chainstay bridge?

[hgrd]

Hello!:) New to this forum, so in short I am a 30 year old teacher from sweden who has a passion for cyclocross, mountainbiking, and drinking coffee in my armchair in between. I am building my second frame, which is for a cx-bike, and wondered if you would say that the bottom bracket I have eliminates the need for a chainstay bridge? This is what it looks like:
//Henrik

[pruckelshaus]

Theoretically, yes, but the cat who designed that shell will probably be in soon to smack me around a bit. However, it will also probably depend somewhat on chainstay length. If you're at 415 or less, you're fine.

[Curt Goodrich]

There is no "need" for a chain stay bridge. If you have no desire to ever mount a rear fender I'd leave off the chain stay bridge. On a cross bike the bridge tends to collect mud. On my race cross bikes I leave off the bridge and leave the bb shell web. If I use a bridge then I remove the bb shell web. There is no wrong answer though. Well unless you put in a bridge and leave the web. That just looks silly.

[Will Outlaw]

There is no "need" for a chain stay bridge. If you have no desire to ever mount a rear fender I'd leave off the chain stay bridge. On a cross bike the bridge tends to collect mud. On my race cross bikes I leave off the bridge and leave the bb shell web. If I use a bridge then I remove the bb shell web. There is no wrong answer though. Well unless you put in a bridge and leave the web. That just looks silly.

I prefer the term "redundant."

But yeah, now that I look at it closely, it does look silly. Son of FrankenFrame is ready for tacking and will go without a bridge.

2012-05-11_09-39-50_874.jpg

I'm glad someone asked the question because I was wondering the same thing and just went ahead and stuck one in, "just in case."

[e-RICHIE]

...to smack me around a bit.

[hgrd]

[IMG]dirty ritchie[/IMG]

Even if there is an atlantic ocean to keep me safe I might have to put a bridge on there just to sleep at night. ;)

From Curt's answer I take it that chainstay bridges are not primarily about adding strength/stability, but more about mounting fenders?

[pruckelshaus]

I always thought they added a bit of stiffness, especially with oval chainstays.

[e-RICHIE]

I always thought they added a bit of stiffness, especially with oval chainstays.

You're over thinking it atmo. On one hand, no one has ever ridden the same bicycle with/without the bridge - at least, it hasn't been done enough to make a conclusion. On the other, the bridge is a vestige that's part of the 22.2mm chain stay era and one in which the cross-member was not yet cast into the shell. According to my opinion, the word redundant is applicable in this thread because the web in the shell IS the bridge. If, in the future, the end user desires a method to attach a fender to the frame, by all means adding a bridge is a safety net. But I gotta say - it won't add stiffness to the point that it's discernible.