The pros and cons of crank self-extractors

Question

I'd like to know more about the reliability of self-extracting crank bolts, but haven't found much information on how they perform (or how they don't).

My interest stems from touring and international travel, but also from practicality. It seems like a no-brainer to be able to remove your crankarms with a common allen key without having to carry around a separate crank puller (or using riskier emergency removal methods).

Beyond concerns of not being able to remove the extractors themselves (for lack of a pin-spanner), I'd like to know whether these have a history of characteristic failure. I haven't found anything in the way of recommending them or condemning them.

I know that FSA, Sugino, and TA manufacture these gadgets, but are they as good on a bike as they are on paper? Are they simply unnecessary?

Answer 1

I have them on my Ultegra equipped nine speed bike and love them. They are especially nice when cleaning up the bottom bracket and crank/chainrings. Just a couple of quick turns with an allen key and off the the crank arm comes and goes directly into the cleaner. I wipe down the bottom bracket area and reattach the crank arm and it's ready to go. Easy peasy, takes maybe ten minutes if that.

Answer 2

I have had cranks with built in extractors before and they generally work as advertised without issue. These used to be common on square taper cranks (i.e., three piece cranks), and still exist on select two pieces designs that do not use pinch bolts to secure the non-drive side crank (e.g., Raceface cadence).

Generally you should never need to extract the end cap, so I would not worry about not having a pin spanner. About the only issue I have ever experienced is an end cap working itself lose, but this is something you would catch in typical maintenance.

Finally, I realize that most crank manufacturers have moved to two piece designs that do not require an extractor for removal, but square tapper three piece cranks still exist on the market and are still in use today (i.e., 2019), so the question still has relevance.

Answer 3

I'd say that they're unnecessary. Given the prevalence of the modern two-piece crank/external bottom bracket combo, what's the point?

The crank can be removed with an allen wrench and maybe - if it's especially tight - a wooden club.

Additionally, the bottom bracket on a two-piece crankset is easier to work on. The BB tool is heavy and bulky tool and you could probably limp along until you found a bike shop that would let you borrow one. Barring that, it can probably removed with a strap wrench (super cheap at any hardware store) and maybe something to provide extra grip (e.g., twigs) in the grooves. I've personally installed BBs with strap wrenches and they've lasted a month or two before requiring attention. It's not ideal, but it's workable.

It's also worth mentioning that loose bottom bracket shell isn't likely to cause catastrophic failure over a few days or even weeks of riding. Especially with a two-piece crankset where the very design limits it from loosening too much.

In the end, you're talking about a much more reliable (and rapidly becoming more universal) crankset that only (maybe) requires a single specialized tool, and could most likely work well enough until you happen to stumble across that tool.