Bottom bracket cutouts
#1
Newbie
Thread Starter
Join Date: Apr 2006
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Bottom bracket cutouts
I have just purchased a hand made steel frame. I noticed that the bottom bracket casing/shell has several cutouts. Could someone enlighten me as to the purpose of those cutouts? My gut tells me that they may be there for better heat dissipation, but I am really just guessing.
Thanks!
Thanks!
#2
Senior Member
Join Date: Oct 2004
Location: Absecon, NJ
Posts: 2,947
Bikes: Puch Luzern, Puch Mistral SLE, Bianchi Pista, Motobecane Grand Touring, Austro-Daimler Ultima, Legnano, Raleigh MountainTour, Cannondale SM600
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
drainage.
#3
Senior Member
Join Date: Dec 2001
Location: n.w. superdrome
Posts: 17,687
Bikes: 1 trek, serotta, rih, de Reus, Pogliaghi and finally a Zieleman! and got a DeRosa
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Likes: 0
Liked 9 Times
in
9 Posts
lots of theories, not sure which is the real reason although I've
seen all of these quoted.
1) lets water drain out of BB shell, seat tube etc.
2) Weight savings
3) looks cool and is good Identifying mark (see a clover got a nago! see an M got a masi).
seen all of these quoted.
1) lets water drain out of BB shell, seat tube etc.
2) Weight savings
3) looks cool and is good Identifying mark (see a clover got a nago! see an M got a masi).
__________________
Sono più lento di quel che sembra.
Odio la gente, tutti.
Want to upgrade your membership? Click Here.
Sono più lento di quel che sembra.
Odio la gente, tutti.
Want to upgrade your membership? Click Here.
#4
Senior Member
Join Date: Oct 2004
Location: Absecon, NJ
Posts: 2,947
Bikes: Puch Luzern, Puch Mistral SLE, Bianchi Pista, Motobecane Grand Touring, Austro-Daimler Ultima, Legnano, Raleigh MountainTour, Cannondale SM600
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
Originally Posted by lotek
3) looks cool and is good Identifying mark.
AD Ultima Superleicht
#6
Senior Member
Join Date: Jul 2004
Location: Yukon, Canada
Posts: 8,759
Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 113 Post(s)
Likes: 0
Liked 16 Times
in
14 Posts
I have an M, but it's a Marinoni!
__________________
1 Super Record bike, 1 Nuovo Record bike, 1 Pista, 1 Road, 1 Cyclocross/Allrounder, 1 MTB, 1 Touring, 1 Fixed gear
1 Super Record bike, 1 Nuovo Record bike, 1 Pista, 1 Road, 1 Cyclocross/Allrounder, 1 MTB, 1 Touring, 1 Fixed gear
#7
ex frame builder
Join Date: Aug 2004
Posts: 523
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 5 Times
in
3 Posts
There was a craze in the mid 1970s for drilling holes in bike components to reduce weight. Chainrings, brake levers, and rear derailleurs were drilled full of holes, even seat posts and handlebars by a few people which was pretty stupid. Some bikes had so many holes in them they didn’t have a shadow.
The craze died out when components started failing and drilling out aluminum alloy parts saved only a small amount of weight anyway. The cut-out bottom bracket shell was a hang over from this and lasted through to the early 1980s. It did save a little weight as the BB shell is a pretty hefty chunk of steel.
Doing this by hand was pretty laborious and Masi like most production framebuilders had a die made that would stamp out the “M” in seconds, using a fly-press.
The craze died out when components started failing and drilling out aluminum alloy parts saved only a small amount of weight anyway. The cut-out bottom bracket shell was a hang over from this and lasted through to the early 1980s. It did save a little weight as the BB shell is a pretty hefty chunk of steel.
Doing this by hand was pretty laborious and Masi like most production framebuilders had a die made that would stamp out the “M” in seconds, using a fly-press.
__________________
History, photos and tech articles on "Dave's Bike Blog." 'dave moulton' Registry including a Picture Gallery https://www.davemoultonregistry.com/
History, photos and tech articles on "Dave's Bike Blog." 'dave moulton' Registry including a Picture Gallery https://www.davemoultonregistry.com/
#8
Senior Member
Join Date: Jun 2005
Posts: 532
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 3 Times
in
2 Posts
First I saw cut out BB shells was in the late 60's, it was on a Masi, before the M it appears. Most I would describe as ports, I guess my 2 stroke youth is showing.
A friend ordered a Harry Quinn in 1973, he asked for a drilled BB shell, and thats what he got, about twenty .20" diameter holes neatly spaced on the underside of the BB shell.
All Styling in my book, but fun.
A friend ordered a Harry Quinn in 1973, he asked for a drilled BB shell, and thats what he got, about twenty .20" diameter holes neatly spaced on the underside of the BB shell.
All Styling in my book, but fun.