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Garage Star Delrin door bushings

Installed. Old design shown.
Garage Star Delrin door bushings
The easiest way to make your car feel stiffer.

Made in the USA

Availability: Out of stock

We are expecting the parts around January 2020.


Such a simple idea.

Your doors are held closed by the latch, but they're locked into place with a bracket that slides over a rubber bushing. That makes it easy to align everything, but it means the connection isn't as strong as it could be. In a convertible, the doors provide a surprising amount of structural rigidity if they're properly anchored.

These replace the soft rubber door bushings with stiff Delrin. The door is solidly locked into place, allowing it to reinforce the chassis. The effect is of a stiffer car with fewer squeaks. We have measured a 3% improvement in torsional rigidity on a 1990.

The second generation design fits the NC and ND more easily than the original. Shipping now.

Installation is quick and easy - simply remove the two bolts that hold the factory rubber in place and replace with this stiff piece. It will have to be properly aligned, and some light sanding might be required for the perfect fit. We've installed them in every car in our fleet, and most bolted right up. Available for all Miatas.

Sold in pairs, enough for one car.

Additional Information

Additional Information

Part number M21-97100
TÜV approval available No
Fits: 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1999, 2000, 2001, 2002, 2003, 2004 (non-MSM), 2005 (non-MSM), MSM, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016 MX-5 soft top, 2017 MX-5 soft top, 2017 MX-5 RF, 2017 Fiat 124 Spider, 2018 MX-5 soft top, 2018 MX-5 RF, 2018 Fiat 124 Spider
Manufacturer Garage Star
Flyin' Miata exclusive No
Fits Exocet? No
Proposition 65 Warning: Cancer and reproductive harm
California emissions Emissions regulations do not apply

Customer Reviews 47 item(s)

Night and Day Difference
I was skeptical that these would actually do anything but I thought, "What the heck?" and gave them a try. Drove the car home on my old bushings, got my package, popped them in, and, WOW. Where I live, the roads are notoriously awful. My poor car used to shake and rattle so badly going over bumps in the road. Now, it honestly feels like driving a new car! The added rigidity is immediately obvious and going over bumps no longer rattles my teeth or ears. I've very excited to do more driving and find other ways that these improve the feel of my car! Added bonus, the doors make a much fuller sound when they close now.
Review by Snerferus / (Posted on 9/16/2019)
Easy Fix
Super easy to install on my 2003. No sanding needed and the doors shut with a nice sounding click instead of the normal cheap car door sound. I do not have to slam the doors, as some others have reported, I can just shut them very easily. For the money and the ease of installation why not.
Review by Eric / (Posted on 7/3/2019)
great value for money spent
these went on a 99 miata with 135,000 miles and a just completed ls3 conversion. They fit great with little or no adjustment and went a long way towards quieting the bumps and rattles in the car. The doors now shut with a satisfying “thunk” This is money well spent.
Review by Mike / (Posted on 6/17/2019)
The improvement is subtle, but you'll notice the increased firmness going over a speed bump. You'll also notice it if you slam the door with more force than necessary, though it took me over a year to figure out that that was what was causing my driver's mirror to -- seemingly randomly -- go out of alignment. (Figured this out from a thread on miata.net where others recorded the same problem.) Not Miata's fault; don't think it happens with the OEM door bushings. I also believe this is the reason my driver's door window regulator came loose; the dealer simply retightened it, and all is good. Now that I understand, I'm gentle in closing the door, and the mirror problems went away. Proof btw, imho that these Delrin bushings really do make the ND stiffer.
Review by DavidF / (Posted on 5/7/2019)
Good good enough
Install was super easy, door shuts just fine, no sanding required. Car does feel a little less rattly on bumps and cracks, can't speak for much else. I'd say don't expect anything unreasonable and you won't regret buying them. NA 91'
Review by LOEWY / (Posted on 5/2/2019)
Great upgrade for your Miata!
Beat money you can spend on your Miata! Easy 10 minute installation and the car feels much more solid and fewer shakes and rattles now.
Review by IndyRob / (Posted on 4/21/2019)
Helped make a '91 a little smoother.
These bushings help make the car a little more rigid. It could be the placebo effect but I'm pretty sure that the car rattles a lot less when driving over bumps.

Definitely follow instructions and only tighten the bolts a little snug, but loose enough to move the bushings around. This allows you to close the door to position the bushing correctly. Finally, you tighten the bolts the rest of the way, the door takes a small amount of extra push to close but nothing excessive.
Review by burnmiata / (Posted on 3/20/2019)
No notlicable benefit
Installed on 2016 ND. Easy
Found no difference in rigidity.
Doors slightly harder to close than with oem bushings.
I had a small crack/chip in windshield, no doubt from a rock.
When I jacked up a corner of the car to do an oil change the windshield cracked open. Have never seen this happen before. These are twisty chassis.
Review by LAMike / (Posted on 1/24/2019)
Looks different but performs the same.
I received these as a Christmas gift. When I opened the box, I was surprised to see that they didn't look like the picture; they look like the OEM parts. I slid them into the pockets in the door by hand and saw that the fit was extremely close, so they'd work as advertised. Installation was easy; just left the bolts snug and closed the doors to align the bushings. It takes a little more effort to close the doors now but far from excessive. Can't wait to take it on the road! So far I have to give it 5 stars.
Review by Jerel / (Posted on 12/27/2018)
Loved them!
I recently bought these bushings for my bone stock '91, and i love them! they make the car noticeably stiffer and they add a nice click when opening the door. It was inexpensive and easy to install, i recommend them for any Miata!
Review by MikeThe Miata / (Posted on 12/7/2018)
Best cheap mod
These bushings were a vast improvement over the worn originals, very noticeably reducing vibrations and rattles.

The key to install installing the new bushings was initially leave the bolts loose, close and reopen the door a couple times (for best positioning), then tightening the bolts.
Review by Laguna Rob / (Posted on 11/24/2018)
Gotta have ‘em if you drive like you stole it.
Took 5 minutes to swap out on my 2004 MSM. AMAZED as to how much it stiffened the body and handling. No body twist when entering turns at high G.
Review by Awol58 / (Posted on 8/6/2018)
The sound of your cars door closing is a signal to the world, make it a good one
I don't know if it makes your car any stiffer but does add a satisfying "thud" when closing the doors. No more tin can slam on entry and exit. 5 minute job, did not have to dremel anything, plug and play.
Review by Buffering... / (Posted on 6/27/2018)
Great on my 90!
I bought the second generation design for my 90 and they bolted right up with no issues. Just use a dry erase marker to mark where the old ones sat then line these up to that line and bolt them on. These not only caused my doors to now feel tight when closed but they've also stiffened up the car significantly. 110% worth the price!
Review by Bo / (Posted on 5/14/2018)
It is an okay buy
Installation for the passenger side went smoothly and required a light sanding. The door now closes with a nice thud. Although the drivers side now requires me to slam the door to shut. After a ton of sanding and refitting I still could not make it work. So I went back to the oem bushing. The bushings do their job as it reduces the creams while riding inside.
Review by T Tran / (Posted on 5/4/2018)
Have patience, young Jedi
Super difficult to install for such a simple product. I did sand but still need slamming. Worry that the slamming will ruin the internal door parts. They should fit right out of the box. I was surprised that these were so simple in theory yet one of the most frustrating parts to install. Having said that, the car seems quieter over bumps and less rattling over potholes. I hope that in time the parts and the doors will form a union, a Vulcan mind meld, a 'force be with you' cohabitation and the doors will shut without slamming....
Review by sportypotato / (Posted on 4/22/2018)
Great buy
The book says buy the bushings. Always listen to the book.
Review by TheTippsyMusician / (Posted on 1/3/2018)
Awesome Little Upgrade
Installed easily on my '06 with no modification. Improved the quality of the door closing and noticeably removed a slight rattle from the doors on the highway.
Review by Sburgauer / (Posted on 12/11/2017)
Was super excited to install these... they cost me 70$ with shipping and all so wasn't exactly cheap! just one thing... my doors wont close unless I slam the living shit out of it... tried adjusting it with the bolts as much as possible, and tightened whi
Was super excited to install these... they cost me 70$ with shipping and all so wasn't exactly cheap! just one thing... my doors wont close unless I slam the living shit out of it... tried adjusting it with the bolts as much as possible, and tightened whilst making sure the delrin isnt wobbling about, and i got the right fit as much as possible, but nope, still gotta slam them, and the more i tighten the bolt down, the harder it is to close. Having said that, i haven't been for a ride yet to determine the stiffness and quietness, as i don't want to be seen outside struggling to close my doors. After reading some reviews, I'v decided to try sand it down! Not that there should be any sanding to do in the first place but anyway... will post another review if all goes well.

Note from Flyin' Miata: Sanding is sometimes necessary, as the rigid nature of Delrin means a small bit of car-to-car variance can't be absorbed by deformation like it can with the soft factory rubber. Guppy, if you continue to have difficulties please contact us.
Review by Guppy / (Posted on 10/12/2017)
Great product and value
Fit perfectly and are extremely well-made. Two hints, use the stock bolts as the coating is more water proof and they give just a tiny bit of wiggle room to get a perfect fit. Use a littel bit of graphite lock lubricant around thee contact areas. They Delrin slips in the pockets slicker than without and after the solvnet dries, there will be no grease to get on your clothing. Best value for the money i have ever spent on my NB.
Review by Topdogue / (Posted on 10/2/2017)
Great cheap mod
10 minute install, instant difference. Less cowl shake and rattles, stiffer feeling chassis. Best 1st mod on a miata
Review by Joel / (Posted on 8/1/2017)
Don't ask too much from plastic.
To enjoy the benefits of this product, I think you need to have the proper expectations for what the bushings will do. After installing, I noticed that the doors were substantially more quiet. My chassis does not feel magically more stiff than before; and I didn't expect it to. My main goal was to have a quieter ride. Goal accomplished. My doors are just as easy to close as before, and I didn't even have to break out the sand paper.

Be careful when tightening your bolts. If you go too far, you can snap the head right off.
Review by IsaacNB / (Posted on 4/15/2017)
They can stop a rattle but they have drawbacks.
These are solidly made products, but they do not significantly contribute to stiffening the chassis in any way. The only thing they can do is keep the door from shaking up and down. If you have good rubber door bushings, these won't offer much improvement. If you need new bushings they could be a good choice if you are willing to handle their drawbacks. If you use these to keep the door from moving side-to-side, then the door will be much harder to close than with rubber bushings. They did require a bit of dremel action to make them fit correctly. In the end, I'm going back to rubber.
Review by TEXMX-5 / (Posted on 3/11/2017)
Quality pieces, but one bushing had to be modified to work properly
I was really excited to get this part after all the raving reviews. So as soon as I received the door bushings I installed them.

Not sure if I feel any difference in stiffness.

With the bushings installed, the passenger door closed fine, with a nice solid click. The driver side door, on the other hand, would not close unless it was slammed to the point where I thought the door window would shatter.

No matter how much I adjusted the bushing and the cup, the door would not close. Now, the car has never been in a accident, all the body panels are straight, no abnormal gaps in the door, door hinges are not loose or sagging.

I had to sand A LOT to get the bushing to sit in the cup so that the door would close normally.

Not sure if one of the bushings I received was defective, but I just wanted to share my experience.
Review by Victor S / (Posted on 3/9/2017)
Stiffer and quieter, albeit with a minor drawback.
I Put a pair of these into an '07 MX-5 PRHT nearing the 100k mile mark. The installation was incredibly easy, requiring only a socket wrench and maybe 10 minutes of time. Prior to installing these, my doors would occasionally rattle a little over bumps in the road, but they're now dead-silent. They firmed up the chassis a little as well, though I didn't really notice it until I had an opportunity to spiritedly drive through some familiar surface transitions a few times.

The only noteworthy downside is the substantial increase in door-closing effort. These will likely require more force or follow-through in your motions than you or your passengers are used to. This side-effect is normal by all accounts I've read so far, but could nevertheless be a source of concern or annoyance to some. I'm fine with it, but your mileage may vary.
Review by t0ast / (Posted on 2/28/2017)
Review by RevToRed / (Posted on 2/18/2017)
They really work, and great.
My brother bought me these as a Christmas present (with my recommendation of course) for my 95. It already has tein coils, fm sways, and poly bushings riding on some direzza IIs so I've been more than happy with handling, but even though It only has 50k miles on it now it had some nasty rattles and an odd unsettled feeling over bumps. I spent less than 5 minutes bolting these on and getting them aligned (seriously it's so easy) and I immediately noticed the more solid sounding door close that others mentioned. First impression driving was that the rattles are all but gone save for hitting some of the nastier bumps and even then the rattles are hardly there. It also lost most all of that unsettling feeling. I can't believe these work that well. I recommend them highly even if just for the noises they help quell.
Review by Sam / (Posted on 2/6/2017)
Best money spent on handling so far
Just like I read from plenty of others before buying... Definite increase in stiffness with nothing else added. My fiance is butt-numb when it comes to feeling any changes from modifications in the passenger seat. She couldn't tell a difference from stock ECU to tuned on megasquirt with AFM delete... This is the first mod she said she could actually feel. The car seems to corner much tighter now, and maybe I was just timid to throw it around corners before, but it really seems to handle much better from these alone.
Review by Bryan C / (Posted on 1/28/2017)
Cheapest and best upgrade you can make for you baby car!
Holy She-ite, I have made less than a half dozen reviews in my life. But this was a must. Best $50 bucks I've ever spent on my 2003 miata, and that's saying a lot since I've dumped thousands of dollars into it. Every time I'd drive over an uneven surface my baby would always creek and moan. No more, no more over potholes . Wow! You can't go wrong for $50.00
Review by Shocker / (Posted on 1/14/2017)
Well worth the money
I was not expecting much when i bought these, but after install lots of little rattles in the car went away and gave the car the feel of having less flex in the body. Loved the results.
Review by TL / (Posted on 12/29/2016)
They work and worth the $45
I was initially skeptical that these door bushings would make a difference in the ride and handling but I finally got a decent drive last night (it's been -20C for 2 weeks) and you can feel the difference. The body doesn't "flop" as much and less squeaks and rattles from the PHRT.

The doors do require a bit of heft to close but I don't mind it. From a 7-8" opening, if I give to strong shove or pull, the doors latch with no problems. I don't need 2-3 tries. Slamming the door doesn't work.

I would recommend it other MX-5 owners.
Review by TOM / (Posted on 12/22/2016)
It's true
I definitely noticed them. The car felt perceptibly more rigid.

I figure this is also a good way to reduce chassis fatigue on my car in the long term.

I strongly disagree with the guy who said it makes the doors easier to close. My doors now require a conscious effort to close. In fact, it usually takes two tries. I have a suggestion for the manufacturer: there should be a longer, shallower "ramp" section of the bushing where the door slides up from its normal hanging position onto the bushing.

This may be a coincidence but the door hinges have started squeaking in the two months since I installed these.
Review by Pete EE / (Posted on 12/10/2016)
Best $45 I've ever spent on a car.
Transformative. I have a dirt driveway, which makes the doors rattle like nuts. Back country roads with lots of potholes, etc., remind me every 100 feet that I'm driving a 25 year old car. These door bushings completely eliminated the door rattles and quieted the car down considerably. Makes it feel more solid overall.
Review by RPerlot / (Posted on 9/20/2016)
Do the install, close the door, take a ride, feel & hear the difference,
Well worth the money, rids nagging squeaks, and amazingly makes the body stiffer. Highly recommend this product. Easy install.
Review by Camp / (Posted on 9/15/2016)
Well worth it, surprising noise reduction
They seem a bit steep price wise at first but these are brilliant over the OEM ones. As far as stiffening, I can't vouch much due to my driving so far, I haven't really thrown it around too much but the noise and rattles you encounter are all but gone. Easily worth the money.
Review by Ted / (Posted on 7/11/2016)
Deffinetley worth the money.
The difference between the OEM and these are night and day. It took a bit to get them adjusted. The staff is available at all times and talked me through over the phone how to adjust them. The doors shut so much tighter now.
Review by Terra J / (Posted on 1/25/2016)
Not a miracle, but worth the investment
I didn't entirely trust all the positive feedback about this item. But, I plunked down the $65 because the rattling in my car was driving me crazy and I just had to confirm. Well, they work. The doors close with a "thunk" now and feel very solid. Most of the minor rattling is gone. I am going to look into the butterfly brace next. These are not a miracle, but if you keep your expectations in check you will be pleased.
Review by Mike H / (Posted on 1/22/2016)
Well woth the noney to quieten down you car!
They work just as advertised and fit with no problem at all
Review by Pete Burrowes / (Posted on 1/14/2016)
It works!!!!
These are so easy to install and it automatically stiffens up the chassis. I immediately felt chassis stiffening when going over bumps, and it reduces door rattles! I'd recommend it to everyone!

Review by Marloon / (Posted on 1/4/2016)
Unfortunately, these bushings would not fit the door cups on my 2005 Miata (build date 09/04). I made sure to align the bushings so that the door closed smoothly without hitting the bushing, but the doors still would not latch.

The problem seemed to be that the curve of the Garage Star bushings curved sooner toward the middle than the door cups do, which keeps the bushings from seating completely in the door cups. The door cups appear original and undamaged, and the car doors have no history of damage or repair (I am the original owner).

After careful installation and reinstallation, and checking hints and tips online, I contacted Ken Raif, owner of Garage Star and the maker of these bushings. Photos of the bushing/door cup fitment problem were sent, and troubleshooting discussions ensued, but a solution could not be found and the bushings were returned for a full refund. I give top marks to Ken Raif for taking time out of his very busy schedule to try to help me with this issue.

Based on positive customer feedback found here and elsewhere, my problem seems to be an isolated incident. However, be aware that there is at least a chance that these bushings may not fit your Miata.
Review by Brady / (Posted on 12/24/2015)
Great bang for buck part to improve the general experience of your Miata
I purchased these bushings following a huge spike in hype on many of the online Miata communities. I was a bit skeptical and debated over it for quite some time because I wasn't sure if they would be worth the $65.

I was immediately impressed with the quality of them before I even installed them. They are very nicely finished, and the installation was effortless.

I was initially disappointed when I first drove with them on because of how much everyone had talked them up, but after I got over the newness and all the expectations I really started to notice differences during day to day usage. The doors now close with a satisfying and final "thunk". I also noticed a dramatic improvement in the sound quality of my stock radio. The lower bass sounds now pack a much bigger punch.

Overall I am very pleased with this product and would definitely recommend it to anyone who's Miata is beginning to feel its age with all the squeaks and rattles.
Review by Cory / (Posted on 12/10/2015)
Lots of tiny improvements for a fairly tiny price
I was mainly shopping for some maintenance things for my Miata, and came across these. Bought them completely on a whim after reading positive reviews, and seeing how cheap they were.

It's very apparent that these are not a cheaply made piece of crap once they're out of the box. Well finished, and I know from experience that delrin is a fairly difficult to machine type of plastic, at least if you're trying to get a very smooth finish.

Installation was very easy to complete. Just remove your old spongy rubber mounts, clean the surface off, and use the worn paint spot as a guide for mounting. They're a slightly different shape than the stock bushings (capital D as opposed to a |} shape), but that's not an issue. The mounting holes are oblong for up and down movement, so I found it easiest to put it where I thought it needed to go, tighten the bolts down only enough to allow movement from a harsh force, and then shut the doors to align them. Tighten them down all the way and you should be good to go. My doors need a little more force to shut all the way now, but I'm sure I could solve that if I sanded the bushings down slightly. As it is it doesn't bother me enough, though. I re-used the old fasteners since they have a lock washer, but these do come with new grade 8 bolts if you want all-new.

The difference is actually quite noticeable. I lost a few interior squeaks, my door speakers don't create as many violent shaking noises in the interior anymore, and most shockingly, the car does feel just an ever so slight less floppy in corners and on bumps. Plus, the doors seem to stay shut better, and that ALSO results in better sealing with the top. All of these differences are small, but they're all positive and for a small price, definitely worth it.

If you're already going to be doing some work on your interior, do yourself a favor and add these to your order, you won't be disappointed.
Review by Greg / (Posted on 10/31/2015)
Just get these. For $65 you cannot go wrong with these.
Probably the best bang for your buck handling upgrade. The car drives noticeably smoother now, and my "highway shimmy" is completely gone. The car also corners better over rough surfaces instead of "skipping" like it used to.
Review by Jacob / (Posted on 10/15/2015)
A tremendously easy install
Although the bushings do not come with instructions, just keep the rounded corners to the outside of the car, match the small line of crud left by the old bushings, and tighten.

The doors on my '97 close with a much more authoritative thunk; we'll see what driving brings.
Review by JJ / (Posted on 9/25/2015)
Worth the price, noticeable, especially if you use the door as an armrest.
WOW! These door bushings make a solid improvement. I already have Frog Arms, FM butterfly brace and frame rails, and every other brace short of a roll bar that I could add to my '96 Miata. I didn't have huge expectations for these door bushings, but I'm all for adding stiffness to the structure. Install was very fast, 10 minutes at most. The change was noticeable immediately. I frequently drive with my elbow braced on the door, and I can tell the door doesn't flex or wiggle like it previously did. My Miata only has 31k miles, so it is still relatively tight, but this was worth the somewhat steep price to add even more rigidity to the car.
Review by James M / (Posted on 9/16/2015)
better ride quality over all, extremely affordable
My NB miata has 67k miles, I know that after a while the bushings will go soft. That is why I bought these door bushings now. Even with such low mileage they greatly improved ride quality over bumps. If you have a higher mileage miata this is one of the best bang for buck mod you can do.
Review by Antuan / (Posted on 9/14/2015)
Make your car a better built car, with ease, and affordably.
Got mine from Garage Star a while back, and it was a great investment. Less squeaks/rattles and a bit less cowl shake, along with somewhat improved audio from the stereo.

Now, let's understand what these are not. First of all, they're not a cage. They're not going to increase the stiffness so much that it feels like it isn't a convertible. However, for the price, and how simple the install is, they make the car feel just that much better. Reminds me of how old Toyotas used to feel, which is to say, very well built.

So, if you're looking for a way to make your car a nicer place to be when you're driving it, this is a good purchase. =)
Review by Brad / (Posted on 9/4/2015)
Instructions for this part are not currently available online.