I am working through a 2005 AT with 145k miles that I picked up this fall, and one of the things I need to evaluate and make a decision about is the suspension.

The problem that I would like to address is that the ride on the potholed local roads is unpleasant, every large pavement joint and hole produces a firm jolt and loud thump.

I primarily use the car for spirited recreational driving on public roads, and I'm unlikely to ever have it on a track, but I will occasionally do long road trips (2000+ miles) to fun places to drive. This is a cheap 'just for fun' AT car and I'm not trying to turn money into better lap times, so I want to try to keep the price for upgrades reasonable (for example, a $2k set of Ohlins seems quite high-priced for this car), but I'm not against spending more than the minimum to maybe do better than the OEM equipment.

About 3000 miles ago the previous owner paid a local shop $600 to put in 'coilovers' (per the receipt), but I don't have any information about the product they used. It appears that they just put in some 1.5" drop springs. The rest of the suspension appears to be stock.

I don't know if the stock shocks have ever been replaced. I don't notice that the suspension seems underdamped, but I haven't driven it much (no plates yet). The springs are so stiff that I can't be sure, my usual method of bouncing a corner and seeing how long it takes to settle doesn't work :D. They look a little sad though, so I suspect that they may be either original or perhaps a second set of OEM shocks.

So I'm looking for recommendations. I'm thinking the shocks probably need replaced. The springs are pretty new, so keeping them might be a good way to save some cash. However, if the stiff springs are the source of the harsh ride, perhaps I need to replace them. If so and I need to replace both shocks and springs, then maybe there are some coilover options I should consider.

 

OEM is generally pretty good on this car. Especially if you can score a Bilstein set off an R3. Really depends on what you want.

Those look like Teins, if they're real Teins they should be OK, but if you can't bounce a corner properly, they might be too much or not real Teins.

At 145k miles those stock shocks aren't doing you any favours. I'd look at a mild drop/mild rate increase like Racing Beat or Progress tech springs with a slightly uprated shock. Or just go back to new stock equipment. This isn't a Civic the stock suspension is great if you're not counting milliseconds.

 

I went out and bounced the car a bit to see how it feels. I can compress them a bit, it's just way firmer than I am used to (to be expected, my daily is a 4Runner). I think I probably should find someone local with more knowledge about this type of suspension to take a look at it and tell me if I'm misinterpreting the feel.

Based on the image in this forum post I agree that my coils are likely Tein S. Tech.
The printing on mine closely match what is in the photo (mine say "F-PIM58-OUO HFC", whereas the spring in the photo says "F-PIM58-OUO EEC"), plus the 1.5" drop that I measure on my car and the price charged for them match the drop and price listed on Tein's site.

I can get a complete used set of R3 Bilsteins shipped for around $280. That seems like a pretty good price. No indication of the mileage though. Not sure I want to spend 70% the cost of new on used, especially when I like the ride-height of my Tein springs.

It looks like I could put Koni shocks in for around $400. I see others have used them with the Tein S. Tech springs and were happy with it.

 

R3 shocks have to use series 2 (2009+) springs. If you're getting the R3 springs as part of the purchase, that's a pretty good deal though and with those springs everything will fit. It's a very enjoyable suspension.

If you go for Koni's, be careful. The specific shocks made for this specific car have a tendency to induce additional drop. So you might up with 2.25 inch drop instead of 1.5 and that starts to get uncomfortable around speed bumps.

The best thing I can suggest at the moment is Mazdaspeed shocks, as seen here: https://www.mazdatrix.com/vehicle-ye...=shocks-struts. They cost a bit more than new original equipment, but should make a good match to your slightly uprated springs. Given the mileage and general state of the bumpstops, I'd replace those too, they're an active part of the suspension, especially if lowered. May want to see if Tein recommends cutting down the bumpstops when installing their springs.

 

somebody put up a full set of R3 springs & shocks up for sale on here this past week because it was “too stiff”

part of the issue is the 4-port non-Sport automatic suspension is softer that the sport/manual suspension. So those aftermarket springs with used Auto shocks is not a good combination.

My feeling is if what you have now is too stiff, then then you probably won’t like the R3 setup any better. There is a certain harshness to the RX8 suspension in general for anyone who is not really into sports car handling. The Mazdaspeed shocks mentioned above are better suited for those springs, but they’re tuned for handling and I’m not sure you’ll be any happier with them over bumps and such.

you’re more likely going to prefer a set of manual trans Sport springs with a new set of shocks over the R3, or even going back to the original Automatic non-Sport springs that were the softest offered for the RX8.

in general though the average person overlooks shock replacement as a necessary maintenance item. IMO you’re likely going to need to replace both to get it more to your liking. You can try shocks only first though. The new Koni STR.T shock is what you probably want over the Koni Sport adjustable shocks that Loki was referencing. See the attachment.

 

I appreciate the input!

I'm still working on getting various issues on this car sorted out, but I suspect, after a recent high-speed drive on a particularly bumpy stretch of highway, that what I'm finding unpleasant about the suspension is probably more related to the shocks being worn out than the springs. I have less than 100 miles driven, so I'm still getting accustomed to the way this car feels. It's completely different from the grand touring model I had previously. I'm going to get the alignment fixed (I don't think it was aligned after these springs were swapped in, and the inside edge of one front tire is down to the cords) and put on new tires, then I'll see how it feels.

After some reading I like the idea of Koni STR.T with the Tein springs, and then maybe changing out the springs if that doesn't work.