Louet Double Treadle Wheels
There is a small axel at the center of the rocker arm. (The rocker arm is the wooden dowel that connects the two treadles)
There is a plastic bushing that sits inside the rocker arm. When we assemble the wheels, we place a small amount of petroleum Jelly in side the bushing, then insert the stainless steel axel, roll it around in the bushing to evenly distribute the jelly, and install the axel with the set screws.
The most common reason for a squeak from the treadle area of a Louet DT wheel is that a piece of dirt or grit, spinning dust, has found its way in-between the bushing and axel. Oil will actually make it easier for this type of material to enter, therefore oiling the axel is not a good solution.
The solution is to remove the axel - two small screws - clean the bushing and axel - wipe with a cloth and use a Q-tip to clean bushing - and then put some petroleum jelly back inside the bushing. Finally, re-assemble. This will eliminate the squeaking.
Care and maintenance for you spinning wheel - This article talks in more general terms about oiling and maintenance for Louet spinning wheels.