Quantcast

start saving - the swedes are coming ...

dilzy

Monkey
Sep 7, 2008
567
1
If all you care about is rigidity and stiffness for the "strength" of the bar then a larger diameter, thinner wall is almost always better. However since you need some minimum wall thickness for any tubing on bike parts for impact resistance you have more constraints you have to optimize within, so larger diameter doesn't always yield better strength/weight.

Also, stiffer bars are not always stronger, and are often much weaker because they cannot be strained as much before failure. http://en.wikipedia.org/wiki/Toughness
Toughness is a property entirely of the material and has absolutely nothing to do with the structure. Strain is a relationship between original length and stressed length. The amount of strain is only dependent on the stiffness of the material and the stress applied. If a structure deflects less, it's because it's under less stress (as it's straining less) and will therefore always be stronger in the designed load path UNLESS it fails to buckling etc, which is often the case for larger monocoque structures designed with max deflections in mind.

In short, you might want a read of a 2nd year mechanics text book, they're full of a wealth of info.
 
Last edited:

gemini2k

Turbo Monkey
Jul 31, 2005
3,526
117
San Francisco
Toughness is a property entirely of the material and has absolutely nothing to do with the structure. Strain is a relationship between original length and stressed length. The amount of strain is only dependent on the stiffness of the material and the stress applied. If a structure deflects less, it's because it's under less stress (as it's straining less) and will therefore always be stronger in the designed load path UNLESS it fails to buckling etc, which is often the case for larger monocoque structures designed with max deflections in mind.
Yes, you are right.

The point I was trying to make was that the stiffness of the bar is dependent on the parameters of the structure (independent of material), such as the bar diameter, wall thickness, etc. The stiffness does not necessarily translate into strength/durability though. And thus a larger diameter bar might not necessarily be stronger if though it's stiffer, although it might.

In short, you might want a read of a 2nd year mechanics text book, they're full of a wealth of info.
Oh wow, you are quite the intellectual colossus.
 
Last edited:

dilzy

Monkey
Sep 7, 2008
567
1
Yes, you are right.

The point I was trying to make was that the stiffness of the bar is dependent on the parameters of the structure (independent of material), such as the bar diameter, wall thickness, etc. The stiffness does not necessarily translate into strength/durability though. And thus a larger diameter bar might not necessarily be stronger if though it's stiffer, although it might.



Oh wow, you are quite the intellectual colossus.

I was just trying to be helpful and since your still making some fundamental engineering mistakes in your paragraph I refer you back to my previous suggestion.
 
Oct 27, 2008
28
0
As said, the shock is something new. Looks really interesting. It looked like they had a cartridge in the boxxer too. Felt like a good boxxer but they thought it had too much stiction to it. See what tricks they come up with. Time will tell.
 

iRider

Turbo Monkey
Apr 5, 2008
5,653
3,093
As said, the shock is something new. Looks really interesting. It looked like they had a cartridge in the boxxer too. Felt like a good boxxer but they thought it had too much stiction to it. See what tricks they come up with. Time will tell.
Come on! In this day and age where every person older than 10 years owns a smart phone with camera we still haven't seen a pic of this shock????? :(
 

- seb

Turbo Monkey
Apr 10, 2002
2,924
1
UK
The issue was with the Demo, not the CCDB. That little swing link that attaches to the shock puts tremendous load on the shock shaft. Issues were not limited to CCDB, but also all other brands.

To be a bit fairer, the issues really only popped up on frames with worn, notchy, sticky bearings in that link, increasing the friction and limiting movement on the link under compression. I haven't heard of issues on new or maintained frames.
As it happens, I know of someone who snapped a CCDB on a 2013 Demo this weekend, that he's had for less than a month.
 

Mo(n)arch

Turbo Monkey
Dec 27, 2010
4,441
1,422
Italy/south Tyrol
As it happens, I know of someone who snapped a CCDB on a 2013 Demo this weekend, that he's had for less than a month.
I know a guy who blew 2 Vivid airs and two CCDB.
First he thought it was the the damper's (Vivid) fault. But then he went out to Specialized and they warrantied the frame with no comments.
The mount ont the mainframe was not in line with that yoke thingy.
 

NAYR

Monkey
Jul 13, 2009
109
0
Truckee
As it happens, I know of someone who snapped a CCDB on a 2013 Demo this weekend, that he's had for less than a month.
Do you know if he had the new version of the DB with the thicker shock shaft that Cane Creek made specifically for the Demo?
 

- seb

Turbo Monkey
Apr 10, 2002
2,924
1
UK
I don't. I know he got an RC4 frame, but took his RC4 off to put a CCDB on. No idea how old/new that CCDB might have been.
 

jonKranked

Detective Dookie
Nov 10, 2005
85,941
24,510
media blackout
nothing new here. spy shots of that go as far back as 2013, although that does look more refined.

their cartridge kit has been available for a while now.
 

Trekrules

Turbo Monkey
Apr 12, 2007
1,226
148
nothing new here. spy shots of that go as far back as 2013, although that does look more refined.

their cartridge kit has been available for a while now.
It will be shown during Crankworx France to the public at the Ohlins booth,they made the picture today probably this looks like the final product after all the prototypes they had before.
 

jonKranked

Detective Dookie
Nov 10, 2005
85,941
24,510
media blackout
It will be shown during Crankworx France to the public at the Ohlins booth,they made the picture today probably this looks like the final product after all the prototypes they had before.
gotcha, thanks for clarifying. i was gonna comment that does look production ready.

scared of the price tag.