Do potholes eat gears?

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DrInnovation   100 W

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Do potholes eat gears?

Post by DrInnovation » May 16 2016 11:22am

I'm looking at upgrading from my LashOut (disk-brake chain side mount with Mac with currie planetary gear connection).. because I eat a planetary gear avery 1-3 months. As I am looking at a replacement, started thinking about what causes it. My hills (10%) and mass (200+backpack+bike=300) don't help but then I got to thinking that maybe it is, at least in part, the many potholes and road-cracks (some 3-4 " across/5" deeps that are absolutely unavoidable. Just thinking about the mechnical issues, hitting a crack while under power/load probably adds a lot of stress to the gears, which might be why things seem to be fine for a while then it shears off teeth from the planetary to the drive shaft.

So now I'm wondering if I should avoid geared hubs (e.g. as on a currie iZip https://endless-sphere.com/forums/viewt ... =4&t=70454) and look only at DirectDrive hubs?
Would high-torque in a singe DD hub have similar issues? Will dual font/back but lower power direct drive hubs be more robust?

Suggestions/Comments?
Last edited by DrInnovation on May 16 2016 3:29pm, edited 1 time in total.
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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spinningmagnets   100 GW

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Re: Do potholes eat gears?

Post by spinningmagnets » May 16 2016 2:32pm

A DD hub "should" eliminate any shock-loading issues on gears. The extra weight of a DD hub would focus pot-hole stress on the spokes with occasional spoke-breakages. You can upgrade to a rear suspension and a fatter rear tire to somewhat alleviate that. (a 24-inch rim with a 2.5-inch tire is roughly the same outer diameter as a 26-inch rim with a common 1.75 tire).

However, if you are using rim brakes on the rear wheel, swapping to a 24-inch rim on a 26-inch wheeled frame eliminates the rear brakes. Going to a large DD hub on the rear is best done on a full-suspension frame with rear disc brakes.

Since you are using a Currie-drive, I assume you are on a tight budget (that's not a hit, I would use a Currie-drive when starting out, too). As much as I am reluctant to recommend a low-end product, the $260 48V Yescom might be the upgrade that would fit your current needs...

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DrInnovation   100 W

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Re: Do potholes eat gears?

Post by DrInnovation » May 16 2016 3:35pm

spinningmagnets wrote:A DD hub "should" eliminate any shock-loading issues on gears. The extra weight of a DD hub would focus pot-hole stress on the spokes with occasional spoke-breakages. You can upgrade to a rear suspension and a fatter rear tire to somewhat alleviate that. (a 24-inch rim with a 2.5-inch tire is roughly the same outer diameter as a 26-inch rim with a common 1.75 tire).

However, if you are using rim brakes on the rear wheel, swapping to a 24-inch rim on a 26-inch wheeled frame eliminates the rear brakes. Going to a large DD hub on the rear is best done on a full-suspension frame with rear disc brakes.

Since you are using a Currie-drive, I assume you are on a tight budget (that's not a hit, I would use a Currie-drive when starting out, too). As much as I am reluctant to recommend a low-end product, the $260 48V Yescom might be the upgrade that would fit your current needs...
Thanks.. so DD's don't have gears so I know that eliminates that part of the problem, but DD hubs take hard shocks well (I was worried about the stator hitting the edges).

I'm oddly split on cost.. I can afford what I want but my tendency is to minimize cost while maximizing value.
My current choices are to upgrade to a new/old-stock 2013 izip ultra (with full warranty so I expect little maintenance) which has a 500w geared rear hub
or to use one or two 36v 800w hubs (e.g. I'm discussing some very cheap ones at https://denver.craigslist.org/bop/5565830107.html ) where I do more tinkering, but can customize it and have more power. Probably even lower end that Yescom.. but at $80 a hub (with controller) I can get 2 and have spare parts or do a dual hub bike.
Thoughts?
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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dogman dan   100 GW

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Re: Do potholes eat gears?

Post by dogman dan » May 17 2016 7:01am

Worth noting that gears in the geared hubs have improved since 5 or 6 years ago. But,,you are packing pretty much right on the weight limit we suggest at E bike kit, for our geared motors. I suspect your motors are running a tad on the hot side, and the older gears can get soft when they run warm enough.

My gut reaction, a better geared motor might do you fine, Mac, Ezee, E bike kit, etc. But on the other hand, a dd is definitely robust, and you might enjoy a motor you can jack up to much higher power later on.

DD will definitely last longer, but if you are going to up the ante, consider a DD with some real power, 35mm stator instead of 28 or 30mm. You'll love 2000w on a heavier loaded bike.

But you can run a yes.com motor up to 2000w as well. :wink:

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