chainring bolts - removal tips

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531colin
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Re: chainring bolts - removal tips

Post by 531colin »

ImageIMG_5534 by 531colin, on Flickr

Here is a little tool I ground on the edge of a cone spanner; just really a peg which locates in the hole in the slotted (female) half of the chainring bolt, the spanner fits the "screwdriver" slot. As you can see, I had to grind this particular spanner a bit thinner.
Grip the home-made tool in the bench vice, hold the chainring bolt firmly onto the tool, undo the (other end of the ) bolt with an Allen key.
It has worked well for me (so far) undoing other peoples' chainring bolts, which are invariably not greased.
If you don't have a bench grinder, you might get lucky with a random bit of steel fitting the slot.
DaveReading
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Joined: 24 Feb 2019, 5:37pm

Re: chainring bolts - removal tips

Post by DaveReading »

I use the thin (but not too thin) metal plate from an old PC expansion card to stop the nut end from rotating while I loosen or tighten chainring bolts.
peetee
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Re: chainring bolts - removal tips

Post by peetee »

I have often come across this problem on other people’s bikes when I repair them, but never my own. When I assemble the parts I apply grease to the bolt thread but nowhere else. I rarely need the special peg tool for the rears, usually there is enough stiction that they stay put when un-threading but pop out of the chainring with a light tap.
Syd
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Re: chainring bolts - removal tips

Post by Syd »

After about 4,000k the front shifting on my Fuji Spotif went a bit ropey. On investigation I found one chainring bolt missing and the remaining ones loose.

In order to get a matching set I purchased replacements and they had the hex key heads on either side as described above. Was able to get them tightened nicely and had no problems since.
mattsccm
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Re: chainring bolts - removal tips

Post by mattsccm »

Whatever tool I am using in the slotted side I clamp in the vice. You can hold the chainset down onto it adding to the security of the tool and the force down on the allen key helps.
hoogerbooger
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Location: In Wales

Re: chainring bolts - removal tips

Post by hoogerbooger »

Those little peg spanners for the back aren't great for leverage. I was dead chuffed with myself for eventually dismantling a 1983 stronglight triple that was being a *ugger. Here's my recipe:

Ingredients:

- partner will need to be out for a while.
- freezer
- gas jet cigarette lighter
- wd40 or penetrating oil of some form
- allen key and bolt peg spanner
- small hammer

Method

Spray with penetrating oil and leave for a few hours or overnight

Put in freezer for a few hours or overnight

Remove from freezer and use cigarette lighter to heat bolt.

Put Allen key in socket and tap it a lot with hammer

Then try to undo with key and peg spanner

Repeat as necessary......or until the partner realises you have oily stuff in kitchen.

Worked for me.


(RE covert creaking, add saddle rails to causes)
Jdsk
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Re: chainring bolts - removal tips

Post by Jdsk »

hoogerbooger wrote: 25 Sep 2021, 8:19amwd40 or penetrating oil of some form
I recommend a penetrating fluid (such as PlusGas) rather than ordinary WD-40.

Jonathan
MikeF
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Re: chainring bolts - removal tips

Post by MikeF »

Rather than grease I use Copper Ease on screw threads. I've used it threads not just for cycles since the 1960's.
Edit. It was called Copperslip in the "olden days", but appears to be the same
"It takes a genius to spot the obvious" - my old physics master.
I don't peddle bikes.
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simonineaston
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Re: chainring bolts - removal tips

Post by simonineaston »

hex key heads on either side as described above
That is such a good idea. I'm gonna right to the United Nations to see if its one of my human rights... ;-)
(rides: Brompton nano & ever-changing Moultons)
slowster
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Re: chainring bolts - removal tips

Post by slowster »

simonineaston wrote: 25 Sep 2021, 12:27pm
hex key heads on either side as described above
That is such a good idea. I'm gonna right to the United Nations to see if its one of my human rights... ;-)
If it is such a good idea, why don't all manufacturers use it?

What is so good about Brucey's posts are his detailed and clear explanations:

viewtopic.php?p=1406976#p1406976
Brucey wrote: 16 Oct 2019, 10:53pm 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.
Brucey wrote: 17 Oct 2019, 8:56am this photo shows a bit more about what they are like

Image

you get about half the threads in engagement vs normal bolts (four full threads in the ones above, so will wear/strip easily with re-use) and there is a nasty crevice in the bore of the assembled bolt (not present in a normal bolt) that easily fills up with water. The bolts shown are not really suitable for every triple chainset, because both ends are slightly domed and are likely to interfere with the chain when it is running on the inner ring.

The ones shown above are from bikediscount.de but there are a few different types available. They all have the same issues AFAICT.
Brucey wrote: 17 Oct 2019, 10:05am note also that the socket which accepts the 6mm key is usually very short. This will probably limit the torque on a new bolt, even if the short engagement doesn't. Needless to say if you carry a typical multitool, you are no better off by the roadside; you need separate 5mm and 6mm keys (in some cases two 5mm keys IIRC) to tighten the bolts.

IME because you can easily assemble these bolts without any grease on them, that is very often the way that they are assembled. Since they corrode more easily too, this means they are quite often found badly seized on bikes. Obviously (because of the crevice) they are still more prone to corrosion even if they are greased, and well-greased bolts of the standard type give very little trouble, so.....
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simonineaston
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Re: chainring bolts - removal tips

Post by simonineaston »

If it is such a good idea, why don't all manufacturers use it?
The obvious answer is expense. If a maker can offer a product which occupies a healthy proportion of the market, then why would they want to adopt a solution that costs more than the existing product? If, on the other hand, your product sits in the same sector, but sells in smaller numbers (imagine, say Shimano & Stronglight...) then one way to raise the no. of sales might be to offer a useful feature that the opposition does not...
(rides: Brompton nano & ever-changing Moultons)
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531colin
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Re: chainring bolts - removal tips

Post by 531colin »

simonineaston wrote: 25 Sep 2021, 6:52pm
If it is such a good idea, why don't all manufacturers use it?
The obvious answer is expense. If a maker can offer a product which occupies a healthy proportion of the market, then why would they want to adopt a solution that costs more than the existing product? If, on the other hand, your product sits in the same sector, but sells in smaller numbers (imagine, say Shimano & Stronglight...) then one way to raise the no. of sales might be to offer a useful feature that the opposition does not...
Apart from a few bike nerds on here, nobody gives a flying wotsit about chainring bolts.
Most of Shimano's output goes to build new bikes.....which mostly aren't ridden, aren't repaired, etc etc.
People buying a bike might recognise the name Shimano, but they ain't going to buy a bike 'cos its got souper-douper chainring bolts, because they don't know what chainring bolts are!
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