: Tue Apr 02, 2013 1:17 am 
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Permon wrote:
The shaking of the bars was just a way to show what R5 does while Dogma does not.
The Dogma felt really STIFF and SOLID like a rock. The R5 does not give me the feeling. That is why I was searching for an advice.


So basically you are telling us that when you apply steering input to the bars (shaking them), the bars on the R5 move and respond to that input while the bars on the Dogma do not?

That doesn't seem like a ringing endorsement of the Dogma's handling, nor a criticism of the R5's.

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PostPosted: Tue Apr 02, 2013 2:43 am 
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Change your bar/stem to a MOst on your R5 and then compare the two for feel. There are a lot ways to maximize your front end stiffness, frame is just a part of the equation. How many sprints have been won on the flexy Soloist/S3's ect over the past number of years?? It really doesn't matter.


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PostPosted: Tue Apr 02, 2013 2:43 am 
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Lol.

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PostPosted: Tue Apr 02, 2013 7:58 am 
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The test you are doing there is actually a fine indicator of a bikes front end stiffness (falsely called headtube stiffness). I always do it when I test a new bike, as well as my friends who are testers of a bike magazine do. It usually corresponds very well with the empiric stiffness bench tests the magazine do. If a bike can be shaken like you do on the video, it's almost always because of lack of stiffness in the top and down tubes.
I must say however, that I am surprised that the R5 is doing that. I have only ridden an R3, but that seemed like a pretty solid bike, without being super stiff. I would suspect the R5 to be like that as well.
Could be that there's a flaw in the frame or fork? Would you know anybody that has an other R5 you could try?


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PostPosted: Tue Apr 02, 2013 8:28 am 
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The R5 I have tested was no noodle. Neither on the road or in a stiffness test.

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PostPosted: Tue Apr 02, 2013 9:18 am 
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Mario Jr. wrote:
The test you are doing there is actually a fine indicator of a bikes front end stiffness (falsely called headtube stiffness). I always do it when I test a new bike, as well as my friends who are testers of a bike magazine do. It usually corresponds very well with the empiric stiffness bench tests the magazine do. If a bike can be shaken like you do on the video, it's almost always because of lack of stiffness in the top and down tubes.
I must say however, that I am surprised that the R5 is doing that. I have only ridden an R3, but that seemed like a pretty solid bike, without being super stiff. I would suspect the R5 to be like that as well.
Could be that there's a flaw in the frame or fork? Would you know anybody that has an other R5 you could try?


Yeah, I almost started to feel like an idiot after reading some posts here....
I always do a "dumb test" like this on bikes and by my opinion it indicates the stiffness very well.
The R5 seems to me worse than my old R3 model year 2007 I used to have....
It looks like, there is somehing wrong with the frameset :? which really piss me off as this R5 is already a replacement for a claimed R3 (2012).
My LBS had another one R5 in the same size on stock. I will contact him to find out, if I can try it out and see what the situation is like.
Maybe I am a big and strong guy, so I can wobble frames like this......but as I said, 3 years old DOGMA felt 300% stiffer thatn the R5.


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PostPosted: Tue Apr 02, 2013 4:41 pm 
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Permon wrote:
Mario Jr. wrote:
The test you are doing there is actually a fine indicator of a bikes front end stiffness (falsely called headtube stiffness). I always do it when I test a new bike, as well as my friends who are testers of a bike magazine do. It usually corresponds very well with the empiric stiffness bench tests the magazine do. If a bike can be shaken like you do on the video, it's almost always because of lack of stiffness in the top and down tubes.
I must say however, that I am surprised that the R5 is doing that. I have only ridden an R3, but that seemed like a pretty solid bike, without being super stiff. I would suspect the R5 to be like that as well.
Could be that there's a flaw in the frame or fork? Would you know anybody that has an other R5 you could try?


Yeah, I almost started to feel like an idiot after reading some posts here....
I always do a "dumb test" like this on bikes and by my opinion it indicates the stiffness very well.
The R5 seems to me worse than my old R3 model year 2007 I used to have....
It looks like, there is somehing wrong with the frameset :? which really piss me off as this R5 is already a replacement for a claimed R3 (2012).
My LBS had another one R5 in the same size on stock. I will contact him to find out, if I can try it out and see what the situation is like.
Maybe I am a big and strong guy, so I can wobble frames like this......but as I said, 3 years old DOGMA felt 300% stiffer thatn the R5.

It's hard for me to believe you guys are being serious...

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PostPosted: Tue Apr 02, 2013 4:49 pm 
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Permon, I don't think yanking your bars and making your bike shimmy is too scientific as a test to verify headtube stiffness (I know you know that too).

I am still convinced that there is an issue with set-up, perhaps headset bearings are set incorrectly? As others have indicated, the R5 is stiffer then the 2007 R3 you owned and if you transferred all the parts over to the new frame then you should experience an increase in front end stability. You should follow your plan and go in to the shop and ride a different R5. Also, have them check out your current build, including taking apart the headset and verifying proper set-up.

Good luck, EM3

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PostPosted: Tue Apr 02, 2013 4:53 pm 
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Permon,

I suspect your test is much more a reflection of a combination of trail/geometry, system/tire damping, spring rate/fork flexion and mass (handlebar, stem, shifters) working in a dynamic setting. While head tube stiffness has some bearing on the test, it reflects much more on the interaction of these other variables.

I had an old Cannondale that behaved one way when stock, when I put speed bars on it, it behaved differently, and had an odd harmonic in the front end (though not quite a shimmy).

Just an opinion.


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PostPosted: Tue Apr 02, 2013 8:36 pm 
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rmerka wrote:
Permon wrote:
Mario Jr. wrote:
The test you are doing there is actually a fine indicator of a bikes front end stiffness (falsely called headtube stiffness). I always do it when I test a new bike, as well as my friends who are testers of a bike magazine do. It usually corresponds very well with the empiric stiffness bench tests the magazine do. If a bike can be shaken like you do on the video, it's almost always because of lack of stiffness in the top and down tubes.
I must say however, that I am surprised that the R5 is doing that. I have only ridden an R3, but that seemed like a pretty solid bike, without being super stiff. I would suspect the R5 to be like that as well.
Could be that there's a flaw in the frame or fork? Would you know anybody that has an other R5 you could try?


Yeah, I almost started to feel like an idiot after reading some posts here....
I always do a "dumb test" like this on bikes and by my opinion it indicates the stiffness very well.
The R5 seems to me worse than my old R3 model year 2007 I used to have....
It looks like, there is somehing wrong with the frameset :? which really piss me off as this R5 is already a replacement for a claimed R3 (2012).
My LBS had another one R5 in the same size on stock. I will contact him to find out, if I can try it out and see what the situation is like.
Maybe I am a big and strong guy, so I can wobble frames like this......but as I said, 3 years old DOGMA felt 300% stiffer thatn the R5.

It's hard for me to believe you guys are being serious...


As I can see, You are the smartest guy all around the forum. :smartass:
Whatever, the matter of fact is, that riding the DOGMA was like riding a SOLID ROCK. Riding my R5 is like riding a noodle :noidea:
That is how it is, no matter what "stupid test" I did to show the wobbling.


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PostPosted: Tue Apr 02, 2013 8:51 pm 
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Permon wrote:
As I can see, You are the smartest guy all around the forum. :smartass:
Whatever, the matter of fact is, that riding the DOGMA was like riding a SOLID ROCK. Riding my R5 is like riding a noodle :noidea:
That is how it is, no matter what "stupid test" I did to show the wobbling.


I honestly meant no offense or disrespect to anyone with that statement and if it was taken that way I apologize. I still think there might be something wrong with your setup though.

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Posted: Tue Apr 02, 2013 8:51 pm 


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PostPosted: Tue Apr 02, 2013 10:08 pm 
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Permon,

http://sheldonbrown.com/brandt/shimmy.html

So I have a 58 VWD and it rock stable, but as the new RCA thread points out all the sizes are really different bikes.

I think if you are really unhappy with your ride I would reach out to Cervelo, email them from their website and ask them to call you. I have reached out to them and they have went far above what I consider excellent costumer service.

Can you test ride a VWD at a local shop?


C


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