Sparta Ion Drive - broken axle?

gstew

Just Joined
Apr 28, 2014
4
0
54
Hello there!

I have been the happy owner of a koga miyata ebike for the last few years. I had a mishap climbing a local hill in a high gear and bike is now unusable.

Symptoms:
there was a cracking noise and now the rear sprocket is no longer connected to the hub - it just spins uselessly.

I have taken the wheel off the bike. Not sure what the next step is? I have removed the six torq screws holding the plate on the hub but was unable to remove.

Can someone help me diagnose the problem - the bike is out of guarantee so I would fix it myself if I knew how - assuming no special tools are required. I looked at a tear down video on youtube of another hub and the mechanic had to use a three pronged auto tool to remove the hub - I am not sure this is even necessary in my case - maybe I just need to replace the sprocket.

Be glad for any tips,

Graham
 

flecc

Member
Oct 25, 2006
52,761
30,348
I'm afraid I can't help with the stripping, but the motor is a Sparta one. That direct drive motor is very different from the internally geared ones that most feature in online videos etc. I think the torque sensing is in the rear wheel and there's also some software linking incorporated since rear wheel removal requires a software reset as you may know..

I can only suggest one of the two agents:

Electric Bike Sales

Justebikes
.
 
D

Deleted member 4366

Guest
Has the gear cluster completely snapped off the motor side-plate or is it still on, but free-wheeling in both direction?
 

gstew

Just Joined
Apr 28, 2014
4
0
54
Thanks for the info. I had forgotten about the software reset. The gear cluster is still on and freewheeling in both directions.
 
D

Deleted member 4366

Guest
That's easy to fix then: There's nothing wrong with the motor and no need to dismantle it. Show us a photo if you don't know whether it's a free-wheel or free-hub. You just need the tool to unscrew it, and then get a replacement, which should cost £5 upwards depending what quality you want.
 

gstew

Just Joined
Apr 28, 2014
4
0
54


Thanks a million - what kind of tool do I need to replace the great set?
 
D

Deleted member 4366

Guest
Unfortunately, you've left some spacers or whatever on the axle, which has blocked the bit from view where you can see whether it's a free-wheel or free-hub.
 

flecc

Member
Oct 25, 2006
52,761
30,348
This Dutch Sparta/Koga motor was first seen as a single speed in the Sparta Ion, using a freewheel, but quickly changed to derailleur after a frosty reception in Export markets. The revised model was named Sparta Ion M-gear.

Therefore I'm pretty sure it will be a multi-sprocket freewheel, but just as well to check with a further photo with that collar removed.

P.S. Crossed with the OP's response confirming it is a freewheel. There are plenty of these 7 speed Shimano MF-HG37 ones on Amazon, and freewheel removal tools.
.
 
Last edited:
D

Deleted member 4366

Guest
You need a free-wheel tool, which you can get from EBay or your local bike shop. This goes in the centre of your gear-set and will allow it to be unscrewed because it works on the fixed part of the hub.

There's one thing you have to look out for though. Many of them don't have a big enough hole for your axle. They have a 12mm hole or 12mm square because a normal axle is shorter and only 10mm. Yours is at least 12mm.

In case you can't find one like that, I can sell you one for £5. Send me a PM if you need it.
 

Herrie

Just Joined
Apr 22, 2019
2
0
68
Heerlen, Limburg NL
The flywheel is multi sprocket, as mine is completely broken out of the motor housing, the plate, I cannot unscrew it since I cannot get grip on the remaining part of the (cast iron?) part that is left.
Do I really need it? Or are these freewheel hubs included in a new set of chainwheels?
They are quite worn as well.
I don't think welding the broken part back into the plate makes sense, cast iron is not easy to weld
Perhaps a 2nd hand wheel would be better, or just the motor housing.
 

Attachments

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,985
Basildon
You probably won't be able to get one of those, but you can use any motor you want. What connector/s are on the end of the cable?
 

Advertisers