Dreamwave Continuity

The Duocons are possibly the smallest subgroup of Transformers, compromising of only Battletrap and Flywheels. They were both created by Shockwave as he attempted to make a Transformer with 3 different modes. His experiment failed as Battletrap and Flywheels could only transform into both their vehicle forms at the sametime which had the unfortunate side-effect of their personalities being spilt between their vehicles modes. This was a big problem with Flywheels since the two sides of his personality hated each other and bickered and argued constantly, even they were united in robot form.
 

Marvel Continuity

Their loyality towards each other is in question as Battletrap abandons Flywheels in the Cybertronian city of Kalis due to the rumours of "the walking dead". Both Duocons later joined the Mayhem Attack Squad. They were murdered by Galvatron as the Squad contronted him and Megatron during the Time Wars.