Why Front Wheel Drive Sucks (And Why Rear Wheel Drive Is Coming Back)

Started by Thorin, December 10, 2006, 10:41:30 PM

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Mr. Analog

Quote from: Ustauk on December 12, 2006, 01:38:45 PMYup, I knew going in they were oversized, but I was too cheap to buy smaller rims, and I did like the way they looked as well.  The tires were brand new when I bought them, and I haven't put that many kilometres on them, so I think it should be ok.

I am deeply concerned for your safety on the highway with the tires you have. You or your family have not been stuck out on the highway before I take it, well I can say from personal experience that it is not pleasant, even in the summer, with a cell phone. You will get towed to the nearest town and (if my experience was typcial) get soundly gouged by the local mechanics for replacement tires + any additional damage to your vehicle that might be required to make it roadworthy.

Sure, AMA did the towing and insurance eventually paid for most things but it takes hours out of your day and, more importantly, it can be potentially fatal to be driving on unsafe tires (the metal was almost showing on both tires in our case).

So consider this; for a mere $450 you can get new all-season tires, installed+balanced at Costco (or wherever) and ensure your own personal safety.
By Grabthar's Hammer

Shayne

Sounds like he is fine with potentially injuring himself and others.

Thorin

Quote from: Ustauk on December 12, 2006, 01:38:45 PM
Yup, I knew going in they were oversized, but I was too cheap to buy smaller rims, and I did like the way they looked as well.

No, you shouldn't have to buy different rims - your car is supposed to have 14" rims and it does; I'm willing to bet the rims are even the expected 6" width.  It's just the tires that are oversized (and not by a lot, but apparently enough to allow rubbing against other parts of the car).  Melbosa, the rims he has on his car, are those actual Celica rims?  I can't remember what they look like.

It's also possible that the bumpstop for the springs has worn out and is allowing the springs to allow the tires too close to the wheel well, or that the springs were shortened by whomever owned the car before and therefore the tires touch the wheel well under heavy load.  It's even possible that the metal that the springs are mounted against has given way a bit and therefore at full compression the springs aren't sticking down far enough.

Quote from: Ustauk on December 12, 2006, 01:38:45 PM
The tires were brand new when I bought them, and I haven't put that many kilometres on them, so I think it should be ok.

Under normal use tires generally last as long or longer than their tread wear warranty.  However, rubbing against the wheel well is not considered normal use, and it definitely causes tires to wear out much quicker.  If it's rubbing enough to heat up to the point that you can smell the tires, a *lot* of the tread has been melted away.  I will add here that I am speaking from direct experience; this is not just conjecture.
Prayin' for a 20!

gcc thorin.c -pedantic -o Thorin
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Melbosa

Quote from: Thorin on December 12, 2006, 03:05:41 PM
Melbosa, the rims he has on his car, are those actual Celica rims?  I can't remember what they look like.

No actually the rims on his car are Mags and not the originals for a Celica.  Even then, most Celica owners opted to find rims from a Supra of the same year as the spoke layout is the same, and the rims on the Supra are by default are wider and Mags.  As to the width of the Mag, that I am not sure.

Quote
It's also possible that the bumpstop for the springs has worn out and is allowing the springs to allow the tires too close to the wheel well, or that the springs were shortened by whomever owned the car before and therefore the tires touch the wheel well under heavy load.  It's even possible that the metal that the springs are mounted against has given way a bit and therefore at full compression the springs aren't sticking down far enough.

Actually last time we had it in the shop we took a look at the struts in the front and rear and they were still in great shape.

QuoteUnder normal use tires generally last as long or longer than their tread wear warranty.  However, rubbing against the wheel well is not considered normal use, and it definitely causes tires to wear out much quicker.  If it's rubbing enough to heat up to the point that you can smell the tires, a *lot* of the tread has been melted away.  I will add here that I am speaking from direct experience; this is not just conjecture.

This is definately true.  Although the rubbing that happens on Ust's car is a result of the wheel well plastic skirt under the metal quarter panel, and isn't the panel itself.  More likely his tire will eventually rip or wear the plastic than melt the tire under the heat.
Sometimes I Think Before I Type... Sometimes!

Ustauk

Quote from: Melbosa on December 12, 2006, 03:27:15 PM
This is definately true.  Although the rubbing that happens on Ust's car is a result of the wheel well plastic skirt under the metal quarter panel, and isn't the panel itself.  More likely his tire will eventually rip or wear the plastic than melt the tire under the heat.
Is this likely to happen imminently?  Should I be replacing my tires and rims with something more appropriate to the car, as suggessted here, Mel?  I'm thinking of taking in my car to the place I got the tires for rotation on Saturday.  Hopefully they can give me an honest opinion on whether they need to be replaced, though there job is to sell tires, so I don't know.  I only smelled rubber that one time going to Lazy's place, with a really full load.  That's the exception, not the norm.  I'll investigate further, and get back to you guys.

Thorin

Quote from: Cova on December 12, 2006, 02:01:38 PM
As for the original subject, I didn't bother to read the article, but yes RWD is ALWAYS better than FWD in all situations (except stupid examples designed to make it bad eg. stopped with only rear-wheels in an icy hole).

Boo for not reading the linked article first.  The point of the article was that RWD produces a more pleasant driving sensation than FWD due to the differences in design (balance, etc).  Don't say "ALWAYS" and then say "except"; it's like begging me to point out all the exceptions to the statement :P  Basically, both drive configurations can be horribly botched with poor engineering of the drivetrain and suspension components.  And you have to admit, in Edmonton's thick snow blanket FWD is easier to use than RWD, especially when trying to start off at icy intersections or crawl your way through slushy, squishy, deep snow.  Given that we have icy intersections and snow at least three months of the year average, this means that FWD is better at least one-quarter of the time.

Quote from: Cova on December 12, 2006, 02:01:38 PM
Tire diameter is really irrelevant as far as traction is concerned - ground clearance is the only thing affected.

The issue of tire diameter was raised precisely because ground clearance is affected, and ground clearance has a distinct effect on traction as soon as it is not enough to clear an obstacle.  That is, as soon as you put the car on top of an obstacle that doesn't let the tires touch the ground, you have zero traction.  Now, if you need only 1" more ground clearance and you put on tires that reduce your ground clearance by 2", then the choice of tire diameter has a profound and measurable effect on your traction in that particular situation.  Given that we were discussing winter driving with deep snow, this scenario is entirely possible.

Quote from: Cova on December 12, 2006, 02:01:38 PM
In the summer on wet/dry surfaces you typically want a wider tire.  On snow/ice you typically want a narrower tire.

Lets qualify this a bit.  Generally, wider tires help you corner better while narrower tires give you better straight-line traction.  If you'll be racing in a straight line, you *don't* want wide tires even if it's on dry pavement.  Think about those top alcohol dragsters.  Their tires look wide, but as soon as they spin up they get horribly skinny.  Because the tires have such low pressure and such a large circumference, though, they still have a huge contact patch to apply torque against the ground.  However, in our day-to-day driving cornering is a much more important ability, so for day-to-day driving on dry surfaces wider tires are better.

I will point out again, though, that a wide Blizzak with crushed almonds and buttery rubber that stays soft at -20 will give you better traction in the winter than a skinny summer tire.  The rubber composition, tread layout, siping, and other items I mentioned before have a profound impact on the ability of the tire to grip - if it were just the width of the tire that mattered, I'd put bicycle tires on all four corners and laugh at everyone who gets stuck.

----

Thanks to those that did make the effort to read the article and indicate whether they agree with its principal point: that RWD produces a more pleasant driving sensation than FWD, even at regular speeds.
Prayin' for a 20!

gcc thorin.c -pedantic -o Thorin
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Mr. Analog

Quote from: Melbosa on December 12, 2006, 03:27:15 PMthe rubbing that happens on Ust's car is a result of the wheel well plastic skirt under the metal quarter panel, and isn't the panel itself.  More likely his tire will eventually rip or wear the plastic than melt the tire under the heat.

The last time we picked up Tom with the windows down we could definately smell burnt rubber after hitting bumps or railroad tracks, up until then I didn't really think about it.
By Grabthar's Hammer

Thorin

Quote from: Ustauk on December 12, 2006, 03:35:41 PM
Hopefully they can give me an honest opinion on whether they need to be replaced, though there job is to sell tires, so I don't know.

You could look for yourself.  There are indicators in the tread that if you see them, you know that you're getting close to the legal minimum tread thickness allowed.  They go across the channels in the tire, between the tread blocks (the raised parts of the tread).  If it looks like tread blocks are connected by skinny little bits of rubber across the channels, and the tread blocks and the indicators are the same height, your tires are definitely worn out.  If you can't tell, you can still ask the people at the shop.  Yes, there's the chance they're going to tell you yes when the answer is no, but you'll have to *assume* that they're not trying to rip you off (otherwise why take your car there at all?).  I still think you shouldn't need new rims, just new tires (if they're worn down enough for the indicators to be visible).  But I don't know the actual width of your rims, so I can't say for-sure-for-sure.

Quote from: Ustauk on December 12, 2006, 03:35:41 PM
I only smelled rubber that one time going to Lazy's place, with a really full load.

I used to drive a Suzuki Swift.  Same as the Chevy Sprint and Pontiac Firefly (well, almost; the sprint had the 55hp 1.0L 3 cylinder engine, the Firefly had the 68hp 1.0L 3 cylinder turbo, the Swift had the 70hp 1.3L 4 cylinder engine; but the body's the same).  I folded down the back seats and put eight adults in there, for a total of about 1,300lbs (way over the maximum payload capacity).  The original tires *did not rub*.  I bought wider tires that had roughly the same circumference, put them on steel wheels intended for a RWD, and put five adults in the car (about 900lbs).  Sure enough, they rubbed, but it was because the rims stuck out to far and the edge of the wheel well was getting the edge of the tire.  I bought FWD rims and put the wider tires on them, then ended up with seven adults in the car (about 1,100lbs).  The rubbing no longer happened.  The springs in the back bottomed out over bumps (as they did with the original tires as well), and everybody's butt hurt when I went over the tracks at 80km/h, but the tires *did not rub*.  And they really shouldn't.  But like I said in a previous post, it could be something other than the tire height...
Prayin' for a 20!

gcc thorin.c -pedantic -o Thorin
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Melbosa

Quote from: Ustauk on December 12, 2006, 03:35:41 PM
Is this likely to happen imminently?  Should I be replacing my tires and rims with something more appropriate to the car, as suggessted here, Mel?  I'm thinking of taking in my car to the place I got the tires for rotation on Saturday.  Hopefully they can give me an honest opinion on whether they need to be replaced, though there job is to sell tires, so I don't know.  I only smelled rubber that one time going to Lazy's place, with a really full load.  That's the exception, not the norm.  I'll investigate further, and get back to you guys.

You can check your tires yourself for wear.  If they are rubbing, it will be very evident on the side walls.  If your not bottoming out (i.e. your tires are hitting the top of the car over bumps), and that you would feel in the steering as well as a very hard bump, you should be fine.  Rubbing on the side walls will show very easily on tires and be very evident if the damage is bad.

As for your struts, just jump on the bumper in each corner of your car.  If it settles easily each time(stops bobbing somewhat fast) then your struts and springs should be fine.  If the car continues to bob for 2 or three times quite noticably, you should get it down to the shop to be looked at.  Basically you would feel this in the front of the car if it was one of them, the steering would jerk when going over a bump.  In the back you would find that you rear would kick out to the bad side when doing a tight turn or joing over a bump.

The guys at the shop are very good (talking Autoya now), and wouldn't let you be driving something unsafe.  It's their ticket on the line if they sold you a vehicle, passed its safety, and then you had an accident to find out your tires weren't safe to ride on.

As for the tred, follow Thorin's advice.
Sometimes I Think Before I Type... Sometimes!

Cova

Quote from: Thorin on December 12, 2006, 03:36:52 PM
Quote from: Cova on December 12, 2006, 02:01:38 PM
As for the original subject, I didn't bother to read the article, but yes RWD is ALWAYS better than FWD in all situations (except stupid examples designed to make it bad eg. stopped with only rear-wheels in an icy hole).

Boo for not reading the linked article first.  The point of the article was that RWD produces a more pleasant driving sensation than FWD due to the differences in design (balance, etc).  Don't say "ALWAYS" and then say "except"; it's like begging me to point out all the exceptions to the statement :P  Basically, both drive configurations can be horribly botched with poor engineering of the drivetrain and suspension components.  And you have to admit, in Edmonton's thick snow blanket FWD is easier to use than RWD, especially when trying to start off at icy intersections or crawl your way through slushy, squishy, deep snow.  Given that we have icy intersections and snow at least three months of the year average, this means that FWD is better at least one-quarter of the time.

No - I don't have to admint that a thick snow blanket makes FWD better, because it doesn't.  When starting off at an icy intersection it may be benificial to have more weight over the drive tires - the problem is poor weight balance of the car, balance doesn't seem to be considered by vehicle makers except in performance vehicles where it affects cornering performance.  The fronts are responsible for steering, the rears (or all) for acceleration, every contact-patch with the road has a purpose - FWD gives too much responsibility to your front two contact-patches, and makes the rears useless for anything other than keeping the back of the car off the ground.  RWD allows you to maintain steering control even when too much power is applied, and if yer good allows extra steering control with your foot.

Quote from: Thorin on December 12, 2006, 03:36:52 PM
Quote from: Cova on December 12, 2006, 02:01:38 PM
In the summer on wet/dry surfaces you typically want a wider tire.  On snow/ice you typically want a narrower tire.

Lets qualify this a bit.  Generally, wider tires help you corner better while narrower tires give you better straight-line traction.  If you'll be racing in a straight line, you *don't* want wide tires even if it's on dry pavement.  Think about those top alcohol dragsters.  Their tires look wide, but as soon as they spin up they get horribly skinny.  Because the tires have such low pressure and such a large circumference, though, they still have a huge contact patch to apply torque against the ground.  However, in our day-to-day driving cornering is a much more important ability, so for day-to-day driving on dry surfaces wider tires are better.

I will point out again, though, that a wide Blizzak with crushed almonds and buttery rubber that stays soft at -20 will give you better traction in the winter than a skinny summer tire.  The rubber composition, tread layout, siping, and other items I mentioned before have a profound impact on the ability of the tire to grip - if it were just the width of the tire that mattered, I'd put bicycle tires on all four corners and laugh at everyone who gets stuck.

If you are drag racing, you want the widest rear tires that will fit in your wheel-wells without rubbing, while taking into consideration the weight of all that rubber will require more power to spin.  Those top-fuel dragsters still have very wide tires even while they are spinning - the large circumference will slightly increase the contact-patch length, but not nearly as much as you can easily increase the width by just using a wider tire.  The reason they have very soft tires that expand so much on those dragsters is so that the hub can twist close to 1/4 of a rotation ahead of the contact-patch - that acts as a kind of shock-absorber for acceleration and allows them to immidiatly apply huge amounts of torque without breaking friction - the moment friction breaks the tire will continue to spin until the driver gets off the gas, by which point the race is already over cause the other guy won.

And don't try and change what I said to imply that having a narrow tire is the most important thing in winter - obviously compound and tread-pattern are far more important.  However in the summer you typically want to maximize the contact-patch with the road - therefore wider tires.  In the winter you want to cut down through snow, such that when cornering you can actually use the sides of the tires against the ruts you form to help control your direction.  It also increases the amount of weight per square inch on your contact patch, which helps whatever studs you may have grip in ice (studs being anything from real studs, walnuts or other "chunky" compounds built into the rubber, or just all the gravel on the road / gravel stuck in your tread pattern).

For a real-world example, on my car I run 225/50R16's in the summer, and I believe a 195/65R15 in the winter.  And if I remember right, the stock tires for my car were 205/55R16.  And I know that both my summers and winters are within 5% of the outside diameter of the stock tires for my car, so my speedo/odometer are still reasonably accurate.

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Ustauk:  Go look at your tires.  If you can see on them by the wear where they are rubbing you have a problem.  If not (and they aren't just freshly put on) then you don't have a problem.