How To Undo A Screw-on Chainring / Acs

[Greetings]

Tools:

-Big vice

-Strong chain

-Blowtorch

-WD40

-Something really long and strong, like a pipe

Right then. This is for chainrings only. Freewheels need a special key although the idea is basically the same. (Added a short ACS removal guide at the bottom)

Mounting the cranks onto a vice

Self explanatory really, don't need to write anything yet do I?

Well, actually I do - the vice needs to be done up really tight!

1st step of making our job easier

Flood the space between the cranks and chainring with WD40. Leave it for 10 minutes until it soaks through

2nd step of making our job easier

Heat the chainring up with a blowtorch, try not to heat up the crank though!

This took me about 2 minutes or so. The chainring needs to be really hot!

WD40 is flammable but it burns slowly so don't worry.

Undoing it!

The tool. Slight overkill but it works. I wouldn't use anything shorter than 3ft.

This thing didn't dig into my cranks at all.

You might want to put some wood between the cranks and your "tool" if you're using something sharper or have i.e. black cranks

Turning towards the left of the pic.

The better the grade of aluminum in your cranks, the easier the chainring will be to undo. In my case, I only had to do a small turn with the extension and I could undo the chainring with my hand. With weaker cranks ie. 6061 alu, you might have to do a few rotations with a long extension before you can undo the chainring, this is because the threads can bend.

Well done!

Edit:

Removing an ACS is really simple even if you don't have that special socket key. Simply cut out a small block of metal that will rest against the notches as in the picture below. Then drill it through so you can put a bolt through it.

Now you need to screw the block of metal to the freewheel. This can be done by putting a screw right through the cranks. This is probably the most difficult part as you will need rather a long and very strong screw that won't bend or snap.

Once you've done that, flood the freewheel thread with WD40 as in the chainring removal guide. Don't use a blowtorch, I can imagine it could damage the freewheel.

To undo, simply place the sticking out block of metal (that you screwed down to the freewheel) in a vice and do it up very tight. Then undo as shown above but in the opposite direction - after all your cranks are facing upwards. While unscrewing, you will need to loosen the bolt in the cranks as it's holding the freewheel and cranks together and you're trying to pull them apart.

Edited April 17, 2007 by Inur

[downhill_rob2@hotmail.com]

Awesome man, that will help me when i need to take mine off...

BTW, i roconment using an old chain to do that... one you dont use... cause i couldnt imagine that would be too nice on the strength squashing it that way...

[JT!]

I have a different way.

Crush it in a wooden vice, or a vice like the one pictured with wooden blocks (saves having to faff with chains) then smash the crap out of the crank arm with a mallet.

[JonCongreve]

Great! In a few eeks i'm going to have to take my screw on chainring/bash off and was going to have to make a post and ask for help, so thanks. This has really helped

[clarkytrials]

I have a different way.

Crush it in a wooden vice, or a vice like the one pictured with wooden blocks (saves having to faff with chains) then smash the crap out of the crank arm with a mallet.

This is the way I do it as well but your way seems more professional

[tomturd]

Any chance me (or you) can stick this in the Wiki?

[Greetings]

Any chance me (or you) can stick this in the Wiki?

Go ahead

I've no idea how to do it.

[Walleee]

I like how you use the word 'simply' when referring to unscrewing a freewheel.

In my experiance, it's not simple. I've said it before and i'll say it again, I tried a 6ft pole with me and a big huge technician from college on the end. No joy. Bathed it in wd40 for a day, tried pulling, slowly applying the load, an also hammering. He ended up bringing in his hammer drill which removed it, like they use at garages for removing car wheels, couple of clicks later and it started to unscrew.

but yeh, the methods you describe simply didn't work (for me)

[basher]

I like how you use the word 'simply' when referring to unscrewing a freewheel.

In my experiance, it's not simple. I've said it before and i'll say it again, I tried a 6ft pole with me and a big huge technician from college on the end. No joy. Bathed it in wd40 for a day, tried pulling, slowly applying the load, an also hammering. He ended up bringing in his hammer drill which removed it, like they use at garages for removing car wheels, couple of clicks later and it started to unscrew.

but yeh, the methods you describe simply didn't work (for me)

The trick is heating up the cog though as it will expand it slightly making things easier.

[Greetings]

I like how you use the word 'simply' when referring to unscrewing a freewheel.

Yeah i actually had more problems with the freewheel but that was because of the dodgy arrangement/lack of a proper socket.

Chainrings are dead easy though, done them many times since without heating the cranks up.