Chain contacting upper, lower chain stay, tensioner misalign..

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Donnyten

New Member
Jun 21, 2015
28
2
3
Durham
So I've been searching various forums including this one for a solution to this issue. I underestimated this build a bit.

I'm using a 90s vintage mountain bike frame to mount a zeda 80 kit on. The issue I've run into is this- the chain makes contact with the bottom and upper stays. The tensioner that came with the kit also seems to go on at an angle that may need modification as well but I'm not too entirely sure. I am only doing a test fit and have not cut the chain to length yet, but there's definitely a chain stay contact issue that I must resolve first before proceeding. The first thing I did was to switch the orientation of rear sprocket but it did not make a difference. I also tried moving the tensioner closer to the sprocket which did not help either.

So far, the solutions that have been presented to me through searching are as follows.

1. Add enough washers on rear axle to bring the rear dropouts further from the sprocket.

The problem with this solution is that my rear wheel has a quick release on it and I'm not sure how I can add washers to this. The embedded axle seems too short to not accommodate any washers. I'm assuming people who recommend this solution are using a through bolt setup. Also, I've tried using a smaller rear sprocket but for some reason the chain will not make contact with all of the teeth on the sprocket. It will cover a few of the teeth and will stop fitting all the way after a certain point. I'm sure there's a simple explanation to this but can anyone explain why this happens? See photo

As for the axle hub type, should I just invest in a through bolt wheel or is there a way to convert the quick release to a through bolt setup if that will allow me to add the washers needed?

2. Bend the frame

I'm not sure how to go about doing this and I don't have the tools to do this. I've seen folk recommend exhaust manifold spreaders to a threaded bolt. I don't have any pictures for reference and it's hard visualizing how any of this is set up so it seems a bit confusing as to how this process is done. Even if I bend the frame, my quick release setup will not accommodate the extra length on the dropouts so that will present another issue in itself.

3. Dremel away contact points on frame.

I'd rather not do this.

4. Ultimately buy a new frame that is more accommodating to the setup.

As a last resort I will consider this, however I got this mountain bike for a steal at only $40 second hand, and it is made of steel. I've ordered a 1" suspension fork and misc components to adapt outdated parts, shims, etc so I'd love to get this working.

So far with the motor mounted, and everything else loose fitted onto the bike, it is SO much lighter than my 65-70 pound 72v ebike. I'm thrilled with the aspect of fueling as I go for practically unlimited range. The ebike is cool but pretty toyish in this regard.

I definitely need to get this setup working. Any help would be appreciated along with photos you have to help explain any solutions. I have attached a few pictures. Hopefully they will suffice.

Note: something is at an angle on this setup on the rear. As you can see, the tensioner doesn't seem to be fully inline with the chain. I'm assuming I will have to bend the upper bracket of the tensioner to accommodate the misalignment?
 

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Greg58

Well-Known Member
May 1, 2011
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Newnan,Georgia
Adding washers to spread the frame as suggested with a dished sprocket facing inward May give enough clearance.
 

Greg58

Well-Known Member
May 1, 2011
5,353
2,575
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Newnan,Georgia
If you don’t have enough adjustment to add the washers you may need to move to a different frame, a cruiser frame has plenty of room.
 

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
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Los Angeles, CA.
Here's an option... It's called a 'top hat' sprocket & adapter.
It will allow the sprocket to sit inward just enough for the chain to clear the frame, (& get better chain alignment)

Also... be very careful bad mouthing e-bikes around here!! There's a couple of members who'll get real b@tt hurt!!! laff

sprocket with top hat.jpg
 
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Donnyten

New Member
Jun 21, 2015
28
2
3
Durham
Thank you for that link. As much as I love e-bikes I....... I'll just leave it at that.


My e-bike is pretty great. It's a custom build. But if I want to go to distance, I think engine cycling is better. Pros and cons to each I suppose.

Great news for now. I cold set my steel frame using a threaded rod, nuts and washers. Can't believe it was that easy. However, the rear wheel axle no longer fits snuggly so it looks like I will have to convert this back wheel to a through axle and compensate with washers or get a new wheel together.
 
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