New Plan - Jeep Grand Cherokee EPS Wobble

[harleyjt]

Originally Posted by VP Chianese

Just last week I was at Freightliner in Gaffney for service. There were probably 20 to 24 coach's there for service each of the two days I was there. At least half were towing a JEEP of one kind or another from Wranglers to Grand Cherokee Limited's.

I counted at least three units with incorrect alignment of the tow bar with the tow. Problem #1 which is easily correctable yet folks just drive with it. But the one that stood out to me was a perfect example of what can and does happen. There was a JEEP Cherokee, don't know what year but it looked to have some type of off road tires on it and a bicycle rack on the rear tow bar of the JEEP. I believe it had only one bike on it. So for grins and giggles let's take a look at that set up. The bike rack weights a good ten to fifteen pounds. My bike weighs 32 lbs and from what I can tell most weigh between 25 -35 lbs. So to be fair I'll guess this was a 30 lb bike. So we now have 45 lbs hanging a good three feet aft of the rear axle. If we had another bike out here we have 75 lbs out there. Not to mention what may or may not be in the back of the JEEP as gear.

The point here is that these little everyday things we do to our tows cause havoc with the front end alignment. The ride height on the front end of that car with just one bike could have changed as little as 1/4". This throws the geometry of the front wheel alignment off.

Some one here mentioned 6-7* Caster angles. I made the mistake of using those numbers but they are not correct. The real numbers are Front Wheels
Caster* FWD +3.51° +/- .40, AWD 3.83 +/- .40 and Lifted 4.13 +/- .40. Also please notice the *. That means that there is no adjustment it is a built in number and the only way it changes is by one doing damage to the front end. You know, off road, bend a spindle, bigger tires, etc. So if the Caster for an AWD needs to be 3.83 the acceptable range is on a that JEEP is 3.43 - 4.23. Changing the ride height either by adding weight to the rear or otherwise changes that value and the result is there is no way that JEEP's steering is gong to be correct.

My point is that we all do things to our units that can cause an unwanted problem. There is no way a manufacturer can account for every ones mistakes. It seems that with the correct alignment and proper use the Wobble problem has been addressed.

Your point is well taken. However, as for the alignment specs you mention, I think you are referencing Cherokee, not Grand Cherokee. This thread is actually dealing with GC, which according to the service information I have seen, does have adjustable caster and camber.
jt

[VP Chianese]

Originally Posted by harleyjt

Your point is well taken. However, as for the alignment specs you mention, I think you are referencing Cherokee, not Grand Cherokee. This thread is actually dealing with GC, which according to the service information I have seen, does have adjustable caster and camber.
jt

I thought it was a GC numbers I was looking at sorry about that. But it does not matter what the number is or if it is adjustable or not. If it is adjustable then the Caster needs to be set to the high end of the scale. If it is not adjustable it still needs to be at the high end. Even the non adjustable can be changed by replacing the worn or bent parts or a frame realignment if the damage is bad enough. Just because it isn't adjustable doesn't mean you have to live with it that way.

No matter what comparing the weight that one can put on the tongue as weight when the JEEP is the unit doing the towing is completely different than when it is being towed. As the towing unit in AWD the front wheels grip the pavement and cause the front to dig in where as a towed unit they just go along for the ride and if they are being lifted by the weight on the rear of the JEEP they may tend to understeer or loose grip of the pavement. Which is pretty much what Wobble is.

I do not know the number of JEEP Grand Cherokee's that actually Wobble while being towed but my guess is the percent that have experienced it compared to the ones that have not is really low. So looking at it from another point of view if in any model year let's take 2019 there were 263,428 total JEEP Grand Cherokee's made in the US and Canada. 1% would require 2,634 units to have experienced the problem. 263 units would be .001 %. Are there really over 263 units from 2019 that have experienced the problem?

Let's be clear here I'm not trying to trivialize this just trying to get the reality of it.

[rpasetto]

If someone can produce stats of the towed vehicles which have had a wobble for each brand it might be useful. The percent of the GC's which are towed and have had a wobble incident is the relevant thing. not the percent based on total # of GC's.

[DrDaveMA]

Originally Posted by jrs

Limited - This probably doesn't matter concerning the wobble issue.

Just to help muddy the waters, we have a 2016 Limited with a Roadmaster Tow bar that is properly aligned, no modifications, a charge line in the tow cable, we have towed it coast to coast several times (like 4) and have not had a problem. I hope I have not jinxed myself.

[Charles L]

I just finished an 8000 mile coast to coast trip towing my 2017 Jeep GC. This included driving to Yellowstone on the Chief Joseph scenic highway and through to Mammoth and the western side, driving PCH 1 in northern California and all the way back to Virginia never having experienced the wobble. I was worried about it in the beginning since I had only towed with this setup 200 miles before leaving on the big trip.

Somehow I completely forgot about this issue after the first day or two.

[VP Chianese]

Originally Posted by rpasetto

If someone can produce stats of the towed vehicles which have had a wobble for each brand it might be useful. The percent of the GC's which are towed and have had a wobble incident is the relevant thing. not the percent based on total # of GC's.

I don't think that Corporate looks at it that way. First off where are you going to get that as a reliable number? Secondly how many have had tires changed, wheels changed, been off road and bent something or what ever. There are way to many variables, tow bar brands, alignment and installations of the various tow plates all of which the manufacturer has no part in yet we want to hold them responsible. Now if JEEP built the tow bars and the tow plates there may be a leg to stand on but they don't. Third as two folks have already said and I have to add as well there are a lot of folks that tow GC's and never have the problem, ever. I have over 50 k miles of towing two different GC's a 2017 and now a 2020 and have not had the issue.

[CWSWine]

First, Jeep admitted the problem was with the electric steer on the Cherokee and developed a harness to fix the steering/wobble It was not the tires, worn or bent parts or not properly aligned was not the issue. So what's the difference - Cherokee was a real safety issue since it would wobble at highway speeds where the GC only wobbles in a slow turn after stopping and not huge safety issue. After doing it twice Fiat had the dealer check all suspension parts and check alignment and no problems were found but still did wobbled one more time before I stop towing it. You can towing a GC a million highway miles and you won't have a problem it's turning from a stop and uneven surface is when it happens. Most reports were less than 5 MPH. So how many of those thousands of miles you have driven were under 10 MPH turn left or right where the wobble happens?

[rpasetto]

Originally Posted by VP Chianese

I don't think that Corporate looks at it that way. First off where are you going to get that as a reliable number? Secondly how many have had tires changed, wheels changed, been off road and bent something or what ever. There are way to many variables, tow bar brands, alignment and installations of the various tow plates all of which the manufacturer has no part in yet we want to hold them responsible. Now if JEEP built the tow bars and the tow plates there may be a leg to stand on but they don't. Third as two folks have already said and I have to add as well there are a lot of folks that tow GC's and never have the problem, ever. I have over 50 k miles of towing two different GC's a 2017 and now a 2020 and have not had the issue.

Take a look at the 2012 FCA patent for "Active shimmy mitigation": United States Patent: 8831854

This has been referenced before. It was first posted in a Cherokee forum back in Nov 2015 and it refers to an FCA patent published in 2012. FCA knew that they had an inherent vibration tendency in many, if not all, of their vehicles with EPS systems. It's not only a Cherokee thing, just that the '14 KL Cherokee was the first in their product line to be flat-towed. KL's are probably still the largest number of towed vehicles in their lines of Jeeps and Pickups.

It would be more useful, IMHO, useful to find out what FCA did in their EPS design for the 2019 KL which apparently solved the wobble tendency than to speculate about reasons why the Grand Cherokee may have a similar problem.

[lass]

Originally Posted by rpasetto

If someone can produce stats of the towed vehicles which have had a wobble for each brand it might be useful. The percent of the GC's which are towed and have had a wobble incident is the relevant thing. not the percent based on total # of GC's.

Approximately 40 members of this forum have reported a wobble during towing of the Grand Cherokee. Model years include 2016, 2017, 2018, & 2019.

I don’t have data on the total number of GC’s being towed but in order to have accurate numbers, start with the 2016 model. Older models do not have the problem.

[VP Chianese]

Originally Posted by CWSWine

So how many of those thousands of miles you have driven were under 10 MPH turn left or right where the wobble happens?

I would guess as many as anyone that has had the wobble unless they just go to Walmart and make right and left hand turns on purpose. I drive on the Interstate, City and county roads and into and out of the same camp grounds that most others do. We stay out , this year being an exception, at least four to five months a year, every year. So that means 100 to 120 nights in various campgrounds from CA to MD, from FL to Montana. So yes I make right turns and even left turns from a stop. Yet I have been lucky enough to not have the problem on two different JEEPS a 2017 and now a 2020. Must be clean living.

As far as the 40 + members that have reported the problem, if that is the member and I'm not doubting it, let's just say there were twice that number that had the problem or for grins let's say 100. We do realize that over the four years of production JEEP built approximately a little over 1.2 million units of GC alone. How many of them are actually flat towed I don't know but when someone builds over one million of anything and has a problem with 1/10th of a percent. The reality is they don't care. As far as they are concerned it has been fixed.

Also it seems that some are focused on what it was that JEEP did to the units to fix the problem. Who really cares? If you had a pace maker put in to save your life do you call the manufacture of the pace maker and require the drawings of the unit and what they did to make it safe after the first ones killed a couple hundred pigs? Of course not.

We are beating a dead horse here.

[rpasetto]

Originally Posted by VP Chianese

........................
Also it seems that some are focused on what it was that JEEP did to the units to fix the problem. Who really cares? If you had a pace maker put in to save your life do you call the manufacture of the pace maker and require the drawings of the unit and what they did to make it safe after the first ones killed a couple hundred pigs? Of course not.

We are beating a dead horse here.

Perhaps another analogy to consider would be at least some of those with a particular pacemaker design who hear that 40 others with that same design have had failures. I say "some, knowing that there are always those out there who think nothing bad can ever happen to them.

Safe travels all.

[VP Chianese]

Originally Posted by rpasetto

Perhaps another analogy to consider would be at least some of those with a particular pacemaker design who hear that 40 others with that same design have had failures. I say "some, knowing that there are always those out there who think nothing bad can ever happen to them.

Safe travels all.

I think you misunderstood the point. With any drug or pacemaker that is approved by the FDA there may have been deaths or side effects before it was corrected and then approved. That's why they have many trials over a very long period of time.

It seems that JEEP has done just that and knowing why or how the problem has been solved is not that important to most folks.

[dpinvidic]

Originally Posted by VP Chianese

Also it seems that some are focused on what it was that JEEP did to the units to fix the problem. Who really cares? If you had a pace maker put in to save your life do you call the manufacture of the pace maker and require the drawings of the unit and what they did to make it safe after the first ones killed a couple hundred pigs? Of course not.

We are beating a dead horse here.

The reason we want to know, is the hope that we can possibly implement that same change ourselves. Maybe it is a interchangeable part, or some other parameter that we could duplicate on the GC.

I too was skeptical when we had our 2014 Cherokee, until the wobble happend to me. It literally feels like someone is in the Jeep, turning the wheel form side-to-side. At least I immediately knew what it was and what to do from being on this forum.

[lass]

I’m getting a little confused. The thread is referencing between the Cherokee and Grand Cherokee, so I need to ask. Knowing that the Cherokee wobble was solved for the current model, are we also saying that Jeep has also solved the Grand Cherokee wobble?