Login required to started new threads

Login required to post replies

Prev Next
Re: New Cervelo S5 [sausskross] [ In reply to ]
Quote | Reply
Damon, what is your experience testing bikes in the wind tunnel with and without a rider/dummy? It occurred to me that testing a bare frame would exaggerate the high yaw angle performance of many aero frames which have tube shapes designed to create lift (which reduces aero drag.) In particular I would guess that the riders legs "block" the the seat tube at higher yaw angles reducing its lift component. Is this consistent with what you have seen in the wind tunnel?
Quote Reply
Re: New Cervelo S5 [Dunbar] [ In reply to ]
Quote | Reply
http://www.cervelo.com/...8-7e87cddcd4f6-0.pdf

Check out the "Road Bikes With Rider" and "Road Bikes Without Rider" plots right near the beginning.

http://bikeblather.blogspot.com/
Last edited by: Tom A.: Nov 20, 14 19:55
Quote Reply
Re: New Cervelo S5 [Tom A.] [ In reply to ]
Quote | Reply
It is interesting to see how the much different the plot looks with a rider onboard. Dramatically changes the results at higher yaw angles. It may sound like I'm joking but do the riders limbs create lift? I'm a private pilot and they taught us that you give pretty much anything enough angle of attack and it will create lift.
Quote Reply
Re: New Cervelo S5 [Dunbar] [ In reply to ]
Quote | Reply
>> 60 Grams lift at 20° YAW / surfing with wheels .. Cervélo/HED2015 << It looks like width with proper deep and smooth sides with soft edges make the trick .. oSo >>

*
___/\___/\___/\___
the s u r f b o a r d of the K u r p f a l z is the r o a d b i k e .. oSo >>
Quote Reply
Re: New Cervelo S5 [Dunbar] [ In reply to ]
Quote | Reply
Dunbar wrote:
It is interesting to see how the much different the plot looks with a rider onboard. Dramatically changes the results at higher yaw angles. It may sound like I'm joking but do the riders limbs create lift? I'm a private pilot and they taught us that you give pretty much anything enough angle of attack and it will create lift.


Pretty much...yeah...some riders "sail" better than others (and it's probably more the torso, than limbs). And it's fair to say, based on that plot, that "Foam Dave Zabriskie" sails pretty damned well.

However, the main takeaway from those plots I get is that the deltas appear to stay consistent, rider or no, which I think answers your question above.

http://bikeblather.blogspot.com/
Last edited by: Tom A.: Nov 21, 14 6:49
Quote Reply
Re: New Cervelo S5 [Tom A.] [ In reply to ]
Quote | Reply
Tom A. wrote:
However, the main takeaway from those plots I get is that the deltas appear to stay consistent, rider or no, which I think answers your question above.


True, but the S3 and S5 have a very similar plot with no rider so that makes sense. The Felt AR does exceptionally well at high yaw angles with no rider onboard. I wonder how much that high yaw angle performance changes with the rider onboard? The more I think about it the whole body would create an area of high pressure on the side wind is blowing from which would create some lift. Here is a Flo Cycling blog post that explains the physics:

http://flocycling.blogspot.com/2011/05/flo-cycling-wind-tunnel-results-and.html
Last edited by: Dunbar: Nov 21, 14 13:48
Quote Reply
Re: New Cervelo S5 [Dunbar] [ In reply to ]
Quote | Reply
Any idea where a modern (internally routed), cantilever cyclocross bike falls on this spectrum? There is a fire sale on s1 framesets that have me almost ready to jump.

Does it give up 30W to and S5, assuming all else is optimized? 35W?

So a CAAD10/Supersix/Tarmac is giving up ~25W to an S5, and 20W to an S2/3, maybe 16-18W to an S1?
Quote Reply
Re: New Cervelo S5 [Tom A.] [ In reply to ]
Quote | Reply
Tom A. wrote:
http://www.cervelo.com/...8-7e87cddcd4f6-0.pdf


Check out the "Road Bikes With Rider" and "Road Bikes Without Rider" plots right near the beginning.


From that same article:
"Anaglyph “Laminate Tools” in conjunction with the NEi NASTRAN solver and FEMAP pre- and
post-processing: F1 composite analysis software tools. Cervélo is the only bicycle company
we’re aware of to use this level of engineering simulation software in house"


AFAIK, Trek uses Abaqus for FEA. Having used both, professionally, to model composite aircraft structure, both programs have their merits but I'd always go to Abaqus (unless I didn't have a fast machine to run on and the results didn't have to be extremely detailed); geometry based model generation is so much more convenient than mesh based generation. Femap users frequently go to some trickery to create composite laminate definition where Abaqus has the built-in functionality (and it's fantastic to use). Pro/E MECHANICA and Solidworks FEA... Yup, they produce contour plots on some imported geometry.


Anyways, back to the regularly-scheduled discussion on aerodynamics. The composite design boom will hit cycling next decade, like aerodynamics hit this decade.
Quote Reply
Re: New Cervelo S5 [damon_rinard] [ In reply to ]
Quote | Reply
damon_rinard wrote:
Hi Sully,

Torsional stiffness is up 35% (measured at the head tube) and BB stiffness is up 6% (measured at the BB).
Comfort is the same. However the new S5 fits up to 700 x 25C tires, so there's potential for more comfort if you want to fit bigger tires.

Cheers,

Sorry for the throwback Damon- is the 35% between the S3 and new S5 or the old S5 and new S5? Im stuck between a S3 and S5.
Quote Reply
Re: New Cervelo S5 [secondchancepro] [ In reply to ]
Quote | Reply
secondchancepro wrote:
damon_rinard wrote:
Hi Sully,

Torsional stiffness is up 35% (measured at the head tube) and BB stiffness is up 6% (measured at the BB).
Comfort is the same. However the new S5 fits up to 700 x 25C tires, so there's potential for more comfort if you want to fit bigger tires.

Cheers,


Sorry for the throwback Damon- is the 35% between the S3 and new S5 or the old S5 and new S5? Im stuck between a S3 and S5.

Shoot, sorry. Im a jack ass. Didn't realize Damon had or is leaving Cervelo. Does anyone else know?
Quote Reply
Re: New Cervelo S5 [secondchancepro] [ In reply to ]
Quote | Reply
This numbers are the differences between the old and new S5. The current S3 already has a in stiffness optimized frame with a tapered head tube ..

*
___/\___/\___/\___
the s u r f b o a r d of the K u r p f a l z is the r o a d b i k e .. oSo >>
Quote Reply
Re: New Cervelo S5 [sausskross] [ In reply to ]
Quote | Reply
That's what I thought. I'm comparing the new s3 and new s5. I guess a test ride is in order!
Quote Reply
Re: New Cervelo S5 [jmh] [ In reply to ]
Quote | Reply
I hear some of the S5 complete bikes are shipping.
Anyone know where a 56cm is on the floor?
I would love to have someone take a couple actual measurements.
Quote Reply
Re: New Cervelo S5 [bootsie_cat] [ In reply to ]
Quote | Reply
It looks like he is riding a 56cm ..

.. and may has them in his shop: http://www.cervelo.com/...es/beyond-aero-.html

*
___/\___/\___/\___
the s u r f b o a r d of the K u r p f a l z is the r o a d b i k e .. oSo >>
Quote Reply
Re: New Cervelo S5 [bootsie_cat] [ In reply to ]
Quote | Reply
And here are geometry tables for the new S5 .. http://www.cervelo.com/...c-e522c6d9bc30-0.pdf

*
___/\___/\___/\___
the s u r f b o a r d of the K u r p f a l z is the r o a d b i k e .. oSo >>
Quote Reply
Re: New Cervelo S5 [bootsie_cat] [ In reply to ]
Quote | Reply
I will hopefully be able to take some in the next week or two. (Prob 2). What type of measurements are you looking for?
Quote Reply
Re: New Cervelo S5 [sausskross] [ In reply to ]
Quote | Reply
I say it is a 58, but what do I know?
It looks too small for him.
Quote Reply
Re: New Cervelo S5 [James Haycraft] [ In reply to ]
Quote | Reply
Actual center to top of a size 56cm frame (from center of bb to top of toptube along the seat tube).
Quote Reply
Re: New Cervelo S5 [sausskross] [ In reply to ]
Quote | Reply
sausskross wrote:
It looks like he is riding a 56cm ..

.. and may has them in his shop: http://www.cervelo.com/...es/beyond-aero-.html


Looks like he could clean up his cabling a bit more.
Quote Reply
Re: New Cervelo S5 [bootsie_cat] [ In reply to ]
Quote | Reply
Excel sports in boulder has one. It is sweet.
Quote Reply
Re: New Cervelo S5 [bootsie_cat] [ In reply to ]
Quote | Reply
Trying measuring stack in comparison to chain stay length (405mm) with a pixel stick it's even just a 54cm frame (542mm stack). The S5 geometry table doesn't show any seat tube length. It looks like a nothing else matters fast first ride on the brand new bike ..

*
___/\___/\___/\___
the s u r f b o a r d of the K u r p f a l z is the r o a d b i k e .. oSo >>
Last edited by: sausskross: Jan 18, 15 23:52
Quote Reply
Re: New Cervelo S5 [goldentech] [ In reply to ]
Quote | Reply
Supposedly complete bikes are shipping.
Quote Reply
Re: New Cervelo S5 [sausskross] [ In reply to ]
Quote | Reply
Replying to you, though not all of my responses are directed at you...

It is a 56. Being a long-legged short-torso rider, the R/S2-3 geometry suits me a bit better. But picking between this and the 58 I opted for the smaller size. The one thing to keep in mind is that I don't typically ride as low as in the picture so my elbows look slightly more bent than otherwise. For reference that's only a 120 stem.

As for the cables, not sure there's a lot I can do on that. Having to go around the excess steerer tube makes it tough. It might be a different story if there was nothing above the stem.

Unless you want a Di2 Dura-Ace, you can get a 56 new S5...


sausskross wrote:
It looks like he is riding a 56cm ..

.. and may has them in his shop: http://www.cervelo.com/...es/beyond-aero-.html
Quote Reply
Re: New Cervelo S5 [AndresLD] [ In reply to ]
Quote | Reply
Hi AndresLD,

thanks for your clarification. Waiting for a 58cm, I'm happy having measured your's head tube size wrong and it's a 56cm already. This picture was shown a few posts before and shows a decision of Jensie about size with a lot of weight and power over the bb ..



The new S5 is stunning and the fastest road bike possible in the universe to date within UCI rules, if some freaky aliens don't build any .. oSo >>

*
___/\___/\___/\___
the s u r f b o a r d of the K u r p f a l z is the r o a d b i k e .. oSo >>
Last edited by: sausskross: Jan 22, 15 23:36
Quote Reply
Re: New Cervelo S5 [jmh] [ In reply to ]
Quote | Reply
Is there a delay delivering new S5 to Ontario Canada? We have been waiting fro our LBS to get inventory since August. Who do I ask guys?
Quote Reply

Prev Next