Dropped seat stays - good bad or ugly?!

General cycling advice ( NOT technical ! )
Jamesh
Posts: 681
Joined: 2 Jan 2017, 5:56pm

Dropped seat stays - good bad or ugly?!

Postby Jamesh » 20 Oct 2019, 9:35am

https://road.cc/content/feature/267053- ... st-gimmick

Not keen on them myself - must load up the seat tube?

Ugly as can be!

Cheers James

Brucey
Posts: 35965
Joined: 4 Jan 2012, 6:25pm

Re: Dropped seat stays - good bad or ugly?!

Postby Brucey » 20 Oct 2019, 10:15am

done well, in carbon, it can increase the frame's movement when you go over bumps.

Done as well as it is usually done, in other materials, it can promote premature failure of the frame. I've seen quite a few break there.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

User avatar
Sweep
Posts: 5777
Joined: 20 Oct 2011, 4:57pm
Location: London

Re: Dropped seat stays - good bad or ugly?!

Postby Sweep » 20 Oct 2019, 10:49am

Not my style of bike and i am no engineer at all.
Isn't the idea sold on increased stiffness?
But do you then get a reduction in stiffness of the entire contraption from the longer "exposed" seat tube and post?
Or is that sold as comfort/flexibility?
Last edited by Sweep on 20 Oct 2019, 4:48pm, edited 1 time in total.
Sweep

User avatar
Spinners
Posts: 1575
Joined: 6 Dec 2008, 6:58pm
Location: Port Talbot

Re: Dropped seat stays - good bad or ugly?!

Postby Spinners » 20 Oct 2019, 4:11pm

Hugely fashionable at the moment (sell 'em more) and probably proving that they're all made in the same factory. I'm not convinced by the "stiff yet compliant" sales blurb but some bikes look OK.
Cycling UK Life Member
PBP Ancien (2007)

mattheus
Posts: 840
Joined: 29 Dec 2008, 12:57pm

Re: Dropped seat stays - good bad or ugly?!

Postby mattheus » 21 Oct 2019, 1:09pm

Spinners wrote:Hugely fashionable at the moment (sell 'em more) and probably proving that they're all made in the same factory. I'm not convinced by the "stiff yet compliant" sales blurb but some bikes look OK.

"stiff yet compliant" is the new
"waterproof yet breathable"
Everyone is putting it on every model they make. Hands-up who is convinced??

The latest press that I have seen claims the dropped seat stays have less drag - which does at least seem feasible. They certainly seem structurally dubious, so I'm not surprised if Brucey has seen failures. Of course in the real world, people put bags on their bikes and/or lights etc, so the tiny aero improvments will be quickly swallowed up. What %age of MAMILs are *actually* riding road-races??

User avatar
Audax67
Posts: 4530
Joined: 25 Aug 2011, 9:02am
Location: Alsace, France
Contact:

Re: Dropped seat stays - good bad or ugly?!

Postby Audax67 » 21 Oct 2019, 1:33pm

As ugly as <not allowed to say that> on a blanket.
Have we got time for another cuppa?

User avatar
100%JR
Posts: 900
Joined: 31 May 2016, 10:47pm
Location: High Green,Sheffield.

Re: Dropped seat stays - good bad or ugly?!

Postby 100%JR » 21 Oct 2019, 2:10pm

Aesthetically I don't mind the look of them.I'm not convinced they're any better or worse than traditional stays.I personally don't like the skinny look of the old 60s/70s frames with curved forks but many love them.Fashion and trends come and go.
Beauty is in the eye of the beholder as they say :)
Canyon Ultimate CF SL
Lynskey R480 build
Boardman CX Comp
We hate "speed" Cameras.Brexit makes no sense!!.

mercalia
Posts: 11526
Joined: 22 Sep 2013, 10:03pm
Location: london South

Re: Dropped seat stays - good bad or ugly?!

Postby mercalia » 21 Oct 2019, 3:27pm

some kind of bending moment at work? Given how thin the tubes are I wouldnt want a bike like that!

Vorpal
Moderator
Posts: 17320
Joined: 19 Jan 2009, 3:34pm
Location: Not there ;)

Re: Dropped seat stays - good bad or ugly?!

Postby Vorpal » 21 Oct 2019, 4:13pm

I guess that it can make some sense with CF, especially for racing cyclists that need every scrap of pedalling efficiency they can hang onto. I don't think that it's a good idea with steel, and it's even worse for aluminium.

There were two reasons to have the seat stays meet at the same place as the top tube, or at least in the same area on traditional diamond frames. The first is to reduce the heat affected zone (from welding or brazing). The second reason is tube thickness. On a butted frame, the thickness varies, increasing in areas where there are stress risers, and and decreasing where stresses on the frame are lower. Having thinner walls allows frame builders & bike companies to save weight. If you lower the seat stays substantially, you need higher wall thickness due to the increased stresses, both from mounting the seat stays there, and from the mounting process, likely welding. The additional material needed for the seat tube is offset by less material needed for the stays.

The additional stiffness does have some advantage in the transfer of pedalling energy. However, that energy will now be transferred through the stays, and as Brucey says, result in premature failure, unless the material is made that much thicker again to make up for the higher stresses, and that kind of defeats the benefit.
“In some ways, it is easier to be a dissident, for then one is without responsibility.”
― Nelson Mandela, Long Walk to Freedom

thelawnet
Posts: 2248
Joined: 27 Aug 2010, 12:56am

Re: Dropped seat stays - good bad or ugly?!

Postby thelawnet » 21 Oct 2019, 5:00pm

It's mostly a way to try and make last year's model look obsolete so they can shift product.

Same with the 12mm TA that is replacing 9/10mm QR. Don't have it? Old-hat.

Another one is 'flat mount' disc brakes.

They are great news for bike vendors because they require a new frameset.

People making MTBs decided it would be a good idea to introduce a dozen different axle widths/diameters as well.

peetee
Posts: 1417
Joined: 4 May 2010, 10:20pm
Location: Cornwall

Re: Dropped seat stays - good bad or ugly?!

Postby peetee » 22 Oct 2019, 10:02am

Did somebody mention bending moments?
Lean a stick against a wall.
Q. Where's the easiest place to break it with a kick?
A. I the middle.
Substitute the stick for a seat tube and the kick for the shock from a back wheel travelling up the stays.

There's the reason why hard tail mountain bikes don't have dropped stays.
Current status report:
Latter side of fifty and feeling less than nifty.
Too many bikes on pegs and too few miles in the legs.

reohn2
Posts: 36401
Joined: 26 Jun 2009, 8:21pm

Re: Dropped seat stays - good bad or ugly?!

Postby reohn2 » 22 Oct 2019, 10:05am

Audax67 wrote:As ugly as <not allowed to say that> on a blanket.

But reputedly to help the same stuff off a shovel.
Last edited by reohn2 on 22 Oct 2019, 10:48am, edited 1 time in total.
-----------------------------------------------------------
I cycle therefore I am.

reohn2
Posts: 36401
Joined: 26 Jun 2009, 8:21pm

Re: Dropped seat stays - good bad or ugly?!

Postby reohn2 » 22 Oct 2019, 10:06am

100%JR wrote:Aesthetically I don't mind the look of them.I'm not convinced they're any better or worse than traditional stays.I personally don't like the skinny look of the old 60s/70s frames with curved forks but many love them.Fashion and trends come and go.
Beauty is in the eye of the beholder as they say :)

And fashion is a master that can never be satisfied :wink:
-----------------------------------------------------------
I cycle therefore I am.

thelawnet
Posts: 2248
Joined: 27 Aug 2010, 12:56am

Re: Dropped seat stays - good bad or ugly?!

Postby thelawnet » 22 Oct 2019, 10:51am

peetee wrote:There's the reason why hard tail mountain bikes don't have dropped stays.


Someone made one

https://www.bikehub.co.za/features/_/ge ... dera-r7773

Image

Marcus Aurelius
Posts: 449
Joined: 1 Feb 2018, 10:20am

Re: Dropped seat stays - good bad or ugly?!

Postby Marcus Aurelius » 22 Oct 2019, 10:59am

From a comfort point of view, they are superb, in my experience, they break the shock pathway up, between the wheel and the seat post to your spine, they also help with aero, and given that you spend 80% of your effort moving air out of your way, whilst cycling, every little helps. They do make the bike look fugly though. All in all, they are worth having.