chain skipping teeth on my single freewheel motor hub

adaoud

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Feb 20, 2017
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5
Hello,
I have a one month old MTB that I converted to Ebike with this rear hub motor that came with only 1 cog freewheel. the original wheel that came with the bike had 9 speed cassette, I had absolutely no issues with it, shifting up down, pedaling hard, etc..
with the new hub motor, the single cog is skipping chain as you can see in the pictures below which were taken with the bike on a stand and reverse pedaling. the same happens with forward pedaling.
what is the problem, how can it be solved, and any idea how to unmounts the single cog from the hub in case in the future it wears out and needs replacement.

thanks.


IMG_0171.MOV.Still001.jpgIMG_0171.MOV.Still002.jpg
 
I can't tell for sure, because there's no edge-on view of the freewheel and chain, but if the freewheel has very thick teeth and the chain is very narrow, it might ride up on the teeth like that.

If that's the problem, you can change to BMX chain to fix it.
 
amberwolf said:
I can't tell for sure, because there's no edge-on view of the freewheel and chain, but if the freewheel has very thick teeth and the chain is very narrow, it might ride up on the teeth like that.

If that's the problem, you can change to BMX chain to fix it.

no the width of the chain is just fine, teeth on the single freewheel are not thicker than normal, what is the problem is the distance between rollers in the chain, doesn't seem to be enough for the freewheel, that's why it engages for a near semi turn before the teeth start misaligning with the grooves between the rollers and hit the rollers themselves.
 
Well, if you are sure it's not the width, then that means the freewheel teeth are not spaced correctly for standard bicycle chain.

So your two options are:
--find out what that chain standard uses that spacing, and change your chain and front sprocket(s) to match,

or

--replace the new freewheel with one that uses the same standard as your existing chain/sprockets.


As for removing it, since I don't see anyplace on the center body of the freewheel to engage a removal tool, there are two options:

You can file notches in the very slightly raised lip at the center ring of the freewheel (where the threads are), so they match an existing freewheel removal tool (like the Park "BMX" style one with four rectangular engagement blocks at it's outer circumference), then use the axle nut and a washer to hold that tool against the freewheel face while you use a wrench counterclockwise to loosen the freewheel. I couldn't find my post about doing this, but here's a pic of it showing the notches I made in it:
file.php


The other option is to get or make a pin wrench to undo the bearing-retainer/lockring (engages the two pins in it), and take the freewheel apart so you can use vise-grips or similar to grab hold of hte actual freewheel body, and unscrew it from the hub. If you're careful you can reassemble and reuse it later if you need it.
 
Cant see your tensioner, but maybe removing two links from the chain could help it some.

Get an old shitty stretched out chain?

I'd try a brand name freewheel first of all.
 
You should read you some Sheldon Brown;

http://www.sheldonbrown.com/bicycleGears.html

When I had some chain skipping prob.s with a DNP free wheel, it was solved by readjusting the derailleur. Basicly, moving it up close and under the gears.
 
From the photo, the chain looks way too slack. For a single-speed without a tensioner, you need horizontal drop-outs to adjust the tension. If you have vertical drop-outs, you need a tensioner of some sort. You can use the original derailleur and lock it in the right position with the high and low adjusting screws.
 
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