Seized Chainring Bolts

Pross
Pross Posts: 42,082
edited November 2009 in Workshop
Sorry, I'm sure I've seen a similar topic recently but couldn't find it! I have just changed most of my drive train (rear mech wheels, chain, cables, cassette) as they have been on the bike for over ten years albeit mainly stored in the shed and not ridden. I have also invested in new 52 / 38 chainrings but I was unable to change these as two of the bolts are seized and are just turning the nut part. Can anyone give me some advice on loosening the bolts or am I going to have to replace the whole chainset? I can't really leave the existing rings as they are slightly worn and I also want the smaller chainring to replace the existing 42 to help me get up hills! :oops:

Comments

  • Have you not got the wrench for the back of the nut?
    Neil
    Help I'm Being Oppressed
  • Wappygixer
    Wappygixer Posts: 1,396
    If you don't have the right tool to hold the back of the chain ring bolts then try gently pulling the 2 rings apart and then undo the allen bolts.
    The rights are toast anyway and sometimes this sort of pressure can help hold the back of the nuts enough to undo them.
    If that fails buy the right tool of drill out the bolts and replace them.
  • sicknote
    sicknote Posts: 901
    A few ways to get bolts out.

    1/ Try to do them up a little as that can some times get them moving so it can be undone.
    2/ DW40 if you have not tried that yet but I guess you might have tried that already.
    3/ Try heating the bolt with a heat gun ( for taking off paint ) but done need to get it too hot or if you have a soldering iron would be better as you would just be heating the bolt.
    4/ Tap it with a hammer but tried to put something heavy behind it so it is just on the bolt.
    5/ If all of the above does not work then I would say get the drill out and put in new one.

    This comes from years of taking out rusty screws and bolts from furniture I have worked on for almost 26 years ( Antique restorer )

    Hope some of it helps.
  • Pross
    Pross Posts: 42,082
    Never seen a proper tool for the back! I've always used a large flat head screwdriver but that is obviously harder to keep still than the tool will be.

    Tried WD40, my next step was going to be white lithium grease but getting it to penetrate between nut and bolt isn't easy. Thanks for the other tips - was going to try heat but was worried the bolt may expand more than the nut making it even tighter. Will remember to grease the new ones regularly even if I'm not using the bike :oops:
  • sicknote
    sicknote Posts: 901
    If you do use heat, just wait for it to cool before trying to undo it.
  • lae
    lae Posts: 555
    IMO WD40 isn't that great. Duck Oil is a much better penetrating fluid. As for holding the screwdriver - put it in a vice and hold the chainwheel down onto it!

    When you restore (i.e. take apart and never put back together) classic cars you have to learn these things... sometimes the nuts and bolts are so rusty it's just a blob of rust on a sheet of rust with no discernable boundary between the two! Then it's time to get the hacksaw out...
  • lae
    lae Posts: 555
    Thinking about it a bit more, it might be easier to put the allen key in a vice with just the end sticking out, then put the chainwheel onto it, then the screwdriver onto that. Then just turn the chainwheel.
  • Get a chainring bolt tool, because they're cheap. If that doesn't work then just drill it out, all the faff with heating it up, and using penetrating oil. If it doesn't come out with the proper tools then destroy it (this only applies to chainrings :wink: )

    Basically if they cannot come out easily then they're probably shagged enough to warrant the low cost of replacement with good stainless steel ones.
  • El Gordo
    El Gordo Posts: 394
    Even with the proper chainring bolt tool it can be hard to get it to grip in the slot. I found using a G-clamp to hold it firmly in place against the ring helped a lot and frees up your hands to work on the allen key.

    If all else fails then get the drill out.
  • El Gordo wrote:
    Even with the proper chainring bolt tool it can be hard to get it to grip in the slot. I found using a G-clamp to hold it firmly in place against the ring helped a lot and frees up your hands to work on the allen key.

    If all else fails then get the drill out.

    "Proper chainring bolt tool" :
    http://www.velobase.com/ViewSingleTool. ... &AbsPos=49
  • El Gordo
    El Gordo Posts: 394
    mmacavity wrote:
    El Gordo wrote:
    Even with the proper chainring bolt tool it can be hard to get it to grip in the slot. I found using a G-clamp to hold it firmly in place against the ring helped a lot and frees up your hands to work on the allen key.

    If all else fails then get the drill out.

    "Proper chainring bolt tool" :
    http://www.velobase.com/ViewSingleTool. ... &AbsPos=49

    Crikey. OK, so the little bit of bent steel I have isn't quite as 'proper' as I thought.
  • Jamey
    Jamey Posts: 2,152
    The biggest mystery in the world of bike maintenance is why "they" don't use chainring bolts with hex key fixings on both sides.

    These are fairly easy to come by and one of the best upgrades you can make when it comes to bike fettling and just keeping your own sanity.

    I've got a chainring bolt holding tool (not that massive one, just a normal one) and I still found it to be a bloody nuisance getting them on and off the bike so I bought some double-hexed chainring bolts and the job is so much easier. Just need a 5mm hex key on one side, a 7mm (I think) hex key on the other and bosh, job done.

    I honestly, genuinely, really have no idea why they weren't designed like this from the beginning and, even more puzzlingly, why all chainring bolts still aren't hex on both sides.
  • Pross
    Pross Posts: 42,082
    Can't work out how that tool works even! :shock:
  • Jamey
    Jamey Posts: 2,152
    Don't even try. Instead, think of it like this...

    I don't like seafood. Does this mean I should look for some kind of magic sauce I can pour over fish to make it more acceptable to my taste buds? No, I should forget it and eat something else instead.

    That tool is an overly elaborate fix for a problem that can be solved much more easily by abandoning the (stupid) system altogether and moving to a better one - bolts that are hexed on both sides.
  • crankycrank
    crankycrank Posts: 1,830
    Jamey wrote:
    I honestly, genuinely, really have no idea why they weren't designed like this from the beginning and, even more puzzlingly, why all chainring bolts still aren't hex on both sides.
    Yes, and I just recieved my new Shimano cranks with Torx head bolts :twisted:. Not to mention the special tool needed for the HollowTech left crank axle nut. They could have very easily just used an allen head type nut like the previous versions. Sometimes I think the mfrs use all these different fasteners just to provide other local businesses with new customers.
  • Jamey
    Jamey Posts: 2,152
    Actually, to be completely honest, the chainring bolts I've been praising came supplied with a torx head on the bolt and a hex head on the nut, but I changed the bolts for normal ones and they work fine.

    I didn't actually have a problem with torx on the bolts but for some reason they were bottoming out before they made full "pinching" contact with my chainrings and I couldn't get them tight enough so I tried it with the old bolts I'd just removed (but still using the new nuts to get the benefit of the hex fitting) and I guess the old bolts must have been marginally shallower as they were able to pinch the chainrings properly, so I went with that.

    But now I look back it's a better system anyway having hex on both sides as I don't have a torx tool in my saddle bag, although it's a small matter to put one in there, admittedly.
  • Pross
    Pross Posts: 42,082
    OK, I got a chainring nut wrench and now have 4 bolts off. However, for some reason the wrench won't grip in the slot of the final bolt so it looks like I need to drill it out. Having never drilled a bolt out before what do I need to do? Do I just need to drill it with a bit that has a larger diameter than the bolt or what? :?
  • sicknote
    sicknote Posts: 901
    If you are going to drill it out, start with a small bit and work up in size.
    That way you have more control over what you are doing plus it is easier to start by drill the small hole first.
  • Pross
    Pross Posts: 42,082
    So do you do several small holes until it breaks then?
  • sicknote
    sicknote Posts: 901
    Just one hole but make it bigger until you can get it out with some pliers or something.
  • andrew_s
    andrew_s Posts: 2,511
    If the problem is the bolt just spinning round when you try to undo it, then all a drill will do is spin it round faster. You would have to hold it still with an allen key, and drill the flange off the back nut with a big bit - 10 or 12mm.
    I'd revert to plan A, as mentioned above, and jam a screwdriver in between the chainring and the spider, then try the allen key.