Saw Something Weird Today (Auto)

[Keebler Elf]

On the road today I saw a Jeep, not sure of the exact model but it was one of the four doors, and both rear tires were noticeably slanted inwards towards the top. I did a double take because it looked so fucked up. It was a noticeable slant inwards and both tires were leaning in towards each other at the top so neither wheel was perpendicular to the ground.

Is it supposed to look like that and if not WTF is up with that?

The car was showing severe signs of rust around the wheel wells so maybe it's just poorly maintained but the slant was so noticeable (and a mirror image on both sides) that it almost looked like it was supposed to be that way.

Anyone know what's up with this?

 

[FAST]

An accident waiting to happen.

Should be taken off the road,... a lot of obvious negative camber in the rear,... is a good sign of major structural problems.

did you happen to notice if it had snow tires on,...

 

[AJstar]

Should be taken off the road,... a lot of obvious negative camber in the rear,... is a good sign of major structural problems.

did you happen to notice if it had snow tires on,...

This sounds like it was customized on purpose as opposed to structural wear damage.
Although I am not an expert on how that would effect the cars handling control.

 

[Promo]

Other than the last few years of Grand Cherokees, I believe Jeeps up until ~2014-15 are solid rear axle (live axle). Was it a fairly new model? Was it one of the boxy models?

Solid rears are considered by enthusiasts to be superior for off-roading. A solid rear axle allows almost no negative camber (https://en.wikipedia.org/wiki/Camber_angle) to be dialed in. I can't imagine what "structural problems" short of a severely bent axle (which would no longer function), would allow this. A worn ball joint will cause a slight NC, but it's almost unnoticeable.

That said there are lots of aftermarket kits available for swapping out the Jeep rear axle with an Independent Rear Suspension (IRS). This set-up would certainly allow for negative camber.

Why do it? Most people do it to improve handling and/or for appearance. Have a look at the rear of a M series BMW and you'll notice this is how the car is configured from the factory. Too much negative camber limits traction, increases tire wear and can impact ABS and steering.

 

[thumper18474]

I see it more on the mini road rockets ..as we call them
mazda3
honda civics and so on...improves cornering
why they do it on a Jeep?? have no clue

 

[Promo]

why they do it on a Jeep?? have no clue

In the southern states there is a huge market for modded Jeeps especially lowered with IRS set-ups. Same with pick-up trucks.

Funny, 20 years ago it was all about raised chassis with giant tires.

 

[FAST]

I see it more on the mini road rockets ..as we call them
mazda3
honda civics and so on...improves cornering
why they do it on a Jeep?? have no clue

There is no advantage to adding a lot of negative camber to the rears only,... other than some think it looks cool,... and would actually create unpredictable handling.

And a lot visual camber,... is pretty much impossible to achieve with a solid axel,... so the Jeep OBVIOUSLY had independent rear suspension,... .

Increasing negative camber is advantageous only if one is doing a lot of high G cornering,... I doubt a Jeep is being used for that.

Were you will see a lot of negative camber,... is on the FRONT of FWD cars at race tracks,... because FWD understeer like pigs when cornering at high G without.

 

[Keebler Elf]

I doubt it was an intentional mod because the vehicle had visible rust on it, not the kind of vehicle you would mod up.

The slant was so noticeable on both wheels that I couldn't help but think of the unequal wear patterns it would put on the tires.

 

[simcity]

In my racing days, not too long ago, negative chsmbering does help with cornering but on a Jeep it’s either old mod for looks or a Jeep that should be taken off the road. I don’t think many off road high flying trucks have even a 2% negative chamber. On another note, im looking for a used Jeep but always heard they had some issues. Any suggestions on year and model I should be looking for

 

[Promo]

Based on Keebler's latest post, most of the below probably doesn't apply, but:

There is no advantage to adding a lot of negative camber to the rears only,... other than some think it looks cool,... and would actually create unpredictable handling.

The optimum negative camber allows maximum grip and therefore best handling. Too much results in less grip. Drifters dial-in optimum camber in the front and excessive camber in the rears. Yes, people use jeeps and pick-up trucks in drifting competitions, mostly for crowd thrill. But the same principal holds true for drivers that like to slide the rear through turns, I know several people who have their car set-up that way. Have you looked at a BMW M3, much more NC in the rear than the front. I can provide numerous other examples.

And a lot visual camber,... is pretty much impossible to achieve with a solid axel,... so the Jeep OBVIOUSLY had independent rear suspension,... .

That was my original point, but:
1) Keebler said: "the vehicle had visible rust on it, not the kind of vehicle you would mod up.". This implies it is an older jeep. The Jeep didn't get IRS on the Grand Cherokee until approx 2011-2012 and the boxy Wrangler-style until approximately 2015. This means either this vehicle had significant problems (which I doubt as a solid axle wouldn't allow for this much negative camber) or the jeep was modded, which is unlikely as it sounds like a junker.
2) In post #2 you said "Should be taken off the road,... a lot of obvious negative camber in the rear,... is a good sign of major structural problems", so you changed your mind since that post?

Were you will see a lot of negative camber,... is on the FRONT of FWD cars at race tracks,... because FWD understeer like pigs when cornering at high G without.

Sort-of-half-true. Skilled teams know it's a combination of driver skill, front and rear tire size, suspension type, suspension settings, tire pressure, etc. A skilled driver will position himself properly on the turn and apply power earlier to overcome FWD's tendency to understeer. My point, they dial in OPTIMUM negative camber.

 

[Promo]

I doubt it was an intentional mod because the vehicle had visible rust on it, not the kind of vehicle you would mod up.

The slant was so noticeable on both wheels that I couldn't help but think of the unequal wear patterns it would put on the tires.

If I understand everything correctly; you are saying is this was a older, kind-of junky Jeep with no obvious signs of mods (lowered, wide tires, in-your-face shocks, underbody ladder braces, etc). Assuming it wasn't a Grand Cherokee and it was many years old (as hinted by the rust comment), it likely wasn't a factory IRS vehicle. Since a solid axle cars, even with worn ball joints, only allows for a few degrees of camber .... so, without seeing the car myself, I have no explanation or experience for what you saw. As a muscle car fan and car modder, you've peaked my curiosity though. ;-)

In the US, "rat rods" are a big thing these days. These are hot rod style vehicles that owners modify for high performance, but intentionally make them look like beat-up rust buckets. The hobby has expanded to include other types of cars/trucks.
https://www.google.ca/search?q=rat+...Ws8HYAhXp6YMKHS7MCMAQsAQIJg&biw=2133&bih=1054

 

[FAST]

In my racing days, not too long ago, negative chsmbering does help with cornering but on a Jeep it’s either old mod for looks or a Jeep that should be taken off the road. I don’t think many off road high flying trucks have even a 2% negative chamber. On another note, im looking for a used Jeep but always heard they had some issues. Any suggestions on year and model I should be looking for

Agreed,... even 2% negative camber on a solid rear axel is pretty much impossible,... as it is not adjustable.

Plus as you no doubt know,... but some don't seem to understand,...negative camber only increase cornering grip,... but actually decreases straight line grip/acceleration.

PS: Do you do any "racing" on a computer ?

 

[shack]

I have noticed that wheelchairs used for athletics have their wheels in tilted toward the top. Would there be some kind of correlation as to why the chairs have them and what OP saw? Just askin'.

 

[thumper18474]

I have noticed that wheelchairs used for athletics have their wheels in tilted toward the top. Would there be some kind of correlation as to why the chairs have them and what OP saw? Just askin'.

same as for cars..better stability and cornering

 

[FAST]

same as for cars..better stability and cornering

Not completely true,... less neg. camber would make a car more stable.

Agreed that more neg. amber, would enable a car to achieve higher cornering forces,... but is rarely achieved on the street.

But unless a car is pushed to high limits of cornering,... more neg. camber will simply wear out the inside of the tread earlier.

Also in the case of wheel chairs, a lot is gained by the lowering of the center of gravity from the neg. camber.

No doubt you may see a post from a certain scum, who thinks simply talking about a subject, but never actually partaking in, is all it takes for him to proclaim he is a self proclaimed expert,... but will post a reply consisting of mostly childish insults anyway.

 

[Promo]

Yet another mis-informed post from FAST! Anyone surprised?

Also in the case of wheel chairs, a lot is gained by the lowering of the center of gravity from the neg. camber.

Completely wrong: Negative camber is designed to provide additional stability in wheelchairs, aid ergonomically in the driver's push and improve turning. There is absolutely no gain from lowering the center of gravity, because the design of the wheelchair is not lowered. <rolleyes>. Even if it was lowered, would 2-5 mm make much of a difference at walking speeds?
"Negative camber provides increased wheel track and thus provide better stability. It also provides better cornering while turning the wheelchair around. ... .", "A manual driver needs to push the wheels forward if camber is not present which is difficult. By providing camber the person can drive it even by providing a downward push which is easy to give as gravit favours him. Thus ergonomically also it is better to drive."
http://www.usatechguide.org/articledisplay.php?artid=23
http://www.rollrev.com/learn/wheelchair-camber-what-is-it-and-why-does-it-matter
http://ablemagazine.co.uk/buyingguide/sports-wheelchairs/
https://www.quora.com/Why-do-wheelchairs-have-slanted-wheels

Not completely true,... less neg. camber would make a car more stable.

Miss-information: A few degrees (<2) of negative camber would improve almost any car's stability for both turns and straight-line performance. Too much will cause tracking problems on uneven roads, or when transitioning the road crown and increase wear. Several manufacturers design tires to operate with more negative camber (Pirelli PZero and Michelin Sport Pilot) for use in high performance cars.
http://en.intraxracing.nl/techniek/camber,-caster,-toe-intoe-out/
http://dsportmag.com/the-tech/extracting-handling-performance-alignment-settings/
http://yospeed.com/wheel-alignment-explained-camber-caster-toe/

Agreed that more neg. amber, would enable a car to achieve higher cornering forces,... but is rarely achieved on the street.

Absolutely wrong. Well maybe if you are a 70 year old man who rarely drives above 40km an hour FAST - lol. Car manufacturers like Porsche, Jag, Ferrari, etc. count on it, even at lower speeds.

But unless a car is pushed to high limits of cornering,... more neg. camber will simply wear out the inside of the tread earlier.

Half true. Depends on the car and the tire. Many manufacturers of higher performance cars build in negative camber and equip performance tires. Porsche, Cadillac, Lotus, Ferrari, Lexus even Infiniti (every Grandpa's brand).

No doubt you may see a post from a certain scum, who thinks simply talking about a subject, but never actually partaking in, is all it takes for him to proclaim he is a self proclaimed expert,... but will post a reply consisting of mostly childish insults anyway.

Straight to the insults eh FAST? I've backed-up everyone of my statements with proof. Where's your proof? FAST, your info is very out-of-date or outright wrong. Why bull-sh*tting all the time?