Seat tube design of Trek Domane SLR

Back by popular demand, the general all-things Road forum!

Moderator: robbosmans

Post Reply
kai-ming
Posts: 97
Joined: Mon Dec 03, 2007 12:53 pm

by kai-ming

Don't you think the concept of it's seat tube design is basically the same as my Kai-ming's seat post of year 2012 ?
http://www.bikeradar.com/road/gear/arti ... ide-46957/
viewtopic.php?f=3&t=106727

benzebub
Posts: 354
Joined: Thu May 07, 2015 1:24 pm

by benzebub

I'm considering this bike as my next bike, so I'm really interested in the durability of the new design.
Won't the new pivot points create more stress at the very end of the tubes (since they have some more leverage now)?
I'm sure someone with an engineering background can elaborate on this?
But I could be wrong

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

www.starbike.com



russianbear
Posts: 683
Joined: Wed Apr 11, 2012 3:40 am

by russianbear

Trek has lifetime warranty on their frames, I wouldn't worry about it.

User avatar
nickf
Posts: 1427
Joined: Sat Mar 06, 2010 10:34 pm

by nickf

Ditto it would be under warranty and they will take care of you.

pyrahna
Posts: 150
Joined: Wed Aug 14, 2013 9:53 pm

by pyrahna

Your design has solid constraints at 2 points along the cantilevered beam. Their design has 5 degrees of constraint at 2 points and a third constraint that is movable along the cantilevered beam to adjust the rate of the beam. That additional constraint you apply at both ends will increase the rate dramatically.

That isn't to mention the fact that the holes you drilled in the CF seat post took a significant amount of the inherent strength out of the post by taking what was single continuous fibers and chopping them up.

kai-ming
Posts: 97
Joined: Mon Dec 03, 2007 12:53 pm

by kai-ming

pyrahna wrote:Your design has solid constraints at 2 points along the cantilevered beam. Their design has 5 degrees of constraint at 2 points and a third constraint that is movable along the cantilevered beam to adjust the rate of the beam. That additional constraint you apply at both ends will increase the rate dramatically.

That isn't to mention the fact that the holes you drilled in the CF seat post took a significant amount of the inherent strength out of the post by taking what was single continuous fibers and chopping them up.

There are a lot to improve regarding details of my seat post, no doubt about it. What I am referring is the concept of the design.

justkeepedaling
Posts: 1707
Joined: Thu Jan 03, 2008 6:14 am

by justkeepedaling

kai-ming wrote:
pyrahna wrote:Your design has solid constraints at 2 points along the cantilevered beam. Their design has 5 degrees of constraint at 2 points and a third constraint that is movable along the cantilevered beam to adjust the rate of the beam. That additional constraint you apply at both ends will increase the rate dramatically.

That isn't to mention the fact that the holes you drilled in the CF seat post took a significant amount of the inherent strength out of the post by taking what was single continuous fibers and chopping them up.

There are a lot to improve regarding details of my seat post, no doubt about it. What I am referring is the concept of the design.


They're not the same at all AFAIK. Yours does not decouple the seattube from the rest of the frame. Also, your idea was to reduce the net tension capability of the beam significantly in order to induce strain. Pretty much you probably violated both the strain allowable and the tension factors of safety for the design. On top of that, you introduce issues like interlaminar shear during bending and stress risers from your drilling.

Not a great engineering direction.

Anytime i have an option at work to not drill into carbon fiber, I take it.

kai-ming
Posts: 97
Joined: Mon Dec 03, 2007 12:53 pm

by kai-ming

justkeepedaling wrote:
They're not the same at all AFAIK. Yours does not decouple the seattube from the rest of the frame. Also, your idea was to reduce the net tension capability of the beam significantly in order to induce strain. Pretty much you probably violated both the strain allowable and the tension factors of safety for the design. On top of that, you introduce issues like interlaminar shear during bending and stress risers from your drilling.

Not a great engineering direction.

Anytime i have an option at work to not drill into carbon fiber, I take it.

Didn't learn after all these year. :noidea:
Drilling is the easiest way for me to make the post more flexible and lose some weight at the same time. My post not just survive but still works great now after years of battering. :thumbup:

justkeepedaling
Posts: 1707
Joined: Thu Jan 03, 2008 6:14 am

by justkeepedaling

Your design may work for you, I have no idea what you weigh or where you ride. But it sure as heck won't work for such a wide array of conditions a Domane may see (cobbes, big 230+ lb guys, etc etc).

FactoryMatt
Posts: 1014
Joined: Tue Apr 14, 2015 4:35 am

by FactoryMatt

Trek copied part for part EEcycles' Brake design Trek/Bontrager never responded to my inquiry on that one. Done with them.

russianbear
Posts: 683
Joined: Wed Apr 11, 2012 3:40 am

by russianbear

IDENTITAIRE wrote:Trek copied part for part EEcycles' Brake design Trek/Bontrager never responded to my inquiry on that one. Done with them.


Craig and Bontrager are using the same open patent. Designs aren't exactly the same..

User avatar
mattyNor
Posts: 337
Joined: Wed Mar 19, 2014 3:18 pm

by mattyNor

Carbon has a fatigue life in the order of a couple magnitudes greater than aluminium or steel so baring any manufacturing defects it should be the last part to fail on the bike

Sent from my SGH-I337M using Tapatalk

mattr
Posts: 4671
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

kai-ming wrote:Don't you think the concept of it's seat tube design is basically the same as my Kai-ming's seat post of year 2012 ?
No.

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

www.starbike.com



Post Reply