HOT: Active* forum members generally gain 5% discount at starbike.com store!
Weight Weenies
* FAQ    * Search    * Trending Topics
* Login   * Register
HOME Listings Articles FAQ Contact About




Post new topic Reply to topic  [ 131 posts ] 
Go to page 1, 2, 3, 4, 5 ... 9  Next
Author Message
PostPosted: Thu Oct 03, 2013 12:41 pm 
Offline
User avatar

Joined: Fri Apr 04, 2008 2:49 am
Posts: 1261
Every now and then I've noticed threads popping up on either light or stiff stems, but when is a stem both stiff and light enough?

Behold this 130mm prototype stem I'm testing that makes the carbon steerer of my Alpha-Q GS30 seem rather elastic.
Image

_________________
RideWert.com
Wert Cycling on Facebook


Last edited by mythical on Sat Nov 23, 2013 11:28 am, edited 1 time in total.

Top
 Profile  
 
Posted: Thu Oct 03, 2013 12:41 pm 


Top
  
 
PostPosted: Thu Oct 03, 2013 2:25 pm 
Offline
User avatar

Joined: Mon Jan 10, 2005 10:47 am
Posts: 896
Location: somewere floating between here and the other side
Jeez louieez !
130mm is a propper lenght aswell, tell us more, how made the stem, is it your handy work ?(;


Top
 Profile  
 
PostPosted: Thu Oct 03, 2013 3:15 pm 
Offline
User avatar

Joined: Mon Nov 02, 2009 8:38 pm
Posts: 292
Wow. Is that fully CNC'd? I'd be slightly concerned about the strength of a CNC'd part at that weight.

_________________
Blog: http://thesetbackpost.com/


Top
 Profile  
 
PostPosted: Thu Oct 03, 2013 4:12 pm 
Offline
Shop Owner
User avatar

Joined: Tue Mar 10, 2009 5:27 am
Posts: 1244
Location: McCall, ID
Ahh a beautiful stem but 130mm? Might as well use a baseball bat for a stem at that point.

_________________
http://www.zencyclery.com


Top
 Profile  
 
PostPosted: Thu Oct 03, 2013 4:20 pm 
Offline
User avatar

Joined: Wed Oct 31, 2007 10:32 pm
Posts: 7412
Location: Los Angeles / Glendale, California
So how much does the 90mm weigh?
And cost?

:twisted:

_________________
Exp001 || TeamLACBC


Top
 Profile  
 
PostPosted: Thu Oct 03, 2013 6:10 pm 
Offline
User avatar

Joined: Fri Apr 04, 2008 2:49 am
Posts: 1261
Here are projected weights for each length.

80 mm =67 grams
90 mm = 71 grams
100 mm = 74 grams
110 mm = 77 grams
120 mm = 80 grams
130 mm = 85 grams

The prototype bolts are hollow so they're lighter than production bolts, which will not be hollow. Prices will be announced when production is underway, once testing is rounded off successfully. This is the 3rd generation prototype already. The angle is 7.5º with a 37.5mm stack height.

The first one can be seen in this Velonews article and the second one (a 150mm) can be seen here: http://www.facebook.com/photo.php?fbid=516676328379025 This one almost passed EN14781 but it wasn't good enough for production. Meanwhile, I fell ill and required immediate medical treatment, though now I'm fully recovered and want to give the world awesome bike parts.

_________________
RideWert.com
Wert Cycling on Facebook


Top
 Profile  
 
PostPosted: Thu Oct 03, 2013 6:19 pm 
Offline
User avatar

Joined: Wed Oct 06, 2004 6:55 pm
Posts: 1903
Location: Vienna, AUT
I fail to see why 130 is anywhere close to being a baseball bat. Pretty standard length for a lot of us out there...

Now, how can we get some real stiffness stats on this proto? Looks quite nice.


Top
 Profile  
 
PostPosted: Thu Oct 03, 2013 6:22 pm 
Offline
User avatar

Joined: Fri Sep 15, 2006 6:02 am
Posts: 2294
Location: On the bike
Nicely done. Look forward to hearing more about it!


Zen Cyclery wrote:
Ahh a beautiful stem but 130mm? Might as well use a baseball bat for a stem at that point.


What is that suppose to mean?



MajorMantra wrote:
Wow. Is that fully CNC'd? I'd be slightly concerned about the strength of a CNC'd part at that weight.


Why are you concerned about a CNC'd part? No need for concern if it is done correctly by a competent person as mythical seems to be in this regard. I would have no concern.


Top
 Profile  
 
PostPosted: Thu Oct 03, 2013 7:05 pm 
Offline
User avatar

Joined: Mon Nov 02, 2009 8:38 pm
Posts: 292
Just because CNC'd parts are inherently weaker than forged ones, and this is a part that's pushing the limits on weight savings.

_________________
Blog: http://thesetbackpost.com/


Top
 Profile  
 
PostPosted: Thu Oct 03, 2013 8:31 pm 
Offline
User avatar

Joined: Fri Apr 04, 2008 2:49 am
Posts: 1261
Allow me to address a few common misconceptions. First of all, whether forged or CNC-machined, the point at which a part fails (and all parts will fail!) is not determined by how it's manufactured, but rather by how well it's engineered. My aim was to build a stronger and stiffer stem in absolute terms. Why? I wasn't satisfied with the selection of stems I tried, e.g. a Ritchey 4-Axis WCS and Thomson X4, all 130mm, and hoped I could do better.

With FEA (Finite Element Analysis) only being a predictive tool, we calculated how my 3D-stem models behaved when applying the stringent EN14781 and EN14766 test protocols (respectively for road and mountainbikes). The published FEA-report concluded that stresses remained well below the fatigue limit of AL7075-T6 aluminum, the material used for this stem. Currently, these claims are undergoing validation through real world testing by our development partner, a trusted handlebar manufacturer in Germany. The project sustained minor delays caused by illness and faulty manufacturing, so final results are still pending.

Should this stem pass the demanding EN-tests, a basic requirement for stems raced in UCI events, an even greater challenge arises: Convincing potential buyers that our stem is sufficiently strong, stiff and durable, and safe enough for its given application despite its low weight.

As for stiffness values, they mean little by themselves. Such numbers only speak through comparative data generated by pitting this stem against competitors. Blessings to those with patience and understanding! :thumbup:

_________________
RideWert.com
Wert Cycling on Facebook


Top
 Profile  
 
PostPosted: Thu Oct 03, 2013 8:38 pm 
Offline
User avatar

Joined: Fri Sep 15, 2006 6:02 am
Posts: 2294
Location: On the bike
MajorMantra wrote:
Just because CNC'd parts are inherently weaker than forged ones, and this is a part that's pushing the limits on weight savings.


That is a misconception many hold. A properly designed and executed CNC part is just as strong. No need to paint broad strokes.


Top
 Profile  
 
PostPosted: Thu Oct 03, 2013 10:53 pm 
Offline

Joined: Thu Jun 28, 2012 10:52 pm
Posts: 173
Location: eNZed
This product has a ww niche. 37.5mm stack is nice. Please also do 17deg for those who go low.

_________________
Less is more.


Top
 Profile  
 
PostPosted: Thu Oct 03, 2013 11:19 pm 
Online
User avatar

Joined: Thu Dec 22, 2011 12:37 am
Posts: 419
Does it come in black?

_________________
650b Ritchey
Colnago Mapei
S-Works Tarmac


Top
 Profile  
 
PostPosted: Thu Oct 03, 2013 11:36 pm 
Offline

Joined: Sat Jun 20, 2009 3:23 am
Posts: 88
Definitely looks like a nice stem. Add me to the waiting list as long as the price is competitive. Keep us updated on those cranks too, Mythical. What's next beyond the stem and cranks? Brakes (I hope)?


Top
 Profile  
 
PostPosted: Thu Oct 03, 2013 11:46 pm 
Offline

Joined: Thu Jan 03, 2008 6:14 am
Posts: 1205
Location: by Crystal Springs (Sawyer Creek Trail)
53x12 wrote:
MajorMantra wrote:
Just because CNC'd parts are inherently weaker than forged ones, and this is a part that's pushing the limits on weight savings.


That is a misconception many hold. A properly designed and executed CNC part is just as strong. No need to paint broad strokes.


It's a misconception? Forging process refines the grain structure of the material itself. Of course, engineering can get around that for the most part, but a forged part will likely be stronger than a machined one, using the same material


Top
 Profile  
 
Posted: Thu Oct 03, 2013 11:46 pm 


Top
  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 131 posts ] 
Go to page 1, 2, 3, 4, 5 ... 9  Next


Who is online

Users browsing this forum: andreszucs, Google [Bot], HakeemT, Yahoo [Bot] and 37 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

   Similar Topics   Author   Replies   Views   Last post 
There are no new unread posts for this topic. Stiff stem?

[ Go to page: 1, 2, 3 ]

in Road

teleguy57

32

1530

Fri Aug 22, 2014 1:20 pm

spatz View the latest post

There are no new unread posts for this topic. Bar / Stem Combo Thoughts

in Road

LoggingMiles

1

609

Sun Jan 12, 2014 9:27 am

Frankie - B View the latest post

There are no new unread posts for this topic. Light bike or stiff bike?

[ Go to page: 1, 2, 3 ]

in Road

Kermithimself

32

2480

Mon Sep 22, 2014 7:19 pm

06SpiceRed View the latest post

There are no new unread posts for this topic. Looking for stiff, comfortable carbon bullhorns.

in Road

Golliwog

2

288

Thu Jul 31, 2014 10:11 pm

PoorCyclist View the latest post

There are no new unread posts for this topic. Attachment(s) Trek Emonda SLR 10, Thoughts?

[ Go to page: 1 ... 12, 13, 14 ]

in Road

customtune

204

21896

Thu Sep 04, 2014 12:33 pm

964Cup View the latest post


It is currently Thu Oct 02, 2014 5:32 am

All times are UTC + 1 hour




Advertising   –  FAQ   –  Contact   –  Convert   –  About

© Weight Weenies 2000-2013
hosted by starbike.com


How to get rid of these ads? Just register!


Powered by phpBB