Need replacement Spindle or BB for 83 Trek 520
09-22-18, 12:17 PM
#1
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Need replacement Spindle or BB for 83 Trek 520
Hi where can I find a replacement spindle or bottom bracket, which ever is readily available, for my 1983 Trek 520? I have the original crankset which has a triple chainring. Any suggestions are greatly appreciated.
Says Sakae 1.37x24t
Says Sakae 1.37x24t
09-22-18, 12:44 PM
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Shimano UN-55 worked well for me. I initially did a 127, but a 124 fit better on on my Trek 700 triple. However, the fit is a bit dependent on the crankset, in my experience.
09-22-18, 01:47 PM
#3
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Whoa, what happened?
I used a Shimano cartridge on a 520 Cirrus as well. Can’t remember the length. If you still have the remainder of the spindle, get a measurement from the B.B. shell to the DS spindle end, and then buy the cartridge unit that matches. Or find the right cup/cone version if you prefer.
I used a Shimano cartridge on a 520 Cirrus as well. Can’t remember the length. If you still have the remainder of the spindle, get a measurement from the B.B. shell to the DS spindle end, and then buy the cartridge unit that matches. Or find the right cup/cone version if you prefer.
09-22-18, 01:51 PM
#4
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Thanks that looks look a good option. How would I determine if it'd be a good it on my crankset? I have the SR Super Custom crankset.
09-22-18, 01:53 PM
#5
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Thread Starter
Whoa, what happened?
I used a Shimano cartridge on a 520 Cirrus as well. Can’t remember the length. If you still have the remainder of the spindle, get a measurement from the B.B. shell to the DS spindle end, and then buy the cartridge unit that matches. Or find the right cup/cone version if you prefer.
I used a Shimano cartridge on a 520 Cirrus as well. Can’t remember the length. If you still have the remainder of the spindle, get a measurement from the B.B. shell to the DS spindle end, and then buy the cartridge unit that matches. Or find the right cup/cone version if you prefer.
09-22-18, 03:15 PM
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If you can salvage the crankset, as @due ruote said, measure the existing spindle - try total length minus the threaded (male) portion of the spindle, if there is one. That will give you a starting point.
If asymmetrical ( drive side different distance from race to end than non-drive side - which is likely on these Treks), see this https://www.sheldonbrown.com/bbsize.html
Scroll down to where the diagram of the spindle is, with the table below. That should bring you home.
Not much downside being wrong here, ultimately you will probably use the other one some day. I usually start out wider (127) and see how the bike shifts. Too close in and either the smallest front chainring rubs on the frame or you will get chainrub on the middle front chainring when on the smallest front chainring and are in the middle rear cogs.
You could also try to figure out chainline, but I'm an engineer and can't figure it out reliably - I just do trial and error (hence a drawer full of different spindles)
09-22-18, 08:51 PM
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Do you have a co-op within vicinity?
Coincidentally, I bought a 520 yesterday. It’s one year newer than yours, but has the same SR crankset. I had to address the bottom bracket right away. It wasn’t broken, but it was installed backwards, which caused the small chainring to rub against the chainstay. Of course, this made the bike inoperable.
I pulled the crank, and removed the bottom bracket.
Upon cleaning the parts up for reinstallstion, I noticed the spindle was pretty chewed up along its bearing surfaces.
The spindle is stamped “3 T,” and according to Sheldon Brown’s website that signifies the spindle is 123mm in overall length.
Today, a visit to the co-op turned up exactly one 3 T stamped spindle, which was luckily in good condition. The replacement is shown above the one being replaced...
Good luck getting your Trek back on track!
Coincidentally, I bought a 520 yesterday. It’s one year newer than yours, but has the same SR crankset. I had to address the bottom bracket right away. It wasn’t broken, but it was installed backwards, which caused the small chainring to rub against the chainstay. Of course, this made the bike inoperable.
I pulled the crank, and removed the bottom bracket.
Upon cleaning the parts up for reinstallstion, I noticed the spindle was pretty chewed up along its bearing surfaces.
The spindle is stamped “3 T,” and according to Sheldon Brown’s website that signifies the spindle is 123mm in overall length.
Today, a visit to the co-op turned up exactly one 3 T stamped spindle, which was luckily in good condition. The replacement is shown above the one being replaced...
Good luck getting your Trek back on track!
09-23-18, 03:01 PM
#8
Senior Member
You could try these guys:
Husky Bicycles: Bottom Bracket Parts
Husky Bicycles: Bottom Bracket Parts
09-24-18, 08:58 AM
#9
Senior Member
So the SR Super Custom would be a new crank or is it the existing crank and you were able to extract the portion of the spindle that broke?
If you can salvage the crankset, as @due ruote said, measure the existing spindle - try total length minus the threaded (male) portion of the spindle, if there is one. That will give you a starting point.
If asymmetrical ( drive side different distance from race to end than non-drive side - which is likely on these Treks), see this https://www.sheldonbrown.com/bbsize.html
Scroll down to where the diagram of the spindle is, with the table below. That should bring you home.
Not much downside being wrong here, ultimately you will probably use the other one some day. I usually start out wider (127) and see how the bike shifts. Too close in and either the smallest front chainring rubs on the frame or you will get chainrub on the middle front chainring when on the smallest front chainring and are in the middle rear cogs.
You could also try to figure out chainline, but I'm an engineer and can't figure it out reliably - I just do trial and error (hence a drawer full of different spindles)
If you can salvage the crankset, as @due ruote said, measure the existing spindle - try total length minus the threaded (male) portion of the spindle, if there is one. That will give you a starting point.
If asymmetrical ( drive side different distance from race to end than non-drive side - which is likely on these Treks), see this https://www.sheldonbrown.com/bbsize.html
Scroll down to where the diagram of the spindle is, with the table below. That should bring you home.
Not much downside being wrong here, ultimately you will probably use the other one some day. I usually start out wider (127) and see how the bike shifts. Too close in and either the smallest front chainring rubs on the frame or you will get chainrub on the middle front chainring when on the smallest front chainring and are in the middle rear cogs.
You could also try to figure out chainline, but I'm an engineer and can't figure it out reliably - I just do trial and error (hence a drawer full of different spindles)
if you want to use your original cups and just replace the spindle, posting the dimensions of your old one may shake a replacement out if the bushes.
Last edited by due ruote; 09-24-18 at 09:02 AM.
09-24-18, 09:35 AM
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I might have one of those laying around. Let me check tonight when I get off work.
EDIT: Nope, don't have one of those.
EDIT: Nope, don't have one of those.
Last edited by Knet; 09-25-18 at 07:52 AM.
09-29-18, 11:11 AM
#11
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Thread Starter
09-29-18, 11:59 AM
#12
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Thread Starter
So the SR Super Custom would be a new crank or is it the existing crank and you were able to extract the portion of the spindle that broke?
If you can salvage the crankset, as @due ruote said, measure the existing spindle - try total length minus the threaded (male) portion of the spindle, if there is one. That will give you a starting point.
If asymmetrical ( drive side different distance from race to end than non-drive side - which is likely on these Treks), see this https://www.sheldonbrown.com/bbsize.html
Scroll down to where the diagram of the spindle is, with the table below. That should bring you home.
)
If you can salvage the crankset, as @due ruote said, measure the existing spindle - try total length minus the threaded (male) portion of the spindle, if there is one. That will give you a starting point.
If asymmetrical ( drive side different distance from race to end than non-drive side - which is likely on these Treks), see this https://www.sheldonbrown.com/bbsize.html
Scroll down to where the diagram of the spindle is, with the table below. That should bring you home.
)
09-29-18, 01:36 PM
#13
Senior Member
09-29-18, 04:23 PM
#14
Senior Member
If the crankset hit the ground with enough force to break a solid steel spindle I would be checking the crankset to see if the arms aren't bent or the rings damaged, cracks, etc, before finding a new bottom bracket.
Last edited by Narhay; 09-29-18 at 06:31 PM.
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