I really like the motif of cycles that you used here... the consistent motif strengthened the poem for me. The first strophe represents it with a physical wheel, while the third strophe does it with time... day sinking to night growing, eternity, and the moon (associated with phases). The second carries less of this, although you could make an argument that "rut" is like being stuck in a loop (the axle line counts too, but I think it only reiterates an image already established in the first stanza). I think you can strengthen the motif in the second stanza (your choice: maybe how the blood is smeared both on the knight and under the wheel?) but really that is just a minor suggestion. 
PS: I agree with Leanne, "spoke" is a good pun; just needs to be rewritten somehow so its less jarring
PS: I agree with Leanne, "spoke" is a good pun; just needs to be rewritten somehow so its less jarring
PS. If you can, try your hand at giving some of the others a bit of feedback. If you already have, thanks, can you do some more?