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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).

Self Extractor

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?

share|improve this question
My 1980 Miyata has them. Its essentially one bolt threaded over another bolt. How many failures could there be? – Ritch Melton Aug 31 '12 at 10:33
The one problem I see with them is that the cap is just a hair flimsy compared to the end of an extractor, and might fail while trying to remove a seriously stuck arm. But how real this hazard is, I can't judge. – Daniel R Hicks Aug 31 '12 at 11:49
Ok, I get that. Normal operation is fine, but what about seized and corroded. – Ritch Melton Aug 31 '12 at 12:44
@RitchMelton, relevant forum post regarding S.E. crank removal (…). It's a bit unclear, but I think his corrosion problem was compounded by not having the right tools. – WTHarper Sep 4 '12 at 23:24
I suppose an important consideration would be to imagine reasons for crank removal. One would be to save space in a bike-box to save on air freight. Another, to access to the small (74 bcd) chainring (to tighten bolts, remove sticks, clean). – WTHarper Sep 25 '12 at 0:13

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.

share|improve this answer
It sounds to me like you're talking about a BB removal tool, when the discussion is about crank removal. – Daniel R Hicks Sep 22 '12 at 11:31
Yeah but a two-piece crankset is also removable by allen keys alone. – user973810 Sep 22 '12 at 12:54
I was talking about both. I tend to think of removing the bottom bracket and removing the crank as two parts of one job since I always take my BB out to clean, re-grease, and re-tighten it whenever I have my crank off. It just makes sense when you're halfway in there already. I edited the answer to make it clearer. – jimirings Sep 22 '12 at 21:43
It is true that some of the industry is moving toward two-piece cranks, unfortunately the same industry doesn't provide for touring setups which generally run on sealed JIS-taper bottom brackets. These BBs last tens of thousands of miles and bike shops always carry them (even outside of the US and Europe), which cannot be said of external-bearing manufacturers. – WTHarper Sep 23 '12 at 0:17
Regardless of what new gizmos the manufacturers are trying to push on the biking public, the original question was about self-extracting cranks, of the sort used on a 3-piece crank. This post is not an answer to that question. – Daniel R Hicks Sep 23 '12 at 12:28

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