Urgent help re removing crank arm

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Old timer

Über Member
Location
Norfolk, UK
Sorry to start a new post

I took advice from members and purchased the tool for removing my chain wheel and and left hand crank arm.

I have screwed the adapter right in so that it will not strip the threads inside the arm. Now tightening the central bolt that now pushes against the spindle and will(hopefully) pull of the arm. Well, I`m no weakling and have applied about the same amount of pressure as you would when removing stubborn car wheel nuts( and you know how tight they can be) I`m holding fire till someone tells me that it is quite common for the arms to be extremely tight.

If that is the case, what next? tapping whilst applying pressure? use an extension bar on the socket set? bang the socket wrench with a mallet?

I gather I haven`t missed anything! in the centre of the tool (the part that goes on the bike spindle) there is a removeable metal plug, I have to remove it because with it in place I couldn`t get enough of the thread to do up in the arm. I can only imagine that that removeable plug is designed for when the spindle is further inside the crank arm?

Q.2 whilst I`m at it. I fitted new tubes and tyres to the bike around 4 weeks ago, the front tyre is down to about half pressure and the rear is down to about two thirds of pressure. should I be looking for punctures or do bike tyres loose air more readily that motor vehicles?

Thanks for your help.

Dave
 

numbnuts

Legendary Member
they can be very tight.......need a bigger hammer
 

ttcycle

Cycling Excusiast
echo numbnuts - can be tight but be patient.

Your tyres just need pumping up- if they're flat within a week or so look for a slow puncture.
 

ColinJ

Puzzle game procrastinator!
Hi Dave.

When I first used a crank extractor I screwed it on with the centre part of the tool already screwed in. That meant that the outer part of the tool didn't get very far in, didn't grip much thread and so I ended up extracting the thread rather than the crank!

The answer there was to ensure that the inner part was fully screwed out, so that the outer part could be fully screwed in, if you see what I mean. After that it was reasonably easy to pull the crank off. That type of crank spindle was solid so there was no need for a 'plug'.

When I came to change the cranks on my MTB recently, I found that the tool didn't work. I then realised that the spindle was hollow and the centre part of the extractor was just screwing straight in without pushing against anything. A quick visit to my LBS revealed that I also needed a special mushroom-shaped plug to put in the end of the hollow crank spindle; one of these. Again, after fitting that the crank came off fairly easily.

A huge force was not required in either case.

As for Q2... It depends on what type of tubes you are using. If you have fancy expensive latex tubes, then expect them to go down pretty quickly (over a few days). Ordinary tubes hold the pressure pretty well but 4 weeks is enough time for the pressure to drop a little. I'm not sure that I'd expect pressure to drop by 50% in that time though! I squeeze my tyres before every ride and if they feel a bit soft, I pump them up. That is probably every few weeks.

Assuming that the tubes have Presta type valves, make sure that you have done the little knurled nuts up tightly after inflating the tubes otherwise they do tend to go down.
 
Q1. They can be very stiff, i suggest some penetrating oil, then tapping with a hammer
.
Q2. Yes, they lose pressure quicker than cars, but shouldnt need a top up more than every 2 weeks or so. Perhaps TT is right with slow puncture
 
OP
OP
Old timer

Old timer

Über Member
Location
Norfolk, UK
No washer.

Finally:biggrin: using a 7lb club hammer and a pro car socket set with solid bar plus a bit of gentle teasing with a small jemmi (Gemmi) between the crank arm and the frame (very gentle no damage) but that extra bit of pressure on the other side was just enough to break the joint. Boy! did those Evans guys put this bike together or what!!!!

So! when I reasemble it what sort of torque setting should I use (8,000lb:smile:

Thanks you guys for the prompt response as always.

I know this should have been in another forum because this is a conversion of my MTB to E bike but this forum is where the help is. The removal of the crank arm was so that I could fit the magnetic disk that works as pedal assist and counts the time between revolutions so it can get the amount of help right for crank speed. It was supposed to be fitted behind the chain wheels but being a triple with a very small inner ring there just wasn`t enough room without removing the small ring and a bit of grinding which I wasn`t prepared to do. So I fitted it on the L/H side and reversed the magnetic ring so that it spins in the right direction. The ring is 65mm diameter so I don`t think it will be vunerable and to be honest it will be a lot easier to maintain and keep clean.

Anyone interested in seeing the pdf instructions can click this link. http://www.alienbikes.co.uk/page20.htm Below the word kits choose the second option (36V with pedelec) and scroll to the bottom of the page where you will see the crank sensor.

Dave
 
OP
OP
Old timer

Old timer

Über Member
Location
Norfolk, UK
Tollers said:
Always happy to (try to) help! :blush: Think we're all interested and wouldnt mind seeing an occasional photo of your work.

Tollers

Link to pdf instructions edited on my last thread. I`ll take some photos of my conversion as I go along.

Dave
 
OP
OP
Old timer

Old timer

Über Member
Location
Norfolk, UK
ASC1951 said:
Jemmy. Assuming you mean the object which the Youf round here carry instead of their own cash.


That`s the kiddy. Very handy little tool. Made by snap-on. size of a large screw driver with indestructible plastic handle , square blade, splade out at the end with 30 degree bend. I`ve used it for maybe 15 years and given it more stick than a donkey and it still is like new. Because it`s fairly small as far as Jemmy`s go you can get it into tight spots.

A good use it to assist with getting crank arms off:biggrin::biggrin:
 
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