mid drive project for pikes peak

[Lenk42602]

yes - I spent a few hours at the machine shop yesterday with my mentor in order to determine how feasible LH threading the disc side shoulder of the hub motor will be.

We are going to cut the threads using one of his older Heidenhain 3 axis machines. Jim is going to supervise and write some quick g-code for the process - I just have to basically move the heavy ass fixture off the tnc machine currenty an set up the cover plate in a chuck.

Going to wait until my LH thread free wheels show up before we do anything, which should be tomorrow. Also purchased a tandem crankset off of ebay for $35, NOS Deore DX. I have a week off beginning 11/13, so I will be at the shop early next week if he can spare some time to make sure I don't destroy anything....

You know, I was thinking about this particular drive set up I am working out - I suppose the reason this is a no go with RC motors is the RPMs they spin at correct?

Len

 

[Whiplash]

Yeah, just too much RPM..

 

[Warren]

" I suppose the reason this is a no go with RC motors is the RPMs they spin at correct?"

You could do a mid-drive, or crank drive with an RC motor. It has been done by folks on this forum. But you would need a primary reduction, like those made by Matt (Recumpence).

Remember, the motor inside your hub has a 5:1 reduction too. To do a single stage drive from the motor to the cranks, with the limited reduction you can get using bicycle chainrings and sprockets, requires a large diameter motor, like a DD hub. A small diameter motor, at low rpm isn't going to develop enough torque.

 

[Whiplash]

Yes warren, I have built two different 25:1 primary reduction boxes, I just meant it can't be done this simply. The only advantages this style would have over the typical setup would ne that it does not run the power through the cranks thus taking the stress normally imposed on the ENO freewheel at the cranks out pf the equation. That would ne worth the effort for really high output systems.

 

[Warren]

Whiplash,

"Yes warren, I have built two different 25:1 primary reduction boxes, I just meant it can't be done this simply."

Sorry, I was responding to Len's question, and hadn't seen your response. I checked out your site. Awesome bikes!

Warren

 

[Whiplash]

Thanks!

 

[jmygann]

IMHO ... Josh is the man ... and he is not talking

http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=31490&hilit=pikes+peak+magicpie