I am investigating whether I can insert cap nuts with too short axle attaching area. The image below is exaggerated but the attaching areas are about 1.2cm and 0.95cm. The difference 0.45cm meant in 6 months that the left cap nut became broken, metal spaghetti. I squeezed about 0.2cm from the past configuration due to the wrong conf, now the difference is about 0.25cm, but suppose I place there a chain tug, it will take away about 0.2cm and the problem may re-emerge: again metal spaghetti and broken cap nuts. So how much space should be reserved for cap nuts in axles?

The cap nut is about 2.1 cm deep.

1.23cm with the right cap nut, no problem, the nut in good condition. After placing there a chain tug, the space is about 1.0cm. 1.04cm with the left cap nut. With chain tug, the space is about 0.8cm. Even with 0.9, I got metal spaghetting and broken cap nut after 6 months. A problem?

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  • question about naming of cap-nuts here

1 Answer 1


I would first try a standard nut on the axle because often the cap nuts have a nice rounded entry to the threaded area which means the trhead doesn't start for a millimetre or so. From the photo it looks as though you should have enough axle for a standard nut to work.

The next step is to grind off some of the antirotation washer so your nut gets more space. Those washers are made of a nice hard steel so they're hard to file. Much better to use a power tool if you can. If not, get the finest, sharpest file you can. And try very hard to keep the surfaces of the washer parallel - if they're not you are much more likely to strip the nut.

And Neil Finn, the cable attachment shown above is the less problematic of the Shimano 8 speed ones that I've seen, but it's still prone to sticking bits of broken gear cable into your fingertips. Note that hhh has a broken strand and there's no end cap on that cable. Unless it's soldered it will eventually fray and then grabbing hold of it to fit it back into the hub gets ugly.

  • tested soldering without paste with unknown solder, did not stick. The reason for threading is wrong cable attachment, it should be opposite: the larger black cap on the right side. It killed the cable and did bad things to the plastic things. It can be verified by Brown here.
    – user652
    Commented Apr 19, 2011 at 21:10

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