Trailer loading and handling tips

[mjr]

Anyone got some? What is best to avoided the dreaded "tail wagging the dog" feeling or, far worse, the trailer trying to overtake you on downhills? I searched a bit without finding much.

I have seen some say to put the heaviest things at the front, while others say to put them over the axle if two-wheeled. Some say what matters is left-right balance. Someone posted that the best way is to spin a low gear but I find that starts the hitch ticking in time with the pedal stroke and then the wobbles start.

About the only thing I am sure of is to ease off momentarily as the trailer climbs over a sharp brow (at the top of an artificial ramp, for example) to avoid getting a shove effect from it!

What have you figured out as the most stable ways to load and ride?

[Tigerbiten]

Large Carry Freedom trailer user here.

I find that keeping the weight cantered just in front of the axle works best.
I'd tip the my loaded trailer up to around 20 degrees (+25%) to check that it still has some nose weight going up a steep slope.
I never wanted it to try and lift my back wheel going uphill.
But the greater nose weight then the greater the resonance.
As to what speed the trailer resonates at is down to the natural frequency to the bike/hitch/trailer combo.
Plus the more play there is in the hitch, the greater any resonance there will be.
Fully loaded with ~20 Kg of camping gear my rig used to resonate at around 60 rpm.
But I only noticed it because the squeak from the hitch got louder at that rpm, not because of some wobble.
Even fully loaded never notice any shove effect from the trailer.
But my trailer wasn't ever over 20% of the total weight of my rig, me + bent trike + trailer + camping gear.
But I do think a bent trike + trailer will be more stable than a bike + trailer.
My rig is fully stable at speed of +50 mph.

One thing to be careful of is tyre pressure.
The higher the tyre pressure then the higher the trailer will bounce if it hits a sudden bump.
So you can flip a light trailer if the tyres are super hard and one wheel hits a sharp bump.

Luck ............

[Brucey]

ideally the tow hitch would mount near the CoG of the combined bike + rider, so that lateral thrusts from the tow hitch don't start wobbles. In practice having it below this point is acceptable too.

Part of the trouble with the tail wagging the dog is that most tow hitches are offset from the bike centreline, so the whole outfit is slightly dog-legged even when you are going in a straight line. A fancy coupling (which creates a virtual pivot point on the bike centreline) would be an improvement in this respect.

If you keep the centred load over the trailer axle this minimises the lateral thrusts on the tow hitch. However most outfits (even cars towing trailers) become more stable when there is a small noseweight on the tow hitch. There is also an argument for keeping the weight near the axle (rather than distributed lengthwise, with the same balance point) because this affects the polar moment of the trailer around the axle; this in turn is important because most riders swing the bike from side to side as they pedal, and minimising the effect of this is a good idea.

Thus with a typical trailer a low towhitch mounting, offset sideways as small amount as is practical, set up with a central load over the axle, but with a positive noseweight of (say)1-5kg should give an acceptable result.

A slack-free, slightly springy coupling (eg a carry freedom lollypop) may help avoid the coupling clunking when riding uphill.

cheers

[Stradageek]

+2

Excellent advice from both above to which I'd add, don't panic, you can ignore a lot of the wobbles and funny sensations there is very little danger of something catastrophic happening.

I've towed my Carryfreedom loaded with three heavy old mountain bikes using either my old three speed folder or my BikeE recumbent without any issues.

I'd reiterate low trailer tyre pressures (often around 20psi) and slight forward weight balance

[gaz]

.

[Mick F]

Carry Freedom Small user.
Get the nose-weight neutral when at the tow-hitch height.
Try towing two concrete blocks!

It behaved beautifully. No tail wagging and no issues other than hard work on the hills.

[mjr]

Thanks all.

I would expect a couple of concrete blocks to be pretty ideal: uniform and easy to centre. I have had fewer wagging problems when towing a single large item than when the trailer contains a load of small items like shopping.

Mine is a seatpost hitch which is probably worse for passing pedalling rhythm back than an axle hitch, but it is far easier to move between bikes.

[Tigerbiten]

Mine is a seatpost hitch which is probably worse for passing pedalling rhythm back than an axle hitch, but it is far easier to move between bikes.

Never tried a seatpost hitch as a bent trike doesn't have one ..... .
I would try a set with of known weights at known distances back along the load bed and see if upping the weight alters where the best COG of the trailer is.
Or how altering the nose weight alters the handling.
Doing this may give you a better idea for a good solution to your loading problem on shopping runs.

Luck ........

[Stroud Active]

I've got a cheap trailer. I've found when loading logs onto it that if they stick out the front then it's fine, if they stick out the back then it starts wagging. Apparently this is well known in the trailer towing world, something to do with the polarity of the mass that's wagging relative to the wheel pivot point. Or something like that.