Install Bottom Bracket backwards?
#1
Senior Member
Thread Starter
Join Date: Mar 2005
Posts: 1,442
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
Install Bottom Bracket backwards?
Any reason I can't install a cartridge BB backwards? Why, you ask?
Hehe- I want a compact crank on my homebuilt recumbent. The present "boom" is from an old ten-speed with an old-style BB. It accomadates an aged full-size triple crank, but that makes my overall gear ratios just a tad too high. I have a nice Alivio compact crank, but it won't work on the present BB and spindle, it won't seat deep enough, and the front DR wont adjust to accomodate it.
So, I have an old Cro-mo Trek frame that was trashed by the frat boys. Seattube and BB still OK, but this would mean reversing the BB to have the "long" end of the spindle (where the crank mounts) on the proper side of the bike. (the downtube is bent.)
(This is one ugly critter, BTW, but functional. It's a test-bed for version 2.0)
Hehe- I want a compact crank on my homebuilt recumbent. The present "boom" is from an old ten-speed with an old-style BB. It accomadates an aged full-size triple crank, but that makes my overall gear ratios just a tad too high. I have a nice Alivio compact crank, but it won't work on the present BB and spindle, it won't seat deep enough, and the front DR wont adjust to accomodate it.
So, I have an old Cro-mo Trek frame that was trashed by the frat boys. Seattube and BB still OK, but this would mean reversing the BB to have the "long" end of the spindle (where the crank mounts) on the proper side of the bike. (the downtube is bent.)
(This is one ugly critter, BTW, but functional. It's a test-bed for version 2.0)
#2
Senior Member
If it's a cup and cone bottom bracket, you could just flip the spindle. Whether or not this helps is a different matter... Sometimes this is an effective tool for getting fixed-gear chainline pretty close on the cheap, sometimes not. You'll have to measure your spindle to see how this affects things...
#3
Senior Member
Join Date: Mar 2005
Location: Happy Valley
Posts: 813
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Originally Posted by Bikewer
Any reason I can't install a cartridge BB backwards? Why, you ask?
Hehe- I want a compact crank on my homebuilt recumbent. The present "boom" is from an old ten-speed with an old-style BB. It accomadates an aged full-size triple crank, but that makes my overall gear ratios just a tad too high. I have a nice Alivio compact crank, but it won't work on the present BB and spindle, it won't seat deep enough, and the front DR wont adjust to accomodate it.
So, I have an old Cro-mo Trek frame that was trashed by the frat boys. Seattube and BB still OK, but this would mean reversing the BB to have the "long" end of the spindle (where the crank mounts) on the proper side of the bike. (the downtube is bent.)
(This is one ugly critter, BTW, but functional. It's a test-bed for version 2.0)
Hehe- I want a compact crank on my homebuilt recumbent. The present "boom" is from an old ten-speed with an old-style BB. It accomadates an aged full-size triple crank, but that makes my overall gear ratios just a tad too high. I have a nice Alivio compact crank, but it won't work on the present BB and spindle, it won't seat deep enough, and the front DR wont adjust to accomodate it.
So, I have an old Cro-mo Trek frame that was trashed by the frat boys. Seattube and BB still OK, but this would mean reversing the BB to have the "long" end of the spindle (where the crank mounts) on the proper side of the bike. (the downtube is bent.)
(This is one ugly critter, BTW, but functional. It's a test-bed for version 2.0)
__________________
It is my belief that every person in this world has something to teach, and everything to learn.
In memory of Jim Price (aka. sydney) ...
It is my belief that every person in this world has something to teach, and everything to learn.
In memory of Jim Price (aka. sydney) ...
#4
Senior Member
Thread Starter
Join Date: Mar 2005
Posts: 1,442
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
I'm actually embarrassed. I had already cut the frame segment away and was simply looking at it wrong. The "short" side of the spindle takes the crank, and the long side goes on the left. I was holding it wrong...
This bit of cro-mo frame should give me a slightly-lighter boom, and the compact crank should lower my overall gear ratios to the point I want 'em. The only fly in the ointment will be mounting the front DR on the rather bent portion of the frame. I think it will go right under the damaged part, though.
This bit of cro-mo frame should give me a slightly-lighter boom, and the compact crank should lower my overall gear ratios to the point I want 'em. The only fly in the ointment will be mounting the front DR on the rather bent portion of the frame. I think it will go right under the damaged part, though.
#5
Perineal Pressurized
Join Date: Oct 2003
Location: In Ebritated
Posts: 6,555
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 2 Times
in
2 Posts
Originally Posted by juicemouse
Most every modern bottom bracket, including the one that's meant to work with your Alivio compact crank, uses a symmetrical spindle. There ain't no "long end" on these units.
Campy has asymmetrical cartridges. Phil Wood has a plethora of em
__________________
This is Africa, 1943. War spits out its violence overhead and the sandy graveyard swallows it up. Her name is King Nine, B-25, medium bomber, Twelfth Air Force. On a hot, still morning she took off from Tunisia to bomb the southern tip of Italy. An errant piece of flak tore a hole in a wing tank and, like a wounded bird, this is where she landed, not to return on this day, or any other day.
This is Africa, 1943. War spits out its violence overhead and the sandy graveyard swallows it up. Her name is King Nine, B-25, medium bomber, Twelfth Air Force. On a hot, still morning she took off from Tunisia to bomb the southern tip of Italy. An errant piece of flak tore a hole in a wing tank and, like a wounded bird, this is where she landed, not to return on this day, or any other day.
#6
Senior Member
Join Date: Jan 2004
Posts: 9,428
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 2 Times
in
2 Posts
Originally Posted by dobber
Some of the Shimano brackets are non-symmetrical. A 107 and a 110 extend equal length on the drive side but the 110 is 3 mm longer on the non-drive side. This lets you fiddle a bit with the chainline if need be.