The importance of toe in with rear drive vans

[booster]

Of course this is based on a sample size of one, our van, currently but have seen similar in past vehicles and my 1996 Roadmaster wagon with the same style steering and drivetrain.


Over the years our van has been tweaked into being very well handling with very small steering corrections needed even in large winds from any angle. Understeer is very much reduced and that along with big swaybars are the major contributors to the improvements.


When we were semi forced to change to Agilis tires last year, the van had not been out for a while due to Covid. The new tires felt good, close to the old very well handling MS2 tires they replaced, but over the year to now with the Agilis tires broken in and me accustomed to driving the van again, I noticed there appeared to be a very slight "softness" to the steering center that required more corrections than it used to.



Since toe in setting can give that kind of feel if it is not enough toed in but not yet positive where it gets wandery I got the van on to the flat surface of the driveway and did a quick toe in check before we went on a near 2K mile trip the last couple of weeks.



I found that the toe in had gone to zero instead of the previously set 1/16" in. It was set about 15K miles ago so that is not unusual at all with this style steering. I reset it to 1/16" in by turning the right side outer tie rod in 1/2 turn. I did only one side as it also made the steering wheel more centered as a bonus.


On the trip we took which included lots of very windy areas, the van handled just like it used to and most of the tire pressure sensitivity that we had noticed with the Agilis compared to the MS2s disappeared also. We had very wide temp swings from under 40*F to near 90*F so the the rear tires saw about a 10psi swing and the fronts about 7.5psi.



Bottom line seems to be that the toe setting, if set to a relatively small 1/16" in will need to be checked about every 10K miles especially if on some of the horrible roads we run across. The service manual spec for toe in has a huge acceptable range compared to the 1/16" so it is very likely that many of the vans are driving around with less than optimum stability because if where the toe is set.


What was very surprising to me was that the amount of tire pressure change off of "optimum" for good steering feel got so much larger just because of the toe in setting change. I can't say if this would be for all tire models or if it is Agilis only, though.

[Kurt Franz]

Interesting - I am going to look into this because I find that I am constantly "correcting" my steering while driving on the highway. The van does not veer right or left as in bad alignment, but I find I am constantly moving my hand 2-3 inches on a regular basis - just enough to irritate me and take away from a relaxed driving experience.

I understand that wind and other factors come into play here as well, however, this occurs when these factors are not in play. I guess it could also be worn steering components as well.

Question I have is when you are driving straight at speeds exceeding 55 mph how much right to left "play" do you have on the wheel. I notice about 3 inches play in that I can move the wheel up and down that amount before effecting the steering.

Since this Express van is new to me I have no idea as to what normal is - but like you said maybe your finding is a real contributor to this.

Thanks for sharing this as I am struggling a bit here because I am leaving on a 1200 mile trip in a few days and I have a feeling that I will be arriving at my destination with a tired arm and in a bad mood

[booster]

Originally Posted by Kurt Franz

Interesting - I am going to look into this because I find that I am constantly "correcting" my steering while driving on the highway. The van does not veer right or left as in bad alignment, but I find I am constantly moving my hand 2-3 inches on a regular basis - just enough to irritate me and take away from a relaxed driving experience.

I understand that wind and other factors come into play here as well, however, this occurs when these factors are not in play. I guess it could also be worn steering components as well.

Question I have is when you are driving straight at speeds exceeding 55 mph how much right to left "play" do you have on the wheel. I notice about 3 inches play in that I can move the wheel up and down that amount before effecting the steering.

Since this Express van is new to me I have no idea as to what normal is - but like you said maybe your finding is a real contributor to this.

Thanks for sharing this as I am struggling a bit here because I am leaving on a 1200 mile trip in a few days and I have a feeling that I will be arriving at my destination with a tired arm and in a bad mood

Our van, because of our mods for a large part, probably has among the smallest corrections of any of the Chevies. I would guess we are less the 1/2" or so in movements, which is small enough to do with a couple of fingers laying on the bottom of the steering wheel. This makes for a very non tiring drive for me. Wind is not a much of an issue for our van as you feel it hit but it is not knocked far off track and the correction is small and easy to do.


The improvements are not rocket science, but follow all the standard handling rules for rear drive vehicles only applying them to a tall, heavy, vehicle. Get the steering parts fixed to new, align to reduce wander and to tight spec, good shocks, good springs, optimized tire pressures, big swaybars, particularly in the rear, good tires, correct offset wheels.


Pretty much all of our improvements and testing are documented here on the forum so plenty to read up on.


If you have 3" of movement you almost certainly need to find the cause of that first. Bad steering gear or worn steering parts are most likely, especially the idler arm.

[Kurt Franz]

I concur - my gut feeling was idler arm or center link or whatever it is called these days. I remember in the old days we would "adjust" our steering gear by tightening a screw on the gear box.

I should add that when we adjusted the steering box back in those days it did not permanently fix this issue - it worked for a while then got worse as the components inside bit the dust quicker - as they were not meant to be adjusted to extent we did it. A worn steering gear assembly will need replacing for sure.

[peteco]

Like booster, the steering in my 2006 Roadtrek 210 has very little play. I now have 140,000 miles. I replaced idler arm, pitman arm and tie rod ends at 50,000 miles. The ball joints were good then and still are now. I just replaced the idler arm because I thought it might be worn but it was just as tight as new. It turned out I had some uneven burnishing on the rotors giving a little shake on heavy braking. I grease the suspension every oil change: 5000 miles. I think this is critical to maintaining a solid suspension. Another key thing is to lube the front wheel bearings. This can be done on even the supposedly permanently sealed front hubs. You can find a description by searching the forum. These heavy vehicles need an OCD approach to maintenance to keep them operating smoothly.

[folivier]

My 2011 C210P takes very little movement to keep going straight. But it does have a pull to the right which I'll get taken of whenever I find a good shop either near Montrose, CO or this winter near Baton Rouge, LA.

[Kurt Franz]

Maybe I made things sound worse than they are - my van will stay straight with my hands off of the wheel. It does not veer right or left. What happens on the highway is like driving in heavy wind most of the time - I have to constantly make small adjustments right and left on the steering wheel - just enough to the point where it is not relaxing. I am leaning towards the conclusion that this is being caused by slightly worn components somewhere in the steering/suspension system. Been keeping the tires at 80 rear and 65 front. Thanks for the input and suggestions on this everyone. I am hitting the road tomorrow

[rtbill]

I had an independent mechanic evaluate the steering on our '01 200V Roadtrek (Chevy 3500 chassis). He recommended tightening the steering box. That took most of the slop out of the steering.

Weigh your van. 80/65 psi is appropriate if the axle weights are maxed out. The front in particular may not be, and you should try proportionally lower pressure. Lower front tire pressure helped settle the steering on our 200.

[KurtFranz]

Completed the trip from Florida to Ohio. Here are my observations:

Van drove as described until I got into South Carolina, where it gradually became more “normal” so to speak. I know this sounds ridiculous, but the steering seemed to tighten up. Of course this would not really mechanically occur and had to be perception on my part, but the change was completely noticeable. It was as if something changed gradually and driving the van no longer consisted of constantly making minor adjustments on the steering wheel. I have come to the conclusion that it had to be wind causing my perceived problems, but I swear my steering began to tighten up as I got further into my trip - it was not my imagination or becoming used to it so to speak.

Regardless, it ended up being a pleasure to drive by the time I got home.

[booster]

Originally Posted by KurtFranz

Completed the trip from Florida to Ohio. Here are my observations:

Van drove as described until I got into South Carolina, where it gradually became more “normal” so to speak. I know this sounds ridiculous, but the steering seemed to tighten up. Of course this would not really mechanically occur and had to be perception on my part, but the change was completely noticeable. It was as if something changed gradually and driving the van no longer consisted of constantly making minor adjustments on the steering wheel. I have come to the conclusion that it had to be wind causing my perceived problems, but I swear my steering began to tighten up as I got further into my trip - it was not my imagination or becoming used to it so to speak.

Regardless, it ended up being a pleasure to drive by the time I got home.

Your observations are certainly not "ridiculous" and probably relatively common.


I think two things probably happened over the distance of the trip.


The first is that you got used to how the new to you van reacts to steering inputs in different conditions so you weren't over or under correcting steering inputs. Over and under corrected inputs mean another input is immediately needed.


Second is if the wind went down some, the van would not be pushed around as much. It is a huge flying brick so it catches a lot of wind and it will get pushed around some. The amount of traction available on each end of the van compared to the area that sees it can determine which end moves the most and even the rocking of the van from the wind will make it turn a bit.



In stock form our vans are chronic understeer vehicles, meaning that the front tires have less traction than the rear. This makes steering corrections less effective than they would be if no understeer was present and that inffectiveness shows up as the larger corrections you see with the van. The size of the corrections also get larger faster with wind increase in vehicles with a lot of understeer so big winds can be a handful.


My guess would be that your van is behaving typically for a stock Chevy class B, and the Chevies aren't horrible handling in stock form, especially without a lot of wind.



Understeer can be corrected quite a bit even in a tail heavy van with simple, but not necessarily cheap, modifications like a big rear sway bar addition. Tire pressure changes can make some difference and of course having very good tires for handling.


Our van handled a lot like you described, being quite good without wind and quite scary if wind got in 25mph+ range. I have done every change I could come up with that would fit on the van and it is now nearly windproof and has been driven regularly in 30+ winds without issues. Our steering corrections are very small even in high winds.



As with all vehicles in high winds, where you are can make a difference too, we have found. On the flatlands of the west the winds tend to be a quite steady force you mostly just hold against so not all that hard to do. In other parts of the country where there a lots of hills and things like tree rows or buildings alongside the road, the wind can be much more variable and feel like it is slamming the van when you come into an open area. It can be fun sometime if you have trailer being towed or a class C RV a ways ahead of you to just watch them. If they suddenly move one way or the other, you can bet you will get hit with a big gust when you get to that spot.