Electric Bikes

[Dustydog]

Like in my day Yaw Inertia was defined. A level physics😜😜
It is equal to the sum of the products of each mass particle of the body, m, multiplied by the square of the respective distance, r, from the axis of rotation.

 

[otherclive]

P

Like in my day Yaw Inertia was defined. A level physics😜😜
It is equal to the sum of the products of each mass particle of the body, m, multiplied by the square of the respective distance, r, from the axis of rotation.

Got it thanks you. Didn’t realise that throughout all these years I’ve been keeping yaw inertia on the back foot.

 

[ProfJohnL]

It can't be "in exactly the same way" as all those masses are within the van and the bikes and rack masses are beyond the van.
So salient in this, is that it is distance squared that drives the yaw inertia.
Thus, something of heavy mass outside beyond the van, has to be further from the axle, where the squaring of that offset distance becomes so powerful a driver.

It is not "the distances from the axles." but the square of the distances.

I'm not disputing its the way its calculated but it's the same calculation and process to work out the yaw inertia's whether the masses are inside or outside. Absolutely! a mass at greater distance has a bigger effect, so the scale is different. but it's exactly the same principle thats involved.

 

[Raywood]

I am afraid that calculation is beyond most of us, although I do not remember it in A level physics, but that was over 55 years ago. We do know now the principles of good loading and should practice them.

 

[Peterh590]

To all of you concerned about the dynamics of towing a caravan with a rear mounted bike rack,I have just returned from the peak district,a 160 mile round trip with my wife's electric bike mounted on the rack.It did not affect the towing characteristics at all and for me it's the way forward for carrying bikes.

 

[Darren.H]

To all of you concerned about the dynamics of towing a caravan with a rear mounted bike rack,I have just returned from the peak district,a 160 mile round trip with my wife's electric bike mounted on the rack.It did not affect the towing characteristics at all and for me it's the way forward for carrying bikes.

I think you have to take the whole outfit into account.
I've dabbled with weights and load configuration a while back using a Millennco Nose Gauge and weighing absolutely every single not nailed down item in the caravan on digital bathroom scales.

You would be amazed the difference only a few kg placement within the caravan makes to the nose weight.

But then towing speed can mitigate a badly balanced outfit, for example we have moved our caravan twice whilst living in it full time. The bikes and full size steel awning goes in/on my car, then literally everything else is just chucked in the caravan, the inside looks like its been in an accident!
I kept my speed to 40 mph driving once from Truro to Liskeard with a rock solid outfit, which was completely overloaded, with a high centre of gravity and a nose weight of who knows what, my experienced guess 40kg or lesser, as we have the transverse bed void full of vac packed clothes even before we slung a load of coats on the bed and the above lockers stuffed again with more clothes!

 

[JTQ]

To all of you concerned about the dynamics of towing a caravan with a rear mounted bike rack,I have just returned from the peak district,a 160 mile round trip with my wife's electric bike mounted on the rack.It did not affect the towing characteristics at all and for me it's the way forward for carrying bikes.

"It did not affect the towing characteristics at all"

That statement defies the physics, a mass located so far from the centre of yaw, has to affect the unit's towing characteristics.
What you described, is so far, you actually did not notice its affect.
Hope that remains the case, but without doubt the margin to instability have reduced.