Tire Stiffness & trailer swaying

On Fri, 26 Sep 2003 12:57:44 GMT, "Bill Daniels"
wrote:

However, any full-time 4WD vehicle will suffer very
expensive damage to the transfer case if the front and rear axles turn at
different speeds for an extended time as they would with different tire
pressures.

That is what I thought for a long time, and it may be true, but 2
friends of mine who are tire engineers at Michelin tell me that
inflation pressure has almost no effect on revolutions per mile ...
the belt lenght doesn't change and thus the pressure affects flexing,
sidewall height, but not effective circumference.

That said, the revolution per mile numbers on manufacturers' websites
always give a pressure ...

I don't know.

I guess the "Ariana Wussies" have hit this forum - even if they aren't from
the US
Give me a break, there are so-called SUVs that can blow the doors off of
anything less than a
new Ferrari and out corner anything built in Japan.
In fact, I'll take my two wheel drive pickup truck and challenge you in
whatever 1000 cc turkey you drive
and race you an any road, any track, anywhere and drub you soundly - and
I'll drub you in a straightaway towing a 2000# load.
And, yes folks, I really can do it!


Now here is a man who loves 1 mile start circles and 6 inch finishes. Man
after my own heart.
(Please include me in you will)

Bruce Patton

Chris,

Another often overlooked issue is the length of the hitch (i.e., the
distance it protrudes from the back of the car). Shortening the hitch
even a couple of inches can drastically improve the handling. Think about
it... if you could mount the hitch ball on top center of the rear axle,
then any sort of steering induced oscillations would be non-existent.
Obviously that cannot be done with a standard vehicle. But at times you
can find a hitch that will fit into the receiver that can be cut down
shorter. I did that on one of my hitches and it made a world of
difference.

Larry Goddard
"01" USA

PS You might even be able to mount the hitch assembly further forward.

chris wrote:

Several people have had good luck towing a glider with a Subaru
Forester.
I do not know why mine is different.
I just bought a 2004 Forester tried to tow with it. Mine is a
nightmare. It is unstable above 50mph. It has a lot of side to side
sway above 50mph if there is any steering input. It is almost
harmonic in nature – it does not dampen out quickly. If feels like
you are driving on Jello. It feels like the problem is much more the
tires than the suspension. Though that is hard to prove.

Even when parked if you push on the hitch with your foot the Forester
will sway side to side [right and left] a lot. You can watch the rim
move right and left in and out of the tire. I think the sidewalls are
just really weak. The tread is probably relatively soft also.

The Forester's tires are Yokohama Geolander G900 P215/60 R16 94H.
Even in normal driving the steering response and cornering are poor.
[Other Foresters may be equipped with 15" tires, and other models of
Geolander tires – rather than the G900].

My Mazda MX-6 [much lower car] has Pirelli P4000 P205/55 R15 87H – it
is stable, and if you push sideways it does not sway side to side
anywhere near the degree that the Forester does. Steering response
and cornering are good.

The Geolander G900 has a tall soft sidewall, it is 4.500" above the
rim rather than 3.625" for the P4000 [24%higher].

My best idea right now is to change to a shorter and stiffer sidewall
tire.
I am considering changing from P215/60 R16 94H
- an "H" rate tire with 60% width/height ratio, to
Bridgestone Turanza LS-V 225/50R16 92V - this is a V rate tire so the
sidewall is stiffer and at a 50 or 55 ratio it is shorter.
This is the V rated version of the tire that some other Forester
owners have [LS-H]. The tread should also be a harder sports car like
compound.

Some of these tires are rated and discussed on www.tirerack.com. It
seems that Steering response and cornering stability are good
expressions of my issue.
On tirerack there are a mass of good comments on the Turanza tire –
though I doubt anyone is towing. As far as I can tell everyone on
"tirerack" hates the geolander 900 like on mine.

Does anyone else have any Experience changing to a shorter V rated
tire for better stability?

My trailer does great and stable to 85+mph behind my Mazda MX-6, so I
do not think it is the trailer. The trailer is a 1979 Komet with a
Mosquito. It weighs ~1800lbs [816kg]. The tongue weight is 153lbs
[69kg]. The Forester's manual says to keep the tongue weight between
8-11% of the trailer. 8%=144lbs [65kg] 11%=198lbs [90kg].
[the max allowed is 200lbs on the tongue] The manual transmission
version of the Forester is rated for 2400lbs [1088kg] towing capacity.

I have already tried raising the tire pressure on the rear tires to
41psi [2.8bar] as recommended by the manual. The trailer tires are
about 40psi.

Chris Ruf

100kph? Do you drive backwards on retrieves for sport? Or perhaps you
always land close enough to the airport that there's no hurry...

Sing what praises you may, they echo hollow among the leather clad
comforts of my 7000 lbs of 4x4 SUV... the best you can achieve with
your little brand-name putt-putt is "adequacy." If you want to excel,
be the envy of every man and the desire of every woman, there's no
substitute for SIZE, POWER, and TRACTION.

But fear not, I'm sure you'll find friends for whom "adeqaute" is
enough.

Tim

You are truly a SIFOW proponent. An 1100cc 106 and an ASW20 is an impressive
combination! I salute you sir!

Ian


"Tim" wrote in message
...
"tango4" s comments read:

Ian - 2300cc ( petrol I will admit ) Ford MPV and about 53 kgs tongue
weight
a proven 100mph combination!

Ian a proven TINSFOS man

Tim - Peugeot 106 1100cc
A legal 60mph combination

--
Tim - ASW20CL "20"

Then
there are the cars I've pulled out of ditches with it during the
winter.

I just returned from visiting Idaho, where I grew up. I was feeling home sick
until I read your comment above. I just remembered why I like San Diego so
much.

Bingo!!!
I never had a better ride puliing my glider-trailer than with My Honda Civic
(90 H.P). Drove it all the way from Montreal to the ridge in Pensylvania, up
the steep mountain roads of Lake Placid, or Sugarbush, many outlandings and
800 km drives to the repair shop. Very steady drive at 110 km/h. I had this
car for eleven years, and I miss my Civic sinceI bought a new car with more
horse power, and a higher c.g. !!!! I guess you want the shortest distance
between rear axle and hitch point (obviously) and the lowest c.g (automobile
engeneering is regeressing) and also all what is mentioned below. It amazes
me mucho to see all theese people driving SUV thinking they are safer!!!
BQ
"CH" a écrit dans le message de
...
I don't know how long it does take for certain people
to recognise, that SUV's and 4-wheel drive cars

- are built for use in the outback and not for driving in towns
- have a high CG and are handling worse on windy roads than
any normal cars with good suspension (European/Japan cars)
- have big tires to suit off road driving, which are worse on
normal roads, worse than normal or low profile tires.
- often do not have independent side stable suspension on the
back which give them bad side stability (push the car sideways
on the rear bumper and let it go - if the hole car swings around
the vertical yaw axis then it does not suit towing)
- have bad aerodynamics and produce more turbulence behind,
which has again bad influence on the trailers stability.

Conclusions:
Quite any car is better for towing, in handling and safety than
a SUV.

I prefer to rent a 4-wheel drive for holiday in the outback,
own a small car with common rail turbo diesel engine
(2000 ccm, 110kW, 250Nm at 1750 rpm, and 4.5 to 6 liters
per 100km consumption).
Like that I can pay many tows with the saved money I do not
spend on petrol.
I can tow any trailer with brakes up to 1500kg stable with
100km/.
And on a windy road the SUV just disappear in the rear mirror.
But I cannot compete offroad with these monsters. I don't mind
because I only need offroad function perhaps 7 days a year.
How often do you need offroad capability?
Think of it when you buy the next car.
Chris


"chris" wrote in message
om...
Several people have had good luck towing a glider with a Subaru
Forester.

My Mazda MX-6 [much lower car] has Pirelli P4000 P205/55 R15 87H - it
is stable, and if you push sideways it does not sway side to side
anywhere near the degree that the Forester does. Steering response
and cornering are good.

Chris Ruf

"szd41a" wrote in message . ..
Bingo!!!
I never had a better ride puliing my glider-trailer than with My Honda Civic
(90 H.P). Drove it all the way from Montreal to the ridge in Pensylvania, up
the steep mountain roads of Lake Placid, or Sugarbush, many outlandings and
800 km drives to the repair shop. Very steady drive at 110 km/h. I had this
car for eleven years, and I miss my Civic sinceI bought a new car with more
horse power, and a higher c.g. !!!! I guess you want the shortest distance
between rear axle and hitch point (obviously) and the lowest c.g (automobile
engeneering is regeressing) and also all what is mentioned below. It amazes
me mucho to see all theese people driving SUV thinking they are safer!!!
BQ
"CH" a écrit dans le message de
...
I don't know how long it does take for certain people
to recognise, that SUV's and 4-wheel drive cars

- are built for use in the outback and not for driving in towns
- have a high CG and are handling worse on windy roads than
any normal cars with good suspension (European/Japan cars)
- have big tires to suit off road driving, which are worse on
normal roads, worse than normal or low profile tires.
- often do not have independent side stable suspension on the
back which give them bad side stability (push the car sideways
on the rear bumper and let it go - if the hole car swings around
the vertical yaw axis then it does not suit towing)
- have bad aerodynamics and produce more turbulence behind,
which has again bad influence on the trailers stability.

Conclusions:
Quite any car is better for towing, in handling and safety than
a SUV.

I prefer to rent a 4-wheel drive for holiday in the outback,
own a small car with common rail turbo diesel engine
(2000 ccm, 110kW, 250Nm at 1750 rpm, and 4.5 to 6 liters
per 100km consumption).
Like that I can pay many tows with the saved money I do not
spend on petrol.
I can tow any trailer with brakes up to 1500kg stable with
100km/.
And on a windy road the SUV just disappear in the rear mirror.
But I cannot compete offroad with these monsters. I don't mind
because I only need offroad function perhaps 7 days a year.
How often do you need offroad capability?
Think of it when you buy the next car.
Chris


"chris" wrote in message
om...
Several people have had good luck towing a glider with a Subaru
Forester.

My Mazda MX-6 [much lower car] has Pirelli P4000 P205/55 R15 87H - it
is stable, and if you push sideways it does not sway side to side
anywhere near the degree that the Forester does. Steering response
and cornering are good.

Chris Ruf



So, pulling anything at 55-65 mph should be fairly safe. What I
want to see is pulling a trailer beyond the rating of a
vehicle-happens more than it should. Yes, many might have an suv but,
given the situation of having to get somewhere where there are
actually grades to climb and areas of less than perfect roads, an suv
is useful. I own one and have used it several times on a "retrieve"
without having to worry about where I'm going.
Personal choice is acceptable in both driving and soaring.

I have a Chev. Tahoe 4x4 and it pulls my trailer very, very well thank
you. At 75mph going up 395 to Bishop it doesn't sway much at all. When
I need to pass a motorhome (caravan)I can accelerate and pass with in
a minimum of time and maximum of safety. When there are cross-winds on
the trip I have the knowledge that I will be directing it down the
road rather than the other way around. Anyone who believes it is ok to
pull a trailer with a car that is smaller and lighter has never been
in a serious wind situation in the western U.S.

It has great ground clearance and if I land somewhere where it can't
get me, well I had better just hire a helicopter. I also use it to
pull my tent trailer off road in Baja California fully loaded with
dive gear, water, etc. Same story. Over the dunes onto the beach
campsites. I think I will leave the Civic to the people who want to
dodge 18 wheelers on the freeway in the city. Of course I DO have a
winch on it, just in case.

Hopefully our politicians will allow us the same freedom of choice for
vehicles as they want us to have for sex! (that wasn't well put, but
you get the message).

I do not support terrorists.

(Larry Johnson) wrote in message . com...
"szd41a" wrote in message . ..
Bingo!!!
I never had a better ride puliing my glider-trailer than with My Honda Civic
(90 H.P). Drove it all the way from Montreal to the ridge in Pensylvania, up
the steep mountain roads of Lake Placid, or Sugarbush, many outlandings and
800 km drives to the repair shop. Very steady drive at 110 km/h. I had this
car for eleven years, and I miss my Civic sinceI bought a new car with more
horse power, and a higher c.g. !!!! I guess you want the shortest distance
between rear axle and hitch point (obviously) and the lowest c.g (automobile
engeneering is regeressing) and also all what is mentioned below. It amazes
me mucho to see all theese people driving SUV thinking they are safer!!!
BQ
"CH" a écrit dans le message de
...
I don't know how long it does take for certain people
to recognise, that SUV's and 4-wheel drive cars

- are built for use in the outback and not for driving in towns
- have a high CG and are handling worse on windy roads than
any normal cars with good suspension (European/Japan cars)
- have big tires to suit off road driving, which are worse on
normal roads, worse than normal or low profile tires.
- often do not have independent side stable suspension on the
back which give them bad side stability (push the car sideways
on the rear bumper and let it go - if the hole car swings around
the vertical yaw axis then it does not suit towing)
- have bad aerodynamics and produce more turbulence behind,
which has again bad influence on the trailers stability.

Conclusions:
Quite any car is better for towing, in handling and safety than
a SUV.

I prefer to rent a 4-wheel drive for holiday in the outback,
own a small car with common rail turbo diesel engine
(2000 ccm, 110kW, 250Nm at 1750 rpm, and 4.5 to 6 liters
per 100km consumption).
Like that I can pay many tows with the saved money I do not
spend on petrol.
I can tow any trailer with brakes up to 1500kg stable with
100km/.
And on a windy road the SUV just disappear in the rear mirror.
But I cannot compete offroad with these monsters. I don't mind
because I only need offroad function perhaps 7 days a year.
How often do you need offroad capability?
Think of it when you buy the next car.
Chris


"chris" wrote in message
om...
Several people have had good luck towing a glider with a Subaru
Forester.

My Mazda MX-6 [much lower car] has Pirelli P4000 P205/55 R15 87H - it
is stable, and if you push sideways it does not sway side to side
anywhere near the degree that the Forester does. Steering response
and cornering are good.

Chris Ruf



So, pulling anything at 55-65 mph should be fairly safe. What I
want to see is pulling a trailer beyond the rating of a
vehicle-happens more than it should. Yes, many might have an suv but,
given the situation of having to get somewhere where there are
actually grades to climb and areas of less than perfect roads, an suv
is useful. I own one and have used it several times on a "retrieve"
without having to worry about where I'm going.
Personal choice is acceptable in both driving and soaring.

Now that is a sensible argument for having the big lump. I just fail to
understand the "bigger is always better" argument.

I most situations that the average driver experiences - an SUV or "full
size" sedan is more liability than advantage. At least the guy with the
compact sedan can dodge the 18 wheeler - in something as nimble as the
agerage big SUV it comes down to trying to intimidate your way on the
road. Problem is that does not work with the average 18 wheeler (at
least where I come from) Fact is that these jobs are less safe, less
economical and more work to drive in most situations. I know the average
US male has never had the opportunity to experience the convenience of
driving a spacious, comfortable and compact car.

If you have a situation that justifies the inconvenience - like having
real need of off road capability - drive the SUV. If you can afford it,
as a couple of my friends can, have the SUV for when you need it and a
more practical vehicle for the commute. (As an extreme - one member at
our club drives a 2ton Landrover Discovery for gliding and
mountaineering, and Scuba expeditions, but commutes in a Mini Cooper S)

Whatever works for you. I just fail to understand those who have to
justify emotional / ego / social purchases by somehow trying to
construct a reasoned argument for why bigger is better. If you take that
to it's logical conclusion you should be buying Peterbilt (Or Mercedes,
or Renault...) horses for commuting in- I mean there is no shortage of
power, leather upholstery, aircon, air suspension, power everything, and
the best thing is you don't have to dodge the 18 wheelers, you are on
their level so to speak.

For what it is worth I have driven military 10ton 6 wheel drives through
Damaraland in Namibia - really needed the traction, power and ground
clearance, especially in case we hit a landmine, but I would hate to put
this on my list of fun vehicles to drive. Also driven all over South
Africa in ordinary sedans and MPVs, most with front wheel drive. Towed
retrieves with vehicles ranging from a Jeep Cherokee, to a 1600 hatch.
Have to say that for comfort, safety, good stability and everyday
convenience the best I have met is a small MPV. The current crop has
adequate power, excellent aerodynamics for stability in those windy
situations and certainly beats driving a truck all day.

Problem is the US carmakers can't make small cars profitably, SUVs are
very profitable because they are made on cheaper "truck" platforms. Once
again we have the victory of marketing and corporate profit over common
sense.