Steering wheel "twitchy"

[Higgins]

I have a new coach with only 1600 miles on it. I have noticed between 60 and 65 miles per hours the steering wheel gets a little "twitchy". Let me describe the concern a little better. It starts to feel like there is "slack" in the steering, i.e a slight amount of movement in the steering wheel before a reaction. No vibration, such as is usually felt with out of balance tires, no vibration or feeling in the seat. Also does not feel like an alignment issue. Being a newby to heavy chassis vehicles I am looking for a little guidance. Thanks

[Higgins]

I have a new coach with only 1600 miles on it. I have noticed between 60 and 65 miles per hours the steering wheel gets a little "twitchy". Let me describe the concern a little better. It starts to feel like there is "slack" in the steering, i.e a slight amount of movement in the steering wheel before a reaction. No vibration, such as is usually felt with out of balance tires, no vibration or feeling in the seat. Also does not feel like an alignment issue. Being a newby to heavy chassis vehicles I am looking for a little guidance. Thanks

[Gary RVRoamer]

Just want to make sure that you have the optional Freightliner XC chassis and not the standard Workhorse UFO under your coach (cause the answers would be different).

A "twitch" in the Freightliner XC with Neway air suspension is certainly not normal and since it is new I would suggest invoking your Freightliner warranty to have them check it out. However, the very first thing they are likely to ask is have you weighed the coach and adjusted tire pressure accordingly. And also whether the coach has been aligned since being loaded with your routine gear. Both of these things are wise owners actions and I would do both of them before going to Freightliner. If nothing else, it arms you with some facts and eliminates some possible excuses for the poor steering.

[Higgins]

It is the XC chassis. It has never been under any load at all to speak of. I might have 200 or 300 pounds of gear in it along with myself and passenger. I have checked tire pressure and have it set at 110 per the sticker in the coach. I am taking it in to the dealer Wednesday for some other issues, maybe they will get me hooked up with the Freightliner folks here in town.

[hondo122]

Unloaded 110# seems high. On my fully loaded XC with Goodyear 670 tires I run 103 front 95 duals,per their rating charts. I would think that could contribute to the problem.

[Higgins]

Hmmm, I reviewed Freightliners recommendation again which is on the label next to the drivers seat and it says 110 all around. The owners manual says the same. Not being argumentative at all, I appreciate all the help I can get, but it makes me wonder why they would recommend such a high pressure in the tires. BTW mine has Michellins on it, don't know the model.

[notslo]

On my xc chassis journey 36 I had twitchy, sloppy, what ever you call it steering. I had some toad hitch slop which also came into play but I weighed the coach, I had been running 105 psi and the michelin chart said I should be 86 in front and 94 in the duals. I did that and it changed the steering about 100%. I think the psi on the coach tag is the maximum not what you should be using. They can't tell you as they don't know your running wieght.

[Higgins]

I am going to dig into my materials and look for that tire chart. Seems like from what some have said my issue could be tire pressure.

[historyljc]

My manufacturer's (Tiffin) chart specifies 110 psi all tires. If I were to load my coach to the weight the tires can handle at 110 psi I will have overloaded the capacity of the axles. The manufacture's set psi rating at the maximum to cover themselves in case someone loads the their coach to the max. If you're not loaded to the max, your coach will not ride well and can have steering problems.

What I call "excessive freeplay" in the steering can have several contributing factors. Have the alignment and ride height checked. Weigh the coach as you will travel and set the air pressure in the tires according the tire manufacture's chart for your size tire and load. With the XC chassis you'll probably find that Henderson's Motion Control Units make a big difference in ride and handling.

[Gary RVRoamer]

The sticker by the driver seat shows the tire pressure needed when each axle is carrying its maximum rated load. You are no where near that and so the tires are very hard relative to the load. That will result in reduced tire contact with the road and that can be "squirrelly" at higher speeds. I'd weigh the coach and adjust tire pressure downwards per the tire manufacturer's tire inflation tables - I'll bet the problem goes away.

[diesellabs]

Ditto...

You should look at the tire manufacturers weight/pressure specifications (there may even be that section in your bag-o-books, or you can go to their web site). But a trip to the scales is needed. You can extrapolate somewhat on what additional weight you may end up carrying and adjust upward...but no way you should be running 110# on a near-empty coach).

[Higgins]

I took the coach into the dealer today for the steering issue and several others. The service guy seemed very knowledgeable about things. He stated what I was probably experiencing was a "sensation" that the coach was actually drifting and I was over correcting the steering. He explained that the coach will move around a bit on the air suspension, while the chassis is tracking straight as an arrow. I told him I did not think this was what I had felt. In any event what really got me was when he told me that he would be glad to take it to the Freightliner shop for examination but if they found no problem I would have to pay for the service and it would not be covered under warranty. I have never had that experience before. He stated he will test drive it and see for himself. If he thinks something is wrong and he assured me he would know he will take it to Freighliner. It still bothers me that I should have to pay, even if I am wrong. I will see what the service guy says.

[Gary RVRoamer]

Don't take chassis problems to an RV dealer - few of them have a chassis shop or competent chassis mechanics. Your chassis is covered by a separate warranty from Freightliner, so take it there yourself and deal direct.

[Bikeboy57]

I suggest you set the toe in at 2/32. Most alignment shops will set it at neutral or slightly in to maximize tire wear.

I know the sensation well, I spent many hours trying to find the cause on a Freightliner XC chassis. The cure was incredibly simple once I had the right poop.