I just bought an old Bridgestone MB-2 (1986 model, I believe) which I'm converting into a fixed-gear commuter. The bottom bracket shell is 70mm wide, and the existing cup-and-cone bottom bracket is marked with ' 1.37" x 24 tpi '. Older threads on this newsgroup indicate that this is British threading.
I'd like to replace this bottom bracket with the modern cartridge variety, but I'm having difficulty finding ones that are both 70mm and British-threaded. (British-threaded usually come in 68mm or 73mm, and 70mm ones usually have Italian threads.) The only one I've seen online is a Campagnolo Veloce that comes with 111mm spindle. However, I plan to use different bottom bracket spindle lengths as the mechanism for adjusting the chainline [1], and I'd like to find some that come in other spindle lengths. Can anyone point me to some? Alternatively, is it possible to use a 73mm BB with spacers? Or a 68mm BB with only partial thread engagement? Or perhaps there's a better solution I have not considered.
Thanks for your time.
[1] I will use a flip-flop hub, and cannot adjust the chainline with spacers and re-dishing the wheel.
I just bought an old Bridgestone MB-2 (1986 model, I believe) which I'm converting into a fixed-gear commuter. The bottom bracket shell is 70mm wide, and the existing cup-and-cone bottom bracket is marked with ' 1.37" x 24 tpi '. Older threads on this newsgroup indicate that this is British threading.
I'd like to replace this bottom bracket with the modern cartridge variety, but I'm having difficulty finding ones that are both 70mm and British-threaded. (British-threaded usually come in 68mm or 73mm, and 70mm ones usually have Italian threads.) The only one I've seen online is a Campagnolo Veloce that comes with 111mm spindle. However, I plan to use different bottom bracket spindle lengths as the mechanism for adjusting the chainline [1], and I'd like to find some that come in other spindle lengths. Can anyone point me to some? Alternatively, is it possible to use a 73mm BB with spacers? Or a 68mm BB with only partial thread engagement? Or perhaps there's a better solution I have not considered.
Phil Wood. He uses the same BB for 68/70 and it is installed with rings that do not rest on the BB shell, so you can move the BB to adjust your chainline, which is helpful on a fixed gear. Phil is expensive, though. -- Jay Beattie.
Unless the B.O.B. knows otherwise I believe you have a 68mm bottom bracket shell. Are you measuring just the frame or any parts of the bototm bracket sticking out of it?
"Stephen Greenwood" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
I just bought an old Bridgestone MB-2 (1986 model, I believe) which I'm converting into a fixed-gear commuter. The bottom bracket shell is 70mm wide, and the existing cup-and-cone bottom bracket is marked with ' 1.37" x 24 tpi '. Older threads on this newsgroup indicate that this is British threading.
I'd like to replace this bottom bracket with the modern cartridge variety, but I'm having difficulty finding ones that are both 70mm and British-threaded. (British-threaded usually come in 68mm or 73mm, and 70mm ones usually have Italian threads.) The only one I've seen online is a Campagnolo Veloce that comes with 111mm spindle. However, I plan to use different bottom bracket spindle lengths as the mechanism for adjusting the chainline [1], and I'd like to find some that come in other spindle lengths. Can anyone point me to some? Alternatively, is it possible to use a 73mm BB with spacers? Or a 68mm BB with only partial thread engagement? Or perhaps there's a better solution I have not considered.
Thanks for your time.
[1] I will use a flip-flop hub, and cannot adjust the chainline with spacers and re-dishing the wheel.
As I recall the metric equivalent to the English threading is the same for an IT BB, except the drive side cup is right hand threaded. So check that too to make sure you have a BSC not an ITL BB
"Kurd" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
Unless the B.O.B. knows otherwise I believe you have a 68mm bottom bracket shell. Are you measuring just the frame or any parts of the bototm bracket sticking out of it?
"Stephen Greenwood" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
I just bought an old Bridgestone MB-2 (1986 model, I believe) which I'm converting into a fixed-gear commuter. The bottom bracket shell is 70mm wide, and the existing cup-and-cone bottom bracket is marked with ' 1.37" x 24 tpi '. Older threads on this newsgroup indicate that this is British threading.
I'd like to replace this bottom bracket with the modern cartridge variety, but I'm having difficulty finding ones that are both 70mm and British-threaded. (British-threaded usually come in 68mm or 73mm, and 70mm ones usually have Italian threads.) The only one I've seen online is a Campagnolo Veloce that comes with 111mm spindle. However, I plan to use different bottom bracket spindle lengths as the mechanism for adjusting the chainline [1], and I'd like to find some that come in other spindle lengths. Can anyone point me to some? Alternatively, is it possible to use a 73mm BB with spacers? Or a 68mm BB with only partial thread engagement? Or perhaps there's a better solution I have not considered.
Thanks for your time.
[1] I will use a flip-flop hub, and cannot adjust the chainline with spacers and re-dishing the wheel.
I just bought an old Bridgestone MB-2 (1986 model, I believe) which I'm converting into a fixed-gear commuter. The bottom bracket shell is 70mm wide, and the existing cup-and-cone bottom bracket is marked with ' 1.37" x 24 tpi '. Older threads on this newsgroup indicate that this is British threading.
I'd like to replace this bottom bracket with the modern cartridge variety, but I'm having difficulty finding ones that are both 70mm and British-threaded. (British-threaded usually come in 68mm or 73mm, and 70mm ones usually have Italian threads.) The only one I've seen online is a Campagnolo Veloce that comes with 111mm spindle. However, I plan to use different bottom bracket spindle lengths as the mechanism for adjusting the chainline [1], and I'd like to find some that come in other spindle lengths. Can anyone point me to some? Alternatively, is it possible to use a 73mm BB with spacers? Or a 68mm BB with only partial thread engagement? Or perhaps there's a better solution I have not considered.
If the threads go far enough into the BB shell, you can just use a 68mm BB; you'll get full thread engagement. In fact, the left retainer will go all the way into the shell. The BB will run 1mm off center to the right, which shouldn't hurt anything when it comes to getting the chainline set where you want it. -- Typoes are a feature, not a bug. Some gardening required to reply via email. Words processed in a facility that contains nuts.
Unless the B.O.B. knows otherwise I believe you have a 68mm bottom bracket shell. Are you measuring just the frame or any parts of the bototm bracket sticking out of it?
I'm measuring just the frame, not the lockrings or anything else. I used a precision caliper, and I just checked it again -- it's 70.0 mm.
If the threads go far enough into the BB shell, you can just use a 68mm BB; you'll get full thread engagement. In fact, the left retainer will go all the way into the shell. The BB will run 1mm off center to the right, which shouldn't hurt anything when it comes to getting the chainline set where you want it.
Thanks, Werehatrack, that should probably work. I installed a Shimano cartridge BB a few years ago, but had forgotten that the left side didn't have some sort of ring that abuts the BB shell.
As for Phil Wood's BBs (suggested by Jay Beattie), they certainly seem technically superior, but using a run-of-the-mill model is more appropriate for what's meant to be a budget bike. Still, I appreciate knowing about this option, so thank you, too, Jay.
I just bought an old Bridgestone MB-2 (1986 model, I believe) which I'm converting into a fixed-gear commuter. The bottom bracket shell is 70mm wide, and the existing cup-and-cone bottom bracket is marked with ' 1.37" x 24 tpi '. Older threads on this newsgroup indicate that this is British threading.
I'd like to replace this bottom bracket with the modern cartridge variety, but I'm having difficulty finding ones that are both 70mm and British-threaded. (British-threaded usually come in 68mm or 73mm, and 70mm ones usually have Italian threads.) The only one I've seen online is a Campagnolo Veloce that comes with 111mm spindle. However, I plan to use different bottom bracket spindle lengths as the mechanism for adjusting the chainline [1], and I'd like to find some that come in other spindle lengths. Can anyone point me to some? Alternatively, is it possible to use a 73mm BB with spacers? Or a 68mm BB with only partial thread engagement? Or perhaps there's a better solution I have not considered.
Thanks for your time.
[1] I will use a flip-flop hub, and cannot adjust the chainline with spacers and re-dishing the wheel.
Frame BB shell has never been faced is all...Take it to a good shop and do same...get it to 68mm.
As I recall the metric equivalent to the English threading is the same for an IT BB, except the drive side cup is right hand threaded. So check that too to make sure you have a BSC not an ITL BB
_ This is wrong.
Italian is just a tiny bit larger. 36mm x 24tpi. BSC (1.375 inches or 34.925mm) x 24tpi
I just bought an old Bridgestone MB-2 (1986 model, I believe) which I'm converting into a fixed-gear commuter. The bottom bracket shell is 70mm wide, and the existing cup-and-cone bottom bracket is marked with ' 1.37" x 24 tpi '. Older threads on this newsgroup indicate that this is British threading.
70mm English threaded BB's do exist. I have some old Nishiki frames that had them and it threw me for a loop as well. I posted a question about it on this group and the consensus answer was to have the shell faced to 68mm and use a standard BB. See:
As I recall the metric equivalent to the English threading is the same for an IT BB, except the drive side cup is right hand threaded. So check that too to make sure you have a BSC not an ITL BB
Quoted message said:
_ This is wrong.
Italian is just a tiny bit larger. 36mm x 24tpi. BSC (1.375 inches or 34.925mm) x 24tpi
True, but that silly millimeter larger is just enough to prevent the threads of an English BB from engaging an Italian BB shell.
