99 Riv bounces like Tigger!

[adoldfield]

I have a 99 Riviera with 35,000 miles. It rides like it has badly worn shocks but my Buick mechanic tells me all is in order, and my air ride suspension is fine. But it bounces up and down on any little dip in the road like the shocks are gone. Help! What can I do to firm up the ride? new struts? any other ideas? I know it is supposed to have soft ride, but this is ridiculous.

I appreciate yoru wisdom.

Alan Oldfield

adoldfield@aol.com

[Guest my3buicks]

Try another Buick Dealership!!!!!

[Dominic_Martinelli]

Alan,

What kind of tires do you have? From the factory, nearly all of them came with Goodyear Eagle GA's, a touring tire. When I purchased my 98 Riv a little over a year ago, my car had Kelly-Springfield Navigator Golds which are regular passenger tires. I have since replaced the tires with Continental Contitrac Tourings and the ride has firmed up somewhat. The car still does the "Buick Bounce" down the highway with only 42,000 miles on it. My dealer's service department has told me that my struts are fine too. Guess these are just really squishy riding cars!

-Dominic

[NTX5467]

The first LeSabre I rented along about in '98 was really an eye-opener for me. It was like they were trying to keep the old big car ride in the smaller car, as best they could. When the car went into a dip, the suspension compressed, then rebounded upward as the car left the dip, then compressed again as gravity took over, and then a final upward motion as the springs resisted the final compression. It WAS smooth, but hardly what I prefer. The car had 17,000 miles on it too. I thought the struts were worn out until I found earlier version Park Avenue out on the interestate and the LeSabre matched it up and down and such exactly. As long as the pace was "deliberate" and turns were slowed down for, things worked fine. Definitely not much damping in those struts!

Tires can make a difference, it seems, to take some of the softness out of the car's ride. That LeSabre had Generals on it. Something with reinforced sidewalls and stiffer tread (compared to the OEM tires) might help.

In previous discussions, one owner recommended KYB gas struts as helping firm things up at a reasonable price. We used to put Bonneville struts on the Buicks that had complaints of being too soft, but after I rented a Bonneville, I don't know if that's a really good choice--of course, in the Delco aftermarket they're usually all the same. From my research on the net, seems that KYB is the only brand with any performance aspirations at all. No KONI or Bilstein or equivalent were found in any listings.

Yes, the calibration probably felt ok when new, but it probably is too soft now that there's some miles on them. Seemingly pretty much "normal".

Also be aware that many of the aftermarket brands (Monroe, Gabriel, and similar) will be cartridges for your struts instead of assembled strut assemblies. The extra labor time to install the cartridges can eat up their initial price advantage.

Just some thoughts,

NTX5467

[86 2dr.ltd]

Our LSS does the boat float too and thats with the somewhat stiffer suspension. It still handles well for a big car, so I dont know if it has progressive rate springs. Its only soft on the top 1-2". It doesnt ride like a car with shot shocks but it does take a second dive.

Eibachs sells a set of springs for 95-96 Aurora, nothing for Riv. and they are lowering springs. Dont know if they are stiffer of same dimensions.

Maybe a set of old LeSabre T-type springs <img src="http://www.aaca.org/ubbthreads/images/graemlins/wink.gif" alt="" />

Tougher struts like the KYBs will most likely help until they get tired of trying to hold the car up but these cars really need more spring rate. Maybe there is a few different spring rates like there used to be.

[Guest Straight eight]

Had you thought about Air Ride inserts? See http://www.centuryperformance.com/detail.asp?Product_ID=ARL-60776. I used these back in the 40s when the front springs were so weak the alignment could not be brought into specification. After installing the inserts it took 6 pounds of air in one and eight in the other, and the front end was all aligned! Don't know how these would behave with today's suspension. Cliff Herold BCA 2366

[NTX5467]

I kind of doubt that these inserts would interface very well with strut suspensions where the spring is outside of the shock absorber structure (i.e., like a "coil over" somewhat). On one of the older cars where the shock absorber was not inside of the coil spring, they would probably be ok, though.

There are some similar inserts for GM motorhome applications where the shock is not inside of the coil spring. Only thing is that you would have to run some airlines as the GM items are just the airbag insert itself.

Eibach springs typically are a little stiffer than factory springs and also will lower the car about an inch or more. Aurora and Riviera are the same basic platform in those years so there might be a little crossover in that respect. Kind of similar to most of the performance stuff for the Regals being first found in the Grand Prix websites.

NTX5467

[Guest Straight eight]

I just went out and looked at mine, and unless Buick forgot something, my rear coil springs are just that, and not supported by a strut in the middle of the spring.

A note from Air Lift states

We fit the rear suspension only on your vehicle. Kit #60776 fits inside of the rear coil springs to add up to 1000 pounds of additional load support. a little air pressure will firm up the rear suspension.

Mike Pung, Air Lift Company

In view of above, this may help our problem.

Clifford Herold <img src="http://www.aaca.org/ubbthreads/images/graemlins/grin.gif" alt="" /> [color:"blue"]

[86 2dr.ltd]

They call the rear "shocks" struts because they are long and go into towers but its true the rears dont have the spring around them. The problem with these front heavy front wheel drives is in the front however. Stiffining the rear may (I dont know) give more handling problems as in uneven body roll = unbalenced.

NTX I wish I could get all the H/W and RIV/TORO/AUR springs and set them side by side and see whats really different, then get them rated.

[NTX5467]

Even with the current batch of front wheel drive cars, or even the rear wheel drive cars which have the same general 60% forward weight bias, the increase in handling is usually the result of putting more stiffness into the rear suspension with springs and larger roll bars.

In prior times, the regular suspension had a "normal" sized roll bar in the front. The upgrade suspensions usually had stiffer springs and shocks all around, plus the addition of a rear sway bar (or a larger one if one was standard). Put some performance oriented tires in the mix and you had the GM F41 code suspension (later variations were also called FE2 or FE3 in some cases).

For example, the 2004 Grand Prix has two basic suspension calibrations. The first one covers all of the Grand Prix cars except for the GTP with the Competition G package. The only real change is from 16" to 17" wheels and tires for the GTP model. For the Comp G package, the rear suspension is stiffened up with different sway bars, stiffer rubber bushings, stiffer rear springs, and the BFG Comp TA KD tires round out that particular part of the package (there are several other items in the package also).

Yes, there is a particular balance between the front and rear with respect to spring rates and sway bar diameters on these more nose heavy vehicles. Sway bar size for the rear usually should be about 75% as stiff as the front one, as I recall and have observed. The whole idea of putting more roll stiffness in the rear is to let that end of the car do more work in the corners instead of all of the roll resistance being in the front end of the car and overloading the front tires quicker. Having too much roll stiffness in the rear can make the rear end of the car reach its limits earlier and resultantly spin out, but it takes some extreme measures for that to happen considering that a good deal of understeer is designed into modern cars. "Understeer" is where the front end of the car slides off the road first, "oversteer" is where the rear end goes first. Ultimately, for completely balanced handling, both would slide at the same time, but it's usually better to have a little understeer at the limit as if you just slow down a little, things come back into line much more easily.

The other variation that you might experiment with is tire pressure. We all know that tires have a particular load carrying and handling capacity that can increase/decrease proportionately with the relationship of load and air pressure. I found out years ago, that in a car with a 55% forward weight bias (typical of front engine rear drive cars of the middle '60s), that using 30 front/28 rear made the car handle and respond better to steering inputs. Plus, it kept the contact patch more even for longer wear. This was when 32 psi was the max inflation pressure and 28psi was the minimum pressure recommended for high speed freeway driving (up to the 75mph or so range) and 24psi was the minimum inflation/smoooth ride inflation pressure. These are things I discovered on my own and you should proceed at your own risk if you do them on your vehicles as the typical factory inflation pressures of the earlier times called for more air in the rear tires than the front. Modern vehicles usually recommend the same pressure in the front and in the rear.

As for which springs have which stiffness and such, GM has become more ambiguous on those issues in more recent times, just giving spring codes for particular applications in the parts database. That means that you'll have to find a Moog or similar chassis parts book that covers springs. In the back is a specs section that details the ride rate and such of the each spring they sell. This is about the only information you can find, but it can also point out which cars have the stiffer springs within a platform family too. What the aftermarket people might sell might not exactly match what GM puts on the cars, but it's a pretty good "ball park" situation. Plus, the aftermarket springs are sold only n pairs. Eibach is a high quality spring manufacturer whose claim to fame is basically lowering springs. There might be some others of merit too, other than the OEM replacement aftermarket springs. Might check some of the Pontiac websites for some additional information also.

Hope this might help explain things a little better . . .

NTX5467