Rodger's Trailer by Sandpaper, on Flickr

I rode from The Maz to Ganonoque with Rodger to help launch and rig his Mac 26. He was getting her ready for a cruise in The 1000 Islands. Here is an interesting story.

Rodger just recently added the dual axle to his trailer. Prior to that, the factory trailer only had a single axle. Rodger's estimate of the boat, gear, and trailer was 4000 lbs. He also claimed that he had averaged 22+/- L/100km (11 mpgUS) with the single axle. Now, with the dual axle, we made 18 L/100km (13 mpgUS)at 80km/hr on Hwy 41, and 19 L/100km (12 mpgUS)at 100km/hr on Hwy 401.

That is remarkable! The numbers are surely empirical and anecdotal, but Rodger is not a person to exaggerate. I trust his observations.

So, what do you think? How would you explain a dual-axle arrangement saving such a significant amount of gas?
Sail Mazinaw