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DPE 12-21-2005 07:46 PM

Spring rates and other basic suspension info
This info can be found elsewhere on the forum, but given we've posted a lot about suspension and have some experience with it, we figured we make it a Sticky right here.

All numbers taken either from the manufacturer, or from other posts on this forum. Some we can verify, and a few we can't. Just keep that in mind. Addtionally, the amount of drop you get varies based on the weight of your particular car, fuel load, and other factors.

Stock 'Sport' Suspension RX-8: 156/113 (F/R)
Mazdaspeed: 280/190 - Drop = 0.8"/0.8" ***** Not Confirmed - Actual rates have tested much lower
Tein S-Tech: 207/145 - Drop = 1.4"/0.7"
Tein H-Tech: 179/129 - Drop = 1.0"/0.3"
Tanabe GF: 179/146 - Drop = 1.4"/1.2"
Tanabe NF: 162/112 - Drop = 1.4"/1.2"
Racing Beat: 187/136 - Drop = 0.5"/0.5" ***** Not Confirmed
Eibach: 180/130 (progressive) - Drop = 1.2"/0.8" ***** Not Confirmed
H&R: 195/141 (progressive) - Drop = 1.0"/1.0" *****Not Confirmed

EDIT: Added advertised drop by request.
EDIT: Added more disclaimers for those springs we can't confirm the rates of

DPE 12-21-2005 08:07 PM

Coilovers and you. . .
To clear up some questions we've seen on coilovers, some have correctly (though confusingly to novice folks) pointed out that the OEM RX-8 suspension is in fact a 'coilover' suspension. By definitition, this generally means a 'coil (spring)-over-shock' setup. So it's awesome, we ALL have coilovers!

But not in the sense they are typically discussed on automotive forums. 'Coilovers' are nearly always aftermarket suspension kits that come with four shocks and four matching springs and are sold as a complete set. What makes these aftermarket 'coilovers' unique is that they all allow the driver to adjust vehicle ride-height by an adjustable lower spring perch or other means, depending on the application. Basic coilovers, including the aptly named Tein Basics, come as a kit with four shocks and four springs, and have an adjustable lower perch. With these you re-use the OEM upper mounts, and a few of the OEM hardware bits to complete the assembly. The shock on the Basics (also called the damper) is not adjustable.

More advanced coilovers such as the JIC FLT-A2s come with come with the upper mount, usually of the 'pillowball' variety (a spherical metal bushing in a metal plate rather than the rubber top mounts that most cars use from the factory). JIC and HKS do not come with a pillowball mount for the rear, deeming it unnecessary, while Tein does include rear upper mounts with their Flex kit. These kits also have adjustable shocks, which allows you to stiffen or soften how the car rides. This is a nice feature for cars that spend time on both the street and track.

Miscellaneous Comment #1: The aftermarket coilovers also come with proprietary springs, so one would never use their OEM springs or an aftermarket lowering spring with their new coilovers.

Miscellaneous Comment #2: There are some coilover kits out there that come just with springs and some mounting hardware, and you cut up a shock designed to fit in the OEM location (often Konis are used), put a threaded sleeve on it, and you've got coilovers! Ground Control is known for making these kind of kits. As far as I know there aren't any of these kits for the RX-8, just wanted to note it lest someone saw 'coilovers' of this kind and wondered about it.

Hopefully that information helps. Feel free to comment, criticize, or berate, just remember I'm the Mod on this specific forum :).

DPE 12-21-2005 08:32 PM

What if I just want shocks and springs? I don't need adjustable ride-height.
At the moment, there are only a few options for shocks, though there are tons of options for springs. The spring choices are listed above, and there are other brands available that we haven't had time to look at. For shocks, though, the list goes like this:

Koni - Sport shocks, rebound adjustable (rear shocks must be removed for adjustment), seem to be compatible with just about any spring.

Tokico - DSP Kit, compression and rebound adjust simultaneously, can be adjusted on the car at all four corners, and should also work well with most springs. Probably a bit softer than the Konis as the softest settings. We have not tried them yet, but will in the Spring.

Mazdaspeed - Non-adjustable, probably best used with MS springs and swaybars to have the kit Mazda intended.

Tein Basic Coilovers - Hey, I said I didn't WANT coilovers! Perhaps not, but for a matched shock and spring kit that you can simply leave at the Tein-recommended ride-height, this kit works quite well. And the price is well within range of buying any of the above shocks with a set of springs.

Over the next couple weeks we'll post some of our impressions on a few of the suspension bits we've tried, and any other info we think might fit this post.

DPE 09-08-2006 10:28 AM

Tein Basic Commentary
This is copied from another post in my forum; just trying to keep all relevant suspension info in this sticky thread....


Here is a post from our very own Craig (TheArchitect), describing his thoughts on the Tein Basics after living with them for a couple months. Took this from another post and edited the content a bit for relevance:

Well, I'll add my $.02 to the mix. I haven't autocrossed with the Basics, but I have had it at the track a couple of times with Basics on and drive daily on them.

In daily driving, I traverse plenty of pothole-ridden midwestern roads, so I appreciate that the Basics aren't super firm. The stock suspension is decent, but definitely soft. The Basics do cure that. I have driven the car on some road trips and it remains plenty comfortable. That the engineers at Mazda have given the car such a good GT/sportscar blend is a testament to their chassis tuning prowess, but there were obviously compromises made. The Basics get rid of those compromises, mostly without making any compromises of their own in harshness. I'm pretty impressed by that. That said, I can see them maybe not being the perfect companion for autox since agility and responsiveness are highly valuable in that setting, and I can see that some would prefer more damping (namely, rebound in the rear, at least in my observations) even in the Basics.

The car with the OEM suspension has a tendency to get a bit of a wiggly butt on track when really pushed deep into a corner under trail braking, and it also has a bit more roll than I personally care for on track. Nothing horrendous, but it could be better. Under hard braking deep into a corner, it seems to me (keeping in mind that I'm not a suspension engineer) that the rear suspension unloads to such a great degree due to lack of rebound control in the rear and softness in the front that you can actually get a fair amount of change in alignment that creates some instability in the rear of the car at the absolute limits (think positive camber and maybe even a positive toe change). The amount of suspension softness actually is good up to about 8-9/10 in my opinion, because it aids in grip to a point and gives a little bit of margin for error before giving up grip and spinning. For most drivers, this is probably a good safety net. At about 10/10 (and especially at 11+/10!), things get considerably dicier on track. In several driving events on the stock suspension, I found that the car gets a bit spooky when really pushed to the limit. We're talking driving really deep into a turn, and frankly overdriving the car, but that was a bit of the point, to try to find the car's weaknesses.

So, on track with the OEM suspension, one can definitely overdrive the car into an oversteering state, albeit a state that is recoverable - in my experience, anyway. After getting the Basics on, I found that the positive traits of the car remained in daily driving, but it really came alive on track. In fact, the car became a lot more entertaining on track. The chassis feels more balanced and more alive. The untoward dive and roll has been tempered a lot. There is still some roll, but it's lessened. Might still want sway bars, but that's a lot about preference.

I have found the car to be supremely balanced with the Basics on track, more so than stock, and I have found that I can balance the car exactly how I want it with the throttle now, whereas throttle induced yaw corrections were less precise on the stock suspension. The car is much more planted in the rear in hard braking and trail braking, which is much appreciated at the limit, without gaining understeer. The car is a whole lot of fun stock on track, but with the Basics it really has gone to a new level when driven hard. It has shown no tendency to give up on me like it did as stock when driven really hard, remains balanced, has sharper reflexes, and yet still allows enough body motion to keep someone like me, with no F1 contract as of yet (I suspect with good reason, but I'm still open to offers...), on the road course and out of the weeds.

So, the Basics might not be perfect for everyone, but I have been very pleased with them. We'll have more to report as time goes on and other developments take place with other product pairings, but so far I can't find much to fault in the Basics for a car that is daily driven and occasionally tracked. If you do autocross also, I could see going with something adjustable being a huge benefit, since the settings for autocross vs. road course would probably need to differ a bit. But, so far so good with the Basics for me.

DPE 09-08-2006 10:29 AM

Konis/H-techs vs. Tein Baics - Road
Another copy of a post from another thread in my forum; my comments on driving Tein Basics vs. Konis and Tein H-tech springs......

As a non-RX-8 owner (soon to change, I hope ), over the last couple years I've been lucky enough to get a lot of seat time in a couple of RX-8s in varying stages of modification. As some of you may know, we were able to directly compare a car with Tein Basics to a car with Konis and Tein H-tech springs. Neither car had any other suspension mods for awhile. We took a drive to the Ozark Mountains in southern MO and northern AR for a 'scientific' comparison between the two cars. There are some phenomenal and deserted twisty roads in this region, in case anyone wonders why we were going there.

Both cars felt much better than stock, and that's saying something. It's easy to improve on a crappy suspension, but much harder to improve on one that's already quite good. But either way there's a notable improvement. The Basics, with their high spring rates, essentially eliminate dive and squat. They also reduce body roll quite a bit, though no more than the Koni/H combination. The Basics make the car feel more controllable in all situations, and generally more responsive as one would expect. And the ride remains surprisingly compliant, despite the high spring rates. Just goes to show what a well-matched spring and damper can accomplish. And of course they are height adjustable, which is either a plus for those who like to mess with it or irrelevant to those who don't. As a set-it-and-forget-it suspension, the Basics work great.

Getting out of the Basics car and into the Koni/H car, the first thing I noticed is the steering seems to be even more alive. Then diving into the first turn at speed, I was amazed at how quickly the car turns in and takes a set. It is truly remarkable how quickly and accurately the car turns in with that combo. And somehow it feels even more buttoned down, more controllable. What I believe is that the valving in the Konis is more sophisticated than that of the Basics, thus allowing more precise shock control, thus allowing more precise handling. And of course you can adjust the damping, which subsequently has proven to be very useful on track. Just unfortunate you can't adjust the rear damping easily. As far as ride, the cars actually rode pretty similar, though if you crank up the Konis all the way you can make it almost uncomfortably firm. Left in the lower settings though, which seems to be where they match up to Tein springs, it's a nice combination. Chassis balance remains neutral with either setup, and can be varied more significantly by tire pressures and alignment settings than the parts themselves.

Keep in mind we're talking small differences here. On a scale of 1 to 10, if the OEM suspension is a 5, then the Basics are an 8 and the Koni/H is a 9. Point being, you can't go too wrong, but if you want the best solution in the $600-700 range and don't need height adjustability, we believe the Konis with Tein springs are a better way to go. And we're happy to sell both, so it's not that kind of bias .

What about Tokico DSP you might ask? A good question. And one we meant to answer earlier this year, but some car shuffling among our RX-8 owners pre-empted our ability to test them out. If all goes well I am personally going to acquire an RX-8 soon, and will likely install Tokico DSP shocks and Tein H-techs so we can directly compare Konis to Tokicos and see which is the better way to go. Don't hold your breath waiting for that comparo, but we might be able to squeeze in a road test comparison before the year is up.

Jedi54 02-12-2007 04:02 PM

Great write-up on the Koni / H-tech. I'm considering a very similar setup. Thanks!

dmc27 03-08-2007 02:56 PM

Tanabe GF: 179/146 - Drop = 1.4"/1.2"
Tanabe NF: 162/112 - Drop = 1.4"/1.2"

This would be around the drop I'm looking for (I wanna be like Ngo!! :lol:)

So is the only difference between the GF & NF the rate? In the interest of $$$ I'm prlly going to do springs only and run the stock shocks. Does that mean the best option for me would be the NF b/c the rate is closer to the stock springs (which means the longevity of the shocks won't be affected too much)?

I've got an 05 base model, in case it matters.


Jedi54 03-08-2007 03:00 PM

dmc: sending you a PM....

DPE 03-09-2007 10:06 AM

DMC: I have not sold any of the NF springs and honestly don't like them in concept. They may work just fine, but lowering a car over an inch without increasing spring rate seems like a recipie for bottoming out a lot. You're shortening the effective length of the shocks yet not compensating for that by stiffening the springs to better control body motions. I could be talking nonsense and I would encourage someone more educated to step in and tell me so if that's the case, but logically speaking from what I know about suspensions, the NF springs are a bad idea.

The GF springs wouldn't be too overwhelming for the OEM shocks I don't believe (yes, they'll wear the shocks faster, but not obscenely so), and they've gotten good reviews from the customers who have them on both OEM and aftermarket shocks. If you want Tanabe, that's the way I would go. And FWIW, I have a set of GF210s in stock. I can also get the NFs for the same price, if you'd like to give them a shot. They just don't sit well with me personally, no pun intended :).

dmc27 03-09-2007 10:58 AM

Excellent point - that would never have occured to me.

Between that & Jedi's pm about the difference between F & R stock height, I'm thinking Tein S is prlly best. Shocks will just be at the top of the xmas list!!


Have you got plenty of Tein S in stock?

DPE 03-09-2007 11:07 AM

I have more S-techs coming in on Monday. 5 sets arriving, but only two of those are unsold. Regardless, I can typically get them within a week if I run out again, so it shouldn't be a problem. Feel free to order if you like, and I get get some headed your way on Monday.

dmc27 03-09-2007 01:14 PM

Thanks for the info. I'll be looking at the end of next week - damn bi-weekly pay. :rant:

newcastle 03-09-2007 02:04 PM

Great info. Thanks for takeing the time to complile all this info.

7andan8 03-17-2007 10:00 AM

Put me down for a set of Basics ... headed to your website now.

Thanks Phil!

DPE 03-20-2007 09:24 PM

Thanks for the order 7andan8! And I like your particular car too; reminds me of one I've grown quite fond of owning over the last 6 months :).

Just FYI for anyone reading this that wants Tein S-tech springs in the near future, we've got two sets arriving tomorrow and Tein is showing 'Limited Stock' on them currently after being out of stock last week. Not to say they're suddenly going to be hard to find, but for the next few weeks they might be harder than usual to get a hold of.

Glad you guys like the info; we'll try and keep it coming as we get back into track season again!

dmc27 03-21-2007 10:05 AM

Glad I ordered mine last week. Now if only the UPS driver was an intelligent being, or at least a little less lazy . . .

Supposedly they tried to deliver it this morning at 9.20am, but said "no such address" ???? My business address generally results in one of 2 things - the good driver, who never has any trouble getting stuff here, and the bad one(s) who are to lazy to walk up a flight of stairs and down a hallway - at which point they'd be forced to walk right by my open door & I could hail them from my desk since there's apparently some reading comprehension skills making the sign on the door an obstacle . . .



Thanks DPE - aside from UPS screwups (on everything I've ever ordered for my 8) the springs ordered on Friday 3/16 got here on 3/21.

icyur2 03-21-2007 10:33 AM

DPE, can you please PM me the price for the Koni/H setup? I have a 2005 RX8 GT package..thanks in advance!!!

DPE 03-21-2007 10:50 AM

icyur2 - You've got a PM!

dmc27 - Perhaps I'll try FedEx next time? You just never know what you're going to get between the two companies; both are generally good, but both do have issues on occasion.

icyur2 03-21-2007 11:05 AM

Thanks!! Got it..hmm..have you had a chance to try out the Koni/S combo? 15% vs. 30% on the handling...I'm assuming ride comfort will still be good vs. the Koni/MS combo..

dmc27 03-21-2007 11:08 AM

Not a big deal - I think they all screw things up equally. There's one UPS guy who NEVER has a problem, then there are some that are either lazy, stupid, or some horrible combination of the 2. So unless there's some way to force UPS to send the good driver, it's a crap shoot.

The office building I'm in pisses them off, I think, b/c there's no suite numbers. IMO, it's prlly one particular driver that is just a complete d-bag who doesn't want to be bothered. The springs aren't the first package to get listed as "No such address" or "A CORRECT COMPANY OR RECEIVER NAME IS NEEDED FOR DELIVERY" when being shipped here. I generally chalk it up to apathy. I've already called UPS and basically described a map from the front door to my upstairs office!!

But thanks for the offer.

NOTE to all who see it - Please don't misinterpret my rant about UPS. Shipping companies are not always the best.

I did NOT have any problems with DPE. Ordering was simple on their site, the confirmation email came immediately, and the tracking info shortly thereafter.

DPE kicks ass!!!

DPE 03-21-2007 03:10 PM

icyur2 - Koni/Tein S vs. Koni/Tein H is one of those differences that's notable but not drastic. I have not tracked a Koni/S car, but I have driven one around and compared it to the Koni/H car on different days. You can tell it's stiffer, and it sits just ever-so-slightly lower (theoretically .4" front and rear lower by the specs, but that's at the most), but it's not like one rides great and the other rides really hard. Most that are happy with one would be happy with the other, it's just if you want to lean toward a bit more aggressive or lean toward a bit smoother. I have not had complaints about either setup riding too hard or not being enough of a difference from OEM.

The MS springs I have not gotten to sample with Konis, though I hope to do that within a few months. By the numbers they should be notably stiffer than either Tein spring.

savedsol 03-22-2007 08:53 AM

1 Attachment(s)
Here's another to add (I have zero experience with these but they are a great Co):
RS*R Down Springs
Model - RX-8
Year - 2003+
Model Notes - ALL
Estimated Front Drop - 30mm(1.2in)
Estimated Rear Drop - 20mm(0.8in)
Front Spring Rate - 3.34kg(187lbs)
Rear Spring Rate - 2.18kg(122lbs)

CTrx8 03-25-2007 09:01 AM

DPE - PM sent

7andan8 03-30-2007 05:41 AM

Basics received Phil, thanks for the quick ship! Headed into the shop today.

setenza 04-10-2007 02:10 PM

I am thinking about picking up some springs. About how much does a decent shop charge for an install?

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