Koni Shocks

[Jon Wehrenberg]

$1700 to buy and install 8 shocks???????????

Wow!

[Gary & Peggy Stevens]

I am talking to the Jim Koni Shock Rep about the issue of their shocks not working on the rear of a Prevost's ?

I explained what some of you had found out, but he had heard of ONLY ONE instance where the dust cover of the shock was hitting the frame and needed to be notched out.

He is calling Prevost to find out what the story is, cause he said if there is a PROBLEM with their shocks he wants to get it fixed so we can contnue to use their products. Makes sense to me.

I hope I didn't stir up some s*** up with Prevost Ft. Worth, but I am just trying to get to the bottom of this before I replace all my shocks.

Gary S.

Gary S.

[Gary & Peggy Stevens]

Just an Update to the Koni Shock issue.

Jim from Koni called me back after talking with Prevost. Apparently there can be an issue with ONLY the Tag Shock Dust Cover hitting the frame. But it has about as good a chance of not hitting the frame when installed as it does hitting your frame. Some guys have replaced and had no issues.

So I asked Koni, if he would suggest another mfg for at least the Tag axle and he said, possibly Monroe, but to check the clearance on that shock as well.

Koni will be taking down the web site listing their Tag shocks as working on Prevosts.

NOW what say you guys about the best possible shocks to replace all around on our bus? Oh, I also called Monroe to see if they had a listing for the correct shocks for my bus, but they have to have the OEM's part number or at the very least all of the dimensions of the shocks I am trying to replace.

Anybody out there have all those numbers for an XLII?

I like to have uniformity of equipment if at all possible. Same Tires, Same Shocks, same Wine Glasses, etc.etc.

Gary S.

[jack14r]

I am surprised that there are some problems because Prevost builds these coaches in a jig that they claim is within thousands of an inch from coach to coach.

[Jon Wehrenberg]

The problem may be that the shocks are attached to the chassis frame (which is precise), but the other end of the shock is attached to the floating suspension assembly. There is a great deal of compliance in the moving structure that carries the wheels and that structure not only goes up and down, but on warped surfaces one side of the structure can have the shock compressed while the other side has the shock extended and is moving in an arc in up and down directions in two planes. I would guess that is where the interference comes about.

Superficially it might seem an easy fix, but I suspect when the CAD analysis of the location of the shocks is made the computers do not factor in movement in bushings and the slight deflection of the structural members due to side forces. Whenever I change a hose or a part such as a fitting I run my bus all the way up and all the way down through full range of motion to insure I have not changed clearances between parts, but I cannot duplicate the relationship of parts that might exist when the coach is exposed to side forces such as a tight turn.

[michaeldterry]

So Jon or somebody - bottom line it for me - what is the current consensus conventional wisdom if one wants to replace all the shocks on a 1995 XLV chassis? I was really liking what I was reading about the the improved (stiffer) ride afforded by the Koni adjustable shocks, but now am confused as to which shocks to choose given the recent disclosures about possible clearance issues....

[pwf252]

Jon, Are you saying WOW good price or WOW bad price??? That quote was for 6 Koni's and 2 OEM. Well that quote was actually rescinded since they claim they can't install Koni on the rear. Anyway I was talking to one of the techs at Fort Worth that apparently came from Tennessee Prevost and he stated that he has put the Konis on quite a few buses and has never heard of any problems . I decided to put them on the front for now and wait on the rear until there is a clear consenses on whether they foul or not.
You know these buses are hard enough to afford and maintain without all this darn confusion.
Now let me get this straight extended life or more frequent changes of the antifreeze??????? JEEEEZ!!!!!!!!!!!!!!

[Jon Wehrenberg]

I don't remember the exact price I paid for the standard shocks, but it was under $50 apiece.

Add $100 to the price of six Konis and you get about $1150, leaving $550 for labor. First, at the price of Koni shocks they have to be so good anybody can tell the difference, something I doubt. If they were that good, Prevost would spend an additional $1000 (on a $450,000 bus or 0.2%) to make them standard. Apparently Prevost does not think they are worth it. As to the cost of labor I think that is a little high, especially considering the Prevost techs should possess the expertise and efficiency to do the remove and replace far more efficiently than anyone else.

I am changing to extended life after the Kerrville rally. I have no clue what my cost differential will be to go from 2 year changes to 6 year changes, but my reasoning is changing coolant is a pain and takes a lot of time so I want to make my life easier.

[Steve Bennett]

I have driven coaches with both (XL's, XLII's & H3's) the difference is noticeable on the front end. The shocks on our busses provide most of their resistance in rebound, with very little compression dampening. My feeling is that the Konis (depending on the setting) will settle the front end of the coach, and eliminate the tendency to pitch. This is most evident on large undulations, particularly when they are of a frequency that amplifies the size of the bumps because of the distance between the bumps matching the wheelbase, etc. My personal feeling is most people will not notice the difference in the rear, but the Konis are likely built to a better standard than the OEM shocks, and may offer a longer service life.

[Jon Wehrenberg]

Don't forget Steve that the weight distribution and the combination air bags and shocks plays a role.

In the early 90's there were two converters who were exceeding Prevost axle weight limits and a pair of shocks and the size air bags used were inadequate. The excessive front axle weight was in excess of the capacity of the shocks and air bags to control jounce and bottoming over the very road conditions you describe. I am sure you are aware that brought about the use of the Mae West airbags and in some conversions the modification to a 4 shock setup.

My point is that while the difference may in fact be noticeable to the average driver on some coaches, other coaches with different weight distribution and air bags it may not be discernable.

For those owners who are looking for direction from owners as to which shock is best I really believe the decision has to be made in the context of the age of the coach, the converter and the axle weights. I have standard shocks (Monroe I think, I would have to confirm) and I have not experienced rebound or jounce issues.

There is no doubt the Konis have a good reputation and installing them to get a better (presumed) quality may be good enough reason to install them. FWIW I have driven my coach and an IFS coach on the highway and secondary roads for several hundred miles and would be hard pressed to identify which was which if I were blindfolded and in the passenger seat. I did not detect a measurable difference as a driver. Maybe my seat of the pants senses are not as good as others.