Correcting negative caster on 97 Accord

BCDrums --

BCDrums > wrote:
>
> I just got a set of Michelins. Toyota says 30psi, the tire dealer put in
> 32. He said that the manufacturer's recommendation was to provide a
> cushier ride, and that 32psi would give better wear. Hmmm...

> What do you think of the chalk-line-on-the-tread method of determining
> ideal pressure?

Not a lot. The only thing it'll show is that when rolling a short
distance straight, different parts of the thread have more or less
contact with the road. No relation to what happens at speed, during
braking or in corners.

Whenever I get a new set of tires on a car, I take half an hour to play:
starting with the manufacturer recommendation, then going up a bit, and
down a bit, front as well as rear. After every change a quick test ride
to check - you'll quickly find how much change is noticeable and what it
does.

Playing around a bit (while never going too far from manufacturer
recommendation and thoroughly ignoring tire dealer input) helps find
your best compromise of ride and roadholding.

cu
.\\arc

"AZ Nomad" wrote

> They have 24-28 in their manuals to avoid overinflation wear. Tire shops
> tend to inflate every single tire to 32-35 psi so that they don't have to
> bother with checking the manufacturer recomended pressure. If the tires
> wear
> out faster, so much the better.
>
> Keep in mind that it is *volume* that matters in having the tire of the
> proper shape and to avoid over/underinflation wear. A car with more
> weight
> will require greater pressure to achieve the same volume and, of course, a
> car with less than the tire's maximum rated load will require less
> pressure.
> Tire shops ignore this.

A million years ago, when I hung out in my dad's tire store, I looked up
tire pressure recommendations in a thick booklet produced by, I think,
General Tire. Their pressure recommendations for a given tire for a given
model of car were different from what the car manufacturer recommended. I
never understood that written difference. In any event, 28 lbs per tire was
the norm.

Marc Gerges wrote:
> BCDrums --
>
> BCDrums > wrote:
> >
> > I just got a set of Michelins. Toyota says 30psi, the tire dealer put in
> > 32. He said that the manufacturer's recommendation was to provide a
> > cushier ride, and that 32psi would give better wear. Hmmm...
>
> > What do you think of the chalk-line-on-the-tread method of determining
> > ideal pressure?
>
> Not a lot. The only thing it'll show is that when rolling a short
> distance straight, different parts of the thread have more or less
> contact with the road. No relation to what happens at speed, during
> braking or in corners.
>
> Whenever I get a new set of tires on a car, I take half an hour to play:
> starting with the manufacturer recommendation, then going up a bit, and
> down a bit, front as well as rear. After every change a quick test ride
> to check - you'll quickly find how much change is noticeable and what it
> does.
>
> Playing around a bit (while never going too far from manufacturer
> recommendation and thoroughly ignoring tire dealer input) helps find
> your best compromise of ride and roadholding.
>
> cu
> .\\arc

FWIW, I gave up playing around a while ago. Now I use a tire tread
depth gauge ($2 or $3 at any auto parts store) to help me figure out
the highest pressure (for max. mpg) consistent with even wear across
each tire. I measure the tread every 5,000 mi. or so at three places on
each tire (inside, middle, outside) and adjust pressure accordingly.

I've been doing this for about 20 years and have to say the resulting
tire pressure is NEVER the OEM's suggested value. My tires are from 4
to 8 psi above (but never exceeding the max. inflation value provided
on the sidewall) the car's suggested pressure. The actual value will
vary with tire brand/type, driving style and ride characteristics.

YMMV

On 1/8/07 5:34 PM, in article
, "ACAR"
> wrote:

>
> Marc Gerges wrote:
>> BCDrums --
>>
>> BCDrums > wrote:
>>>
>>> I just got a set of Michelins. Toyota says 30psi, the tire dealer put in
>>> 32. He said that the manufacturer's recommendation was to provide a
>>> cushier ride, and that 32psi would give better wear. Hmmm...
>>
>>> What do you think of the chalk-line-on-the-tread method of determining
>>> ideal pressure?
>>
>> Not a lot. The only thing it'll show is that when rolling a short
>> distance straight, different parts of the thread have more or less
>> contact with the road. No relation to what happens at speed, during
>> braking or in corners.
>>
>> Whenever I get a new set of tires on a car, I take half an hour to play:
>> starting with the manufacturer recommendation, then going up a bit, and
>> down a bit, front as well as rear. After every change a quick test ride
>> to check - you'll quickly find how much change is noticeable and what it
>> does.
>>
>> Playing around a bit (while never going too far from manufacturer
>> recommendation and thoroughly ignoring tire dealer input) helps find
>> your best compromise of ride and roadholding.
>>
>> cu
>> .\\arc
>
> FWIW, I gave up playing around a while ago. Now I use a tire tread
> depth gauge ($2 or $3 at any auto parts store) to help me figure out
> the highest pressure (for max. mpg) consistent with even wear across
> each tire. I measure the tread every 5,000 mi. or so at three places on
> each tire (inside, middle, outside) and adjust pressure accordingly.
>
> I've been doing this for about 20 years and have to say the resulting
> tire pressure is NEVER the OEM's suggested value. My tires are from 4
> to 8 psi above (but never exceeding the max. inflation value provided
> on the sidewall) the car's suggested pressure. The actual value will
> vary with tire brand/type, driving style and ride characteristics.
>
> YMMV
>

I have been doing exactly the same thing for about 15 years. I check it
every 5,000 miles when rotating the tires. My gauge was a freebee from a
Michelin dealer 20 years ago. The right answer to get even wear on the
tires is always 4 to 7 pounds more than the door sticker. The handling
characteristics of the cars usually improves vs. running them at the door
sticker number as well. Except for the '91 240sx (a fairly light car), the
right answer has generally turned out to be 33-35 PSI. 31 does it on the
240sx.

E Meyer wrote:
>
>
> On 1/8/07 5:34 PM, in article
> , "ACAR"
> > wrote:
>
>> Marc Gerges wrote:
>>> BCDrums --
>>>
>>> BCDrums > wrote:
>>>> I just got a set of Michelins. Toyota says 30psi, the tire dealer put in
>>>> 32. He said that the manufacturer's recommendation was to provide a
>>>> cushier ride, and that 32psi would give better wear. Hmmm...
>>>> What do you think of the chalk-line-on-the-tread method of determining
>>>> ideal pressure?
>>> Not a lot. The only thing it'll show is that when rolling a short
>>> distance straight, different parts of the thread have more or less
>>> contact with the road. No relation to what happens at speed, during
>>> braking or in corners.
>>>
>>> Whenever I get a new set of tires on a car, I take half an hour to play:
>>> starting with the manufacturer recommendation, then going up a bit, and
>>> down a bit, front as well as rear. After every change a quick test ride
>>> to check - you'll quickly find how much change is noticeable and what it
>>> does.
>>>
>>> Playing around a bit (while never going too far from manufacturer
>>> recommendation and thoroughly ignoring tire dealer input) helps find
>>> your best compromise of ride and roadholding.
>>>
>>> cu
>>> .\\arc
>> FWIW, I gave up playing around a while ago. Now I use a tire tread
>> depth gauge ($2 or $3 at any auto parts store) to help me figure out
>> the highest pressure (for max. mpg) consistent with even wear across
>> each tire. I measure the tread every 5,000 mi. or so at three places on
>> each tire (inside, middle, outside) and adjust pressure accordingly.
>>
>> I've been doing this for about 20 years and have to say the resulting
>> tire pressure is NEVER the OEM's suggested value. My tires are from 4
>> to 8 psi above (but never exceeding the max. inflation value provided
>> on the sidewall) the car's suggested pressure. The actual value will
>> vary with tire brand/type, driving style and ride characteristics.
>>
>> YMMV
>>
>
> I have been doing exactly the same thing for about 15 years. I check it
> every 5,000 miles when rotating the tires. My gauge was a freebee from a
> Michelin dealer 20 years ago. The right answer to get even wear on the
> tires is always 4 to 7 pounds more than the door sticker. The handling
> characteristics of the cars usually improves vs. running them at the door
> sticker number as well. Except for the '91 240sx (a fairly light car), the
> right answer has generally turned out to be 33-35 PSI. 31 does it on the
> 240sx.
>
but all this assumes tire wear is unaffected by suspension dynamics. it
may "work" on old solid axle vehicles where camber and thrust angles are
not constantly changing, but that's not the case with a 4-wheel
independent, wishbone, deflection compensated honda. all these factors
mean tire edges wear faster. that's why modern sport tires already have
feathered tire edges. over-inflating to make tire wear "look" better is
kind of not the point.

jim beam wrote:

> over-inflating to make tire wear "look" better is
> kind of not the point.

The tires don't look better, they wear longer and deliver better mpg
under normal driving situations. Accords and Civics are not set up for
high performance driving from the factory; they're commuter cars.

ACAR wrote:
> jim beam wrote:
>
>> over-inflating to make tire wear "look" better is
>> kind of not the point.
>
> The tires don't look better, they wear longer and deliver better mpg
> under normal driving situations. Accords and Civics are not set up for
> high performance driving from the factory; they're commuter cars.
>

regarding wear and mpg, with radial tires, that's not true like it used
to be with bias ply. provided pressure is in the right range, rubber
compound will have more effect on mpg than air pressure.

regarding "commuter cars", sure, they're not "performance" vehicles from
factory, but they sure do handle better than any other vehicles in their
class from factory. or at least, the wishbone ones do.

you sure they replaced strut's?? because it sounds like a bent strut or
a tire pull..caster is not a tire wearing angle...but it is a pulling
angle...
to check to see if its a tire pulling switch right to left front tires
good luck....

scrapper....


--
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