longpath

iTrader: (1)

SARRAS

If the above is with the new shockers in the car - did they reset the preloads on the suspension? Definintely looks tail droopy to me...

Torotor

This made me lol for realz. haha

longpath

iTrader: (1)

I've been too swamped to do the installation myself, so I had it done at a garage locally. I don't know if they reset the preloads or not, although, just to be clear, the shocks are Koni yellows, not coil-overs. The springs and everything else in the suspension is stock. I am hypothesizing that the springs are fatigued and need to be replaced; but if there is the possibility that they were just not reinstalled properly, then I'm willing to take shot at that.

What is correct free length for the springs (that is, when completely unloaded and off the car, how long should they be)?

longpath

iTrader: (1)

I tried searching the forums and the shop manual and can't find anything about resetting the preloads.

longpath

iTrader: (1)

I did find this about the free length:

https://www.rx8club.com/showpost.php...02&postcount=8

Quino

So my '04 started doing this a couple of weeks ago. I was about to order some replacement shocks - but I'm confused after reading this post. It sounds like the recommendation is to replace all four corners EVERYTHING..?

Also - what am I damaging while I think about it...? (the car has not been driven but about 10 miles since)

longpath

iTrader: (1)

For some reason, the rear springs and shocks seem to fail together. If I am reading all the suggestions together, your options come down to:

1. Replace the rear springs (with new OEM) and all four shocks
2. Replace all four springs (with aftermarket) and all four shocks

The rationale is because the springs have to come out when the shocks are replaced anyway, so there's no point in having to do the job twice.

GeorgeH

iTrader: (2)

No, springs do not fail as fast as shocks. That's simply untrue. Shocks have friction surfaces and seals that wear, and oil that gets contaminated. Springs are just steel.

Shocks are far more important to ride & handling than most people give them credit for around here. They affect everything - turn-in, ride harshness, etc. If your shocks don't work it doesn't matter what springs you have. But good shocks on OEM springs handle amazingly well on the RX-8.

There's nothing wrong with replacing the springs at the same time - if you want to lower the car, then by all means do it all at once - but there is no reason to replace the springs just because your shocks are worn.

Also, the OEM springs are linear on the front, and progressive on the rear. 90% of aftermarket springs are the same way.

But, glad the OP got this taken care of. Nothing will ruin a fine handling car like worn out shocks.

40w8

Condensed version,

If you have OEM springs and you're bottoming; replace the rear shocks with something like Bilstein.

If still bottoming near the front replace front shocks, and you're set.

Plenty of people have put different springs on and bottomed anyway.

GeorgeH

iTrader: (2)

True, except I'd never reccomend that somebody replace the rear shocks but not the front, particularly when you are going from OEM to Bilstein/Koni/Tokico. That can result in oversteer in transitions. Replace all four to keep balanced handling.

Quino

See - clear as mud!

I think I will replace all 4 shocks - although it is tempting to lower it...

Thanks guys (I mean it)

chuckyb1010

I know this post is a few months old, but I am new to the RX8 club, Just bought a 2004 with 60k miles on it, I too am having the same problem with it bottoming out. I purchased new rear shocks and installed them and drove right out the drive way and the something happened, bottom out. I have been reading everything about what to do, so without spending the money I went about bought a $10.00 set of spring helpers and jacked the car up and put the spacers in the springs and what do you know my car does not bottom out anymore, so I am going to say it was springs all along. So now my question how can I find a good set of factor ride height springs for the rear that won't cost me a arm and a leg?

longpath

iTrader: (1)

My final solution was to change my approach to speed bumps, going over large ones diagonally so as to have at least one front and rear tire on the bump at the same time. That eliminated the scraping that was occurring under the catalyst and under the rear seat.

painoracing

I had the same problem but changed the shocks, springs and bump stop. This last part was completly demolished..it was basically disintegrated. After that, no problem. Normally, shocks and/or bump stops can be the problem, I just changed the springs just to be sure.

Also, if you are replacing with oem parts, I don't think it's necessary to change all 4 shocks if you don't feel or see anything wrong in the front (or viceversa).

REDRX3RX8

+1

If I find one axle doing something wrong on any car, I work that out as well as possible, and that gives me opportunity to see how the total feel of the car is changed.

I've only aligned my car in 4.5 years and 27k miles, but I like the feel now, and I think I'd have to work real hard to get the suspension in a dangerous oversteer situation.

mlplunkett

I'm looking for bilstein HDs for the rear of my 2004 GT but all the web sites seem to only show a shock for the base model for 2004-5. Nobody shows a shock for the 2004 GT. Anybody know what's going on? Did all 2004 models use the same shock?

kuro hachi

i think the only diff between gs and gt is navigation. they didnt up HP or any other performance aspects. so the 04 base should fit the 04 gt but im no expert ive only read what i can find on the internet and have no actual exp with the rx8. i just bought a 07 took a quick walk around at the shop but wasnt standing far enough back to see my rear sagging 1" lower than the front which i really dont like, and if the stock suspension fails at around 40k then its time to change mine cuz car came with 58k im gonna go with an aftermarket coilovers ive yet to research price.

ShellDude

iTrader: (12)

This is the most valuable piece of info in this thread... and yet it remains unanswered.

rotary magic

Sounds like a combination of not shaving bumps and needing an alignment.

Installing Koni Sport and HR spring kit this week on my 04 w/173K miles and will let you know my impressions.

Who IS that lady? 😏

OtherSyde

Thanks to all the replies so far in this thread - definitely a lot of good info here.

Quick question in light of this thread's findings - I have TEIN S.TECH springs installed (which is only a 0.7" drop in rear), but my (stock) rear shocks bottom out hard (hit the bump-stops) if I hit a speed bump with any speed at all (like over 5-7mph), and if I have even one mid-sized person (like 170-190lbs) in the rear, the shocks bump hard with any significant dip. If I have two people in the rear it feels like the car is basically riding almost directly on top of the bump-stops and bumps hard at the slightest provocation.

At first I thought this was just because I'd lowered it, but now after reading this thread I really think my shocks might be getting low. The TEIN S.TECH springs say in their description that they were designed for use with OEM or OEM Replacement shocks, meaning maybe despite being lowering springs, they still should not cause this kind of hard bumping. I also just read in this very thread that our stock shocks often go out around 40,000km (about 25,000 miles) and my car is at about 48,000 miles...

It sounds like my stock rear shocks (the front is fine, no problems at all) are in need of replacement - should I go with OEM shocks, or can someone recommend a good OEM replacement that might grant me longer life and a little more bump-forgiveness with these lowering springs to avoid bottoming out (meaning hitting the bump-stops, not the bottom of the car scraping on stuff) in the future?

Also, I'd like to keep my current height, which might be slightly lower than normal if my shocks are shot, right? Would new shocks rob me of some of my drop and make the car sit high up? Would the new shocks having a slight lowering of up to a half-inch over the stock shock height be beneficial in that regard, as long as said new shocks are resistant enough to compensate and prevent hitting the bump-stops?

04Green

iTrader: (1)

I chased a similar problem for months, finally bought a new suspension, replaced it, when I tore the old ones out the rear bump stops were gone. Look there first. You may be able to peek up from the bottom. The dust that was left on mine, and the little bit trapped in a washer, was pink. The rear springs, even he stiffer S, are still under 150 lbs per inch. That is soft. The bump stop is a working part of the suspension.

Jmanie9515

What is the length of stock bump stops?

claybaby

My rx8 2004 sounds like it hits real hard if there is any weight at all in the back
wasn't sure what it is I was also told everything looks fine

Nisaja

It's the bump stops. Replace them. Does your car's rear sit way lower than the front? Then your rear shocks add worn out too. Replace the bump stops to get rid of the hitting/knocking sound.