Planetary drive IN the crank gear??!!

[Whiplash]

I'm not sure this is what I think it is, but another thread here got me thinking.... Why not design and build a planetary drive that fits on a normal crank set? There seems ample space to do it in a strong way, and it could be a simple bolt on affair! Maybe I am not understanding how they work correctly, but it seems you could have a thin housing with a 44T outer sprocket and have that drive through some planets into the sun gear at the center that goes to the chain. This would work no? Somebody tell me if its worth pursuing because I think it might just be the ticket for us through the gears guys!!

 

[Thud]

that is called a Schlumphf drive:

http://www.schlumpf.ch/hp/schlumpf/antriebe_engl.htm

Get yours today.... $$$$$$$$$$$$$$$$$$$$$$$$$

 

[StudEbiker]

Truvativ is also making one now as well.

http://www.google.com/products/catalog?hl=en&ds=pr&sugexp=ldymls&pq=truvativ+noir&xhr=t&q=truvativ+hammerschmidt&cp=11&qe=dHJ1dmF0aXYgaGE&qesig=uWYHAXLKpkqWNe4Qp9P3Jw&pkc=AFgZ2tlG09T949pUcqC6p4oweOu2VlYJYhc4q_xvcWZSAkHPQvvPtV7WhzNQxpYcGMBozjA3iS6fywMmAn4vi1IFIG_dHDqeeQ&safe=off&client=firefox-a&hs=kwk&rls=org.mozilla:en-USfficial&bav=on.2,or.r_gc.r_pw.&biw=1152&bih=808&um=1&ie=UTF-8&cid=1655735070463645333&sa=X&ei=y-K2TZnAIIi-sAPL_7CpAQ&sqi=2&ved=0CGcQ8wIwAA#

Also, someone just got a great deal on a Schlumpf equipped Bike E.

http://cgi.ebay.com/Bike-E-Recumbent-Custom-Used-Great-No-Reserve-/280660915773?pt=LH_DefaultDomain_0&hash=item4158b1b63d

 

[Whiplash]

Hmm, these look good, but I guess they are a bit pricey! I was thinking if you powered the main large cog with a motor, you would need the overdrive version to actually reduce the gearing and then where the crank would typically mount, you would attach a driven gear there for the rear cluster...

 

[bobc]

A normal epicyclic gear has a couple of issues, main one is limit to reduction ratio available, esp. considering that the "sun" cog has to fit around the normal crank/bottom bracket gubbins, so it would need to be a certain size. If you're trying to get down from RC motor type speeds (5 - 10krpm) to crank speeds (~70rpm) that's 100:1. That's why I'm enthusiastic about the harmonic drive option in the other thread
http://endless-sphere.com/forums/viewtopic.php?f=28&t=27132
Other issues include lubrication & protection of spur gears & location of the fixed ring gear - all do-able I'm sure.
You could get the required ratio by going to double epicyclic sections, starting to look even more bulky/expensive....
Oh yeah - normal system for getting max reduction ratio from an epicyclic box is to input to the sun gear, keep the outer ring fixed and take the output drive from the 'spider' holding the axles of the planet gears. This lends itself to stacking reduction modules one after the other (sun gear for next stage just sits on the spider of the previous)

 

[Whiplash]

I saw that one, I don't really understand how it works, but if it does, then cool! It would need to tolerate a decent amount of power though, like 3000 watts at least to be a viable option for everyone..

 

[Green Machine]

I love the sclumpf drive..especially in my 20" folder...spent more on the schlumpf than i did the entire bike but well worth the cost. Now i get exercise at 30mph...and an extra 4-5 mph with the extra pedal power...win win.

 

[ebikes-sf]

As already mentioned above, Schlumpf high speed drive with 2.5X overdrive is great for higher speed ebikes. For anyone interested in getting one, be aware that special tools are required for installation as explained in this video:

[youtube]0teCnQJskgQ[/youtube]

 

[Whiplash]

HMM, after seeing that, it would seem that you could simply attach a sprocket to the actual shaft of the unit that spins with the pedals and run that to the rear cluster and then drive the main sprocket with a motor assy. and you would get another 2.5:1 reduction before the crank! That could net you over 18:1 if you ran a 705T #25 chain sprocket in place of the bike sprocket on the outside and ran a 10T sprocket on the motor! This is INTERESTING! Do you think there is enough room to install a sprocket to drive the rear cluster on the crank axle?? That is the only thing that would hold you back! That and would it hold any decent power.... It would have to handle at least 3000 watts to be of any real use...


The cool thing is you could SHIFT IT!! if the gearing could be good enough to handle the 1:1 ratio. Maybe in the bikes lowest rear gear? Just for crazy high speeds once in a while!

 

[Green Machine]

I got my speed drive schlumpf from illia by the way at ebikes sf...nice video illia...great work.

He gives the best pricing on the sclumpf i have seen...even on the web. Really good guy, a real pleasure to work with cant say enough good things about him.

He can also install the system for you if you live in the bay area...as you can see it is tricky install.

Everyone i know who has ridden on a schlump ebike just loves it....having cadence at speed is critical for having the feel of a bike on an ebike and getting exercise etc...it feels great to pedal around corners at 30+ mph....even at 40+ you still have plenty of cadence.

I like schlumpf very much with rear in gear hub shifter...alfine 8 and schlump...and front wheel hub drive....awd.... is wicked combination IMO.

Can not say enough about schlump...have it on 3 bikes...on 1 bikes the schlumpf cost more than the complete bike (without electrics).

And did i say enough about Ilia? Really good guy. I am so glad he has quit his job at adobe and is now devoted to ebike part sales...a real blessing and i pray every night he doesnt have to go back to work in the real world...he is blessing for the ebike guys.

 

[adam333]

Everyone i know who has ridden on a schlump ebike just loves it....having cadence at speed is critical for having the feel of a bike on an ebike and getting exercise etc...it feels great to pedal around corners at 30+ mph....even at 40+ you still have plenty of cadence.

Did you bought the regular 27T Chainring coming with the High speed drive to be able to pedal at 30-40 Mph?

 

[MattyCiii]

I got my speed drive schlumpf from illia by the way at ebikes sf...nice video illia...great work.

He gives the best pricing on the sclumpf i have seen...even on the web. Really good guy, a real pleasure to work with cant say enough good things about him.
...
Everyone i know who has ridden on a schlump ebike just loves it....having cadence at speed is critical for having the feel of a bike on an ebike and getting exercise etc...it feels great to pedal around corners at 30+ mph....even at 40+ you still have plenty of cadence.

Glad I saw this... Your comments validate what I've read elsewhere about the High Speed Drive, and what I have experienced personally dealing with ebikessf and using the ATS Speed Drive.

I ordered a High Speed Drive from ebikessf this past Monday from ebikessf. I'm going to install it in my 2009 A-Line project. It didn't take me much convincing, only about 50 miles on my pedal-only Dahon with an ATS Speed Drive from ES user Accountant. Given that the A-Line is going to be reallyheavy, I geared the pedal drive down pretty low. When powered, I'd prefer to pedal than fake-pedal... that 1:2.5 will hopefully be enough!

 

[FFR Trikes]

The Schlumpf HSD is hard to beat if you're looking for a nice low gear, and a very tall high gear at 1:1 and 2.5:1. If you don't need as tall of a high gear, the ATS Speed drive was also designed by Florian at Schlumpf, and is a good bit more affordable with a 1:1 low, and a 1:1.65 high.

Did you bought the regular 27T Chainring coming with the High speed drive to be able to pedal at 30-40 Mph?

With a 26" rear wheel, most definitely...

The standard 27T Schlumpf HSD with a 26" rear wheel @ 80RPM = 38 mph, @ 90 RPM = 42.7 mph


Here's a great resource for calculating gear ratios and speeds: http://sheldonbrown.com/gears/

-Tommy