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Removing a stuck chainring bolt

Posted: 16 Oct 2019, 5:15pm
by Sweep
Must admit to being profoundly ashamed for having to post this.

Will try to explain as best as I can.

I was doing some tinkering with an unused 8 speed triple Shimano chainset, seeing if I could get some brand new chainrings from another Shimano 9 speed series to fit it.

In screwing the new 9 speed big ring into place I managed to forget that the bolts and nuts that secure the big ring also pass through the middle ring. So, with the middle out I screwed down the bolts on the big ring and "duh" was initially puzzled to see that there was some slack in the assembly even with the bolts screwed straight down.

Realising my stupidity (no other word for it) I unscrewed everything.

Except one bolt/nut assembly is stuck.

I can't get the peg spanner to grip on the nut on the back - essentially because the bolt is screwed in so much it stands high in the centre of the "nut" and stops the peg spanner seating properly.

Have struggled and struggled but am now throwing myself on the merciful expertise of you good folks.

Any suggestions?

After failing to get the peg spanner to grip it did occur to me that very often you don't have to use one as the nut is held tight against the metal of the ring and the bolt pulls against that friction as you undo it. But of course thanks to my cack-handedness, although the bolt/nut interface is tight - too tight - the bolt does not push against the chainring - there is a gap - thanks to the missing middle ring. It did occur to me that maybe I could jam something in this gap like perhaps a small thin spanner but I don't have such a thing.

Clearly I am hoping for solution which doesn't damage my nice new crankset or nice new 44T Deore chainring.

Re: Removing a stuck chainring bolt

Posted: 16 Oct 2019, 5:22pm
by reohn2
Have you tried gripping the rim of the slotted nut with a pair of pliers?

Re: Removing a stuck chainring bolt

Posted: 16 Oct 2019, 5:24pm
by landsurfer
I would run a drill the OD of the female thread through the chairing bolt and it falls apart without any damage to the chainset.

Re: Removing a stuck chainring bolt

Posted: 16 Oct 2019, 5:35pm
by fausto99
If this is all off the bike, could you possibly (wrongly) use the tips of a pair of long nose pliers instead? The long nose will reach further in than the proper peg spanner.

Re: Removing a stuck chainring bolt

Posted: 16 Oct 2019, 5:41pm
by slowster

Re: Removing a stuck chainring bolt

Posted: 16 Oct 2019, 5:48pm
by reohn2

Re: Removing a stuck chainring bolt

Posted: 16 Oct 2019, 9:23pm
by mtbsteve1981
That's a great idea. When mine was stuck I just gripped the but you put the peg spanner with mole grips and gently drilled out the Allen key side so it removed the head and I was able to push it through. Didn't have to drill far as the head is quite thin.

Re: Removing a stuck chainring bolt

Posted: 16 Oct 2019, 9:41pm
by Mick F
reohn2 wrote:

Good idea. :idea:
Better idea is to stop using those stupid chainring bolt thingies.

My Stronglight on Moulton has Allen on both sides.
Takes two sizes ........ 5mm on the outside and 6mm on the inside.
Sod the chainring spanner tool thing! :wink:

Why aren't they all like that?

Doesn't help Sweep though, so sympathies to him. He needs to grip it and maybe uese the spanner idea on YouTube.

Re: Removing a stuck chainring bolt

Posted: 16 Oct 2019, 10:34pm
by reohn2
Mick F wrote:........My Stronglight on Moulton has Allen on both sides.
Takes two sizes ........ 5mm on the outside and 6mm on the inside.
Sod the chainring spanner tool thing! :wink:

Why aren't they all like that?......


Sounds like a good idea.
I've never seen chainring bolts like that,a photo would be nice :)

Re: Removing a stuck chainring bolt

Posted: 16 Oct 2019, 10:46pm
by Sweep

Will try that sometime in next few days and report back.

If not, it's the drill.

Suppose on the bright side, this will ensure that I don't do anything (or at least this thing) so daft again.

Seem to remember that I did it once before, though retrieved the situation far more easily.

Re: Removing a stuck chainring bolt

Posted: 16 Oct 2019, 10:53pm
by Brucey
re sweep's stuck bolt;
it can't be that stuck, after all how could it have been tightened that much?

I would suggest holding an allen key in a vice, sitting the bolt onto it, .and then using a drift and a very small hammer to 'massage' the sleeve with radial blows, from different directions. It will soon slacken off.

In this position you can use heat to your advantage too.

If you try and hold the sleeve with pliers this might work very well but instead it might distort the sleeve worse than ever so that it won't undo.

The chainring bolts with two allen key fittings seem like a good idea in principle but they are a crap idea in practice;

- the sockets are shallow (they have to be, the bolts are not very long)
- the length of the socket on the rear of the bolt subtracts from the threads that are in engagement, so they are less good as bolts (less strength in tension, fewer uses before they strip)
- the ones I have seen are not well plated so corrode easily
- there is a crevice on the inside of the assembled bolt that could have been scientifically designed to collect
water and cause corrosion.
- you can't easily vary the length of this design of chainring bolt
- the shortest bolts of this sort are entirely unsatisfactory.

The problems with normal chainring bolts are normally caused by a failure to grease them adequately, or something equally daft as that. With the allen-key type ones, failing to grease them results in corrosion that is at least as bad.

cheers

Re: Removing a stuck chainring bolt

Posted: 17 Oct 2019, 5:41am
by Mick F
reohn2 wrote:
Mick F wrote:........My Stronglight on Moulton has Allen on both sides.
Takes two sizes ........ 5mm on the outside and 6mm on the inside.
Sod the chainring spanner tool thing! :wink:

Why aren't they all like that?......


Sounds like a good idea.
I've never seen chainring bolts like that,a photo would be nice :)
OK, I'll see what I can do later maybe after breakfast.
I've often wondered why they're all not like that, as it makes complete sense. Why you need a special tool for a chainring bolt, seems a daft system.

I had the chainset off and stripped down the other day, but I can take it off easily enough. All nice and spotlessly clean now! :D

Re: Removing a stuck chainring bolt

Posted: 17 Oct 2019, 5:46am
by Mick F
Sweep wrote:

Will try that sometime in next few days and report back.

If not, it's the drill.

Suppose on the bright side, this will ensure that I don't do anything (or at least this thing) so daft again.

Seem to remember that I did it once before, though retrieved the situation far more easily.
Just thinking.
Can you not get a big screwdriver right across the flat slots?
When I've had one that kept turning, I didn't have a screwdriver long enough to go right across, so I found a piece of metal plate that did it. I mounted the plate vertically in the vice and balanced the chainset on it and turned the outside Allen bolt.

That specific bolt - on Campag Chorus on Mercian - remains an issue as it won't grip. The others are no problem.

Re: Removing a stuck chainring bolt

Posted: 17 Oct 2019, 8:21am
by Mick F
Photos as requested.
All self explanatory with the inner 34t chainwheel removed.

61t big ring and 48t middle.
IMG_0418.jpg
IMG_0419.jpg
IMG_0420.jpg

Re: Removing a stuck chainring bolt

Posted: 17 Oct 2019, 8:30am
by reohn2
Thanks for that Mick,where did you get them from?