What is the purpose of the idler pully and cable

Hello All,


I've searched and looked all through the Mirage FAQ but can't seem to find the answer.

My cable broke right before a trip last year and after I removed it I couldn't see a difference in the operation of the drive so I never replaced it. Put many miles on it in that condition.

Last trip out I had a chain break right in the middle. So now I am replacing both chains and sprokets. Already ordered the parts and now am wondering if I should have ordered the idler pully cable too but don't know what it does.

Excellent question!

Without the idler cable, the rear chain/cable becomes the primary driver. It pulls the rear sprocket/fin across AND operates the opposite drum which in turn pulls the front fin across in the opposite direction. This not only adds strain to the rear chain/cable but also tends to jerk the front chain back and forth due to normal slack in the system.

The idler cable transfers part of the load from the active drum directly to the opposite drum, distributing the stress and making the operation of the Drive smoother. As you know, the Drive can operate without it but tends to feel a little jerkier and is harder on the chains and remaining cables.

In addition, you'll get better reliability and greater longevity from your Drive by using all three cables and making sure they are properly adjusted.

Thanks for the answer. I knew there had to be a reason but it just wasn't making sense to me. I guess I will be putting in another order.