Opinions on Prevost's IFS (Independant Front Suspension)

[OneLapper]

Can anyone provide some opinions on the IFS used in a 1998 Prevost XL?  I'm looking at a diagram and it seems overly complicated, maybe even expensive to fix ( ).  Is it an option that should be avoided?  Is the ride noticeably better than the solid axle?

Thanks!

Mark

[TomC]

Ride is much better, handles better, and turns much sharper. I doubt you'd put enough miles on a sound front end to wear it out. Practically all buses and high end motorhomes are using IFS.

[luvrbus]

From 1997 to 2002 they were a nightmare and they are very expensive to repair 3000 bucks a side for the upper A frames,the ride didn't seem that much better on our 1997  with IFS than our friends 1997 with the straight front axle.They did a lot of improvements constantly up to 2000 and 2002 they made it much better it's still big bucks to repair that hasn't changed   

[muldoonman]

Comparing the ride and handling on the Class A Holiday Rambler's I've owned in the past, I wonder how much better the ride is on the newer Prevost models with IFS. My 1991 XL rides and drives a 100% better than the Class A's I've had.

[buswarrior]

As a seated coach driver through those years, in a first line fleet that mixed Prevost H3 and MCI D,E,J models

Didn't notice?

The maintenance shop may have...

Choose your conversion based on its overall condition, and understand the repair costs that you may be exposed to shortly.

Don't buy a coach that has systems used up, you'll go broke...

happy coaching!
buswarrior

[TomC]

With my transit, and straight beam axle with steering gear mounted on the axle, the turning is sharp. It rides well, I have never understood the need for a driver's air ride seat. The simplicity of the standard 4 air bag per axle air suspension is enough for good ride, and cheap to service. The only thing I've done to my suspension system was new air bags and convert from manual air assist steering to Sheppard hydraulic. Haven't had it aligned, or changed any bushings. Good Luck, TomC

[HB of CJ]

Just as a comparison of very old stuff, my 1974 Crown Supercoach 40 foot 10 wheeler rode quite firm using plain old leaf springs with big tube shocks.  Make that very firm.

16,000 pound front axle and springs to match.  The "Drivers" had the old fashioned Hendrickson Walking beam suspension with many leafs.  Rated for 34,000 pounds.  Yikes.

Factory GVWR was "only" 43,000 pounds.  Stripped empty weight was right at 24,500 pounds.

The turning circle was also quite limited.  Make that large.  We called her the "Queen Mary" when making tight left hand turns.  I imagine new stuff is very soft and nice indeed.

When empty the Crown frankly rode like a truck, but handled like a sports car.

The road manners of the Crown, even when dead light empty, were truly excellent.  Mountain curves could easily be taken at speed keeping up with fast traffic.  Amazing bus.

[Jon]

Clifford's answer was right on the money. As someone with around 300,000 miles of straight axle driving before I had the chance to drive an IFS equipped Prevost I can say my butt is not sophisticated enough to even detect the slightest difference in the ride between the two. The turn radius was the only clue. It is sharper in the IFS.

I have about 50,000 miles of IFS under my belt now and the only real difference to me is a few more grease fittings.

[Geoff]

General Motors, the genius of bus building, came out with IFS way back in 1977-78 with the RTS buses.  I have a 1982 RTS 40'er with the independent front wheel suspension and having driven newer RTS's where they did away with IFS for a lower maintenance I beam front end;  I can tell you the riding quality ride of the RTS IFS is far superior to the I beam.  When you hit a bump on one side of the bus it doesn't carry over to both sides of the front making for a much more smoother ride.

--Geoff

[luvrbus]

Eagle has had IFS since 1958 but they got right the first time ask any Eagle owner 

[daddyoften]

General Motors, the genius of bus building, came out with IFS way back in 1977-78 with the RTS buses.  I have a 1982 RTS 40'er with the independent front wheel suspension and having driven newer RTS's where they did away with IFS for a lower maintenance I beam front end;  I can tell you the riding quality ride of the RTS IFS is far superior to the I beam.  When you hit a bump on one side of the bus it doesn't carry over to both sides of the front making for a much more smoother ride.

--Geoff

Correct me if I'm wrong but doesn't my 4107 have air ride IFS? I'm sure the 4106's had the same setup. I'm not sure about pre that though. I drive a 2015 kenworth with a straight front axle leaf spring and I love driving my bus hands down compared to that :-)
Eric

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[OneLapper]

The 4107 and 4106 have a solid front axle.  What makes the ride nice in these old buses is the four front airbags.  The Kenworth is most likely on left springs (taking a guess here).  Theoretically, on a bus with IFS, if one wheel hits a pothole the other wheel is not affected.... except for the jolt through the steering drag links, etc.  So, IFS should be better, but it's not THAT much better that it's worth seeking out.

The Prevost in question here has brand new upper and lower control arms left and right at $3800 per side (according to the receipts).  Not including the above control arm ball joints, I count 12! tie rod, control arms, drag link, relay rods, idler and bell crank ends.  If one is worn out, the alignment is off.  Just seems overly complicated.  Replacing all those ends, if it needs them, is going to be costly affair.



 

[Jon]

I have had two solid axle Prevost coaches, and one IFS. It is true the solid axle coaches are simpler, but there is no way I would consider the type of front suspension to be a deal breaker. There are so many other considerations when buying one, the front suspension doesn't even come close to being of importance.

[OneLapper]

IFS or solid axle, neither is a deal breaker.  I'm considering a Prevost with IFS.  I saw that the seller just installed upper and lower control arms so I was wondering about the other 12 tie rod end in the system.  With 12 tie rod ends, it just seemed like a complicated system.  But if it works, then I'm not too worried about it.  I'll check the entire system out before I commit to it.

Thanks for all the info!

[luvrbus]

You will probably end up replacing all the tie rod ends it's just a high $$$ maintenance item on a Prevost there is no way around it.Just in case you don't know Mark be sure the weight is off the wheels before checking 

good luck on your new purchase