Replacing front tires

On Sun, 3 Sep 2006 13:01:32 -0700, "Floyd Rogers"
> wrote:

>"Bill Funk" > wrote
>> On Sun, 3 Sep 2006 11:38:49 -0700, "Floyd Rogers" wrote:
>>>> On a FWD car, the rears simply follow the front. They don't even
>>>> provide power, as they do on a RWD car.
>>>> There's no need to replace good tires on the rear.
>>>
>>>I think this should be clarified. When buying two tires (usually
>>>to replace the fronts which wear faster than the rears on a FWD
>>>car), the NEW tires should be placed on the REAR. The reason
>>>is that leaving the worn (but still legal) tires on the rear exposes
>>>the car to possibly severe oversteer conditions in wet when the
>>>rears hydroplane and the fronts (with new rubber) do not.
>>>
>> IMO:
>> Sounds good in theory, but in practice, my experience (very limited!)
>> is different.
>> In an F-250 (>6000lbs) with equal tires front & rear, the only
>> hydroplaning experience I've had occured; the front tiers were
>> hydroplaning. When I turned the sterering wheel, nothing happened. I
>> let up on the throttle, and a few seconds later, the truck turned.
>> It wasn't the rear tires (the less loaded tires) that floated, but the
>> fronts (with equal water on the road all around). When I let off the
>> throttle, the rear tires slowed the truck.
>> Just my (limited) experience.
>
>That's a very different situation: 1) RWD vs. FWD, 2) equal tread
>depth (vs. less depth in rear), 3) understeer vs. oversteer (induced
>by hydroplaning.).
>
>Placing the best tires on the rear virtually guarantees that the fronts
>will hydroplane 1st, which results in an understeer (and easily controlled)
>condition.

Not so easily controlled when you want to steer, and get no steering
because the front tires are just floating along.
>
>Oversteer is rarely encountered because most drivers are used to
>understeer (all FWD cars understeer, indeed most RWD cars are
>tuned to provide understeer as a first response). Oversteer is
>definitely to be avoided by the majority of drivers, since almost
>none of them have experienced or trained for it.
>
>FloydR
>
--
Bill Funk
replace "g" with "a"

Floyd Rogers wrote:
> "Bill Funk" > wrote
> > On 2 Sep 2006 18:06:41 -0700, "SP Cook" > wrote:
> >>Wally wrote:
> >>> I have an '89 Olds car with 4 Goodyear Aquatred tires on it.
> >>> I need to replace the front pair of tires as the car will not pass
> >>> state inspection because of tread depth. I want to just replace the
> >>> front tires as the rear tires are still in good shape, tread-wise.
> >>
> >>It is dangerous and foolish to replace only two tires on any front
> >>wheel drive car.
> >>
> >>Spend the money and buy four good standard tires.
> >
> > On a FWD car, the rears simply follow the front. They don't even
> > provide power, as they do on a RWD car.
> > There's no need to replace good tires on the rear.
>
> I think this should be clarified. When buying two tires (usually
> to replace the fronts which wear faster than the rears on a FWD
> car), the NEW tires should be placed on the REAR. The reason
> is that leaving the worn (but still legal) tires on the rear exposes
> the car to possibly severe oversteer conditions in wet when the
> rears hydroplane and the fronts (with new rubber) do not.

I've experienced a bit of hydroplaning in my time and *never* have the
rear tires lost traction before the front... and that event seems very
unlikely to occur at "normal" velocities and in "normal" water depths
when the front tires are pushing the water out of the path of the
rears.

IMO to reduce the chances of hydroplaning the tires with the most
resistance to hydroplaning, those with the deepest tread depth, should
be mounted on the front in either F or RWD instances.

Even in an loss of traction from only the rear tires I think it's most
likely best to have as much steering control as possible. But if only
the rear tires are hydroplaning (?) the fronts are not likely far
behind and adding steering correction at that moment seems inadvisable
to me. Google 'friction circle, tire' or see
http://www.auto-ware.com/setup/fc1.htm
-----

- gpsman

gpsman wrote:
> Floyd Rogers wrote:
> > "Bill Funk" > wrote
> > > On 2 Sep 2006 18:06:41 -0700, "SP Cook" > wrote:
> > >>Wally wrote:
> > >>> I have an '89 Olds car with 4 Goodyear Aquatred tires on it.
> > >>> I need to replace the front pair of tires as the car will not pass
> > >>> state inspection because of tread depth. I want to just replace the
> > >>> front tires as the rear tires are still in good shape, tread-wise.
> > >>
> > >>It is dangerous and foolish to replace only two tires on any front
> > >>wheel drive car.
> > >>
> > >>Spend the money and buy four good standard tires.
> > >
> > > On a FWD car, the rears simply follow the front. They don't even
> > > provide power, as they do on a RWD car.
> > > There's no need to replace good tires on the rear.
> >
> > I think this should be clarified. When buying two tires (usually
> > to replace the fronts which wear faster than the rears on a FWD
> > car), the NEW tires should be placed on the REAR. The reason
> > is that leaving the worn (but still legal) tires on the rear exposes
> > the car to possibly severe oversteer conditions in wet when the
> > rears hydroplane and the fronts (with new rubber) do not.
>
> I've experienced a bit of hydroplaning in my time and *never* have the
> rear tires lost traction before the front... and that event seems very
> unlikely to occur at "normal" velocities and in "normal" water depths
> when the front tires are pushing the water out of the path of the
> rears.
>
> IMO to reduce the chances of hydroplaning the tires with the most
> resistance to hydroplaning, those with the deepest tread depth, should
> be mounted on the front in either F or RWD instances.
>
> Even in an loss of traction from only the rear tires I think it's most
> likely best to have as much steering control as possible. But if only
> the rear tires are hydroplaning (?) the fronts are not likely far
> behind and adding steering correction at that moment seems inadvisable
> to me. Google 'friction circle, tire' or see
> http://www.auto-ware.com/setup/fc1.htm

Yes, hydroplaning rear tires is very rare, simply because the fronts
tend to clear a path for the rears - the water doesn't have time to
cover the road surface before the rear tires get there, unless it's
*really* deep. However, locking the rears first under hard braking is
seriously bad juju, you do NOT want that to happen, trust me. Also the
rears braking loose under hard cornering can be scary - on the street,
cornering hard enough to break traction generally tends to happen in an
emergency-avoidance type maneuver, not steady-state cornering, so
"plowing" (fronts break loose first) is generally easier to deal with
by a surprised or unskilled driver than oversteer (i.e. a big ol'
spin.)

nate

Floyd Rogers wrote:
> [On a FWD car]
> Placing the best tires on the rear virtually guarantees that the fronts
> will hydroplane 1st, which results in an understeer (and easily controlled)
> condition.
>
> Oversteer is rarely encountered because most drivers are used to
> understeer (all FWD cars understeer, indeed most RWD cars are
> tuned to provide understeer as a first response). Oversteer is
> definitely to be avoided by the majority of drivers, since almost
> none of them have experienced or trained for it.

You really think understeer is better than oversteer ?

When the front wheels lose traction, you cannot control the
direction of the car any more. If you're on a corner -- YGHN
(you go to hospital/heaven now).

Having said that, I have a RWD car. The only time I have
hydroplaned, was while driving a FWD hatchback in a passing
zone on a rural road, in heavy rain. There was traffic to one side,
and oncoming traffic about 2 metres away at a speed differential
of about 200km/h.

I felt the fronts lose traction (thankfully, it was on a straight),
and had no idea what to do. I just held the wheel straight and
continued to apply light throttle as I had been before the
hydroplaning started. Thankfully again, traction came back
a couple of seconds later. What's the best thing to do in
this situation?

Old Wolf wrote:
> Floyd Rogers wrote:
>
>>[On a FWD car]
>>Placing the best tires on the rear virtually guarantees that the fronts
>>will hydroplane 1st, which results in an understeer (and easily controlled)
>>condition.
>>
>>Oversteer is rarely encountered because most drivers are used to
>>understeer (all FWD cars understeer, indeed most RWD cars are
>>tuned to provide understeer as a first response). Oversteer is
>>definitely to be avoided by the majority of drivers, since almost
>>none of them have experienced or trained for it.
>
>
> You really think understeer is better than oversteer ?

For most people, yes. Most OEM's agree with that assessment, as most
cars "out of the box" will be set up to "plow" a little. The reason is
that the recovery procedure for understeer - getting off the gas - is
reflexive even for an untrained driver. The recovery procedure for
oversteer is not.

>
> When the front wheels lose traction, you cannot control the
> direction of the car any more. If you're on a corner -- YGHN
> (you go to hospital/heaven now).
>

That's true. However, the car will continue in the direction it was
pointed when it lost traction, which is reasonably safe, assuming that
you were pointed the direction you wanted to go.

> Having said that, I have a RWD car. The only time I have
> hydroplaned, was while driving a FWD hatchback in a passing
> zone on a rural road, in heavy rain. There was traffic to one side,
> and oncoming traffic about 2 metres away at a speed differential
> of about 200km/h.
>
> I felt the fronts lose traction (thankfully, it was on a straight),
> and had no idea what to do. I just held the wheel straight and
> continued to apply light throttle as I had been before the
> hydroplaning started. Thankfully again, traction came back
> a couple of seconds later. What's the best thing to do in
> this situation?

gradually lift off the gas and let the car coast down, but nothing else.
Definitely do not turn the steering wheel as you don't want to
unsettle the car when traction comes back.

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel

"Nate Nagel" > wrote
> Old Wolf wrote:
>> I felt the fronts lose traction (thankfully, it was on a straight),
>> and had no idea what to do. I just held the wheel straight and
>> continued to apply light throttle as I had been before the
>> hydroplaning started. Thankfully again, traction came back
>> a couple of seconds later. What's the best thing to do in
>> this situation?
>
> gradually lift off the gas and let the car coast down, but nothing else.
> Definitely do not turn the steering wheel as you don't want to unsettle
> the car when traction comes back.

Very nice response, Nate.

FloydR

"Floyd Rogers" > wrote
> "Nate Nagel" > wrote
>> Old Wolf wrote:
>>> I felt the fronts lose traction (thankfully, it was on a straight),
>>> and had no idea what to do. I just held the wheel straight and
>>> continued to apply light throttle as I had been before the
>>> hydroplaning started. Thankfully again, traction came back
>>> a couple of seconds later. What's the best thing to do in
>>> this situation?
>>
>> gradually lift off the gas and let the car coast down, but nothing else.
>> Definitely do not turn the steering wheel as you don't want to unsettle
>> the car when traction comes back.
>
> Very nice response, Nate.

Late thought: rather amazing to actually be posting ON-TOPIC
to RAD...

FloydR

In article >, Bill Funk wrote:
> On Sun, 03 Sep 2006 14:53:39 -0500,
> (Brent P) wrote:
>
>>In article >, Bill Funk wrote:
>>> On Sun, 3 Sep 2006 11:38:49 -0700, "Floyd Rogers"
> wrote:
>>>
>>>>> On a FWD car, the rears simply follow the front. They don't even
>>>>> provide power, as they do on a RWD car.
>>>>> There's no need to replace good tires on the rear.
>>>>
>>>>I think this should be clarified. When buying two tires (usually
>>>>to replace the fronts which wear faster than the rears on a FWD
>>>>car), the NEW tires should be placed on the REAR. The reason
>>>>is that leaving the worn (but still legal) tires on the rear exposes
>>>>the car to possibly severe oversteer conditions in wet when the
>>>>rears hydroplane and the fronts (with new rubber) do not.
>>
>>> IMO:
>>> Sounds good in theory, but in practice, my experience (very limited!)
>>> is different.
>>> In an F-250 (>6000lbs) with equal tires front & rear, the only
>>> hydroplaning experience I've had occured; the front tiers were
>>> hydroplaning. When I turned the sterering wheel, nothing happened. I
>>> let up on the throttle, and a few seconds later, the truck turned.
>>> It wasn't the rear tires (the less loaded tires) that floated, but the
>>> fronts (with equal water on the road all around). When I let off the
>>> throttle, the rear tires slowed the truck.
>>> Just my (limited) experience.
>>
>>Your experience supports putting the good tires on the rear. This way
>>instead of having the rear come around, one can just let up on the
>>throttle and allow the vehicle to slow to where the fronts grip again.

> My experience was that the front tires floated; why would this support
> putting the better (not *good*; the rear tires were good) on the rear?
> Then the fronts still would have floated.

Because if the rears had 'floated' the ass end of your truck might have
come around on you sending it into a spin....

>>Even in a FWD car, there is friction to slow the car, just not engine
>>braking from the rear.

> This would mean you'd want the better tires on the front, to provide
> engine braking. The rear tires on a FWD cars just follow along,
> providing very little resistance (friction losses to speed). You can
> see this by jacking up the car, and spinning the rear tires.

No. You do not want the ass end of the car to come around under any
circumstances.

In article >, Brent P wrote:

> You do not want the ass end of the car to come around under any
> circumstances.

Before the sniping trolls step in with some special case where one wants
the ass end of the car to come around, I clearly mean normal street
driving, not some movie stunt or whatever other special case you are
thinking of.

Floyd Rogers wrote:
>
> I think this should be clarified. When buying two tires (usually
> to replace the fronts which wear faster than the rears on a FWD
> car), the NEW tires should be placed on the REAR. The reason
> is that leaving the worn (but still legal) tires on the rear exposes
> the car to possibly severe oversteer conditions in wet when the
> rears hydroplane and the fronts (with new rubber) do not.
>
> FloydR
>
>

That's exactly why you SHOULD place the new tires on the front and leave
the old ones on the rear. Finally, a FWD car that doesn't plow.

Seriously, having put new tires on the front of the wife's car last
winter I can confirm this is exactly what happens, and if you don't want
it, it's not a good thing. (some of us find that a little less plow and
a little more loose IS a good thing.)

(and fwiw, the wife's car will get new tires probably this winter if we
keep it another winter. Since we've had the car we seem to replace a
set every two-three years.)

Ray