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Topic: 2001 320 suspension 40' (Read 1807 times) previous topic - next topic

2001 320 suspension 40'

Confused:  When reading the original specs, this unit is said to have 8 air bags and 8 Koni shocks from the factory. We have a 112K on the unit now. Purchased recently. In love with coach.

However, I ordered new shocks and now have learned there is only 1 air bag and 1 shock instead of two in the front. It appears to have independent suspension up front. Can anyone tell my why?

David

Re: 2001 320 suspension 40'

Reply #1 –
Standard WAS 8 outboard air bag suspension with 8 shocks and solid front axle.

Optional and found on only a handful of Foretravels was the IFS front suspensions.

They take a very different shock than the solid front axle coaches.

Re: 2001 320 suspension 40'

Reply #2 –
As I recall, the air bag for those IFS front suspensions in '01 is MUCH larger than the standard air bag used on our coaches with solid front axles.

Re: 2001 320 suspension 40'

Reply #3 –
Thanks for the update guys.

Brett, did they have success with the IFS?Did they only use for the one year? It handles very well. I was experiencing some porpoising and felt like a pretty definite thud on bridges and such. All the bushings look good. I am suspecting with 112K, the shocks were probably in need of changing?

Any thoughts or anything you think I need to be looking for?  The air bags do not appear to be much larger that rears. How can they compensate for leaving off 2 air bags and 2 shocks?

David

Re: 2001 320 suspension 40'

Reply #4 –
David,

First thing is to verify that ride height is to spec.

Check with Foretravel parts or James Triana for their suggestion on what shock to use as replacements.

 It may be that you have Koni adjustable shocks that can be adjusted to give a firmer ride. They are red-brown in color.

Brett

Re: 2001 320 suspension 40'

Reply #5 –
Brett,

I have heard about checking ride height. Is this some or test I can perform myself? What are the specs? How is set?

Thanks,

David

Re: 2001 320 suspension 40'

Reply #6 –
David,

I don't have front end ride height specs for the IFS.  Check with James Triana at Foretravel.

Ride height is measured with a tape measure with coach on dead level ground with suspension aired up.

Also, check on the color of your shocks (assuming they are Koni).  If red-brown, they are adjustable.  Check them (as you would any shock) for oil leakage and bushing wear.  When you go over a parking lot speed bump at regular low speed, how many times does the front end bounce?  What about rear bounce?

Re: 2001 320 suspension 40'

Reply #7 –
Brett,

What is the top measurement? Top of fenderwell arch I suppose?

I will call Mr. Triana on Monday.

I know the shocks are red, don't know about red/brown though.

Thanks,

David

Re: 2001 320 suspension 40'

Reply #8 –
Suspect ride height measurement will be from some "hard  part" vs fender. But, look forward to you getting the info from James.

What is the Koni part number that is stamped on the shock?

Re: 2001 320 suspension 40'

Reply #9 –
Quote from: dwest –
Brett,

What is the top measurement? Top of fenderwell arch I suppose?

In some cases, ride height is measured as the vertical distance between the metal mounting plates of the airbags - basically the airbag rubber height. 

Ride Height Adjustment [ForeForums Foretravel Motorcoach Wiki]

But James will know for the IFS coaches.  He can also answer other questions you may have more easily if you provide your 4-digit build number.

Red/orange shocks should be Koni Adjustables.  Gold would be FSD which are non-adjustable (have frequency sensitive dampening built in).

Congrats on the coach and welcome to Foreforums!

Michelle

Re: 2001 320 suspension 40'

Reply #10 –
Quote
How can they compensate for leaving off 2 air bags and 2 shocks?
The four air springs are actually a but overkill for the weight on a front axle but apparently FT wanted to use the same components on the front as on the back (unless it was an IFS).  When I worked at Country Coach in the chassis group it wasn't uncommon to hear customers complain of porpoising (all their chassis' had IFS).  They put the largest shock in they could but sometimes people wanted more.  This might be one slight disadvantage of IFS but you have a huge advantage when it comes to turning radius - so enjoy it.  I would still check into new or better shocks but it's just something think about.  The Golds (which were not available when your coach was built) are supposed to be quite better - any you only need to buy two :)

Re: 2001 320 suspension 40'

Reply #11 –
Quote from: JohnFitz –
When I worked at Country Coach in the chassis group it wasn't uncommon to hear customers complain of porpoising (all their chassis' had IFS). 
That's interesting.  Is that common in all RV's with IFS?  Having IFS would be one of the factors in my buying decision if I ever wanted another RV.  I thought IFS was a big upgrade.

Re: 2001 320 suspension 40'

Reply #12 –
I would suggest IFS is more a current buzz word than an across the board improvement.

There are good ride and handling coaches on solid front axle and those on IFS's.

There are poor ride and handling coaches on solid front axles and those on IFS's.

There IS more maintenance on IFS suspensions, as some of the front end geometry that is built into the solid front axle suspensions is not built into IFS's.

Koni does not list an FSD shock for the IFS suspension.  You might contact them after you find out from James Triana about ride height AND exactly what IFS suspension you have.  Also, tell Koni the part number stamped on your shock.

But, as stated earlier, you loose nothing by removing the shock you have and adjusting them firmer (unless shocks are bad, bushings bad, etc).  Instructions for adjustment are simple, require no tools and take less than one minute after the shocks are removed.  This applies to all Koni red or as I call them red-brown color shocks: Koni-RV.

Brett

Re: 2001 320 suspension 40'

Reply #13 –
I had and some customers had in demo drives real issues with the early IFS suspension on various country coaches. Coach could not be driven from the bottom of the wheel.  Required constant input. 

Don Fults, dick Martin, don kelly from country coach all told me it was fine.  No way.  And it porpoised. 

That was then.  Unknown on foretravels or later stuff.

Bob

Re: 2001 320 suspension 40'

Reply #14 –
Thanks everyone for their input. I am going to be in touch with Triana tomorrow. Just to clarify, the coach drives beautifully and handles great. My concern was porpoising  (not badly) and a definite thud when hitting raised areas road.

David

Re: 2001 320 suspension 40'

Reply #15 –
Just so you know - if you have an IFS coach its a rare one. It was like an $18,000... option and I believe there were less than 10 made. I thing Barry may have some numbers on that. It was a love it or hate it option.

Re: 2001 320 suspension 40'

Reply #16 –
David sent me a PM-- others may benefit as well:

I still do not have color. Coach not close by. But, yesterday I wrote down numbers on shock before leaving. two sets of numbers.  #2799  and #901968SP1. The latter doesn't sound like the number you need?

When you mentioned adjusting, is this a matter of twirling shock say clockwise or counter to lengthen or shorten?

I assume once the right height is correct you would synchronize them by maximum extension? All this assumes they are adjustable of course.

David


David,

I looked up that shock in my old Koni Catalog.  The Koni 901968SP1 is the larger size (90 series vs 88 series) and has a compression value (13 ips) of 169 and rebound ((13 ips) of 2765. That is a significant dampening force on rebound (where you want it, as dampening on compression adds to ride harshness) and should be a good beginning point for adjustment.

Try adjusting them-- see my earlier link-- adjustment is NOT for length, but for dampening on rebound!

Let us know what you find-- no idea if yours are set full soft or full firm.

Brett

Re: 2001 320 suspension 40'

Reply #17 –
I'm not sure if this is the exact series you have...
Koni North America - ITT - Adjustment
BTW... I always thought the color was orange (maybe just faded red) ;)

Re: 2001 320 suspension 40'

Reply #19 –
The "thud" you are experiencing is almost certainly the air bags set too low not giving enough suspension travel.  I had same problem.  Set everything to spec. and now all is well.  Shocks really won't help with a bottoming suspension.  They do not support the coach only control rebound.  As Brett suggested first call James and get the info for your coach and set the ride height to specs.  Take it for a ride and see how it behaves.

Keith