Giant Revive "Spirit" Mid Drive Chain Adjustment

[Noel]

Does anyone know the procedure for chain adjustment on the Panasonic Mid-Drive on a 2005 Giant Revive pedelec? No archival info at the Giant site (that i know of).

The bike was never used and all sprockets and chain appear new.

when i first got the bike when i applied full power i could hear the jackshaft drive sprocket slip. I tightened the chain somewhat and it alleviated most of the skipping but still skips once in a while.

I dont want to overtighten the chain.

Also, the chain tensioner spring doesnt spring back like it should when i move it to slaken the chain, seems like the tensioner spring is binding?

 

[flecc]

If it's anything like the usual Panasonic "tensioner", it's actually intended as a chain wrapper rather then a tensioner, the tensioning being done in the usual bicycle way at the rear wheel. The distance of the wrapper idler from the motor drive sprocket is the critical thing.

This item on my Panasonic support site gives the setting and the following couple of paragraphs apply too. It's important for the arm to freely swivel and it can sometimes jam for various reasons. Then the reason needs to be established and problem rectified.

This item gives further advice on diagnosing the causes of slipping, some of it relevant to your situation.
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[Noel]

If it's anything like the usual Panasonic "tensioner", it's actually intended as a chain wrapper rather then a tensioner, the tensioning being done in the usual bicycle way at the rear wheel. The distance of the wrapper idler from the motor drive sprocket is the critical thing.

This item on my Panasonic support site gives the setting and the following couple of paragraphs apply too. It's important for the arm to freely swivel and it can sometimes jam for various reasons. Then the reason needs to be established and problem rectified.

This item gives further advice on diagnosing the causes of slipping, some of it relevant to your situation.
.

Thanks for your quick response! I thought something was wrong with the chain wrapper as it didnt move freely and is binding. After I get off work today I'll check it out. I'm going to the site now and read the information. Thanks!

 

[Noel]

I adjusted the distance between the wrap pulley shaft and the drive shaft to 65mm as per Panasonic.
Now it seems that the chain is VERY tight. When i rotate the crank by hand i feel above average resistance, esp at the elliptical high point of the front chainring. Im wondering if its supposed to be that tight.
Also, the idler wrap pulley cage is binding. I loosened the bolt until it just springs back freely but the bolt isnt tight enough to stay secure. Ill try to install a flat washer behind the cage shoulder as per Panasonic..
Ill try and attach 2 pics. One pic shows me putting upward pressure under the chain with a screwdriver. It doesnt move much.

 

[flecc]

Yes, that is a bit too tight. Normally the thing to do then is adjust the chain a little at the back wheel. That might seem like the same thing but perversely it usually works, but of course this only applies if you have a hub gear version.

If it does have a hub gear, try moving the wheel just a little forward to ease the chain tight point.

I know what you mean about the wrapper arm pivot, they do seem to need some tweaking to be free, it isn't one of Panasonic's best design efforts.
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[Noel]

I lubed the wrapper arm pivot with silicone grease and now it springs back freely, even when torqued down.
I then moved the rear wheel fwd a little bit and to slacken the chain. I took it for a test spin and what a diffeence! Quiet compared to before. Now the pedal assist responds almost instantly. Before I tightened the chain there was a hesitation of the pedal assist.
I'll check the chain and wrap arm pulley for wear periodically to make sure that the chain isn't too loose or too tight.
Thanks for your help!

 

[flecc]

A pleasure Noel. The transmision on the Panansonic crank unit bikes can be a bt fiddly to set up working ok, but works well when all is right.
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[Noel]

Addendum: I took the bike out the following morning and it started slipping again in 3rd gear.
I had a solid 86.5 mm pushrod and i put it in the hub in place of the spring loaded pushrod. No slippage at all now. I put over 18 miles on it with the solid pushrod and still no slippage.

I dont know anything at all about internal hubs but im guessing that the spring loaded push rod was moving laterally while in 3rd gear due to the higher load (?).

Whew! I was getting ready to flip the drive sprocket over and then possibly replace the chain and then the hub.

I guess God looks after sailors, drunks and amateur bicycle mechanics!

 

[flecc]

Well done on sorting that out Noel. As you may have seen on my website about Diagnosing drive slippage, there are so many possible reasons for it on the Panasonic system e-bikes.
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[Noel]

Hi flecc,
You are right, a lot of avenues to go down to figure slippage out. Again, thanks for getting me there!

I'll think i'll go and find a headwind to pedal into!
noel