It was three years ago in July when I installed the KYB AGX with a set of H & R lowering springs. Over the past three months, suspension noise has been steadily increasing. At first I thought it was strut bearings. But it continues to get worse. This sounds like the noises from the 99 I30 when the struts on it blew out. The rest of the suspension is roughly three years old. I also replaced LCAs, tie rod end, and basically everything with that strut job.

So in a couple of months, I will be moving the 99 to run Koni STR.T like the 98 model.

 

I'm surprised you haven't moved to coilovers!

 

I just put the fronts in my 99. OEM Springs and OEM everything except Koni (orange) STR-T Struts. Overkill with the spring insulators and FINALLY, a nice ride, better handling and QUIET! Shoulda done this 106K miles ago!

Tuesday, the rear Koni/OEM everything else strut assemblies will also go in.

Thanks to Craig, I made the right choice.

All I can say is poor to no spring insulation on all the aftermarket choices will make you sorry. If not right away, eventually for sure.

As promised, Craig: https://www.koni-na.com/en-US/NorthAmerica/Rebate/

 

Thanks for the link KP. I am getting ready to order another set. I think may have enough parts on hand to build up another set. I have new OEM SE "taller" top hats and bearings.

On a side note, I received a set of front Febest boots to take a look. They have the correct shape and look just like the OEMs. Though they don't have white mold release wax covering that I had one the OEMs. They look very good. Though I saw where someone posted in the 5th gen section where a set disintegrated in about 9 months. That post has me worried.

 

Febest? LOL

You're the guy that convinced me OEM is truly the best path! Don't even begin to question yourself. Craig knows what he's talking about!

I kinda like the waxy buildup on the OEM rubber.

 

Since hindsight is always 20/20, I should have spent more time researching KYB AGX performance with lowering springs. I guess I'm lucky that I got three years out of them. Its funny how three years seems to be the threshold for knowing how long an aftermarket part or some modification will hold up. Often the vehicles have been swapped for something different withing three years, so we don't see how well a product holds up for the long haul.

So I'm not the only person to experience problems with KYB AGX when running a lowered suspension.

https://forum.miata.net/vb/showpost....54&postcount=2

https://forum.miata.net/vb/showpost....05&postcount=5

The following points from the Koni product page attracted me to the Koni STR.R

- Entry level performance shock absorber

- Complements lower springs

- Perfect for OE replacement or vehicle improvement

- Non-adjustable

- Lifetime Warranty

 

Out of curiosity, doesn't KYB usually have a lifetime warrantee on their shocks/struts? I know the GR2 line used to; not sure about the AGX though.

 

They probably do. It turns out I bought them from Rock Auto. If I could get one adjusted, then I have an odd set. I wouldn't put them on a car with H & R springs again. They are a nice strut for a car with regular springs. I should have spent more time researching struts for use with lowering springs. So the lesson learned is to not use KYB struts with lowering springs.

After replacement, both 98 and 99 model daily drivers will have an identical H & R + Koni setup.

Meanwhile we are thinking about experimenting with coilovers on the 97.

 

I want to add my experience with Febest boots. For me, after about 10k miles of use, my boots started to rip at one of the folds. I would suggest go with OEM.

 

OEM ordered. It's a shame they don't last.

 

Well, your custom insulators and neoprene strut gaskets are there. Now all you need is the struts and rebate form. LOL

I sent two 48" DSG-Canusa CFW 0750 for two coil wraps on the top and bottom of each rear spring. If you order one more, you can still do the bottom of the springs with 24" each, but the tops up to 48", which is almost 4 coils. No spring noise like what you're getting now.

Dead coils mean noise and these are the best solution IME by far.

I sent almost 16 feet of the CFW 1100. You also have enough to do two coils on both top and bottom of each front spring. It's a real PITA, but well worth it when done!

Hopefully, this link will work for one more: http://a.co/bqu7XvU

Have fun with your new toy!

 

Thank you KP. I appreciate it. It all looks GREAT! The link works and I just ordered another section. The Koni struts arrived today. Now I'm just waiting for the boots and mount insulators to arrive from CourtesyParts and a good weekend to put it all together.

Just feeling inside one of the 48" tubes, I can see how it needs some lubricant to help it slide on the spring. Possibly some dry lubricant like "Corn Starch" might work.

 

Good luck!

 

double mistake post