Originally Posted by
steelbikeguy
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Steve in Peoria
This indicates that there are two versions of that battery pack, one for the GH6 dynohub and one for the AG or FG which I assume is not a dynohub.
We still do not know if the bikes the OP has dynohubs.
I would not try disposable type batteries in it if there is a dynohub charging it, I would only use NiMH.
In my previous post I suggested AA NiMH batteries in D size adapters, I made that recommendation because AA NiMH are quite common and easy to buy.
But if it is not a dynohub system, I would expect that three D sized batteries might be perfect, disposables could be used.
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Note to the OP - The tires, if they are labeled 26 X 1 3/8, they are not the common 26 inch tires that a lot of bike shops stock. So, do not just go into a store and buy some 26 inch tires. If they are that size, they would have a bead seat diameter of 590mm, more on tire sizes here:
https://www.sheldonbrown.com/tire-sizing.html
You probably could use inner tubes for 650b but you can't use 650b tires on that bike. You might have to buy tires on line to get the correct size.
Plastic stuff, like hand grips, etc., some 303 protectant might help rejuvenate the plastic somewhat.