I’ve had a 1997 Infiniti I30 (Base, non-touring) for about 3 years now. Mileage is coming up on 92k. Engine’s fantastic, transmission shifts brilliantly for a 4-speed, all accessories work. The problem is the suspension, and I don’t know what else to try. On a smooth road, the ride is impeccable. Buttery, silky, but not oblivious. The trouble appears with the introduction of even slight bumps. They make their presence known, both audibly and physically. The only thing I can say to describe is that it feels and sounds like there is very little that the suspension is actually doing. It feels like a smack in the butt, and it sounds like the suspension can’t handle it. This is just the smaller bumps, the large bumps are downright jarring.
I have replaced the struts (Monroe Sensa Trac all around), strut mounts, sway-bar bushings & links, and most recently the entire front control arm on both sides (not all searching for this fix, but hoping they’d at least offer some relief). No dice. Bumps of all shapes and sizes still intrude into the driving experience.
In comparing to other cars, I’ve ridden in a '96 Infiniti G20, '95 BMW 318i, '95 Chevy Lumina. I would describe their bump-handling characteristics as sort-of letting you know something was there, but in a very mannered sort of way. The bump wouldn’t every jar you (unless it was a massive hole), and very rarely made much of a presence at all.
I’m stuck. I have no idea what to even think about looking at anymore. Mechanics I’ve taken it to haven’t mentioned anything else. Any ideas?
I wonder if somewhere along the line your tires were over-inflated. My suggestion is to spend $10 on a good tire gauge and see if the pressure matches the recommended pressure on the placard on the left door pillar for the manufacturers recommended pressure. Do not go by the pressure on the sidewall of the tire. This is the maximum pressure the tire can take. It’s worth a a try and if this isn’t the problem, you have a tire gauge for future use.
When you check the tire pressures (with a good gauge, round dial or digital) also check the amount of tread, worn tires can ride noisier/slightly rougher.
What sort of tires are on this car, and how old are they?
Tires were about the first thing I tried playing around with. When I got the car, they had a set of Michelin Harmony tires on there. Traction in the rain was terrible and I wanted something I could leave on year-round and still get around in the snow, and noise levels were too high. I replaced those with Bridgestone Potenza RE960 tires (these are all stock sizes, 205/65-15). Traction improved but eventually the ride quality got to me. I replaced those with a set of General Altimax HP tires (very highly rated on Tire Rack), hoping to tame the ride. I think it might have had a marginally positive effect.
I can’t remember what it was like with the Harmony’s on originally. I don’t remember being unhappy with ride quality until sometime after installing the Potenzas, and haven’t been happy with it since. In the meantime, I’ve replaced struts, mounts, bushings, links, and control arms. Nothing has really done anything to mitigate what I would still describe as a sub-par ability to buffer the occupants of the car from the shock of hitting a bump. As bad as “a” bump is, in northern Indiana we have rows of pot-hole-filled-bumps that are just terrible in this car. Driving along those in the 1995 BMW 318i (which had the same General Altimax HP tires, and could have used a strut replacement) was a night-and-day difference. In the I30, I avoid them like the plague. In the 318i, it was no big deal. This was an eye-opener for me. The other was when riding in a friend’s 1996 Infiniti G20 (a much smaller car, intended for more spirited maneuvering). I was astonished when all I felt was a little nudge when we went over a bridge and hit than initial bump.
The tires are about 2 years old, probably have somewhere in the area of 20k miles on them. I did try to keep them at the recommended tire pressure of 29 per the little placard. Anytime you take it in to a shop for even an oil change they seem to pump it back up to 35. I can’t say that I ever truly noticed a difference in bump absorption, so I stopped trying to get it down there. The fronts now have a very slow leak, so it may be time to swap them out anyway. I’m just having a very difficult time imagining the tires are the culprit. Have people experienced such a drastic change with different tires?
The Infiniti I30 cars are known for having a stiff chassis, and suspension tuning.
If you want a softer ride, you are probably going to have to change vehicles, as this Infiniti is tuned for a sportier ride.
You might be better off looking at a Lexus ES300.
BC.
On long trips, how uncomfortable is the ride? I ask this question because you describe the ride as “. …rivaling a truck from the 80’s”. I actually find a stiffer ride less tiring on long trips than a softer ride. As another post pointed out. the I30 cars have a stiffer chassis.
Maybe you are comparing the ride of your I30 to the wrong vehicles. When I wanted a smoother ride from my 1950 Chevrolet 1 ton pickup, I would go disk a field with the Farmall F-12 tractor. The Chevrolet 1 ton then seemed to ride like a Cadillac. If you can, drive another I30 and see how your Infiniti compares.
On longer trips, the ride’s pretty good. I generally take toll roads going from IN to WV, and they’re mostly in good condition so not too many bumps along the way.
I have a 2011 Mazda CX-9 for a couple days, and the ride feels almost a little more firm than the I30. What I have noticed though is that even though it’s firmer, the amount of noise generated by hitting a bump is significantly less (almost none). I’m starting to wonder if the issue really is noise generated by bumps and not so much the actual bump itself. Thoughts? I’m aware that the exhaust system (cat - back) should be replaced. We’ve had to have it worked on a couple times, and both times they’ve just welded some things back together. That could be making noise.
Also - I’ve had some issues with the front strut mounts, and have had both replaced twice (once with the strut replacement, and again about a year later). Possible these are producing noise if for some reason they’re bad again?
On test ride the 16" wheels had a softer ride than the 17". I’m guessing the higher tire sidewall made the ride noticeably softer…I see that the I30 would handle 15" wheels, maybe someone with automotive knowledge can chime in here if this would be a good upgrade as far as a comfy ride.
The OP already stated that the tires were 15". Don’t need “an automotive type” to read do we. And just as an aside you’re almost 8 years late for the party.
After 7 years, I bet they don’t have the car any more, much less the tires.