Changing from square taper Bb to external

[Baxter22]

I am contemplating changing my single speed drivetrain from the usual square taper bb and associated
cranks to an external bottom bracket and a through axle. Anyone had any experience with this? I run a
68x103 with a 45mm chainline. Reasons for this is I have gone through 3 sets of cranks even with
appropriate regular tightening, locktite etc. It isn't the biggest gearing either with 44t up front and 16t out back.
Any assistance would be appreciated.
Cheers

[rustychisel]

have used square taper [English] BB with many cranks, and external FSA MegaEXO.

You don't say what BBs, what cranks (most importantly!!), and what external you're talking about. Are you questioning whether they work? Whether the chainline matches up? Whether they're more robust?

In the lack of such information I would suggest something isn't right in this scenario and most likely the use of cheap cranks - or poorly maintained 2nd hand cranks - is the cause of your woes. Or is it the BB? Either way, there is nothing intrisically weaker or less robust about a good quality internal BB, when properly installed and maintained.

More info please.

[rkelsen]

^ What he said.

I've got cheap, no brand square tapers on my commuter and they're still going strong after 40k km. I see no need to switch.

They shouldn't need regular tightening. You need to do them up to about 50 Nm, then forget about them.

[RonK]

I've done it. It's a piece of cake.

But external bearings may not be any more durable.

[Wingnut]

I've got bikes with both in Campagnolo...I think I prefer the square taper BB's still..,

[KGB]

I've done it. It's a piece of cake.

But external bearings may not be any more durable.

Agreed.

[Baxter22]

have used square taper [English] BB with many cranks, and external FSA MegaEXO.

You don't say what BBs, what cranks (most importantly!!), and what external you're talking about. Are you questioning whether they work? Whether the chainline matches up? Whether they're more robust?

In the lack of such information I would suggest something isn't right in this scenario and most likely the use of cheap cranks - or poorly maintained 2nd hand cranks - is the cause of your woes. Or is it the BB? Either way, there is nothing intrisically weaker or less robust about a good quality internal BB, when properly installed and maintained.

More info please.

Thanks for the comments, additional information for this situation is that I have run both sugino messenger cranks on a sugino BB as well as cheaper driveline ones and both cranks have had issues coming loose. I've tightened them up to the recommended torque. The bottom bracket has never been an issue.
The question I have is thus one of recommendation for an external BB and crankset to go with it. From the sounds of it I may have just gotten a couple of cranksets that havent quite worked for whatever reason and that a square taper bottom bracket setup is still fine.

Thanks for the comments!

[RonK]

You do realise there are two standards for square taper?

If not, time to look it up with Sheldon.

[Baxter22]

You do realise there are two standards for square taper?

If not, time to look it up with Sheldon.

2 comments RonK and both not helpful or constructive. Thanks everyone else.

[RonK]

You do realise there are two standards for square taper?

If not, time to look it up with Sheldon.

2 comments RonK and both not helpful or constructive. Thanks everyone else.

You asked if anyone had experience changing to external bottom brackets - I replied that I had and it was easy but not necessarily an improvement.

You mentioned problems with square tapers loosening - I replied that there are two standards and gave you a reference. You should be able to look up Sheldon and work out for yourself if you have a mismatch that may cause the loosening, but I guess that is too much trouble.

Sorry if this isn't sufficient hand-holding for you.

[am50em]

Actually 3 standards - I did look up Sheldon Brown!

[RonK]

Actually 3 standards - I did look up Sheldon Brown!

So there is. Wasn't that difficult was it?

And did Sheldon illustrate any potential issues with mismatching them?

[KGB]

I'd stick with square taper. I never had BB bearing issues before going to external.
I'm a fan of my current PF30 setup but square taper is still a good system, I still have some nice record square taper cranks on my TT bike.

[rustychisel]

You'd think Sugino Messenger would be okay.... I use Sq taper BB on 3 fixed gear bikes, Shimano cranks mostly, not an issue bar usual maintenance.

So yes, you could easily switch over to external BB but doubt there's any benefit to be gained.

[am50em]

Actually 3 standards - I did look up Sheldon Brown!

So there is. Wasn't that difficult was it?

And did Sheldon illustrate any potential issues with mismatching them?

I am not the OP - I did not know there were more than one standard so just read out of interest.
I have square taper (shimano) on my commuter bike and they work very well.

[slidetaker]

have used square taper [English] BB with many cranks, and external FSA MegaEXO.

...and maintained.

More info please.

..I may have just gotten a couple of cranksets that havent quite worked for whatever reason and that a square taper bottom bracket setup is still fine.

Thanks for the comments!

I share your pain. I have also experienced this situation on some component setups, but for fixed gear bike only.

I run JIS components on all my bike, good condition, proper torque, no grease. No issue with all free wheel bikes. But for some fixed gear bikes, the creak will start and grow and it will come loose. I do not know why. I am starting to think that the chainline and the material of the BB spindle and crank may have something to do with it.

Any other members experience this?

[rustychisel]

Nup, Plenty of grease and plenty of torque after thorough cleaning.

My main bike is English BB with Shimano BB and 7400 cranks, another has English BB with Shimano and old 105 cranks, the third is an old cup and cone track BB with Sugino BT cranks.

[RonK]

I am not the OP

Yeah I know that - just making the point that you were able to look up the reference.

The section contains (right at the beginning) photos showing the potential issues mismatching the tapers may cause.

[eeksll]

have used square taper [English] BB with many cranks, and external FSA MegaEXO.

You don't say what BBs, what cranks (most importantly!!), and what external you're talking about. Are you questioning whether they work? Whether the chainline matches up? Whether they're more robust?

In the lack of such information I would suggest something isn't right in this scenario and most likely the use of cheap cranks - or poorly maintained 2nd hand cranks - is the cause of your woes. Or is it the BB? Either way, there is nothing intrisically weaker or less robust about a good quality internal BB, when properly installed and maintained.

More info please.

Thanks for the comments, additional information for this situation is that I have run both sugino messenger cranks on a sugino BB as well as cheaper driveline ones and both cranks have had issues coming loose. I've tightened them up to the recommended torque. The bottom bracket has never been an issue.
The question I have is thus one of recommendation for an external BB and crankset to go with it. From the sounds of it I may have just gotten a couple of cranksets that havent quite worked for whatever reason and that a square taper bottom bracket setup is still fine.

Thanks for the comments!

you might get more help in the shed area.

Are you changing BB with each new crank? I believe once you have screwed up the square taper on the BB you will need a new one as it will forever screw up your new cranks.

I have changed a shimano square taper BB for a external shimano 105 style BB. For me at least I just had to get the correct tool to remove the old BB and do a quick test. Then I took it to the LBS to chase and face for the external BB. You will also need sure you can get the right crank and chainring size you want.