Suspension bushings
The NA's rubber suspension bushings wear out, and the choice most owners face is new rubber or polyurethane. This page says what owners reported about polyurethane and which kits the sellers offer. It is not a repair guide; fitting a full set is a big job.
How to read it. The owner accounts are from one Miata.net forum thread (NA and NB, November 2013 with posts to September 2015) that I read in full on 1 October 2026. They are individual owners' experience, some of it a decade old. Kit descriptions are the sellers', read on their own pages that day. There are no prices on this page.
What owners say about polyurethane (NA and NB)
The thread, "For those that have tried poly suspension bushings", was a poll limited to people who had replaced their rubber bushings with polyurethane. Its author reported that 72 per cent were happy and would do it again, 16 per cent regretted it and 8 per cent went back to rubber. Other posters pointed out it was a small, self-selected sample, so read it as a rough sample of replies, not a measurement.
- Handling. Most who were pleased said the car felt tighter and more responsive; one said the improvement included lower friction in the suspension. One poster who fitted them with coilovers said the ride got much harsher, but could not say how much was the bushings. Another said it would not be worth it on a daily driver.
- Squeaks, and grease. The commonest complaint was squeaking, especially in cold weather and after a year or two. Several posters said to lubricate them well when fitting and again each year, and to fit grease (zerk) fittings and drill the bushing so the grease reaches the bore; the poll author said anyone converting should ask whether they will spend an hour a year under the car with a grease gun. Greases named included Energy Suspension's own lube, dielectric grease, and, in a 2015 post, Swepco 101 molybdenum grease, which that poster said kept his rear upper arms free for two years.
- Swelling and binding. A poster said polyurethane bushings swell in summer heat and, especially on the rear upper control arms, bind until the ends are shaved. Another reported in 2015 that after roughly 30,000 miles his SuperPro bushings were binding even with grease fittings; he found them over-long for the inner sleeves and was going back to rubber.
- Bonded polyurethane. One poster fitted UK-made Polybush bushings, which are bonded to the sleeves like the factory ones, and liked them; two others reported squeaking, and one said the rear lower bushings broke away from the arms and the maker gave no warranty for that.
- Harder rubber. Some posters preferred harder rubber bushings of the Mazdaspeed or Mazda Competition type, or copies of them: one said his copies were silent and more responsive than polyurethane, but added that Mazda Competition differential bushings gave no real gain in control and more differential whine.
- Is mine worn? In the 2015 posts, one poster's rule of thumb was that if the car still rides badly after new shocks, bump stops and soft tires, suspect the bushings; another said to look for many small cracks in the rubber, and otherwise to judge by feel against another Miata.
Kits for the NA and NB
| Seller | What it says it offers | Fits (as stated) |
|---|---|---|
| Moss Miata | Prothane polyurethane complete car kit (908-120), with Prothane's grease. Prothane gives a lifetime guarantee and Moss 12 months against defects. The page notes that the sway bar bushings fit 1990-97 end links only, the front ones fit a 19 mm bar (not the 20 mm R-package bar), and the rear ones a 12 mm bar | 1990-2005 |
| Moss Miata | Prothane front control arm kit (908-100), with the same sway bar notes; the page adds that the differential mounts in it are for 1990-97 only. A rear control arm kit (908-115) is also listed; I did not open it | 1990-2005 |
| Flyin' Miata | SuperPro polyurethane kit: control arm bushings and stock NA end links (not NB end links). Flyin' Miata lists a lifetime warranty against squeaking and failure, including track use, and says the kit adds little or no noise. It says tubular control arms must use stock-size bushings, and calls the install moderate to advanced | 1990-97 and 1999-2005, including the 2004-05 Mazdaspeed |
NC
Moss lists Energy Suspension polyurethane rear control arm bushings (910-412) for 2006-2015. I did not look for other NC bushings, and no owner thread on the NC was read.
Named in search results, not opened
Good-Win Racing sells a Whiteline full bushing kit and other bushings (its pages are behind a bot check I do not pass); Energy Suspension and Prothane have their own sites; I did not open them.
Not covered yet
- Harder-rubber bushings (Mazdaspeed or Mazda Competition type, or copies), which several owners prefer to polyurethane, and who sells them.
- Owner accounts of fitting a set, tools needed (a press is often mentioned), or shops that do it.
- Anything for the ND.
© 2026 Fischer Interactive LLC. Written for the Ref Sensor app's Miata users. The seller's page is the authority.