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Cartridge BB square taper vs cup&cone square taper axle length

Miljan Nikolić

New Rider
Hub Hero
Hello Relja,

What is equivalent axle length ( marking ) for old cup&cone system to Shimano D-NL ( 122.5 mm ), 68mm diameter ?

I noticed that they have two - digit codes ( 3U, 5S, etc. ) and I understood that " 3 " is for 68mm diameter but I am unable to identify what length of that old style axles will match cartridge Shimano D-NL 122.5 ( 68mm ).

Thank you!
 
Hello Relja,

What is equivalent axle length ( marking ) for old cup&cone system to Shimano D-NL ( 122.5 mm ), 68mm diameter ?

I noticed that they have two - digit codes ( 3U, 5S, etc. ) and I understood that " 3 " is for 68mm diameter but I am unable to identify what length of that old style axles will match cartridge Shimano D-NL 122.5 ( 68mm ).

Thank you!

Hi Miljan,

That is a very good question that I still haven't written an article about. Thank you. :)

Short answer​

For triple cranks that aren't road-cycling specific (road ones are rather rare these days), Shimano BB-UN300 Bottom Bracket - BSA 68mm - JIS Square Taper - 122.5mm (LL123) should work fine. Example (from a German store):
https://www.bike24.com/p2372409.html

For double cranks (usually road-cycling cranks and front derailleur), Shimano BB-UN300 Bottom Bracket - BSA 68mm - JIS Square Taper - 113mm should do the job. Example (again, from a German store):
https://www.bike24.com/p2372398.html

Explanation​

I hope that @VlPo and @bluedovebike will correct me if I write something wrong. :)

As far as I can tell, you are looking for a square taper bottom bracket, with a British threaded standard, and a 122.5 mm long axle.

Today, Shimano sells D-NL, and LL square taper bottom brackets (maybe they offer some more, but I don't know about them).

  • Shimano D-NL (Dyna-Drive Narrow Line) is designed for older style bikes and road bikes with narrower chain line.
  • Shimano LL (Long Line) is designed for modern mountain bikes with a wider chainline.
So, for a similar total axle (spindle) length, the LL bottom brackets should have the axle protruding further out on the right-hand-side (compared to a D-NL bottom bracket), and have it protrude less on the left-hand-side (again, compared to a D-NL bottom bracket).

The 5S and similar are old standard marks as far as I know.

For most current non-road triple cranks, a LL bottom bracket with the spindle length from 122 to 123 mm is usually good, and usually gives a ~ 50 mm front chainline.

That usually works well with most current Shimano MTB or "Treking" triple square taper cranks.

A D-NL bottom bracket with a similar total spindle length will give you a 47 mm front chainline.

This is my square taper axle recommendation list. For road cranks, it is best to look for D-NL, while LL bottom brackets work best for other cranks (MTB, Treking etc.).

Relja
 
Hi Miljan,

That is a very good question that I still haven't written an article about. Thank you. :)

Short answer​

For triple cranks that aren't road-cycling specific (road ones are rather rare these days), Shimano BB-UN300 Bottom Bracket - BSA 68mm - JIS Square Taper - 122.5mm (LL123) should work fine. Example (from a German store):
https://www.bike24.com/p2372409.html

For double cranks (usually road-cycling cranks and front derailleur), Shimano BB-UN300 Bottom Bracket - BSA 68mm - JIS Square Taper - 113mm should do the job. Example (again, from a German store):
https://www.bike24.com/p2372398.html

Explanation​

I hope that @VlPo and @bluedovebike will correct me if I write something wrong. :)

As far as I can tell, you are looking for a square taper bottom bracket, with a British threaded standard, and a 122.5 mm long axle.

Today, Shimano sells D-NL, and LL square taper bottom brackets (maybe they offer some more, but I don't know about them).

  • Shimano D-NL (Dyna-Drive Narrow Line) is designed for older style bikes and road bikes with narrower chain line.
  • Shimano LL (Long Line) is designed for modern mountain bikes with a wider chainline.
So, for a similar total axle (spindle) length, the LL bottom brackets should have the axle protruding further out on the right-hand-side (compared to a D-NL bottom bracket), and have it protrude less on the left-hand-side (again, compared to a D-NL bottom bracket).

The 5S and similar are old standard marks as far as I know.

For most current non-road triple cranks, a LL bottom bracket with the spindle length from 122 to 123 mm is usually good, and usually gives a ~ 50 mm front chainline.

That usually works well with most current Shimano MTB or "Treking" triple square taper cranks.

A D-NL bottom bracket with a similar total spindle length will give you a 47 mm front chainline.

This is my square taper axle recommendation list. For road cranks, it is best to look for D-NL, while LL bottom brackets work best for other cranks (MTB, Treking etc.).

Relja
Thanks again for helpful and very precise answer.

This is not first time that I solved my problem with your You Tube videos, site and now - forum✅

Best regards,
Miljan Nikolić
 

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