Bearings in a "Currie" 75mm planetary?

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Kodin   1 kW

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Bearings in a "Currie" 75mm planetary?

Post by Kodin » Feb 25 2014 12:04am

Just picked up a 4.5:1 75mm planetary off ebay. Supposedly from a "Currie" scooter of some kind. Seeing how much play exists between the gears in the gearset, I wonder to myself... Would I benefit from taking the planetary carrier apart at the rivets, boring out the planetary gears, and installing ball-bearings or needle-rollers to replace the (loose) sleeve bearing design? I can only imagine it'd end up running a lot quieter as well with all the extra slop cut down... If I can make it better, I'd rather rebuild it now when I have everything in parts and I'm not shoving huge wattage down it's throat... Anyone ever tried what I'm suggesting?

Pic of what I mean (overlay of where bearing would go inside the planetary gears in red):
Image


Needless to say, when I'm done it'll be housed in an oil bath as well to keep the parts wearing cleanly long-term.


If a planetary gearset fails, what usually goes first? The friction point between shaft and planetary gear or teeth?
Tank Bike - (Previously YAG - Yet Another Genesis) - LeafBike 1500W 5t, custom shaft, 9 speed cassette, Chinese "Tank" EEB clone frame, Sabvoton SSC048150

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DrInnovation   100 W

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Re: Bearings in a "Currie" 75mm planetary?

Post by DrInnovation » Oct 27 2015 11:14am

Curious how you rebuild turned out. I just destroyed my second of these in slightly over a year.
This time the gear teeth that attach to the chain sprocket ate through the gears in the planitary.
IMG_20151026_185349.jpg
IMG_20151026_185349.jpg (235.24 KiB) Viewed 191 times
Last time the rivets poped and it destroyed the alignment elements
https://endless-sphere.com/forums/viewt ... 30&t=64427

Ordered another (29$ on ebay) but would like to find a more permenant solution than replacing them every year.
Owner of a Crystalyte 4012/409 with 10aH 16s Headway on a old huffy frame. Its not fast but it climbs my daily commute up 8% and 10% grades nicely. Washout frame with a "e-bike" front-drive hub with a home-built 18650-based 20ah-36v. My bigger "E-ride" is a chevy volt.

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Kodin   1 kW

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Re: Bearings in a "Currie" 75mm planetary?

Post by Kodin » Oct 27 2015 2:49pm

Ended up not going that route; I went with a Leafbike 1500W hubmotor. That said, I should really look at doing the bearing mod soon just for grins. Might drill out the rivets this weekend just to see what it would take. Should be able to clamp the gears in my ER32 collet and bore them for bearings rather easily. ...Unless the gears are larger than 3/4", in which case I'd have to fix my chuck alignment on the big lathe and do it there. After that I doubt I'd need to worry about rivets ever popping.
Tank Bike - (Previously YAG - Yet Another Genesis) - LeafBike 1500W 5t, custom shaft, 9 speed cassette, Chinese "Tank" EEB clone frame, Sabvoton SSC048150

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