Additional Notes:Paraphrased from comments by the item submitter:
This part when compressed, as if trying to fit into an envelope, is thinner, and longer by about 8mm than tread 680c01. It is not as flexible as 680c01. It may be thought of as plastic compared to rubber for 680c01, though the exact composition of neither is known. Viewing the 'inside' of the tread, 680c01 has thin wheel holder lines going side to side between the 'outside' tread grips whereas the new x1681 is smooth with rounded squares running along its length. The Technic tread uses Technic Tread Hub, part 32007, whereas the Non-Technic one uses Wheel 30.4mm D. x 20mm without Pinholes, with Reinforced Rim, part 56145. I do not think the technic tread hub can be used with the non-technic tread or vice-versa as the two treads do not have the same physical construction.
Paraphrased from comments by the item submitter:
This part when compressed, as if trying to fit into an envelope, is thinner, and longer by about 8mm than tread 680c01. It is not as flexible as 680c01. It may be thought of as plastic compared to rubber for 680c01, though the exact composition of neither is known. Viewing the 'inside' of the tread, 680c01 has thin wheel holder lines going side to side between the 'outside' tread grips whereas the new x1681 is smooth with rounded squares running along its length. The Technic tread uses Technic Tread Hub, part 32007, whereas the Non-Technic one uses Wheel 30.4mm D. x 20mm without Pinholes, with Reinforced Rim, part 56145. I do not think the technic tread hub can be used with the non-technic tread or vice-versa as the two treads do not have the same physical construction.
