8Fun mid drive with Hammerschmidt added on the side

[chris_comber]

Hi Everyone,

I've just bought a Truvativ Hammerschmidt for £70 (described as for spares, pos working but I'm sure its complete..) from the USA. My aim is to see if I can stick this on the side of my 250W 8Fun mid drive kit.. I will leave the Hammerschmidt in constant overdrive mode, so the gear shifter will be disabled on it. For the chainline, I need to track down a spider adaptor (any help would be very welcome) so everything lines up. My hope is this modification will improve the performance of the 8Fun.. At the moment I have a Shimano Nexus 7sp on my back wheel.

I'm sure some of you are wondering why I'm bothering to try this out, well to be honest I would like speed and hillclimbing, but at the moment I can't have both on my bike.. If you look at my profile pic, you'll see my bike. On the flat my bike is great and loads of fun to ride, but on hills (example, anything like the Zip Zap on Box Hill) my bike just won't hack the climb. I could go for 36t ish and 16t is setup, but I'm still not sure I'll be satisfied.

Another reason (maybe the real reason I'm doing this), I've not see anyone attempt this Hammerschidt/8Fun mod before, so I'm interested to see what is or isn't possible,,

So, over to the community to crit my idea..

Thanks,

Chris

 

[chris_comber]

Pics

 

[chris_comber]

Hammerschmidt

 

[Deleted member 4366]

I don't think it will fit. The BBS01 has a square taper shaft. The Hammerschmidt needs a special splined bottom bracket.

 

[chris_comber]

Hi d8veh,

I don't think it will be a problem. I don't intend to use the Hammerschmidt crank arms. Also, I'll be a attaching the hammerschmidt to the area where the standard 8Fun chainring goes.

 

[chris_comber]

I've found the spider adaptor I need.

 

[chris_comber]

I now have the spider. Just waiting for the Hammerschmidt to be delivered.... Also, just incase I need it, I have bought a Truvativ square taper crank arm (for 4 bold chainrings).

I really hope the Hammerschidt arrives tomorrow so I can work on this on Sunday...

 

[chris_comber]

Getting there. I'm having to work this out as I go along. The black casing will be screwed to the side of the mid drive (I think). An additional cog (not shown) will attach to the drive plate on the mid drive and drive the planetary gears and chainring. Make sense?

 

[chris_comber]

Getting there. I'm having to work this out as I go along. The black casing will be screwed to the side of the mid drive (I think). An additional cog (not shown) will attach to the drive plate on the mid drive and drive the planetary gears and chainring. Make sense?

I still need to work out how I will attach the chainring.

 

[chris_comber]

So, if I get this mod working, I will post a video. Hoping to have some more time today to work on this.

I have to say, I'm surprised people aren't really interested in this mod.

 

[Nealh]

I'm not much help Chris with pictures and descriptions, I tend to be a bit more practical and need to have the object/s in front of me. Good luck with your perseverance and a solution is there somewhere. Spoke to Keith yesterday some old biddy bugggered his front wheel on his Forza not happy with only trying to run in to him once she did it again, no injuries just a fuming ebiker.

 

[chris_comber]

Hi Nealh! Sorry, I just meant people in general. I thought more people would be interested in this modification.

Sorry to hear about Keith. If he needs any help or anything.. We could maybe meet at Box Hill and work on his bike or something.

 

[BAH48]

I'm watching with interest.

 

[Nealh]

Talking to Keith it sounds like a new rim is needed.

 

[chris_comber]

Ok, so I've spoken to an engineer friend. He's up for trying to find a solution. It might mean casting news parts and drilling the 8Fun drive shaft face...

 

[chris_comber]

Talking to Keith it sounds like a new rim is needed.

Rims are fairly cheap I guess. Not as bad as it could have been maybe?