Mismatched cranks loosening from square taper BB

[Veloo]

A long time ago, I was using the Dura Ace 8 speed 7410 crank with a Syncros Ti, square taper, English BB.
The drive side would work itself loose and I eventually got fed up and sold the BB. Went back to Shimano OEM and all was fine again.

Currently using a UN51 with a Sugino crank on the commuter and it works fine. It's an old BB so it may come time to replace it soon.

I've been eyeing some non Shimano square taper BB like Miche, FSA and Token but also wondering if I'll run into the same problem with the Syncros.

Has anyone else experienced loosening of the crank on square taper when mixing brands?

[mmfs]

I’ve mixed brands with no issues, but learned that once a crank arm comes loose it may be deformed, continually become loose in the future on any bottom bracket, and needs to be replaced.

[nalax]

I had the a similar problem with a Race Face Taper-Lock bottom bracket around 20 years ago. The non-drive side always loosened. Replaced it with Shimano and no problems. Currently running a White Ind. bb with a VBC crank but that's same company. The VBC also worked fine with the Shimano bb.

[ultraman6970]

I have used miche with campagnolo cranksets and worked ok. Same with token BB.

[slambers3]

It would be wise for one asking such questions to investigate the relevant differences between ISO and JIS spindle tapers, and to research the brands and models that used each standard. Also, to echo an earlier post, if a square taper arm has worked itself loose while being ridden (and isn’t immediately tightened down) There’s a good chance it’s ruined, tapers distorted beyond usefulness.

[dddd]

I've measured a great many JIS spindles, from cheap to expensive and all models/brands in between. JIS spindles always seem to be made to consistent dimensions versus certain older non-JIS tapers from the mid-80's and earlier.
So I don't think that it's the JIS taper on the spindle that is the problem.

There can be a good deal of variation as to how well that a crankarm gets seated on the spindle, not just bolt torque but the presence of lubricant as well as the use/abuse history of the crankarm.

In all cases when I've re-used a crankarm that has come loose out on the road or the CX course, whatever, I will torque the bolt, then jump on the pedals, then remove the bolt and apply LocTite blue heavily to both mating threads and re-torque the bolt. They do stay tight at that point.

If the arm's taper flats are really gouged or in any way misshapen, the arm is toast as there will always be excessive movement at the joint.
I've finished a season on such an (Topline) arm, but then removed it forever.