Want to go Urethane On my Car but. . . .

[RidingOnRailz]

Don't want to have to wait another 50,000 miles/4 years for urethane bushings to become available on a 2008 Kia!

Car handles fine now - only 19,000 on it, but as they say, the stock rubber bushings on anything wears slowly, so sloppy handling creeps imperceptibly up on you.

Any suggs?

[shorod]

You might be able to match something up from Energy Suspensions to work for your application.

-Rod

[RidingOnRailz]

Originally Posted by shorod

You might be able to match something up from Energy Suspensions to work for your application.

-Rod

Yeah, Energy does seem to be the center of the universe concerning non-rubber suspension bushings, etc. I guess some of these cars are just considered disposable commodities and so enthusiast-quality replacement suspension parts for a car like a 2008 Optima aren't given a second thought.

[turtlecrxsi]

You sure you want that stiff feeling on your relatively new car? From what I've heard urethane bushings stiffen the car so much that you get that race car feel but it rattles everything. I have Eibach Pro Kit springs on my Spectra5 and I can take turns at 40mph in 4th gear with used up 20k miles on my Goodyear All-seasons. Good enough for me. Maybe consider spring upgrade for your KIA? Check out Kia http://www.kia-fx.com/

[RidingOnRailz]

Originally Posted by turtlecrxsi

You sure you want that stiff feeling on your relatively new car? From what I've heard urethane bushings stiffen the car so much that you get that race car feel but it rattles everything. I have Eibach Pro Kit springs on my Spectra5 and I can take turns at 40mph in 4th gear with used up 20k miles on my Goodyear All-seasons. Good enough for me. Maybe consider spring upgrade for your KIA? Check out Kia http://www.kia-fx.com/

Wow - than-Q! No springs, buuuut: I see they have a strut bar specifically for my generation Optima ( http://kfxperformance.ca/ixxocart/pr...r-2213-56.html )

Have to check them out - that's a DIY project I could handle in a few hours after work or on a weekend.

[curtis73]

I personally hate urethane bushings. They seem to offer a very modest increase in handling, but a very large increase in harshness and noise. Lots of downside with an almost imperceptable benefit.

You're also going to be limited by econobox geometry. That suspension was designed to be functional, compact, and reliable... handling is half geometry and half weight transfer. You can certainly improve it, but bushings would be the last thing I'd change. Springs and stiffer valving on the struts would be a great upgrade first, then tire/wheel.

IMHO, putting urethane bushings on an economy strut suspension is kinda like using platinum spark plugs in a Briggs and Stratton lawn mower. Your money can be spent more wisely elsewhere.

[RidingOnRailz]

Originally Posted by curtis73

You're also going to be limited by econobox geometry. That suspension was designed to be functional, compact, and reliable... handling is half geometry and half weight transfer. You can certainly improve it, but bushings would be the last thing I'd change. Springs and stiffer valving on the struts would be a great upgrade first, then tire/wheel.

.

2008 Kia Optima LX 4cyl about to turn 20(thousand miles that is.). Wife loves it. Used to drive my 2005 Malibu which I also bought new - She said that car was a hold-on-tight-white-knuckled experience if there ever was one - compared to this Optima.

Springs & struts - your first sugg - are obviously factory. Would Monroe or another brand offer something with a tighter rate?

Tires: Actually downgraded from H-rated Kumho Solus Grand Tourings(which slid on anything but damp or dry streets!) to T-Rated MasterCraft(Cooper) Avenger LSRs(which surprisingly were as quiet as the Solus but ate up snow and asked for seconds!). *Incidentally those Kumhos looked BRAND NEW - I bought the car as a used '08 with only 14,000+ miles on it, but if they were the original tires they wouldn't look like that.*

Next time will purchase these tires as H-rated(will stiffer sidewalls hurt snow perf. though??).

Suggestions appreciated.

[curtis73]

Stiffer sidewalls alone won't necessarily affect snow performance. The main factors involved there are tread width, tread design, and tire compound. In general as you go up in speed rating, you get larger treadblocks and wider tread, both of which are not ideal for snow. Higher speed rated tires also tend to have a rubber compound that reacts more linearly with temperature, meaning they are at their peak grip when hot. When they get cold they tend to be about the consistency of vinyl

[MagicRat]

Originally Posted by curtis73

both of which are not ideal for snow.

...which explains why my Potenzas fired me off into the ditch last winter without even a 'sayanora'

Actually... j/k.

But this does explain why, last week when I bought 2 tires, the tire retailer recommended against mixing new tires with used ones of different speed ratings... the first time I have heard of this guideline.

[RidingOnRailz]

Originally Posted by curtis73

Stiffer sidewalls alone won't necessarily affect snow performance. The main factors involved there are tread width, tread design, and tire compound. In general as you go up in speed rating, you get larger treadblocks and wider tread, both of which are not ideal for snow. Higher speed rated tires also tend to have a rubber compound that reacts more linearly with temperature, meaning they are at their peak grip when hot. When they get cold they tend to be about the consistency of vinyl

I've driven with H-rated tires in snow before, in most cases quite competently mind you, so I think in the case of the Kumhos they were simply not built for snow - period.

Could I also experiment with different front & rear tire pressures? The 2006-09 Optima calls for F/R: 30psi/30psi. I tend to run a tad higher(32/32)in all my cars due to a history of shoulder wear at all four corners. In that vein, I was thinking along the lines of F:33psi/R:31psi. We rarely have back seat passengers, so the rear in my car is always slightly "live".

Optima F/R weight distrib is listed as 61%/39%.

IIRC correctly GM originally speced the Corvair to have a much lower front tire pressure than in the rears - owing to it's rear-engine configuration. A front-eng/front-whl-drive like mine is quite the opposite, explaining my reasoning for setting tire pressures thusly.

The one car I NEVER, EVER could understand was the Contour. My '96 called for F31/R34. Was somebody assuming that the Contour would be used for hauling cinderblocks in the trunk full-time?? I ran it that way and had no problems - perhaps Ford knew something I didn't about front vs rear weight and tire pressures?

[RidingOnRailz]

Originally Posted by turtlecrxsi

From what I've heard urethane bushings stiffen the car so much that you get that race car feel but it rattles everything.

True! This generation Optima feels quite solid to me, and I don't need pieces of dashboard & headliner falling in my passenger's laps!

[RidingOnRailz]

I did as I said over the Labor Day Weekend, regarding the tire pressures.

Given this car has a 61/39% Front/Rear weight ratio, I altered the tire pressures slightly. I normally keep 32 psi front/rear.

Because the front wheels bear most of the weight here, I upped the fronts to 33psi, and lowered the rears to 31psi.

Results: The last three days I noticed the following:
- A slight oversteer depending on how quickly/sharply I enter a turn, but again, very slight.
BUT...
- I cannot break the rear-end loose on the Optima with those pressure settings! Which is what tended to happen with equal pressure settings front-rear(whether 30/30 per factory or slightly higher as I had them).


- There is no "slop" in the rear end, even with the lower pressures(I'm still a pound above factory).
- Up front, the rough ride associated with higher tire pressures is offset by the weight of an engine & transmission over those front wheels. The car accelerates, tracks, & stops straight, the steering is weighted decently, and the steering wheel returns quick enough from turns.

33F/31R, that's where they'll stay. I don't want to up the fronts or lower the rears any more, as I do have occasional back seat passenger(s), but this combo seems to have hit a sweet spot, and I encourage other Optima owners to try it - expecially with the V6 option.

I would still like some opinions on Monroe's shocks/struts, esp their gas models. Would they be a decent upgrade over the factory's?

And finally, with 31F/34R, what was Ford thinking with the Contour?? It handled good enough for me, but don't you think the rear end would break loose pretty quick with more psi in the rears??