Yes the idlers can be split in half. One half has little pegs and the other half has matching holes.
I've used a drop glue on my plastic one and a drop thead-lock on my metal ones to hold them together.
HL Panzer III | HL Tiger | HL Jagdpanther | HL Panther | Mato Sherman
Hooben Elefant | HL Pershing | HL Bergepanzer IV | Tamiya Leopard 1A | WSN T-34
HL "Golden" Pan-Tiger | M16 Halftrack | HL Panzer IV | Tamiya KV-1 | Tamiya Tiger