Really... I thought any trailer would be prone to it if loaded tail heavy, I stand corrected.
Well,
technically, you were correct originally, but as
@Snoking1127 mentioned, it
seldom occurs cos it takes a fair bit of weight imbalance biased toward the back end, and most tandem axle load sharing set ups tend to minimise any imbalance like that anyway - but you still should aim for about a 10-15% weight bias toward the front!
And another couple of things that can cause fish-tailing in a tandem trailer under tow, apart from that weight imbalance, is being too sudden/tight in the direction changes of the tug vehicle, so that the two axle set-up, which can't turn as quickly as most tug vehicles because of the short distance between the axles, cause the wheels to bind up &/or try to scrub sideways; or incorrect/mis-matched tire pressures, especially when they're different enough to mean that your front & rear tires have significantly different rolling radiuses.
So
technically, fish tailing a tandem trailer under tow
can happen, but as
@Snoking1127 posted, it's just not as likely or as easy to induce as it is on a single axle trailer.
Ps: Sorry, it's been a minute since I last ran the towing course, and this one slipped my mind for a bit... But there's another possible cause of fish tailing in a tandem trailer under tow - strong &/or gusty cross winds, especially if you've got a '
somewhat less than aerodynamic' load. Shouldn't be a problem with forward facing Spyders tho, despite them being a bit of a brick when it comes to pushing them thru the air.
