Seat stay design - true statement or marketing gimmick? Discuss...

[scottcw2]

Came across this on the web. True or market speak?

X pioneered the use of carbon-fiber seat and chain stays on their aluminum frames, the design of which is called the X double stay design. The advantage of this design is better comfort compared to the monolink design that is prevalent among racing bicycles (such as on the Columbus Muscle stays). The monolink design was used in earlier carbon seat/chain stay design in order to save costs, since only one piece needs to be welded to the main triangle of the frame.

[e-RICHIE]

hmmm. that is a tough one.

[davids]

hmmm. that is a tough one.

http://www.glarkware.com/media/product_main_g_irony.jpg

[pdxmech13]

who's Irony ?

[davids]

who's Irony ?

http://www.mathcs.emory.edu/~mic/images/funny/sarcasm.gif

[scottcw2]

To clarify the question... is there a benefit to separate seat stays that are joined on either side of the ST v. a wishbone design?

[David Kirk]

To clarify the question... is there a benefit to separate seat stays that are joined on either side of the ST v. a wishbone design?


What is your gut feeling?

Dave

[bostondrunk]

To clarify the question... is there a benefit to separate seat stays that are joined on either side of the ST v. a wishbone design?

My gut feeling is that opinions will depend on who's decals are on the frame...
I think DK's frames are really nice, but do I believe a funky curved seat stay makes a difference? No offence, not trying to point the finger at any particular brand, just my opinion.

Oh, and the real answer to your question is.......no.

[scottcw2]

What is your gut feeling?

Dave

I know nothing about bike design, but I would guess no.

[David Kirk]

I know nothing about bike design, but I would guess no.

Technically speaking a pair of individual stays should be stiffer than a monostay laterally. It's a more direct load path and uses the stay in a more pure compression mode instead of a slight bending mode.

That said it may or may not be depending on materials, diameters, and overall design. It all depends.

Dave

[vaxn8r]

But isn't a monostay really just a shorter double stay?

[Dr. Doofus]

oodf pionered the double eyebrow

the monobrow is an inferior design, chosen mainly to reduce production costs

[David Kirk]

But isn't a monostay really just a shorter double stay?

In effect it is but with a stem coming out the top.

Picture a pair of traditional seatstays from the rear. The make a single tall triangle (triangles are good). The lower leg of the triangle is the rear axle and the other tow legs are the stays themselves.

With a mono-stay the triangle ends just above the wheel and them goes into a single tube to meet the back of the seat tube. The issue (depending on design of course) comes where the lower seat stay triangle meets the monostay. You've taken a nice neat triangle and hooked it to a single tube that won't/can't have the same lateral stiffness. You can have some serious flexing at the point where that nice stiff triangle meets the single strut. It can act like a pivot.

The big caveat here is the diameter of the mono-stay itself. There are some out there that are 9/16" in dia. ( I built some Serotta team issue TT bikes years ago with this design - not good) and some are huge 1 1/4" tubes. These might even be stiffer that a pair of stays.

It all boils down to actual design imho.

Dave

[scottcw2]

The big caveat here is the diameter of the mono-stay itself. There are some out there that are 9/16" in dia. ( I built some Serotta team issue TT bikes years ago with this design - not good) and some are huge 1 1/4" tubes. These might even be stiffer that a pair of stays.

It all boils down to actual design imho.

Dave

Here is a pic of the bike in question. It is a COLUMBUS MUSCLE WISHBONE STAY (http://i6.ebayimg.com/01/i/06/80/3e/3f_3.JPG).

[Ken Lehner]

In effect it is but with a stem coming out the top.

You can have some serious flexing at the point where that nice stiff triangle meets the single strut. It can act like a pivot.

Dave

What fraction of a millimeter might the rear dropout move as a result of this "pivot"? Could you even measure the deflection?

[Frustration]

It would depend on the shape of the stay as well wouldn't it?

[saab2000]

What fraction of a millimeter might the rear dropout move as a result of this "pivot"? Could you even measure the deflection?

Whether or not it is significantly measurable, an improperly designed thing here will make the difference between a solid frame with some life in it and a mushy, dead-feeling frame. I think.

It is this that has me a bit leary of the ST stays, though I also know that these get good reviews. I just wonder how they would be on a race bike.

So there.

[Kahuna]

Here are some interesting seatstays you guys can discuss...

CSC is using this bike mostly for races that have long sections of cobblestones.

[Fixed]

bro those look like thin seat stays . I like the bike though cheers
did basso ride one like that yesterday?

[jerk]

monostay versus double-stay or whatever they're calling it? who cares? does anyone really believe it makes a bit of difference when regardless of the stay design it is attached to the drop-out with a bolt the manfuacturer deems too small to hold the waterbottle cage else where on the frame?

as for that cervelo; check out those chainstays. all the seat stays are doing is hoilding the brake in place an insuring uci compliance....that's the only "compliance" going on with that thing. the r3 is super stiff and super light (although it rides like wood), and csc will use it in the classics mostly because it has better tire clearance and can only be built to uci weight limits with "regular" 32 spoke wheels and heavier tires.

jerk

[Fixed]

bro the jerk is really smart he told me to do one thing with my bike and the difference was day and night. I'd be happy if i knew 1/10 as much as this cat .cheers
oh yeah thanks for your help bro

[Dr. Doofus]

yo jerk

now that doof's bars are 16mm lower

and his saddle is 1mm lower

what's the one thing he should do with his bike?

(other than sell it and take up canasta)

[stevep]

the monostay came about because it simplifies the manufacturing process...with a monostay the rear end can be prefabricated and they are all the same...then just mitred and stuck in the size frame required.
it is just a way to reduce inventory and speed manufacture.
work better? work worse?
probably neither... although i remember laughing at the first bike merlin made with the monostay..they could not fit 700-23 tires!!!
a real scream. ( not for them, though )

[manet]

http://www.glarkware.com/media/product_main_g_irony.jpg

http://www.buzzle.com/img/cards/ironing_med.jpg

[jerk]

yo jerk

now that doof's bars are 16mm lower

and his saddle is 1mm lower

what's the one thing he should do with his bike?

(other than sell it and take up canasta)


stp measuring it and ride it.

jerk

[e-RICHIE]

stp measuring it and ride it.

jerk


man - that is true craig's list material atmo.

[Dr. Doofus]

thanks

ride it?

thought it was just for looking good on the hardwood floors....

[jerk]

thanks

ride it?

thought it was just for looking good on the hardwood floors....


no you're confusing your bike for your sister again.

jerk

[Dr. Doofus]

no you're confusing your bike for your sister again.

jerk

thanks bro

so which one do I put the chainlube on?

[manet]

.

[jerk]

thanks bro

so which one do I put the chainlube on?


ahmmm....could you please repeat the question?

[Dr. Doofus]

helter skelter

i got blisters from my sister

or maybe i just need to change the bar tape

or wear gloves