Cobra trailer tire size?

On 6/1/2010 9:45 PM, sisu1a wrote:
LT tires are a good match for trailers (better than P type - passenger
car tires - for the same size and speed rating)

Why are they better?

stiffer sidewalls = less sway...

-p



Given similar sizes, the tires on a passenger car that will be subject
to high cornering loads will flex more side to side than the tires on a
truck or trailer that need not handle high cornering loads? That seems
counter intuitive to me.

LT tires are a good match for trailers (better than P type - passenger
car tires - for the same size and speed rating)

Why are they better?

stiffer sidewalls = less sway...

-p

Given similar sizes, the tires on a passenger car that will be subject
to high cornering loads will flex more side to side than the tires on a
truck or trailer that need not handle high cornering loads? *That seems
counter intuitive to me.

Trucks and trailers are generally designed to handle higher loads
loads than passenger vehicles, hence stiffer tires which apparently
aren't as comfy a ride.

LT- light truck tires- will most often are on similar sized but
heavier vehicles driving the same roads at similar speeds as lighter
loaded cars, corner loads and all.

-Paul

A couple of years ago, I struggled with trying to understand trailer
tires and ratings. I still do not understand them, but took Ray's
advice and have been very happy with these tires on my Cobra trailer
with a heavy 2 place sailplane.

===============
The tires on my Cobra trailer from the factory are marked
185R14C8PF (102/100N)LT

They appear to be GT Radial Max Miler X
Load Range D 1875 lb at 450KPA 65# cold

Try tirerack.com - they have Kumho trailer tires that match what you
have. I've used their semi trailer tires and found them to be
acceptable, but I don't have any experience with the smaller ones.
They list them for $ 80.00 each plus shipping.

Ray Warshaw
==============

"sisu1a" wrote

Trucks and trailers are generally designed to handle higher loads
loads than passenger vehicles, hence stiffer tires which apparently
aren't as comfy a ride.

LT- light truck tires- will most often are on similar sized but
heavier vehicles driving the same roads at similar speeds as lighter
loaded cars, corner loads and all.

-Paul

Add to that that light truck tires generally (always?) have a much higher
maximum pressure rating, so if you pump them up to max allowed pressure,
they will get really stiff.

A couple weeks back, my 3/4 ton full sized van needed tires. I generally
carry about a thousand pounds of tools ALL the time. I was not paying close
attention to the tires I selected to put on, so they went with the tire I
told them, which was a P rated tire.

The guy that put them on came out and got me after they were mounted so I
could see how they looked. In short, they looked like they were about 15
pounds low on pressure, but they were at max rated pressure. I told the guy
that these will never do. I don't have all the load on that they will often
see, and they are almost flat. I appreciated him giving me the chance to
change my mind.

He went with a LT tire that I then chose, and all was well. Instead of
being rated at 36 pounds, they were rated at 55 pounds. They are indeed
much stiffer, and most of that is in the flexibility of the sidewall. I
a\have no doubt that it would be a better trailer tire than a P rated tire.

I'll tell you all what to try. Go to a tire store and pick out a certain
sized tire in a P rating. Push down on the unmounted tire, hard enough so
that it really deflects a lot. Now get a LT tire of the same size and press
it down the same amount. You will be surprised.
--
Jim in NC

On 6/1/2010 8:56 PM, Greg Arnold wrote:
On 6/1/2010 8:46 PM, Eric Greenwell wrote:
On 6/1/2010 9:29 AM, Andy wrote:
On May 31, 8:47 pm, Eric wrote:

The Yokohama tire you list is a LT (light truck) tire. Does Yokohama
have a trailer rating for it in addition to the LT rating?
Don't know. Maybe the dealer lied to me. I asked for trailer rated
tires and he told me they were. They were not a stock item he needed
to move, they were ordered from the Yokohama warehouse. Normally I
do a lot of research on something like this but I was distracted by
other things and just needed to get it done.. Anyway they seem to
work just fine so far.

LT tires are a good match for trailers (better than P type - passenger
car tires - for the same size and speed rating)

Why are they better?
Here's what I wrote for the ASH 26 E owners "tech site":

Commonly available tire types are P (passenger car), LT (light truck)
and ST (special trailer). While each tire series shares basic
construction methods, the details vary meaningfully among the three.

There are other differences:

1. P tires use a load rating system that is different from ST and LT
tires; generally, you have to discount their rating 10% to get the
equivalent ST or LT rating.
2. ST tires speed rating is 65 mph. The speed rating increases to 75
mph IF you increase the tire pressure to 10 psi above the pressure
required for your load at 65 mph. These are not the tires for
folks that like to drive 80 mph across the Nevada highways in 100
deg F temperatures.
3. ST tires come in both bias-belted and radial construction. The
only advantage to a bias-belted trailer tire is it's cheaper.
4. LT tires are a bit "stiffer" than either P or ST tires, and are
available in speed ratings to at least 118 mph.

Suggestions:

1. P tires might work fine, but I don't know what speed and load
ratings would ensure this. If I decided to use P tires, I'd use
them at the pressure that gave a load rating of ~40% more load
rating than the load they has to carry. I'd choose a speed rating
at least 20 mph higher than the speed rating on my tow vehicles
tires.
2. If you like the way the trailer tows, staying with the same make
and model of tire means no surprises. The same type and size tire
from an equally trusted manufacturer is probably good, too.
3. If you like to tow faster than 70, don't use ST tires; instead,
get an LT tire rated at least 20 mph more than your intended tow
speed.

This web page has more information on trailer tire safety, written by
Tom Wilson for Trailer Life magazine in 2002:
https://www.subaru.com/my-subaru/tire-safety.html
http://www.google.com/url?q=https%3A%2F%2Fwww.subaru.com%2Fmy-subaru%2Ftire-safety.html&sa=D&sntz=1&usg=AFrqEzfNgJTx0_JddUB7NR 7ejOvGSR2NYw


--

Eric Greenwell - Washington State, USA (netto to net to email me)

- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl

- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz

On 6/7/2010 10:28 PM, Eric Greenwell wrote:

This web page has more information on trailer tire safety, written by
Tom Wilson for Trailer Life magazine in 2002:
https://www.subaru.com/my-subaru/tire-safety.html
http://www.google.com/url?q=https%3A%2F%2Fwww.subaru.com%2Fmy-subaru%2Ftire-safety.html&sa=D&sntz=1&usg=AFrqEzfNgJTx0_JddUB7NR 7ejOvGSR2NYw


Besides the damage Google Sites does to the link, the page isn't there
anymore, anyway! This link goes to an article by the same author that is
nearly the same as the one that was on the Subaru site:

http://www.carlisletire.com/product_...ety_031505.pdf

--
Eric Greenwell - Washington State, USA (netto to net to email me)

- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl

- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz