Wandering at highway speeds

One other thing you might try, Jeff, is to reduce your Comfort Drive to less than 3 (maybe near 2)when you encounter "squirrely." Occasionally conditions (wind or road) are such that the CF subtly fights you.

For those not familiar with the Newmar Comfort Drive, it's an addition (factory) to the steering that attempts to keep you straight, but occasionally it's a bit less than perfect. However I do find myself less tired at the end of the day than I did with my Beaver, so it definitely helps overall, except under certain conditions. It's adjustable with a knob on the dash, and the larger numbers make it "fight harder" to keep you straight, resulting in a bit stiffer steering response for you (often good at highway speeds), but the lower numbers make it not react as much and make it easier to turn the wheel.

Larry, I'll normally run between 3and 4 on the hiway. I do kick it up in windy conditions. I've also buried the needle just to see but that needs some getting used to. I'll try a lower setting.
Thanks, Jeff

John Stephens said:

I agree with Gary. If reducing tire pressure is going to make a difference in how it handles, the front tires will be impacted more than the rears. I have a 38' so we're close in size and after weighing my coach, I dropped the fronts from 105 to 90 and the rears from 95 to 85. The problems I had when trucks pass me virtually disappeared. But, comma, at the same time, I had also become more familiar and comfortable with how the coach drove overall and was able to drive more relaxed, keeping my vision a quarter mile down the road most of the time, only occasionally watching the lines passing by. So your issue may be corrected by either thing. Unless I have a strong cross wind blowing me sideways, I don't have a problem keeping the thing in a straight line.

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John, do you remember what your front axle weighed in at? If I drop to 95psi on the fronts I am under inflated by 70lbs axle weight. Is that what we call close enough?
Again, maybe it's me just expecting a better road grip than what I'm getting.
I also don't hear anyone else proposing a positive caster adjustment. I'm intrigued by that suggestion but have zero experience in this area.

Alpena Jeff said:

John, do you remember what your front axle weighed in at? If I drop to 95psi on the fronts I am under inflated by 70lbs axle weight. Is that what we call close enough?

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Others may disagree, but I would call it close enough and at least try going down to 95 in the front to see if it makes a difference.  I'm no expert, but I know that getting the caster set properly can make a huge difference.  From other posts on the forum, however, it appears the challenge can be finding a shop that knows how to do it.

And focusing a long ways down the road helps too.

Thanks to all that replied for your understanding and patience.
I will lower my psi to the lowest safe levels that I'm comfortable with.
I will also focus my line of sight further down the road and try to relax my grip and mind. Only time and experience behind the wheel will tell.
If I'm still not happy I will pursue other options discussed.
Best, Jeff

My running weight rear axle is 650 lbs below Michelins lowest chart entry of 85psi.
Are you saying 85psi plus 5psi is the lowest inflation I should have on the drive tires even with my low weight?

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First,  650 lb low is a noise-level difference when we are talking about an 18,780 load. Second it is likely the load is not 50/50 on the axle anyway, so one end may be 9780 while the other is 9000 even. You must inflate for the heavier end, not th average. Third, the tires should never be inflated at less than the minimum shown in the inflation table, so 85 is rock bottom for yours. The actual inflation changes with temperature, so the 85 you did on a warm afternoon may become 81 on a chilly morning.

I suggested 90 psi so that you can be confident the rears are always adequately inflated, even if you get into colder weather or add some load for a trip, e.g. fill the water tank.  Always err on the high side.  And for the rear tires, there is almost zero reasons to try to keep the psi low.

Load and clear Gary. Your PSI numbers are right where I was heading so thanks for the reinforcement!
As you can see this topic is most important for my happiness, comfort and safety for my family.
Bless you all!!!!
Jeff  )

It also pays to learn how to "read" tire wear when it comes to inflation.>>>D

Alpena Jeff said:

John, do you remember what your front axle weighed in at? If I drop to 95psi on the fronts I am under inflated by 70lbs axle weight. Is that what we call close enough?
Again, maybe it's me just expecting a better road grip than what I'm getting.
I also don't hear anyone else proposing a positive caster adjustment. I'm intrigued by that suggestion but have zero experience in this area.

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Jeff, I'm sorry, but my CAT sheet is in the coach, which is in storage. My best memory of the weight was between 10,000 and 11,000, and I want to say it was something around 10,750, but I'm not sure. 70 lb axle weight is no big deal if that figure on the chart is closer than the next closest, but remember that under inflation is worse than over inflation.

[quote author=Alpena Jeff]I also don't hear anyone else proposing a positive caster adjustment. I'm intrigued by that suggestion but have zero experience in this area.[/quote]

It's something to check. A friend with his own capabilities/knowledge checked & adjusted his. Can't recall the details or the outcome. There are specialist shops such as Anderson Alignment who go further with the front end.

As Tom says, it's something that maybe should be checked. Along with the rest of a "front end alignment".  An out-of-spec caster will indeed cause steering problems, but so will improper toe or camber.  When people complain about steering, the first two mechanical steps are to make sure that tire pressure and alignment are correct. For a Class A rig, the non-mechanical first step is "driver education/experience", getting over the difference in the driving position in a Class A and getting your years of car-driving "muscle memory" retrained.  That's the part about focusing further ahead and stop fidgeting with the steering wheel.

I'm going to keep the alignment thing in my back pocket for now and focus on driving technique, patience and proper tire inflation as we proceed north next month.
I'd clearly be lost without this forum. I appreciate all you do!

Elaborating a bit on the driver aspect...
Newcomers to a Class A encounter three related problems in their driving technique. These are a natural result of the dramatic change in vehicle size & type, so don't go thinking "dumb" or "lousy driver".  Some adapt faster than others, of course, but for most the learning can be helped along with a few tips.

#1.  The new Class A coach is longer and wider than anything you have ever driven, so you are naturally concerned about keeping it between the lines, watching for other vehicles behind or coming up on you, etc.  You unconsciously spend a lot of your eyeball time looking in the mirrors and watching the lane markers instead of watching where you are going.  It's well known that the body naturally moves toward wherever the eyes are looking, so you steer slightly sideways as you look left or right. Then you have to correct slightly as your eyes move front again. The act of correcting makes you worry again that you may be out of yuor lane, so you check the mirrors and the cycle repeats.  You probably aren't even aware of it, except that you seem to be constantly correcting.

#2. The scenario described in #1 keeps your eyes focused close to the front of the coach and you lose parallax. Parallax is the perception that a road or tunnel narrows in the distance and it is the natural result of having two eyes spaced somewhat apart.  You will naturally follow a straight line toward whatever point you are looking at. If the point is near and changes every few seconds, you take a series of short straight lines that invariably zig-zag.  If you keep your eyes mostly focused on a more distant point, your path straightens out into a long line toward a far away goal. Obviously you can't always be looking out to infinity, but you really need to be focused well ahead. That also helps you anticipate traffic and road changes, which is much more important in a large vehicle that doesn't change direction or stop as easily as a car.

#3. The difference in the driver position, i.e. higher and over the steering axle, throws off the years of ingrained "muscle memory" you learned driving a car. Your responses to the perceived vehicle position are wrong, or at least skewed somewhat, so you over or under correct and then re-correct.  It takes some time to get your senses and muscle re-calibrated, but most people get it within a 1000 miles or so.  As with any sort of training, shorter trips spaced weeks apart do not build the new skills quickly or well.  It's probably best learned in a single longish trip, sort of total immersion therapy.

I suffer from #2. Not just in motorhome, but everything I drive. What makes it even worse is that I have ridden motorcycles since I was 9 years old and know better. I am aware that I do this, and make a conscious effort to look further down the road. It used to a natural thing for me, but has gone away as I got older.

kdbgoat said:

I suffer from #2. Not just in motorhome, but everything I drive. What makes it even worse is that I have ridden motorcycles since I was 9 years old and know better. I am aware that I do this, and make a conscious effort to look further down the road. It used to a natural thing for me, but has gone away as I got older.

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Same here. I know what to do, I try to do but then I see a big rig coming up fast and my eyes go left to make sure he has room.
Practice! I've only got less than 2k miles in the seat with breaks in between.
I will work on it.

Jeff..Although we have a 2000 Georgie Boy 31' Maverick "C" on  a Ford E450 chassis, I can fully agree on the caster effects, at least for us.  When we got the unit in  Jan 2014, the dealer had us take into a  truck shop for an alignment. It turned out OK....A trip to Moab shortly there after brought out the problems. I then started reading the threads and comments here about the caster settings....esp., from Harvard. I checked the data from the first alignment and found that it was set at about 3 1/2 degrees positive...about in the middle of Ford's recommended range. Shortly before a cross country trip to Maryland in fall of 2016, I returned to the shop where the first alignment was done. I talked to the service manager and he knew of the problems with the E450's and was happy to increase the caster as I asked. The alignment tech was also familiar with it and ended up with settings close to 5.5 degrees positive. WHAT A DIFFERENCE! The unit tracked straight down the road, passing semis no longer caused a white knuckle hold on the wheel, and overall it was just a lot more enjoyable. It did however increase steering effort a little but not anything to worry about.  But,be sure that the shop you go to is willing to "think outside of the box". Our first alignment was "plain vanilla", right in the middle like it was always done. Second time out, they were very willing to increase settings beyond what normally would be done, and still stay with in Ford's guidelines (0-7 degrees, I believe). I realize that our E450 chassis is an entirely different animal than yours, but I was trying to add support to the caster increase thinking and how it helped us......if you go down that road.

Thanks for the info Gary. I'll know more after my trip back north next month. I will hang onto this note.

Alpena Jeff said:

Load and clear Gary. Your PSI numbers are right where I was heading so thanks for the reinforcement!
As you can see this topic is most important for my happiness, comfort and safety for my family.
Bless you all!!!!
Jeff  )

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You have a nice coach and you have gotten some good advise. One more thing, have you ever had an all wheel alignment done? You should have it loaded like you were going on a trip. I did full water 1/2 on gray and black, full propane.
Tell the shop you want max caster.
I would use a +10# on the tires as it beats trying to do 10% and close enough.Most coaches come off the line have never had a proper allwheel alingment. Some ware in your paperwork it will mention that it is the custemers responsibility to do it after loading the coach for travel. The reason is eveyones coach will weigh diferantley and weight efects the alingment and ride hight.
Let us know what you find.
Geting some more miles will also help you get more comfertable.
Bill

Update.
We are home and the results are in.
As Gary suggested rear pressure was adjusted to 90psi to prepare for lower temps back home.
Fronts I adjusted to 95 while still in Florida and needed to add air as cold temps factored in moving north.
I immediately noticed a change in handling for the better. This more stable ride allowed me to focus line of sight further down the road and KEEP it there even as trucks were passing. I gained more confidence as each mile passed and was able to relax, finally, while in the seat.
Bottom line, a 5 psi reduction in the front tires made all the difference in the stability of our coach which allowed me to focus on technique. Thanks to all that contributed! Me happy, wifey happy!
Final question on this topic.
Front tire scenario, 95psi is my cold temp target. Once we hit colder temps my psi cold was 91. I aired up to 95. Was I correct in doing so or would I have been ok knowing I would be at 95 in just a few miles eventually peaking at somewhere over 105psi? Or does this fall into the "close enough" bucket?
Thanks, Jeff