Comfort Drive Steering instructions

[jmlmeyer]

Ken

Thanks, very helpful

[snickers]

I set it around 3 and usually leave it until late in the day than turn it down a bit. Don't know how I drove without it.

[cmaxcliff]

Ken, I just had a wheel alignment done on my 2010 DADP 4320 with 10k miles. We found the toe-in was a bit excessive and corrected that. No other issues. The reason that I was concerned was that the wheel was turned clearly left when going straight before the alignment. Based on their 50+ years of truck alignment experience they adjusted the toe and used the drag link to correct the wheel. They have not worked on a Comfort Drive before. When we test drove the MH the wheel was still a bit left. We did the TRW steering reset procedure and nothing changed. The next time the rig was driven the wheel was to the right when going straight. I know about the 3 different resets that TRW details in the manuals but I am just plain confused about how to get the system to know exactly where the "electrical center" is so that it matches with the "mechanical(hydraulic?) center so that the wheel is centered each time the motorhome is used. Also, I am curious how many degrees "out of sync" does the CD system have as a range as opposed to the straight ahead position on the alignment rack.

What is the correct way to set the CD wheel position to be consistently straight?

[KenSherwin]

Before I spell out the adjustment procedure (and I will), I have some questions and answers.
1. The CD has absolutely NO effect on the position of the steering wheel. The only thing it can change is the amount of torque you have to put on the wheel at any given time.
2. Adjusting the drag link to get everything straight might or might not be the correct place, depending on what the problem really is.
3. You mention the "TRW steering reset procedure" and "3 different resets that TRW details". Where did you find these procedures so I can find what you are looking at?
4. The CD can correct for a poorly adjusted system along with road crown and crosswind up to a total of 90 degrees either side of center.
5. You want a way for the "electrical center" is so that it matches with the "mechanical(hydraulic?) center so that the wheel is centered each time the motorhome is used." I promise this is a futile effort. My Kountry Star required me to hold the steering wheel a little more than 10 degrees different in the left lane than in the right lane. My Peterbilt requires 7 degrees. Since the CD does not change the steering wheel position, the steering wheel position while driving straight down the road is purely a function of the vehicle geometry, the road, and the wind. I have frequently measured the straight ahead position move around on a single trip more than 25 degrees and saw a 53 degree offset from a crosswind late one night in a bad snowstorm that I didn't want caught in.

When you tell me about these reset procedures, I can tell you want they do and we can talk more about the correct adjustment procedure.

[cmaxcliff]

I have two TRW sources, an "Owner's Manual"(a few pages stapled together) included in the Spartan binder that comes with the coach and this source found online...
http://trucksteering.trw.com/sites/t...df/CDV-101.pdf

Still confused;"4. The CD can correct for a poorly adjusted system along with road crown and crosswind up to a total of 90 degrees either side of center." Do you mean that the steering wheel is always at the exact same correction angle as a non CD equipped vehicle when fighting a side wind etc the only difference being driver effort??? If so then an alignment should be like any other truck, time the steering box, the steering wheel should be straight, do the alignment so that the road wheels are aligned to the chassis.

The biggest confusion is, why is the steering wheel position inconsistent on a flat surface. On the day of the alignment it was a little left and now it is a little right with no adjustment made. The vehicle drives fine(I'm on a 1500 mile trip right now) so I'm not worried but rather more interested in the absolutely correct procedure and why it's done that way. I've spent 45 years in the automotive and motorcycle service industry and racing community and I am compelled to get things as close to perfect as possible. Thank you for your patience.

[KenSherwin]

Originally Posted by cmaxcliff

I have two TRW sources, an "Owner's Manual"(a few pages stapled together) included in the Spartan binder that comes with the coach and this source found online...
http://trucksteering.trw.com/sites/t...df/CDV-101.pdf

I have no idea what an "Owner's Manual" that Spartan puts in a binder might be, but let me explain what's going on with CDV-101.

There is an encoder in the CD that must get its electrical center initialized after the battery has been disconnected and reconnected. This reinitialization is what is being described in CDV-101. It finds the existing center, it does not create a new one.

Still confused;"4. The CD can correct for a poorly adjusted system along with road crown and crosswind up to a total of 90 degrees either side of center." Do you mean that the steering wheel is always at the exact same correction angle as a non CD equipped vehicle when fighting a side wind etc the only difference being driver effort??? This is exactly correct! If so then an alignment should be like any other truck, time the steering box, the steering wheel should be straight, do the alignment so that the road wheels are aligned to the chassis. Also exactly correct!

The biggest confusion is, why is the steering wheel position inconsistent on a flat surface. On the day of the alignment it was a little left and now it is a little right with no adjustment made. I would wonder "How flat?" and "How much is 'little'? Many big vehicles change steering wheel positions by 5 to 10 degrees, just by changing lanes. I have also seen lash in steering systems cause this sort of behavior. Have one person wiggle the steering wheel back and forth a bit and have somebody else check every connection in the steering system, looking and feeling for very slight motion in what is supposed to be solid connections.

The vehicle drives fine(I'm on a 1500 mile trip right now) so I'm not worried but rather more interested in the absolutely correct procedure and why it's done that way. I've spent 45 years in the automotive and motorcycle service industry and racing community and I am compelled to get things as close to perfect as possible. Thank you for your patience.

The correct procedure for checking the alignment between the CD, the roadwheels, and the steering wheel is:
1. Start by driving the vehicle in a straight line long enough to determine the straight-ahead steering wheel position. Mark this position. Typically a piece of masking tape can be used to mark this position. Note: Torque at the steering wheel does not matter at this time. If this position changes, this is not a CD problem but the cause must be found before continuing.

2. Find a safe location for the following test, such as a large empty parking lot.

3. Position the steering wheel at straight ahead as determined in 1, let the vehicle roll a few feet to relax the tires, then stop.

4. Turn the engine off and the steering wheel should not move. Wait 30 seconds, then restart the engine and drive slowly without touching the steering wheel. This will allow the ColumnDrive to turn the steering wheel back to the ColumnDrive mechanical center if it is awake.

Note:
A correctly-installed system will continue to track close to straight-ahead.

A mis-assembled but awake system will turn the steering wheel away from the real straight-ahead position. The specified tolerance on that off-center position is half of one intermediate shaft serration or ±5 degrees. This is almost 1" of travel at the rim of the steering wheel. Due to the serrations, it cannot be set any closer than that, but it doesn't matter because variations in road crown and crosswind will affect the steering wheel position more than that.

[Capt. Bill]

Is there any way to eliminate the steering wheel 'Kick' of the CD when shutting off the coach?

[KenSherwin]

Don't stop with the wheels turned then let the CD bring it back to straight ahead because that winds up the tires. Then when you turn off the key, you have neither the hydraulics or the CD to keep the tires preloaded so they unwind with a vengeance.

To prevent this, either let the coach roll a few feet with the tires straight or pull it past straight ahead 90 degrees or so then let it come back to straight ahead. The whole goal is to eliminate that tire windup.

[Freestyle21]

I'm new to Newmar and learning something everyday. There is a lot of very good information in this thread alone.

[Drummer Mike]

A great thread!

I've been researching a purchase of a used unit for almost a year now and am zeroing in on either the 08 Dutch Star or Kountry Star. The CD is the capper for me. Reading everyone's replies on this and other threads simply states what a terrific unit Newmar makes...not to mention some brilliant engineering on the Comfort Drive Ken..

So much useful info on this iRV2 forum, even though at times it's a bit hard to separate the wheat from the chaff...but hey, that's what research is all about!

Thanks again everyone!

[Dutchstar08]

Every one talking about the various setting they use. Where are you seeing the setting numbers?
My 08 Dutch Star only has a black knob on the dash, no number.
And for what it's worth I don't feel any difference in steering from all the way CC to all the way CCW.
This is a new rig for us for our 2006 goof stream.

[SWag]

Originally Posted by Dutchstar08

My 08 Dutch Star only has a black knob on the dash, no number.
And for what it's worth I don't feel any difference in steering from all the way CC to all the way CCW.

Might be that your system isn't working properly. I notice a huge difference from one end of the scale to the other. I typically drive with the setting on 3, if I encounter steady wind on the side of the coach I'll dial it up to 4 and there is quite a bit of difference in those two settings. Amazing system for sure.

[spinn]

Originally Posted by Dutchstar08

Every one talking about the various setting they use. Where are you seeing the setting numbers?
My 08 Dutch Star only has a black knob on the dash, no number.
And for what it's worth I don't feel any difference in steering from all the way CC to all the way CCW.
This is a new rig for us for our 2006 goof stream.

My '08 Essex with CD but it is not adjustable, me thinks yours isn't either . I believe the variable CD offering didn't happen until 2010.
Steve

[racer0624]

FWIW, my '09 was adjustable.