Removing crank arms

Alex von

New Member

I've just bought an e genius 720 plus and been out on its maiden ride. Love it! Now I'm cleaning it down I would like to remove the crank so I can take the Bosch casing off and give it a clean up inside but it has a crank different to what I am familiar with. Can anyone tell me what sort of puller I need to get the arms off without damaging the splines?

It is fitted with a Miranda delta boost crank
You simply need an ISIS crank extractor.

This is my version, but there are many others.


You are also going to require a Bosch Spider tool to remove the guard behind the pedal crank.


I would also bin the OE locking ring/sprocket guard, because as you are already finding out, all that it does is prevent debris and mud from clearing the sprocket area. It won't be long before you will suffer from chain suck in muddy conditions, or the chain starts to slip when debris builds up.


With the guard removed, your set up will then look this this.

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Eddie, you're one crazy rider! :D, I agree with the Isis puller, that's a pretty common setup.
Thanks a lot guys, both very helpful. Thanks for the tip about the spider tool as I would have only found another hurdle once I had taken the crank arm off to find that. Where do you suggest to get the spider tool from as I imagine it's a more specialist part than most?

I did in fact find that problem out today with the sprocket guard which was a little concerning at first, I didn't realise it could be removed. Is the third picture down what you replaced it with or have you just removed it altogether? It's hard to tell from the amount of mud on your setup pic :) looks like you had some fun that day!
Alex, do take a moment and search our site for other of EddieJ's posts; he LOVES mud and night riding and all sorts of challenging terrain which are exhilarating to watch :eek:
Not sure about that one. :oops:

Alex if you are in Europe, I can suggest a couple of places for you to buy the parts from.

There are a couple of different versions of the locking ring removal tool. Bosch actually gave me mine, which is the design as shown.

Picture three is of the required parts. As a disclaimer in respect of safety; removing the guard does run risk that you could always trap your fingers or whatever around the sprocket. Hardly likely, but worth mentioning. :)

As for the photo of the dirty bike, it has just occurred to me that the photo was taken last Xmas morning. Not a bad way to spend a couple of hours, out riding before everyone is up. :)

As for Instagram, if you have a Facebook account, I have just recently set up an "electric mountain bike" group page. Feel free to join in, as the page needs plenty of like minded members to make it active and worthwhile. :)

Yes Eddie I am in the UK (yorkshire) If you could suggest a link to the required parts after I have removed the OE locking ring/sprocket guard too that would be much appreciated. (disclaimer taken onboard I shall count up all my digits before and after maintainence ;))

I have actually considered riding early Christmas morning this year myself! Figured it would be quiet!

I shall look up the fb group now :)
I tend to use a couple of German based companies.

Bike and (Link Removed - No Longer Exists)

In the UK it seems as though most people use either or

I have found that Connex make the best sprockets for the Bosch motor system, and tend to order those from either of the first two links. I hadn't realised the cost of the spider tool. It is almost mortgage money!

I have actually shattered part of my knee cap from a fall a month ago, so it is currently looking as though my own planned Xmas day morning ride might not happen. It'll be a shame though, as it has become a bit of a tradition. :(
bloody hell that sounds nasty!

You did well to get one from Bosch, like you say they are not cheap considering what they are. I think I will use e bike shop. Before I order the spider tool can you confirm that I will need this as well in replacement of the removed OEM sprocket guard;

it's £4.99 each time for delivery and I'm a tight yorkshireman so I just want to make sure I'll be needing this too? I'm sure all will become clear once I get the crank arm off but until the tool for that arrives mid week I can't tell whats beyond that :confused:
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Yep that is the upgrade that you require. :)

Other than making something, or being an animal with a punch and hammer, there isn't sadly any other real option available.

Note that it is a left handed thread, so undoing is clockwise. :)

As for the knee, it happened about 7 miles into a 32 mile Evans ride. The last 5 miles were very painful and I hardly managed to drive home, yet the next day onwards, I had no pain at all. It all came to head last week after doing some ladder work, as fluid started to build, and I touched the knee cap, only to find that it had gone flat with a big hole in it. Other than burning pain, there is still no pain. Very weird. I also broke my nose in the same fall, and oddly again, it is only just last week that it has started to hurt.

No sense, no feeling I guess!!! :D

Forgot to say, thanks for joining the FB group. :)
That is strange? Well done for carrying on throughout all that!

I did an Evans 'off road' ride last March but was disappointed about how much road riding was involved.

No worries. I must say the e bike community has been far more helpful than other general mtb groups I am on. :)
Funny that you mention the road work. Their rides are dreadful for it. I do one if their rides a year, just to catch with old friends, then that is it. Wiggle do a couple of good ones around here, and the Purbeck ride is amazing, but it is just too far away for me to do it again.

And yep, the eMTB crowd want nothing more than to see other riders out enjoying themselves. It could be an age thing, as we all have nothing to prove. ☺
Age thing!? I'm only in my late 20's But I don't care what others think I ride my bike to p ut a smile on my face and the e bike certainly does that!

Cheers for the advice, all the parts and tools arrived today and I've done the modifications now.


Any advice on what dielectric grease to use and where it's best purchased?
That looks much better. :)

Ref the dielectric grease, I am afraid that I can't recommend a brand, as I get given mine by a cousin that works in a bearing/engineering shop, and there is no makers name on the container.

Sorry about that.
I'll revive this thread. No amount of crank pullers or hammering will remove my crank it's stuck fast. I've tried everything I can.