Difference shimano Octalink 300 and ES51 BBs?

[Sweep]

An obscure question I know.

Buying some bits for a bike.

Both of these are available in the correct axle lengths.

I stress that I care nothing for weight savings.

[Brucey]

I think it is mainly a question of finish. Not sure if there is a real difference in the bearings/seals or not.

Note that there is Octalink V1 and Octalink V2 which each have a different spline (length) . You need to get the right BB type as well as spindle length.

If in doubt you can check the spline length and compare, and/or check the relevant techdoc. There is also a list on Sheldon Brown.



BB-ES25 and BB-ES300 are (the longer spline) V2 type.

cheers

[Sweep]

I think it is mainly a question of finish. Not sure if there is a real difference in the bearings/seals or not.

Note that there is Octalink V1 and Octalink V2 which each have a different spline (length) . You need to get the right BB type as well as spindle length.

If in doubt you can check the spline length and compare, and/or check the relevant techdoc. There is also a list on Sheldon Brown.

cheers

Thanks Brucey, though it would seem odd if it was just finish - I know there are a fair few ultra vain points scoring cyclists out there (thankfully few here) but you can't show off something hidden in the shell.

On your advice I'll go whichever is cheaper then, unless someone knows more.

Version 2 is the one I need.

axle 126mm.

For Ridgeback Expedition which came with a 300.

[Brucey]

I think that BB-ES300 is theoretically a 'better' BB but in what way exactly I'm not sure. [possibly the plated ES300 is less likely to get stuck in a BB shell?] What with random sale prices and so forth you might be able to buy an ES300 cheaper than an ES25 right now.

BTW if the chainset is a triple, check the clearance of the chainrings from the chainstay and the crank from the BB shell etc. If it is more than 4mm then you may be able to use a 118mm spindle length rather than the 126mm one. If it is more than 2.5mm then you may be able to use a 121mm spindle length. Either thing may well improve the chainline (check to be sure). The other thing that may trip you up is the front mech; anytime you move the chainset inwards the FD needs to be able to move in the new position too, and sometimes it can't.

Often manufacturers play it safe with BB lengths and fit one that is longer than it needs to be, at the expense of chainline.

cheers

[Sweep]

I think that BB-ES300 is theoretically a 'better' BB but in what way exactly I'm not sure. [possibly the plated ES300 is less likely to get stuck in a BB shell?] What with random sale prices and so forth you might be able to buy an ES300 cheaper than an ES25 right now.

BTW if the chainset is a triple, check the clearance of the chainrings from the chainstay and the crank from the BB shell etc. If it is more than 4mm then you may be able to use a 118mm spindle length rather than the 126mm one. If it is more than 2.5mm then you may be able to use a 121mm spindle length. Either thing may well improve the chainline (check to be sure). The other thing that may trip you up is the front mech; anytime you move the chainset inwards the FD needs to be able to move in the new position too, and sometimes it can't.

Often manufacturers play it safe with BB lengths and fit one that is longer than it needs to be, at the expense of chainline.

cheers

Thanks Brucey, will bear that info in mind for one of more problematical bikes.

But will stick with original specs on the Ridgeback Expedition - Ridgeback clearly knew what they were doing - all changes wonderfully despite my efforts to screw this up with now and again letting the bike fall over.

[Brucey]

the reason I mention the chainline is that a 'road triple' with ~45mm chainline is centred on a 9s cassette when it is in a 135mm oln frame. Pretty much anything with a MTB chainset has a chainline that isn't really centred properly.

cheers