What crank extractor do i need for my brompton spider crank ?

[snaz]

Hi

Newbie here regarding replacing cranks:

Model: Brompton 2019
Crankset: Spider 50T crankset replacement - silver for black.

I'm not familiar with crank extractor tools - is there a certain size i need for this job or will any do ? Can i just buy any one off ebay ?

thanks
sp

[Jdsk]

Welcome.

While we're waiting for the experts... is that like this?
https://brilliantbikes.co.uk/brompton-chainsets/1940-brompton-crankset-with-50t-spider-chainwheel.html

Jonathan

[snaz]

Hi

Yes that's the silver Brompton crankset i'm replacing for this black one:

https://brilliantbikes.co.uk/brompton-c ... wheel.html

so like for like - just changing the colour....

sp

[willcee]

Normal std crank extractor will do the job.. buy the best you can, cheapies are crap... ensure the threads in your cranks are clear and clean [toothbrush with gt85 0r wd40.]. screw the big bolt heads in until you cannot get any more travel and start to wind the handle.. now they can be easy peasy or bloody difficult no one knows until they are at the coal face.. seen me having to resort to an angle grinder.... luck..will

[alexnharvey]

I've never tried a 'nice' crank extractor so maybe I cannot fairly compare but I have been using a cheap extractor from an old lidl toolkit for the last 13 years without incident. IIRC the brompton takes a standard square taper crank and a normal square taper type extractor will do.

Tips for success with a cheap extractor (which hold for more expensive ones too)

The crank threads should be thoroughly cleaned if they are dirty and road grit brushed away.

Inspect the thread in the crank carefully for prior damage to the threads.

The crank face may not be perpendicular to the hole, do not rely on it for reference.

If the initial threading won't go smoothly by hand don't force it with a tool.

The thread is very fine and typically the crank is aluminium so the extractor must be seated as deep as possible before the extracting force is applied.

Remember to adequately retract the 'pushing' pin before installing the extractor.

I like a little oil or grease on the extractor when threading it in initially by hand.

[snaz]

Thanks.

1. What's the pushing pin ? I've not heard refs to that before ?
2. For the extractor tool head-taper type - i found these on ebay - which would you recommend ?
https://www.ebay.co.uk/itm/Bike-Bicyle- ... SwuRpe2yE~
https://www.ebay.co.uk/itm/Bike-Bicycle ... Sw1SFfBZjh
https://www.ebay.co.uk/itm/Icetoolz-04S ... SwU8ReXnk4
They all look a bit cheap and chearful but will they do ?
3. I understand this is only used to remove - when it comes to mounting the new crank i don't need to use this tool . Is that correct ?

thanks
sp

[alexnharvey]

By pushing pin I mean the central screw on the tool which threads through the body and pushes on the end of the square taper to force the crank off.

A reasonable branded tool would be this https://www.ebay.co.uk/itm/IceToolz-Bik ... 3191099598 There's also a nice used shimano one which is likely to be excellent but presumably it will be bid up a bit over the next week.

If you buy a cheaper one you have to accept that you are taking a bit of a punt on something neither you and I have seen or handled. You should also bear in mind the delivery time, presumably you do not want to wait 3 weeks for it to ship from china. A crank extractor really is quite a simple tool, if the fine thread is well formed then that's the most critical feature.

[snaz]

Hi that ice toolz one you linked me to - if i purchased that all i would need is a spanner to grip the thing with and turn - is my understanding correct ?

Also i'm browsing youtube vids using searches like how to use a crank extractor - this one seems informative on procedure :
https://www.youtube.com/watch?v=cPQyQnNdews
this one on crank identification:
https://www.youtube.com/watch?v=VMV-SOIhM2c
i'm assuming the brompton is a 3 piece type

if these are wrong, if anyone can link me to one they think covers it - appreciated.

cheers
sp

[alexnharvey]

A 16mm socket or spanner and an 8mm Allen key would be required.

I think a square taper BB and the pair of cranks is sometimes described as three piece but not very often in the UK. The term is also used to refer to some BMX BB setups that are slightly different so it is not very clear. Square taper cranks can be swapped for different ones reasonably easily whereas some of the BMX ones are proprietary, only those cranks fit that axle and so it makes more sense to refer to those as a three piece system.

[Jdsk]

... if these are wrong, if anyone can link me to one they think covers it...

I'm generally cautious about YouTube videos of unknown provenance... your bits might be different.

How about starting with the two great sources:

Sheldon Brown Tool Tips
https://www.sheldonbrown.com/tooltips/cotterless.html

Park Tools Repair Help
https://www.parktool.com/blog/repair-help/how-to-remove-and-install-a-crank

Jonathan

[snaz]

thanks folks

i'm going to purchase the Ice tool alexnharvey linked me to above unless anyone says different. I'm assuming the taper head is compatible with my Brompton.

I think that about covers it unless anyone has anything else to add !

Only to thank you for your time.
cheers
sp

[snaz]

Hi ......ONE FURTHER QUESTION !

While i'm on this replacing a crank set learning curve...... can i ask for some advice about bike grease vs oil. My understanding is bike lubrication hot spots are basically split between the two .

Is this correct:

1 Grease for : (?)
crank extractor thread
pedal thread

2. Advice seems divided about applying grease to the bottom bracket once the crank to be replaced is removed - it's a new bike so i'm assuming NOT to add grease to the bottom bracket ? It's also a new crank set so should i add grease to the crank arm mounting port/hole ?

3. Do i need to put any grease OR oil on the new crank set chain cog or will the existing oil on the chain be ok ?

4. Can you link me to a reliable but inexpensive grease product - i gather grease has a shelf life so i don't want to over buy and be left with off-grease in the future.

Any other grease/oil advice not already mentioned welcome.
thanks again.
sp

[alexnharvey]

Grease is oil plus thickener. This is described at greater length in some of the long grease threads that you will find in technical too good to lose viewtopic.php?t=64417

You can use oil or grease as you thread the extractor into the crank. I think this helps you get it started by hand. It is not essential just personal preference.

You should use grease or use anti seize (a special grease, sort of) in the pedal thread and especially on the bottom bracket threads which go into the frame. Bottom brackets can be very difficult to remove after many years if not greased. You can use it on the crank bolt if you like.

A general purpose nlgi2 grease is useful for most of these jobs i am currently using thermaplex calcium sulfonate thickened moly bearing grease for general purpose but it is nothing special. You shouldn't go out of your way to get the same one. Ask ten people here what grease they prefer and you'll get ten answers. I don't think grease goes out of date for many years. If it separates just mix it up.

To grease or not to grease the square taper crank interface is controversial with strong opinions on both sides. I think I prefer a clean dry joint, ie cleaned thoroughly or wire brushed if there is any dirt present.

[Brucey]

I would suggest that you use Copper-ease on static parts that might corrode and you don't want to seize up, eg pedal threads, seat pins, wheel nuts etc.

Some brands of ST crank fit better if they are greased when first assembled (eg shimano) but may be better re-assembled without grease when they are refitted. If you do use a grease here, use a simple grease, not one with solid lubricant additives.

For every application there are greases which can be good, better, best. Wanting to buy cheap grease is a pretty good way of increasing the likelihood of problems.

cheers

[snaz]

cheers - v helpful