On Friday, December 20, 2019 at 11:56:12 PM UTC-5, Eric Greenwell wrote:
India November wrote on 12/20/2019 7:53 PM:
On Tuesday, December 17, 2019 at 2:01:56 PM UTC-5, Eric Greenwell wrote:

Anyone that wants to hear more from Nelson Funston can download his OSTIV paper on
trailer stability he

http://journals.sfu.ca/ts/index.php/...wnload/779/737

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Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...load-the-guide

Interesting paper, thanks for the link.

But I'm puzzled by Funston's remark at bottom of p34 that "Bias ply tires generally have 25 % io 30% lower lateral stiffness than radials and are not recommended for use on glider trailers".

Almost every other article I've seen on the web about trailer tires recommends the opposite: i.e. bias ply trailer tires (marked "D" on the sidewall) have stiffer sidewalls and cut down trailer sway.

What are others' opinions on bias vs radial trailer tires?

These claims are made by people that do not realize it is the tread stiffness
(resistance to lateral deflection) is the important factor in a tire's behavior.
The stiffer the tread, the smaller the slip angle, and small slip angles improve
vehicle stability.

https://suspensionsecrets.co.uk/tyre-slip-angle/

This is not opinion, but engineering fact. Instead of seeking opinions, I suggest
you look for facts; for example, look at tire company websites, tire
recommendations for things like travel trailers, or even wander about a RV trailer
lot, and note the radial tires on all the trailers. The only good feature of a
bias ply trailer tire is the lower price.

As a side note, bias ply trailer tires don't necessarily have the "stiffest"
sidewall (as measured by the "push" method). A few years ago, I measured that
stiffness on three similar sized tires, with the same load rating, for a glider
trailer. The stiffest was an LT (light truck tire), 2nd stiffest was the ST radial
tire, and least stiff was the ST bias ply tire. The LT tire was the most stable,
the ST bias ply tire was the least stable. I can send you a copy of the test
results if you want it.


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Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

Hi Eric,

Thanks for your reply. I hear you and accept what you say.

Many sources out there on the www (wild, wild web) with advice on trailer towing say that bias-ply tires have stiffer sidewalls and reduce trailer sway--just one example being https://www.westmarine.com/WestAdvis...er-Tire-Basics. Not arguing, just sayin'.

I am interested in reading your test results. Please email me at iandotgrant12atgmaildotcom

Many thanks!
IN