Self-extracting crank bolts?

[bulliedawg]

Does anyone out there use these things? Brand recommendations? Pros and cons?

I remove my cranks when I clean my bike about every other month, and it sure would be easier with self-extracting crank bolts. Oh, yeah. Isis bottom bracket.

[Smiley]

Don't make a habit of using self extracting bolts to remove cranks. I had a shop guy strip my crank because he was too lazy to use a tool. They are OK in a pinch but not what I would suggest for everyday use.

[gt6267a]

what you write here about taking the cranks on and off once a month totally conflicts with that the LBS guys are telling me.

they told me that everytime the cranks are taken off and put back on again that the spline digs in a little deeper into the crank casing. they say this can only be done so many times before the BB spline gets to the end and can no longer be put on properly.

therefore, he recommends taking off and putting on the crank only when necessary and very infrequently. in this line of thought, to take the cranks off once a month would be insane.

my questions: does putting the crank back on do damage? how many time can you put it on before there is a problem?

am i the one that is insane?

[bulliedawg]

GT:

That problem is probably greater with tapered BBs that it is with Isis BBs. I use a torque wrench, so I'm pretty precise about the amount of force I use in this process.

However, if someone has specific information on this subject, I'd love to hear it.

[Kevin]

Taking the cranks off once a month is a little excessive. My LBS has me following the once per year program (5,000 miles). You can get the bike as clean as it needs to be and still leave the cranks on the bike. The constant removing and re-installing of the cranks can't improve the lifespan of the cranks or the BB.

Kevin

[TimD]

Independent of whether installing and removing crank arms is a wear activity, I do not see how use of self-extracting crank bolts could be a problem. The mechanical arrangement seems pretty good to me and not a lot different from what a (screw-in) crank puller does.

[CarbonTi]

Setting aside the intervals that you plan to remove and install the crank, using self extracting BB bolts is still a bad idea.

These bolt contraptions have all the torque for both removing and tightening run through a 8mm recessed bolt. That socket cap bolt doesn't last very long when you use it to tighten and loosen at the newton-meters a crank bolt is tightened. Don't do it.

[Too Tall]

Puppy - Self extracting bolt choices for ISIS are somewhat limited. Look at FSA natch', it is a well made product. As with ANY self extracting key you need to keep a dab of lube between the crank bolt head and inner surface of the cap or bad things will happen. There is NOTHING wrong with these cool devices, they were invented by a higher being to make your life easier.

ISIS is probably the least prone to early failure due to repeated removal and install due to it's non-taper, precision and steel stop...and you use a torque wrench ;) I'd give even odds you can continue with your (aheem) enthusiastic methods for a looong time with no harm. Can I talk you into switching to cleaning the rings with a nylon brush a bucket of hot water and some orange peel type cleaner instead...you are making the other kids (with dirty bikes) nervous.

[bulliedawg]

What can I say? I like to pull my cranks...and I've never had any troubles, despite what people say.

There seems to be quite a difference of opinion about the self-extracting crank bolts. It sounds to me like the guy who ruined Smiley's cranks was a ham-fisted idiot.

And just to clarify: Originally wrote that I remove my cranks "about every other month," which is half as often as "every month." And with the qualifyer "about" really means that I do it more like four or five times/year. Which might mean the the self-extractors are a waste.

[JohnS]

That setup was too easy. I pass. :D

[saab2000]

I am not familiar with any ISIS cranks so what I have to say needs to be taken in the context of square taper BBs and cranks.

I have used Campagnolo cranks my whole life, except for one exceptional set of the 1st generation DA low-profile cranks. They remain my all-time favorites, but I don't mix brands (well, yes I do - see below) , so they are not being used at the moment.

My experience has been that removing cranks and re-installing them does indeed do a bit of damage each time. I had a bike on which my Record crank was installed and their was extremely little space between the small ring and the right chainstay. I sent the frame off for some work, including having a dent "installed" in this area. That was not done unfortunately (and the framebuilder never answered why not - maybe there is a good reason) and when I reinstalled the crank and BB the small chainring rubbed slightly. Maybe the paint/powdercoat was a bit thicker but the fact is that it rubbed. I solved the problem with a different brand of BB which gave me about 2 mms of clearance.

I did the unthinkable of using a 103 DA bottom bracket with a Campagnolo crank. The taper is the same, but the diameter of the BB is supposedly slightly larger and this prevents the crank from pulling on completely. But the lesson has been learned. I am not removing it any more except in unusual cases. The DA bb should last for the rest of the life of that bike. They last forever as far as I can discern.

My recommendation is to NOT take off the crank very often. Do your best to clean it on the bike. It is not as good a solution, I know, but it is better for the crank.

One suggestion I would make would be that when the cranks are removed the BB should also be removed in order to reapply the anti-sieze in the threads. I once had a BB sieze in a frame and it was a real mess.

Regarding the self-extracting bolts, I have tried them too. My experience was mixed. I like the simplicity, but they are a compromise. They are slightly heavier I think (who cares really...) but the real problem was that the bolt accepted only 6 mm allen wrenches. The torque involved with the removal and reinstallation of a crank is significant and I think that this bolt should be 7mm at least and 8 would be optimal. The flats of the bolt began to round out and deform after just several re-installations.

If you can find a good one go for it, but beware of this danger.

It is my opinion that the regular tools for crank removal are not a big enough hassle to go for the self-extracting bolts.

So there!!!

[Kevin]

Come on John S, say it. I don't want to be the first one to pass comment.

Kevin

[JohnS]

I'd "ruin" my reputation.

[slowgoing]

I don't know how self extracting crankbolts work. Will they help remove a crank on which the threads for the crank-puller have stripped?

[Richard]

No, for stripped cranks there are two options that come to mind. First, there exists a kit that can be used to cut oversized threads into the crank arm. This kit comes with an extractor. Second, a handy person can use JB Weld to rebuild the thread area and, after the stuff sets, to cut new threads in the original diameter. Either works.

[slowgoing]

Richard - Thanks.