# Chain Stay Bridge?



## crux (Jan 10, 2004)

I have noticed that some frames incorporate a chain stay bridge others do not. (Not sure of the exact terminology, but it is the little tube connecting the two CS by the BB) Was curious is this little piece is needed and what it adds or subtracts from a frame in terms of stiffness? 

Thanks in advance for answering this odd unimportant question.


----------



## Schmitty (Sep 7, 2008)

Seach button is your friend.. hashed out a million times here to no real conclusion other than builder preference, anecdote, and a nice place to hang a fender.

-Schmitty-


----------



## Walt (Jan 23, 2004)

*Endless electrons have been spilled...*

... in this debate. The consensus is that there is no agreement on whether the bridges are 
A) Necessary to prevent the chainstays from breaking or conversely make the chainstays more likely to break.
B) Needed for rear triangle stiffness or totally irrelevant.
C) Divinely inspired or sent here by Old Scratch himself.

For what it's worth, I have ridden frames (that I built) both before and after chainstay bridge installation and could tell no difference. Generally I only install the bridge if the customer wants a kickstand or full fender mounted, so most of my frames do not have them. None has broken, none has come back because it was too flexy. At least so far.

Many reputable people will vehemently disagree with me, of course. In theory, the bridge should make the rear end stiffer. Maybe I'm just too scrawny to notice it when riding.

-Walt



crux said:


> I have noticed that some frames incorporate a chain stay bridge others do not. (Not sure of the exact terminology, but it is the little tube connecting the two CS by the BB) Was curious is this little piece is needed and what it adds or subtracts from a frame in terms of stiffness?
> 
> Thanks in advance for answering this odd unimportant question.


----------



## customfab (Jun 8, 2008)

I too tried a frame with and without because nobody seemed to have a clear answer. Half way into the first ride I knew I wanted the bridge. I don't know if I would have noticed it if I wasn't 190# and I didn't have edge wheels on the bike. putting the bridge in definitely helped out a lot.


----------



## scottzg (Sep 27, 2006)

I cut the bridge off a frame i had damaged the seat tube on (might as well experiment with a totalled frame) and the change was pretty obvious when standing in the saddle. I'm a big guy though.


----------



## mikesnowdon (Sep 25, 2009)

Does the same apply to the seatstay bridge or is it less important? Merely a convenient place to mount a mud guard or brake perhaps?


----------



## Brad Bedell (Apr 18, 2009)

customfab said:


> I too tried a frame with and without because nobody seemed to have a clear answer. Half way into the first ride I knew I wanted the bridge. I don't know if I would have noticed it if I wasn't 190# and I didn't have edge wheels on the bike. putting the bridge in definitely helped out a lot.


I bought a pretty 'hurt' airborne Titanium frame and repaired it (had to replace a seat tube and straighten the frame). I'm 190#, I could flex the frame out of the saddle on climbs and sprints. Enough that my wheel would hit the chainstay. (+1/4") After a bridge, the frame still flexed, but I didn't have any wheel clearance issues. My experience has been that it does increase the stiffness a little, but if one uses a stuffer tube set, I'm not sure it would be noticeable; especially for people who spin at high cadence or are lighter in weight.


----------



## customfab (Jun 8, 2008)

the bigger the rider the more important it is.

Customer feed back is the best kind their is


----------



## Schmitty (Sep 7, 2008)

Not as important as putting stays that match the rider. Make someone a fantastic frame with appropriate tubes, and they will rave about it. They'll be a convert to whatever material, bridge, no bridge, or whatever else you tell them.

-Schmitty-


----------

