Community Forums

dr2casto · 09-09-2014, 08:22 PM

I am asking this question for a friend, additionally I am new to the forum but have already found it handy to reference for much needed info.
Question: Are the tag axle wheels supposed to lock in straight position while backing?
Reason for asking: Today while my friend was backing I noticed his tag axle wheels turning in horribly opposite direction they should have (if they were supposed to turn at all) than what would have been appropriate to assist in turning the vehicle a 45' American w/Spartan K2 Chassis. (Note: This occurred on a gravel surface)
I had him pull into a straight position and try several attempts at this procedure again and got mixed reactions from the tag axle turning in opposite directions while in reverse.

What I read so far seems to state that the K2 Chassis is supposed to "lock" the tag axle in a straight position while in reverse. Is this correct? Any help on recall or things to check would be helpful as we are at a remote camp ground.

Skip426 · 09-09-2014, 08:44 PM

The tag wheels are locked , and the condition you observed is called scrubbing; because the chassis is pivoting, on the duals, the tag has to drag sideways , with side wall flex, in order to stay behind the axle.
The sharper the turn backing up to more pronounced the scrub.
If you see a dual axle TT. or 5er , doing similar turn , you will see the same thing.

BTW. Welcome to iRV2.

dr2casto · 09-09-2014, 09:20 PM

skip426.....
Thanks for the reply....but I mean the tires are turning "as in" not locked.....scrubbing is just when the tire flexes correct? The wheels are actually turning while in revese, and I believe that his vehicle is "not" locking into a straight position before he begins to reverse......I think the "locking" mechanism is malfunctioning correct? Thanks for the quick response.

DieselTech39 · 09-09-2014, 09:22 PM

Glad you're aboard. When you say "turning in the opposite direction", do you mean the tires seem to be pulling off the rim, or do you mean the tires and wheels are pointed in the opposite direction of the direction of the bus? I am not aware of any American that has a steerable axle, but if it were, as you say it is, and the wheels and tires were turning opposite of the turn it could be because there was no weight on them; or, if equipped as you say with a lock, then that suggests the lock is not working. JMHO Best of luck in finding an answer. Enjoy your adventures and be safe.

[Edit] I read your above post after I posted...type too slow....do you mean they are turning as in rotating on the axle; or, do you mean as I posted above. Thanks.

Skip426 · 09-09-2014, 09:40 PM

You could try Spartan MH Support.
They may require serial number and pictures.
1-800-543-4277

Gordon Dewald · 09-09-2014, 09:43 PM

I am not aware of any steerable tag axle on MH.

I am having difficulty visualizing what turning in the opposite direction actually looks like. I am visualizing the back of the coach turning to the left. If the axle has been dumped the tag tires should skid on the pavement or ground with a slight flex of the sidewall to the right. If the tag dump is not working (air has not been dumped) the skid will be more difficult as the tire has more traction and the flex of the sidewall will be significantly pronounced depending upon the skid resistance of the surface the coach is on.

Gordon Dewald · 09-09-2014, 09:46 PM

Quote:

Originally Posted by dr2casto

skip426.....
Thanks for the reply....but I mean the tires are turning "as in" not locked.....scrubbing is just when the tire flexes correct? The wheels are actually turning while in revese, and I believe that his vehicle is "not" locking into a straight position before he begins to reverse......I think the "locking" mechanism is malfunctioning correct? Thanks for the quick response.

Scrubbing is the tire skidding on the surface the tire is in contact with. It will either leave black marks on pavement or turn up gravel etc on a gravel parking lot.

PDR John · 09-09-2014, 09:51 PM

Starting last year passive steering tag axles became available on motorhomes.

Your friend is having a problem, the tag should lock straight when in reverse.

CALL SPARTAN!!!

As you can see by the responses here, there is not enough experience with them for us to help.

Please post up what he learns.

DieselTech39 · 09-09-2014, 10:00 PM

Quote:

Originally Posted by PDR John

Starting last year passive steering tag axles became available on motorhomes. Your friend is having a problem, the tag should lock straight when in reverse.
CALL SPARTAN!!! As you can see by the responses here, there is not enough experience with them for us to help. Please post up what he learns.

Thanks John. I thought I read that somewhere and I found these:

Spartan Chassis

Spartan Chassis

https://www.youtube.com/watch?v=hP9g0wN_pwo

I know it's an American but the video is just for example of how it works.

I agree, call Spartan. Could be any number of reasons.

Please post what you find out.

dr2casto · 09-09-2014, 10:22 PM

You are correct....the wheel is not locking while backing.....the tag wheels are turned either way left or right, no particular direction after repeating the backing procedure several times the tag "wheel and tire" turn randomly.....I will call and post the solution when I find out.
Thanks to all you who answered.

Gordon Dewald · 09-10-2014, 08:07 AM

Good to know. Learned something new.

Looks like it could be a good thing if they can make it bulletproof. It would be a major inconvenience if this went wrong while you were trying to back into your RV site. Ergo a situation such as the OP has encountered.

There should be a manual way of locking the axle straight if it does go wrong. Does the manual make any mention of a corrective action or work around? Or do you just bite the bullet and back up until you are where you have to be or something really goes wrong?

Ramets · 09-11-2014, 05:48 AM

I talked with the CEO of Freightliner at the Tampa super show last Jan. Their new tag is steerable(?). But he said it's supposed to lock when backing. I think I remember him saying that Newmar was going to use his chassis on some models.

Tony Lee · 09-11-2014, 05:56 AM

It is the same as the front wheels on a toad. When you pull the toad forward the castor geometry allows them to steer with the turn, but if you try to reverse when towing a toad, the toad front wheels will turn to full lock and get pushed sideways along the road.
If the copilot gets in the toad and holds the steering wheel then a toad can be reversed with care.

336muffin · 09-11-2014, 06:08 AM

I'm confused.........the tag axel tires roll but don't steer. If he is in reverse long enough the tag air bags deflate thus taking off the pressure to the ground. When this happens and the driver is using the brake the tag tires can stop rolling and slide. I am not aware of a American Coach with a steering tag axel.