Seeking humble opinions

[TroutBum]

I posted this a while back in response to a question about off road PUP's, and had included a question of my own  to which I never recieved replies.  So I thought I'd start it as a new thread.  

"As for towing on the highway, I lose a couple MPG because it rides higher, the tires drag more, and it simply weighs more than a comparable "on-road" model. Conversely, the larger tires make it very stable to tow. I haven't experienced any sway at any point including highway speeds. I am guessing that the little "frisbee wheels" on a regular pop up cause a bit of towing instability. I do know that the wheels rotate at fewer RPMs with the big tires, and thus are easier on the bearings"

I would love to hear back from someone who understands physics on the big vs. small wheels thing as it relates to towing, bearings, sway/stability etc.

[SpeakEasy]

I'm certainly no physics expert, but I'll jump in with what I know. The smaller the tire, the more times it has to go around in order to go the distance. A 12" tire would go through a whole lot more revolutions in a mile than would a 14" tire, for example. That 2" difference in diameter turns into more than 6.28" difference in circumference (2 x pi). It is the circumference that turns into miles on the road. Mile after mile that really makes a big difference in terms of wheel bearings. You'd have to re-pack your wheel bearings a lot more often with small tires.

Concerning sway, I think it has a lot more to do with where the balance point of the weight of the trailer is. If your tongue weight is too low, you'll have sway, regardless of tire size. Maybe larger tires will lead to less sway, but I can't think of a reason why this would be so.


Oh, I forgot to say IMHO.

[AustinBoston]

Most here would say I don't have any humble opinions, though I do have plenty of opinions.  I'm not inclined to disagree with them.

I there are a lot of variables in trailer sway, and so I don't think you can say "the tires are bigger, and that's why it sways less".

Tongue weight is the biggest issue, but distance between TV rear axle and hitch ball, ratio of trailer weight to tow vehicle weight, stiffness of tow vehicle suspension and tires, stiffness and type of trailer suspension, and how high the weight in the trailer is (pop-ups have a definite advantage on that last one) all play a part.  In addition, dynamic loads, unusual aerodynamics, and driving style can come into play in certain circumstances.

If you changed from 12" tires to 14" tires on the same pop-up and it seemed more stable, I'd say you were on to something.

Austin