Honda Car Forum

"jim beam" <nospam@example.net> wrote in message
news:j7WdnScMGNJjEqnZ4p2dnA@speakeasy.net...
> Ray O wrote:
>> "jim beam" <nospam@example.net> wrote in message
>> news:BoSdneMt95YQIq7ZRVn-rg@speakeasy.net...
>>
>>>Ray O wrote:
>>>
>>>>"jim beam" <nospam@example.net> wrote in message
>>>>news:BNmdnQYK-tq_sq7Z4p2dnA@speakeasy.net...
>>>>
>>>>
>>>>>Ray O wrote:
>>>>
>>>><snipped>
>>>>
>>>>>>>>All 4 tires will not necessarily spin at equal speeds unless the
>>>>>>>>vehicle is equipped with front and rear locking differentials and a
>>>>>>>>transfer case or center locking differential. If any of the
>>>>>>>>differentials are open, then the tire(s) with the least traction
>>>>>>>>will spin while the others do nothing.
>>>>>>>
>>>>>>>that depends on the diffs you have.
>>>>>>>
>>>>>>>http://www.quaifeamerica.com/
>>>>>>>
>>>>>>>those are always "open".
>>>>>>
>>>>>>
>>>>>>According to the web site on the link, the Quaife differential is not
>>>>>>an open differential, although they say that it performs like an open
>>>>>>differential during normal driving.
>>>>>>
>>>>>>An open differential is one that does not have any means of locking or
>>>>>>limiting slip. By definition, the Quaife differential is not an open
>>>>>>differential.
>>>>>
>>>>>it's "open" in that there's no locking mechanism. it simply transfers
>>>>>torque to the wheel with the most traction, unlike a traditional diff.
>>>>
>>>>
>>>>I guess my explanation of "open differential" was a little lacking.
>>>>When a differential is "open" it does not mean that there is no locking
>>>>or slip limiting mechanism or fluid. An open differential is simply a
>>>>conventional differential. Any variation to the differential designed
>>>>to transfer torque to the side with traction means that it is no longer
>>>>ann "open" differential. Even Quaife says that their differential is
>>>>better than an open differential - IOW, it is not "open."
>>>
>>>open means free to turn one wheel relative to another. locked means both
>>>wheels turn together.
>>>
>>>
>>>>
>>>>>more common lsd's use clutches, ratchets or locks to keep both wheels
>>>>>turning together so some energy is still lost. i've not driven a
>>>>>quaife, but from what i understand, always driving the wheel that gives
>>>>>traction works like a charm.
>>>>
>>>>
>>>>A differential that is locked has no energy loss.
>>>
>>>that's not true. lsd's with clutches lose energy big time. but that's
>>>not what i'm getting at: if a diff is locked, both wheels turn together,
>>>one has traction, the other not. the one that doesn't is simply
>>>scrubbing energy away.
>>
>>
>> A limited slip differential and a locking differential are not the same
>> thing.
>
> agreed.
>
>> A limited slip differential does lose some energy because kinetic energy
>> is converted to heat.
>
> agreed.
>
>> With a locked differential there is zero slippage and therefore zero
>> energy loss when locked..
>
> not agreed. the tire that's still slipping is still slipping. that's
> loss. if you mean loss /within/ the diff, that's true, but it's no good
> worrying about that if you're losing ground on every turn.
>

When you work with a bunch of anal retentive engineers like I used to, it
rubbs off. They would say that since the original discussion was
differential efficiency, then the same would have to be true of a locked
differential, with a foot note describing the enery loss from the tires.

>>
>> You were close but not quite correct in your example of a locked
>> differential with both wheels turning together where one wheel has
>> traction and the other does not.. In that example, it is the wheel/tire
>> that is scrubbing the energy, not the differential.
>
> see above. i've been talking about energy transferred to the road all
> along.
>

We were talking about similar but different things. The nit picker in me
would say that if we were discussing energy transfer to the road, then the
words "energy transfer to the road" should have been included at the
beginning of the discussion as opposed to differential energy. Since you
were talking about energy transfer to the road, then you were correct,
however, I still believe that your characterization of the Quaife diff as
"open" is still incorrect because "open" does not mean the lack of clutches,
silicone fluid, locking sleeves, etc. - I guess Quaife and I will have to
agree to disagree with you there. ;-)
--

Ray O
(correct punctuation to reply)

"jim beam" <nospam@example.net> wrote in message
news:B8KdnXc_2MpsC6nZRVn-iw@speakeasy.net...
>
>>>><snipped>
>>>>>>Every type of suspension system has trade-offs. In the ideal
>>>>>>suspension system, the wheel will move up and down perpendicular to
>>>>>>the road surface and maintain camber so that the tire maintains
>>>>>>maximum contact and traction throughout the limits of wheel movement.
>>>>>>Also, designers try to minimize unsprung weight to minimize wheel
>>>>>>bounce. In a mass-produced vehicle, cost is a very big factor.
>>>>>>
>>>>>>A double wishbone suspension does a very good job at maintaining
>>>>>>camber throughout its movement because it acts like a pantograph but
>>>>>>is more expensive to produce than a strut suspension.
>>>>>
>>>>>agreed, but i don't see that as a disadvantage for me. there's no
>>>>>price differential at the consumer end.
>>>>
>>>>
>>>>What makes you think that there is no price differential at the consumer
>>>>end?
>>>
>>>er, the price i pay when i buy the car?
>>
>>
>> If a double wishbone suspension costs the automaker $50 more than a strut
>> suspension, do you think the automaker would put put double wishbones in
>> all cars and not pass that cost on to the consumers?
>
> so what's the price difference between the camry and accord?
>
> according to edmunds, the base [wishbone] accord is $18225, the [strut]
> camry is $18270.
>
> i therefore re-state, car manufacturers do /not/ sell on a "cost plus"
> basis, so the price of parts is irrelevant.
>

Your comparison of the Camry and Accord would be valid if the suspension
type were the only differences between the cars. Toyota and Honda have
different cost structures with labor, raw material, plant and corporate
overhead, advertising, travel and entertainment, etc. as well as different
content, distributor markup, and dealer markup. I am not aware of any
vehicle where a strut and a different type of front suspension is availble
so it is not easy to make a comparison unless you have a background in how
automakers price their vehicles. Trucks offer different front suspensions
for RWD and 4WD versions and for different capacities. The Japan market
Estima Van had an independent rear suspension and the U.S. Previa van had a
live axle, but neither rear suspensions were strut type.

Your point is valid in that "cost plus" is not the sole determing factor in
vehicle pricing, however, the automaker's cost to produce a vehicle is the
starting point in determineing what the final MSRP will be. Market
competition plays a big factor as well as market demand. I susect that
we're saying the same thing differently.


>>
>> <snipped>
>>
>>>>You sound like you have read a lot of auto enthusiast magazines but have
>>>>not had formal training in automotive design, engineering, or service or
>>>>experience working for an auto manufacturer. If you had, you would know
>>>>instinctively
>>>
>>>whoa there!!! let's go out on a wild-ass limb here and speculate that i
>>>have some training and experience... wtf has that got to do with
>>>instinct???
>>
>>
>> I meant no insult, just an observation, and I apologize.
>
> ok, no problem.
>
>> My intent is to share the experience and knowledge I gained while
>> working for an automaker and correct people's misconceptions about how
>> cars work. The more people know about their cars, the more realistic
>> their expectrations of the car's performance and the more satisfied they
>> weill be with their car.
>>
>> When I said "know instinctively," I meant it from the point of view of a
>> professional who spends all day working on and studying a subject and
>> knows something without giving it consccicous thought. For example, a
>> carpenter whose specialty is framing houses will know instinctively when
>> he looks at a new house being built whether it is framed correctly or
>> not.
>>
>> You mentioned that maintaining tire contact is not as important in an
>> environment where traction is poor, and someone with an auto engineering
>> background or who works with cars day in and day out would know without
>> conscious thought that this statement was incorrect.
>
> i disagree. go to any parking lot where there's a big-tired mercedes or
> bmw that's on full lock. the "outside" tire has the full contact patch
> flat against the ground. the "inside" tire however is riding up on one
> edge because the camber is all wrong. this is an "acceptable" situation
> as, in practice, hardly anyone drives these cars hard enough for it to be
> a real issue. with 10" [or whatever] of rubber on the side of the car
> making the most load, who notices? /but/, when you're driving at
> 10/10th's, that extra little bit of rubber on the /inside/ tire that's
> more correctly positioned can get you through the corner faster than the
> other guy. my no means are hondas the most powerful cars on the road, but
> they sure do hang well with the big boys as soon as there's a bend.
>

The effect you're describing about camber changes is not caused by the type
of suspension, i.e., strut vs. double wishbone. It is caused by lots of
positive caster, like 10 or more degrees, and you will see the same effect
whether the car has a strut of wishbone suspension if there is lots of
positive caster. Another effect of vehicles with lots of positive caster is
that you will see the front end of the vehicle actually dip when the wheel
is turned full lock. This effect is magnified somewhat by the large wheels
and tires. Automakers will design lots of positive caster to provide
straighter tracking, and the tradeoff is slightly less responsive turning.

<confusing stuff snipped>
>
> with mcpherson it's the "approximation" that's required for every element
> of geometry that makes it less than perfect. but it's ok for sedans,
> cheap, comfy and doesn't roll much. wishbones are better on road where
> there's greater steering precision possible. disadvantages of wishbones
> are cost, a little comfort, and the need to address roll since the greater
> degree of freedom the body has within the system leaves it free to do so.
> i'd draw a pic, but in ascii it would suck. also consider the fact that
> mcpherson first came out when bias ply tires were all you could get -
> again, no need to be precise there!

Aaah! What I'm getting from what you're describing is different from what I
got from your other posts. In your other posts, I got that you were saying
that strut suspensions offered superior handling to wishbones. What you are
conveying here is much more accurate than your previous posts - we're on the
same page now (we probably were before but on different frequencies).
--

Ray O
(correct punctuation to reply)

Ray O wrote:
> "jim beam" <nospam@example.net> wrote in message
> news:qOidneHXFblprK7ZRVn-sw@speakeasy.net...
>
>
> <snipped>
>
>>>>>McPherson strut suspensions are not great off-road. Take a look at
>>>>>purpose-built off-road vehicles and see how many have strut suspensions.
>>>>
>>>>i'm sorry, /how/ many rally world championships have been won with
>>>>mcpherson struts??? i'm talking cars, not "purpose-built off-road
>>>>vehicles".
>>>
>>>
>>>Here is a pretty good explanation of suspension systems:
>>>http://www.carbibles.com/suspension_bible.html
>>>
>>>Every type of suspension system has trade-offs. In the ideal suspension
>>>system, the wheel will move up and down perpendicular to the road surface
>>>and maintain camber so that the tire maintains maximum contact and
>>>traction throughout the limits of wheel movement. Also, designers try to
>>>minimize unsprung weight to minimize wheel bounce. In a mass-produced
>>>vehicle, cost is a very big factor.
>>>
>>>A double wishbone suspension does a very good job at maintaining camber
>>>throughout its movement because it acts like a pantograph but is more
>>>expensive to produce than a strut suspension.
>>
>>agreed, but i don't see that as a disadvantage for me. there's no price
>>differential at the consumer end.
>
>
> What makes you think that there is no price differential at the consumer
> end? Automakers examine the cost of every part and component in every
> vehicle.
>
>
>>>A strut suspension generally has a lower control arm that the wheel is
>>>attached to. The lower control arm pivots where it is attached to the
>>>strut so the wheel's movement is actually an arc instead of straight
>>>vertical movement. The biggest advantage of a strut type suspension is
>>>that it is less expensive to produce while still providing more than
>>>adequate performance for every day street driving so you see it widely
>>>used on lower and mid-range cost vehicles.
>>>
>>>Rally cars do not have strut suspensions because they are great off road;
>>>they have strut suspensions because the stock versions of the cars have
>>>strut suspensions, and the stock versions have struts because they cost
>>>less to produce than other types of suspensions.
>>
>>you're correct about cost, but the fact still remains, struts have proven
>>themselves to be good in low traction environments where the little
>>nuances of maintaining tire contact patch that are addressed by wishbones
>>are vanishingly unimportant. they also give a comfy ride and are less
>>susceptible to roll. put all that on a street car and use wider tires to
>>make up for the geometry issues, and you have something that approximates
>>to acceptable.
>
>
> You sound like you have read a lot of auto enthusiast magazines but have not
> had formal training in automotive design, engineering, or service or
> experience working for an auto manufacturer. If you had, you would know
> instinctively that maintaining tire contact with the ground is more
> important in a low traction environment than in an environment where
> traction is not as much of an issue. You would also know that a strut
> suspension is not more or less susceptible to roll (I'm assuming that you
> are referring to body roll). Spring rates and anti-roll bars are what
> affect body roll. Most strut suspensions are more susceptible to camber
> changes. Also, wider tires do not make up for geometry issues.
>
> McPherson and Chapman strut suspensions are in wide use not because of their
> superior handling characteristics, but because they are inexpensive to make
> and lightweight. Most people know little or nothing about suspension
> designs so it sounds good when the automaker points out a "MacPherson Strut"
> suspension and so small and mid-size vehicles that are not actually
> performance oriented will have them installed. You usually will not see
> strut suspensions on performance and high-end vehicles, particularly those
> with RWD. Over the years, engineers have made improvements to strut
> suspension geometry to more closely approximate the better performing
> suspensions and they are certainly acceptable for the majority of the
> driving public, but a someone who is knowledgeable about automotive
> suspensions or performance would not hint that a strut suspension is the
> preferred design for any reason other than cost control.
Struts are the wave of the future. Not only are struts less expensive,
but struts are also more space efficient than double-wishbone
suspensions. Carmakers can design a roomier cabin and more capacious
trunk for a car when using struts.


A sign that struts have come along is that the new BMW 3 series uses
them. If they're good enought for "the ultimate driving machine" then
they are quit good now. Take note on how the 3 series is now a much
roomier car and it is still quite a driving machine.

CD

jim beam wrote:
>>
>> A locked diff will make sure both spin at the same speed, so the power
>> is distributed in proportion to the traction.
>
>
> no, if they're locked, they're not in proportion to traction. they're
> just locked, so the wheel that's still scrubbing is wasting energy.
>
<snip>

Jim, I stand by what I said.

The power delivered to the road is a multiple of speed and force.

So if one wheel has twice as much grip as the other, twice as much power
will go through it. (assuming they are both traction limited!)

Yes, you will waste some - which is why the tyre smokes when you try
really hard - but the *delivered* power will be proportional to the
traction.

Another rider - you may be delivering the power to the gravel, not the road!

Andy

Codifus wrote:
> Ray O wrote:
>
>> "jim beam" <nospam@example.net> wrote in message
>> news:qOidneHXFblprK7ZRVn-sw@speakeasy.net...
>>
>>
>> <snipped>
>>
>>>>>> McPherson strut suspensions are not great off-road. Take a look
>>>>>> at purpose-built off-road vehicles and see how many have strut
>>>>>> suspensions.
>>>>>
>>>>>
>>>>> i'm sorry, /how/ many rally world championships have been won with
>>>>> mcpherson struts??? i'm talking cars, not "purpose-built off-road
>>>>> vehicles".
>>>>
>>>>
>>>>
>>>> Here is a pretty good explanation of suspension systems:
>>>> http://www.carbibles.com/suspension_bible.html
>>>>
>>>> Every type of suspension system has trade-offs. In the ideal
>>>> suspension system, the wheel will move up and down perpendicular to
>>>> the road surface and maintain camber so that the tire maintains
>>>> maximum contact and traction throughout the limits of wheel
>>>> movement. Also, designers try to minimize unsprung weight to
>>>> minimize wheel bounce. In a mass-produced vehicle, cost is a very
>>>> big factor.
>>>>
>>>> A double wishbone suspension does a very good job at maintaining
>>>> camber throughout its movement because it acts like a pantograph but
>>>> is more expensive to produce than a strut suspension.
>>>
>>>
>>> agreed, but i don't see that as a disadvantage for me. there's no
>>> price differential at the consumer end.
>>
>>
>>
>> What makes you think that there is no price differential at the
>> consumer end? Automakers examine the cost of every part and component
>> in every vehicle.
>>
>>
>>>> A strut suspension generally has a lower control arm that the wheel
>>>> is attached to. The lower control arm pivots where it is attached
>>>> to the strut so the wheel's movement is actually an arc instead of
>>>> straight vertical movement. The biggest advantage of a strut type
>>>> suspension is that it is less expensive to produce while still
>>>> providing more than adequate performance for every day street
>>>> driving so you see it widely used on lower and mid-range cost vehicles.
>>>>
>>>> Rally cars do not have strut suspensions because they are great off
>>>> road; they have strut suspensions because the stock versions of the
>>>> cars have strut suspensions, and the stock versions have struts
>>>> because they cost less to produce than other types of suspensions.
>>>
>>>
>>> you're correct about cost, but the fact still remains, struts have
>>> proven themselves to be good in low traction environments where the
>>> little nuances of maintaining tire contact patch that are addressed
>>> by wishbones are vanishingly unimportant. they also give a comfy
>>> ride and are less susceptible to roll. put all that on a street car
>>> and use wider tires to make up for the geometry issues, and you have
>>> something that approximates to acceptable.
>>
>>
>>
>> You sound like you have read a lot of auto enthusiast magazines but
>> have not had formal training in automotive design, engineering, or
>> service or experience working for an auto manufacturer. If you had,
>> you would know instinctively that maintaining tire contact with the
>> ground is more important in a low traction environment than in an
>> environment where traction is not as much of an issue. You would also
>> know that a strut suspension is not more or less susceptible to roll
>> (I'm assuming that you are referring to body roll). Spring rates and
>> anti-roll bars are what affect body roll. Most strut suspensions are
>> more susceptible to camber changes. Also, wider tires do not make up
>> for geometry issues.
>>
>> McPherson and Chapman strut suspensions are in wide use not because of
>> their superior handling characteristics, but because they are
>> inexpensive to make and lightweight. Most people know little or
>> nothing about suspension designs so it sounds good when the automaker
>> points out a "MacPherson Strut" suspension and so small and mid-size
>> vehicles that are not actually performance oriented will have them
>> installed. You usually will not see strut suspensions on performance
>> and high-end vehicles, particularly those with RWD. Over the years,
>> engineers have made improvements to strut suspension geometry to more
>> closely approximate the better performing suspensions and they are
>> certainly acceptable for the majority of the driving public, but a
>> someone who is knowledgeable about automotive suspensions or
>> performance would not hint that a strut suspension is the preferred
>> design for any reason other than cost control.
>
> Struts are the wave of the future. Not only are struts less expensive,
> but struts are also more space efficient than double-wishbone
> suspensions. Carmakers can design a roomier cabin and more capacious
> trunk for a car when using struts.
>
>
> A sign that struts have come along is that the new BMW 3 series uses
> them. If they're good enought for "the ultimate driving machine" then
> they are quit good now.

what an utterly stupid comment. bmw do many things, including seal
their transmissions so the fluid cannot be changed, design their crumple
zones so "early" deformation occurs in parts of the shell that render
the vehicle irreparable, etc. but because they label themselves with a
catchy advertising tag-line, whatever they do /has/ to be good?
complete carp.

> Take note on how the 3 series is now a much
> roomier car and it is still quite a driving machine.
>
> CD

Ray O wrote:
> "jim beam" <nospam@example.net> wrote in message
> news:B8KdnXc_2MpsC6nZRVn-iw@speakeasy.net...
>
>>>>><snipped>
>>>>>
>>>>>>>Every type of suspension system has trade-offs. In the ideal
>>>>>>>suspension system, the wheel will move up and down perpendicular to
>>>>>>>the road surface and maintain camber so that the tire maintains
>>>>>>>maximum contact and traction throughout the limits of wheel movement.
>>>>>>>Also, designers try to minimize unsprung weight to minimize wheel
>>>>>>>bounce. In a mass-produced vehicle, cost is a very big factor.
>>>>>>>
>>>>>>>A double wishbone suspension does a very good job at maintaining
>>>>>>>camber throughout its movement because it acts like a pantograph but
>>>>>>>is more expensive to produce than a strut suspension.
>>>>>>
>>>>>>agreed, but i don't see that as a disadvantage for me. there's no
>>>>>>price differential at the consumer end.
>>>>>
>>>>>
>>>>>What makes you think that there is no price differential at the consumer
>>>>>end?
>>>>
>>>>er, the price i pay when i buy the car?
>>>
>>>
>>>If a double wishbone suspension costs the automaker $50 more than a strut
>>>suspension, do you think the automaker would put put double wishbones in
>>>all cars and not pass that cost on to the consumers?
>>
>>so what's the price difference between the camry and accord?
>>
>>according to edmunds, the base [wishbone] accord is $18225, the [strut]
>>camry is $18270.
>>
>>i therefore re-state, car manufacturers do /not/ sell on a "cost plus"
>>basis, so the price of parts is irrelevant.
>>
>
>
> Your comparison of the Camry and Accord would be valid if the suspension
> type were the only differences between the cars. Toyota and Honda have
> different cost structures with labor, raw material, plant and corporate
> overhead, advertising, travel and entertainment, etc. as well as different
> content, distributor markup, and dealer markup. I am not aware of any
> vehicle where a strut and a different type of front suspension is availble
> so it is not easy to make a comparison unless you have a background in how
> automakers price their vehicles. Trucks offer different front suspensions
> for RWD and 4WD versions and for different capacities. The Japan market
> Estima Van had an independent rear suspension and the U.S. Previa van had a
> live axle, but neither rear suspensions were strut type.
>
> Your point is valid in that "cost plus" is not the sole determing factor in
> vehicle pricing, however, the automaker's cost to produce a vehicle is the
> starting point in determineing what the final MSRP will be. Market
> competition plays a big factor as well as market demand. I susect that
> we're saying the same thing differently.

no, you're just back-tracking.

>
>
>
>>><snipped>
>>>
>>>>>You sound like you have read a lot of auto enthusiast magazines but have
>>>>>not had formal training in automotive design, engineering, or service or
>>>>>experience working for an auto manufacturer. If you had, you would know
>>>>>instinctively
>>>>
>>>>whoa there!!! let's go out on a wild-ass limb here and speculate that i
>>>>have some training and experience... wtf has that got to do with
>>>>instinct???
>>>
>>>
>>>I meant no insult, just an observation, and I apologize.
>>
>>ok, no problem.
>>
>>
>>> My intent is to share the experience and knowledge I gained while
>>>working for an automaker and correct people's misconceptions about how
>>>cars work. The more people know about their cars, the more realistic
>>>their expectrations of the car's performance and the more satisfied they
>>>weill be with their car.
>>>
>>> When I said "know instinctively," I meant it from the point of view of a
>>>professional who spends all day working on and studying a subject and
>>>knows something without giving it consccicous thought. For example, a
>>>carpenter whose specialty is framing houses will know instinctively when
>>>he looks at a new house being built whether it is framed correctly or
>>>not.
>>>
>>>You mentioned that maintaining tire contact is not as important in an
>>>environment where traction is poor, and someone with an auto engineering
>>>background or who works with cars day in and day out would know without
>>>conscious thought that this statement was incorrect.
>>
>>i disagree. go to any parking lot where there's a big-tired mercedes or
>>bmw that's on full lock. the "outside" tire has the full contact patch
>>flat against the ground. the "inside" tire however is riding up on one
>>edge because the camber is all wrong. this is an "acceptable" situation
>>as, in practice, hardly anyone drives these cars hard enough for it to be
>>a real issue. with 10" [or whatever] of rubber on the side of the car
>>making the most load, who notices? /but/, when you're driving at
>>10/10th's, that extra little bit of rubber on the /inside/ tire that's
>>more correctly positioned can get you through the corner faster than the
>>other guy. my no means are hondas the most powerful cars on the road, but
>>they sure do hang well with the big boys as soon as there's a bend.
>>
>
>
> The effect you're describing about camber changes is not caused by the type
> of suspension, i.e., strut vs. double wishbone.

ok, stop right there. camber doesn't change [much] with struts, but
with wishbones, it can change substantially. check your facts before
making garbage like that up. it's not like you don't have an internet
connection and access to millions of web articles on such stuff.

> It is caused by lots of
> positive caster, like 10 or more degrees, and you will see the same effect
> whether the car has a strut of wishbone suspension if there is lots of
> positive caster.

rubbish. caster is [one way] to create trail. there's no hard rule
differentiating struts and wishbones.

> Another effect of vehicles with lots of positive caster is
> that you will see the front end of the vehicle actually dip when the wheel
> is turned full lock.

that's not just caster guy, that's camber, caster and trail.

> This effect is magnified somewhat by the large wheels
> and tires. Automakers will design lots of positive caster to provide
> straighter tracking, and the tradeoff is slightly less responsive turning.

eh? you have no idea what you're talking about. larger trail provides
more self-centering which is good on a freeway, but makes it /harder/ to
turn the steering wheel - it doesn't make it less responsive. if
anything, the opposite.

>
> <confusing stuff snipped>

no fooling.

>
>>with mcpherson it's the "approximation" that's required for every element
>>of geometry that makes it less than perfect. but it's ok for sedans,
>>cheap, comfy and doesn't roll much. wishbones are better on road where
>>there's greater steering precision possible. disadvantages of wishbones
>>are cost, a little comfort, and the need to address roll since the greater
>>degree of freedom the body has within the system leaves it free to do so.
>>i'd draw a pic, but in ascii it would suck. also consider the fact that
>>mcpherson first came out when bias ply tires were all you could get -
>>again, no need to be precise there!
>
>
> Aaah! What I'm getting from what you're describing is different from what I
> got from your other posts. In your other posts, I got that you were saying
> that strut suspensions offered superior handling to wishbones.

no, re-read what i wrote. i said struts are a successful design for
off-road uses because their shortcomings are less important than they
are on-road.

> What you are
> conveying here is much more accurate than your previous posts - we're on the
> same page now (we probably were before but on different frequencies).

i'm definitely not on the same page as you.

but right now, i don't care. i'm going away for a few days, so knock
yourself out with any face-saving response you like. or maybe you can
use the time to go to the library and do some homework.

"jim beam" <nospam@example.net> wrote in message
news:QYmdnduZ46k9fajZ4p2dnA@speakeasy.net...
> Ray O wrote:
>> "jim beam" <nospam@example.net> wrote in message
>> news:B8KdnXc_2MpsC6nZRVn-iw@speakeasy.net...
>>
>>>>>><snipped>
>>>>>>
>>>>>>>>Every type of suspension system has trade-offs. In the ideal
>>>>>>>>suspension system, the wheel will move up and down perpendicular to
>>>>>>>>the road surface and maintain camber so that the tire maintains
>>>>>>>>maximum contact and traction throughout the limits of wheel
>>>>>>>>movement. Also, designers try to minimize unsprung weight to
>>>>>>>>minimize wheel bounce. In a mass-produced vehicle, cost is a very
>>>>>>>>big factor.
>>>>>>>>
>>>>>>>>A double wishbone suspension does a very good job at maintaining
>>>>>>>>camber throughout its movement because it acts like a pantograph but
>>>>>>>>is more expensive to produce than a strut suspension.
>>>>>>>
>>>>>>>agreed, but i don't see that as a disadvantage for me. there's no
>>>>>>>price differential at the consumer end.
>>>>>>
>>>>>>
>>>>>>What makes you think that there is no price differential at the
>>>>>>consumer end?
>>>>>
>>>>>er, the price i pay when i buy the car?
>>>>
>>>>
>>>>If a double wishbone suspension costs the automaker $50 more than a
>>>>strut suspension, do you think the automaker would put put double
>>>>wishbones in all cars and not pass that cost on to the consumers?
>>>
>>>so what's the price difference between the camry and accord?
>>>
>>>according to edmunds, the base [wishbone] accord is $18225, the [strut]
>>>camry is $18270.
>>>
>>>i therefore re-state, car manufacturers do /not/ sell on a "cost plus"
>>>basis, so the price of parts is irrelevant.
>>>
>>
>>
>> Your comparison of the Camry and Accord would be valid if the suspension
>> type were the only differences between the cars. Toyota and Honda have
>> different cost structures with labor, raw material, plant and corporate
>> overhead, advertising, travel and entertainment, etc. as well as
>> different content, distributor markup, and dealer markup. I am not aware
>> of any vehicle where a strut and a different type of front suspension is
>> availble so it is not easy to make a comparison unless you have a
>> background in how automakers price their vehicles. Trucks offer
>> different front suspensions for RWD and 4WD versions and for different
>> capacities. The Japan market Estima Van had an independent rear
>> suspension and the U.S. Previa van had a live axle, but neither rear
>> suspensions were strut type.
>>
>> Your point is valid in that "cost plus" is not the sole determing factor
>> in vehicle pricing, however, the automaker's cost to produce a vehicle is
>> the starting point in determineing what the final MSRP will be. Market
>> competition plays a big factor as well as market demand. I susect that
>> we're saying the same thing differently.
>
> no, you're just back-tracking.
>
>>
>>
>>
>>>><snipped>
>>>>
>>>>>>You sound like you have read a lot of auto enthusiast magazines but
>>>>>>have not had formal training in automotive design, engineering, or
>>>>>>service or experience working for an auto manufacturer. If you had,
>>>>>>you would know instinctively
>>>>>
>>>>>whoa there!!! let's go out on a wild-ass limb here and speculate that
>>>>>i have some training and experience... wtf has that got to do with
>>>>>instinct???
>>>>
>>>>
>>>>I meant no insult, just an observation, and I apologize.
>>>
>>>ok, no problem.
>>>
>>>
>>>> My intent is to share the experience and knowledge I gained while
>>>> working for an automaker and correct people's misconceptions about how
>>>> cars work. The more people know about their cars, the more realistic
>>>> their expectrations of the car's performance and the more satisfied
>>>> they weill be with their car.
>>>>
>>>> When I said "know instinctively," I meant it from the point of view of
>>>> a professional who spends all day working on and studying a subject and
>>>> knows something without giving it consccicous thought. For example, a
>>>> carpenter whose specialty is framing houses will know instinctively
>>>> when he looks at a new house being built whether it is framed
>>>> correctly or not.
>>>>
>>>>You mentioned that maintaining tire contact is not as important in an
>>>>environment where traction is poor, and someone with an auto engineering
>>>>background or who works with cars day in and day out would know without
>>>>conscious thought that this statement was incorrect.
>>>
>>>i disagree. go to any parking lot where there's a big-tired mercedes or
>>>bmw that's on full lock. the "outside" tire has the full contact patch
>>>flat against the ground. the "inside" tire however is riding up on one
>>>edge because the camber is all wrong. this is an "acceptable" situation
>>>as, in practice, hardly anyone drives these cars hard enough for it to be
>>>a real issue. with 10" [or whatever] of rubber on the side of the car
>>>making the most load, who notices? /but/, when you're driving at
>>>10/10th's, that extra little bit of rubber on the /inside/ tire that's
>>>more correctly positioned can get you through the corner faster than the
>>>other guy. my no means are hondas the most powerful cars on the road,
>>>but they sure do hang well with the big boys as soon as there's a bend.
>>>
>>
>>
>> The effect you're describing about camber changes is not caused by the
>> type of suspension, i.e., strut vs. double wishbone.
>
> ok, stop right there. camber doesn't change [much] with struts, but with
> wishbones, it can change substantially. check your facts before making
> garbage like that up. it's not like you don't have an internet connection
> and access to millions of web articles on such stuff.
>
>> It is caused by lots of positive caster, like 10 or more degrees, and
>> you will see the same effect whether the car has a strut of wishbone
>> suspension if there is lots of positive caster.
>
> rubbish. caster is [one way] to create trail. there's no hard rule
> differentiating struts and wishbones.
>
>> Another effect of vehicles with lots of positive caster is that you will
>> see the front end of the vehicle actually dip when the wheel is turned
>> full lock.
>
> that's not just caster guy, that's camber, caster and trail.
>
>> This effect is magnified somewhat by the large wheels and tires.
>> Automakers will design lots of positive caster to provide straighter
>> tracking, and the tradeoff is slightly less responsive turning.
>
> eh? you have no idea what you're talking about. larger trail provides
> more self-centering which is good on a freeway, but makes it /harder/ to
> turn the steering wheel - it doesn't make it less responsive. if
> anything, the opposite.
>
>>
>> <confusing stuff snipped>
>
> no fooling.
>
>>
>>>with mcpherson it's the "approximation" that's required for every element
>>>of geometry that makes it less than perfect. but it's ok for sedans,
>>>cheap, comfy and doesn't roll much. wishbones are better on road where
>>>there's greater steering precision possible. disadvantages of wishbones
>>>are cost, a little comfort, and the need to address roll since the
>>>greater degree of freedom the body has within the system leaves it free
>>>to do so. i'd draw a pic, but in ascii it would suck. also consider the
>>>fact that mcpherson first came out when bias ply tires were all you could
>>>get - again, no need to be precise there!
>>
>>
>> Aaah! What I'm getting from what you're describing is different from
>> what I got from your other posts. In your other posts, I got that you
>> were saying that strut suspensions offered superior handling to
>> wishbones.
>
> no, re-read what i wrote. i said struts are a successful design for
> off-road uses because their shortcomings are less important than they are
> on-road.
>
>> What you are conveying here is much more accurate than your previous
>> posts - we're on the same page now (we probably were before but on
>> different frequencies).
>
> i'm definitely not on the same page as you.
>
> but right now, i don't care. i'm going away for a few days, so knock
> yourself out with any face-saving response you like. or maybe you can use
> the time to go to the library and do some homework.

We'll have to agree to disagree. I stand by what I said, I assume you stand
by what you said. Have a great trip!
--

Ray O
(correct punctuation to reply)

On Thu, 06 Apr 2006 15:16:51 -0400, Codifus <codifus@optonline.net>
wrote:


>Struts are the wave of the future.


<Retch>

Accords used to use them. Don't any more. I'd like to see someone
accuse Honda of being behind the times.



> Not only are struts less expensive,
>but struts are also more space efficient than double-wishbone
>suspensions.


Maybe. But they distribute the space useage differently.

Advantageous for transverse engines. Possibly less advantageous
without that and with a V type engine. Depends.


> Carmakers can design a roomier cabin and more capacious
>trunk for a car when using struts.


If you want to maximize trunk space with front wheel drive you use a
beam axle and leaf springs. So there! And I recall the Renault
Alliance has a very roomy trunk for the size of the car... IRS, too...
transverse torsion bars.

>
>
>A sign that struts have come along is that the new BMW 3 series uses
>them.

BMWs have used struts for a long time. Its nothing recent.


>If they're good enought for "the ultimate driving machine" then
>they are quit good now. Take note on how the 3 series is now a much
>roomier car and it is still quite a driving machine.


They're good enough for the customers who believe its the ulitmate
driving machine. Not quite the same.

jim beam wrote:


>
> what an utterly stupid comment. bmw do many things, including seal
> their transmissions so the fluid cannot be changed, design their crumple
> zones so "early" deformation occurs in parts of the shell that render
> the vehicle irreparable, etc. but because they label themselves with a
> catchy advertising tag-line, whatever they do /has/ to be good? complete
> carp.
>
>> Take note on how the 3 series is now a much roomier car and it is
>> still quite a driving machine.
>>
>> CD

Perhaps I didn't make myself clear. BMW has quite reputation, which I
agree with, for making a driver's car, so the slogan fits. I don't buy
into marketing. The fact that they have used a strut to make high
performance driver's car says alot about what can be done with a strut.
Wishbones are better, but struts have closed the gap, asswipe.

CD

edward ohare wrote:
> On Thu, 06 Apr 2006 15:16:51 -0400, Codifus <codifus@optonline.net>
> wrote:
>
>
>
>>Struts are the wave of the future.
>
>
>
> <Retch>
>
> Accords used to use them. Don't any more. I'd like to see someone
> accuse Honda of being behind the times.
>
Honda isn't behind the times. Honda beleives in making the best handling
FWD car, so they went for the wishbones. The Acura TL is acknowledged as
the best handling FWD sedan out there. Compared to its pseudo arch
enemy, the Nissan Maxima, the Maxima is a much roomier car, about the
same power, and handles not as well as the TL. Maxima uses struts and
Honda uses wishbones.

>
>
>
>>Not only are struts less expensive,
>>but struts are also more space efficient than double-wishbone
>>suspensions.
>
>
>
> Maybe. But they distribute the space useage differently.
>
> Advantageous for transverse engines. Possibly less advantageous
> without that and with a V type engine. Depends.

In the examples above, both have V6 engines. The wishbone car is not as
roomy as the strut car.
>
>
>
>>Carmakers can design a roomier cabin and more capacious
>>trunk for a car when using struts.
>
>
>
> If you want to maximize trunk space with front wheel drive you use a
> beam axle and leaf springs. So there! And I recall the Renault
> Alliance has a very roomy trunk for the size of the car... IRS, too...
> transverse torsion bars.
>

There are always exceptions, and the beam axle, the way Nissan did with
the 95-03 Maxima or Infinit G20 was not such a bad thing. I actually
like it. Fact is, when you compare the strut to the ideal, the wishbone,
the strut is catching up, and because of all strut's other advantages,
it will take over.

>
>>
>>A sign that struts have come along is that the new BMW 3 series uses
>>them.
>
>
> BMWs have used struts for a long time. Its nothing recent.
>
>
>
>>If they're good enought for "the ultimate driving machine" then
>>they are quit good now. Take note on how the 3 series is now a much
>>roomier car and it is still quite a driving machine.
>
>
>
> They're good enough for the customers who believe its the ulitmate
> driving machine. Not quite the same.

BMWs, especailly cars like the M3 and M5, have long been recognized as
extremly high performance driving machines. People buy BMWs for that
reason, even if probably some 90% wont' even drive them for the driving
machine that it is. The fact this BMWs are recognized by real drivers as
driver's cars, not those customers who have to keep up with the Jones's.
That says alot about how they build their cars: the engines and
suspensions being paramount components. BMW has kept the spirit of the
driving machine whilst using a strut. I find that impressive about what
can be done with a strut.

CD