Why 4Runner isn't rollover prone like Lexus GX

[dekeman]

Autoblog just posted this interesting bit about why the 4Runner isn't as rollover prone as the Lexus GX 460.

Not surprising, it's because the Lexus is too heavy. But this may kill any notion of getting a V8 back in the 4Runner in the near future.

Why the Lexus GX may be rollover-prone (and the 4Runner isn't) — Autoblog

 

[Grape Ape]

I think it's sad that they had to stop selling them because there are so many bad drivers who don't know cornering 101.

 

[fxoffroad]

I think it's sad that they had to stop selling them because there are so many bad drivers who don't know cornering 101.

Sad? Seriously? :happens:


It's sad that Toyota/Lexus didn't do more testing before they started selling the vehicle. That's sad. And its great that the 4Runner isn't included. Amen.

 

[Grape Ape]

Sad? Seriously? :happens:

Not really as sad as it is absurd. Everything is so protective now, the idiot proofing of America is making dimwits more and more acceptable. They never learn anything, they just rely on someone else making things work to the lowest common denominator of society.

 

[T4Fun]

anyone here know what the weight distribution is of the 4runner. i assume its something like 60% front 40% rear??? i am sure this had something to do with back end spinning out on the gx

 

[M1911]

I think it's sad that they had to stop selling them because there are so many bad drivers who don't know cornering 101.

I disagree. Consumer Reports does the same procedure on every vehicle that they test. Only the GX460 performed that badly, and the tested dozens of other SUVs.

Trailing throttle oversteer, within limits, can be fun in a sports car or sports sedan. It is neither fun nor safe in a top-heavy SUV.

anyone here know what the weight distribution is of the 4runner. i assume its something like 60% front 40% rear??? i am sure this had something to do with back end spinning out on the gx

Consumer reports tested dozens of SUVs and trucks, many of which likely have similar weight distributions as the GX460. Those other trucks did better. Furthermore, vehicles most prone to lift-throttle oversteer are those with rear engines and most of the weight over the rear wheels -- early 911s, Corvairs, VW Beetles. Weight distribution is part of it, but suspension design and tuning is another (along with tuning of the ESC).

This behavior is not inherent to all trucks. The GX460 really does have a problem and Toyota can fix it.

 

[philsey]

CNN this morning is reporting Toyota has stopped production on the GX 'til they determine the problem.

 

[westwind77]

Anyone who has driven a a new 4R in the snow KNOWS that is not a problem for us! I have TRIED to kick the rear end around in the snow (testing how the VSC performs) both at slow speed and high speed (empty parking lots) and as soon as the 4R starts to swing the VSC QUICKLY puts it right back on track.

 

[philsey]

Anyone who has driven a a new 4R in the snow KNOWS that is not a problem for us! I have TRIED to kick the rear end around in the snow (testing how the VSC performs) both at slow speed and high speed (empty parking lots) and as soon as the 4R starts to swing the VSC QUICKLY puts it right back on track.

WHAT! No more donuts?? Dang, I could make my Pathfinder do 360's like a pro. In a parking lot of course.

 

[Fuzion]

Tokyo Drift 2? arty:

 

[SeattleMike]

CNN this morning is reporting Toyota has stopped production on the GX 'til they determine the problem.

That only means more 4Runners get built

 

[westwind77]

WHAT! No more donuts?? Dang, I could make my Pathfinder do 360's like a pro. In a parking lot of course.

Well....if you want to do them you can....just press and hold the TRAC button for 3 sec and VSC turns off and hang on What can I say, I like to play in the snows sometimes!

 

[M1911]

Anyone who has driven a a new 4R in the snow KNOWS that is not a problem for us! I have TRIED to kick the rear end around in the snow (testing how the VSC performs) both at slow speed and high speed (empty parking lots) and as soon as the 4R starts to swing the VSC QUICKLY puts it right back on track.

Well, this isn't about heavy throttle input causing oversteer, this is about trailing throttle oversteer. Two different behaviors.

 

[westwind77]

Well, this isn't about heavy throttle input causing oversteer, this is about trailing throttle oversteer. Two different behaviors.

The reason why it happens is a moot point. It could happen because of rain, snow, ice, heavy throttle or trailing throttle, the VSC system takes input from the steering position relative to the actual direction of the 4R, sensing yaw, etc. The VSC system in the L should kick in the split second the rear of the L starts to slide out, the steering has not changed but the yaw has dramatically changed, that is how it works in the 4R, and works well! I watched the video and was amazed the system did not kick in.

 

[dekeman]

Toyota said Thursday they are now going to test ALL their SUVs for this problem. That's part PR, for sure, but it probably means they're going to overreact and make the stability so sensitive so that it cuts in at the slightest bit of upset. Good grief.

 

[M1911]

The reason why it happens is a moot point. It could happen because of rain, snow, ice, heavy throttle or trailing throttle, the VSC system takes input from the steering position relative to the actual direction of the 4R, sensing yaw, etc. The VSC system in the L should kick in the split second the rear of the L starts to slide out, the steering has not changed but the yaw has dramatically changed, that is how it works in the 4R, and works well! I watched the video and was amazed the system did not kick in.

I disagree.

In any vehicle that is RWD (or 4WD with a bias in torque to the rear), if you give it heavy enough throttle input mid-corner (and the ESC and traction control let you), you can break the rear wheels away and thus slide the rear out. Doing so does not involve weight shift and thus is not really a function of suspension design and tuning.

But this is not about power-on oversteer, it is about power-off oversteer, when you lift off the throttle in mid-corner. In trailing throttle oversteer, the behavior of the suspension during the weight shift from rear to front is critical. Yes, the ESC should have intervened earlier and more forcefully. But if the suspension was designed and tuned better, the truck wouldn't have had such a significant tendency to lift-throttle oversteer in the first place.

If you take most vehicles, turn off the ESC, and try the same maneuver, the vehicle will just continue to understeer. Sporty cars might gently tighten their lines.

 

[westwind77]

I disagree.

In any vehicle that is RWD (or 4WD with a bias in torque to the rear), if you give it heavy enough throttle input mid-corner (and the ESC and traction control let you), you can break the rear wheels away and thus slide the rear out.

Maybe, but...as soon as the rear wheels start to slide out the VSC should (and do in the 4R) kick in within a split second to stop that from happening. The rear of the vehicle should NEVER be able to 'slide out' with a properly functioning VSC system. Sure, you can break the tires free (with TRAC off), burn them to the rim, as long as the vehicle remains 'in-line' the system will not kick in, only when 'drift' is detected. (no Tokyo drift with the 4R with VSC active)

But this is not about power-on oversteer, it is about power-off oversteer, when you lift off the throttle in mid-corner. In trailing throttle oversteer, the behavior of the suspension during the weight shift from rear to front is critical. Yes, the ESC should have intervened earlier and more forcefully. But if the suspension was designed and tuned better, the truck wouldn't have had such a significant tendency to lift-throttle oversteer in the first place.If you take most vehicles, turn off the ESC, and try the same maneuver, the vehicle will just continue to understeer. Sporty cars might gently tighten their lines.

I'm not getting into the oversteer/understeer/suspension, you could be right on the poor design of that, however, it should not matter how poorly that is designed because once the VSC system 'feels' a problem it should activate and correct it, but that is not happening with the L's.

 

[M1911]

I'm not getting into the oversteer/understeer/suspension, you could be right on the poor design of that, however, it should not matter how poorly that is designed because once the VSC system 'feels' a problem it should activate and correct it, but that is not happening with the L's.

I agree that the ESC system should kick in faster and correct the oversteer. And I'm guessing that Toyota's fix will be to reflash the ESC to do just that.

But if Toyota had designed the suspension properly in the first place, it wouldn't have that great a tendency to oversteer, and the intervention of the ESC would not have to be as great. I've been driving since 1976. As you might imagine, very, very few of the cars and trucks that I've driven had ESC. And very, very few of them had lift-throttle oversteer.

ESC is very valuable and statistics have shown that it significantly reduces traffic fatalities. It is a life-saver. But it shouldn't be used as a band-aid to overcome basic handling problems. Toyota messed up two things here: 1) the ESC tuning and 2) the suspension design and tuning.

 

[mikeync]

I think it's sad that they had to stop selling them because there are so many bad drivers who don't know cornering 101.

See below from Q&As: Electronic Stability Control

Either most people don't know how to drive and then ESC is warranted or they know how to drive and ESC is still warranted. Either way ESC saves lots of lives and every other car manufacturer and even Toyota on other vehicles manages to implement it properly. It is sad that they did not on the 460. In addition they are now testing every vehicle......

In Institute studies, ESC has been found to reduce fatal single-vehicle crash risk by 51 percent and fatal multiple-vehicle crash risk by 19 percent for cars and SUVs. Many single-vehicle crashes involve rolling over, and ESC effectiveness in preventing rollovers is even more dramatic. It reduces the risk of fatal single-vehicle rollovers by 75 percent for SUVs and by 72 percent for cars. If all vehicles were equipped with ESC, as many as 9,000 fatal crashes could be avoided each year.1 Federal studies also show large benefits. The National Highway Traffic Safety Administration (NHTSA) estimates the installation of ESC reduces single-vehicle crashes of cars by 26 percent and single-vehicle crashes of SUVs by 48 percent. NHTSA estimates that ESC has the potential to prevent 64 percent of the car rollovers and 85 percent of the SUV rollovers that would otherwise occur in single-vehicle crashes.2

 

[sandcrawler]

funny. i found this out first-hand earlier this week when i absent-mindedly goosed it into a sharp turn. VSC kicked in immediately and startled the sh!t out of me for a half-sec. then, realizing what had happened, i thought, "cool. now i know it works!"