Disclaimer: I am not benefiting financially from this review. I am not receiving any kick back or royalty from Garage Star for sales of these bushings. I never thought this review would become so popular or so controversial. I also have no idea if the below observations will apply to YOUR Miata. The below is my experience with the Garage Star Door Bushings. I posted it only in a desire to help others enjoy their Miatas.
This is something that totally came out of left field, at least for me. I had no idea that stiffer door blocks were a thing. I guess Toyota offers something for the FT-86/BRZ/FRS? Anyways, this was seriously not something I ever knew I needed. And just looking at them, I had no idea how they would help anything.
Spoiler: every Miata on the planet needs these. You can stop reading now if you want and go buy a set.
Ken at Garage Star has created something awesome.
How they work (I think): The Miata is floppy. This is not news to anyone. A major chassis point is apparently the spot where the door and frame connects. Mazda uses a combination steel and rubber piece to make this connection. The base is steel and soft rubber is bonded on top.
There’s a pretty good amount of space between the cup and that rubber stock door bushing. By “a good amount” I mean around 1mm of space. Add to that a soft rubber bushing. You don’t get much extra chassis rigidity from the factory parts.
The Garage Star bushings are machined to super-accurate tolerances – .01mm according to their website. This allows the door to make a firm connection with the chassis and move the sides of the box up slightly. It’s not like adding a cage or door bars or whatever, but… holy crap is it effective.
Did I mention all 4 of my stock door blocks (Sharka’s and Bucky’s) had slightly different measurements? No doubt they’ve been squished over years of driving and the doors bumping around.
Before you get confused, the above shot is not how they install. I’m just including it to show how tight the fit is.
The door cup is installed on the lower part of the door from the factory. The bushing is installed on the frame. As you close the door, the cup closes over the bushing. And check out how tight they fit! I was able to easily place the bushing in the cup and take this photo.
It isn’t a TIGHT fit by any means. The bushing is ever so slightly diagonal in the cup to get this photo. But just barely. On my cars, there’s less than .2mm of wiggle room between the cup and the bushing (.12mm according to my feeler gauge on this particular block). That’s just enough to allow the door to close without any extra effort, but also a tight enough fit to eliminate door rattles and firm up the chassis when it flexes.
That’s it. Two screws. I used my fancy JIS screwdriver. The P.3 was a perfect fit.
To install, just remove the old door blocks and put on the new ones. Get the screws a little more than finger tight and slam the door. Then open and slam 5x. Then tighten the screws and repeat. Your door should not be any harder to close than with the factory door bushings, but it will give this lovely little pop/click noise. When you’re happy with the fitment, tighten the screws all the way.
A note of caution – the screws can come loose if you only tighten them with a screwdriver. More on this below. The final tightening should be done with a ratchet and 10mm socket.
After driving about 150 miles with these, I have a pretty good feel for them and think I can give some good feedback. (Sorry about the wall of text. Hard to take photos of feelings.)
Car: base 2001 NB with a rollbar and TEIN Basic suspension. There’s like no bracing on Bucky at all. No diagonals on the rollbar either. The windshield shakes CONSTANTLY. Or at least it did.
I installed the blocks and went for a quick 10 mile spin around some familiar city streets. The whole car felt immediately transformed. The windshield hardly shook and I could actually feel the front and rear suspensions being independent of each other. I only got cowl shake on one bump (an offset manhole cover) on this test drive. I was hugely impressed.
The door bushings seem most effective on low speed bumps, like bumps taken between 15 and 35 mph. Higher speed bumps don’t upset the chassis as much (at least not on Bucky), but the lower speed ones were always pretty punishing. The world would end for a second or two after the bump before returning to normal. Now? That’s all gone.
I then drove around 50 miles the next day. The car started out nice and firm, but by the end of the day, I was seeing some windshield shake and the car was feeling more like a normal Miata. I was a bit disappointed. I figured that the first day was just new-part-excitement and maybe things weren’t as magical as I was imagining. I don’t have any NVH meters after all. It’s all subjective. But it definitely felt shaky.
When I got home, I installed Sharka’s door blocks. I did this with a ratchet since no JIS screwdrivers were handy at the time. I was amazed at how much the bolts kept tightening down after I felt like I’d gotten them tight. The delrin smooshes down a pretty good amount. On a whim, I opened up Bucky’s driver door and tightened down the door blocks there. The driver door? TOTALLY LOOSE. The screws had worked their way loose and were barely finger tight. I zipped all 4 down with the ratchet (passenger side was decently tight still).
On the next Bucky drive, the feeling of strength and rigidity returned. Bucky felt like a real car again, and that feeling lasted all day. I covered about 35 miles today over a bunch of surfaces. The “Miata feel” of a wet noodle with a shaky windshield never came back.
I effectively gave myself a blind test. I had no idea that the door blocks had loosened and I could definitely feel something had changed when driving around with them loose. I’m rather amazed this happened. It was an awesome blind test to take.
Car: PEP (popular equipment package) 1995 NA with various braces, Blackbird Fabworks rollbar and 2nd gen XIDA suspension. And a hardtop, can’t forget that. That piece of fiberglass provides a top for the box and a tremendous amount of rigidity. Sharka is very stiff. The rollbar made an actual noticeable difference in NVH and the XIDAs mean every bump is magically handled. Sharka is not a fair test. I didn’t expect to notice anything.
And? To quote a song, you don’t know what you’ve got until it’s gone. Sharka is now invincible. All bumps just… go away. Railroad crossings used to give me a bit of mirror shake and some drama. Now? None. Bump-bump-DONE. Potholes are barely noticed. I’m afraid I’ll bend a wheel before I feel a big bump now. It’s just amazing.
Sharka now feels like a much more expensive car. BMW-like comes to mind when driving. Bumps barely exist, even with the hard Elise seats.
These things WORK. I imagine Ken will be extremely busy making these since 100% of all Miatas on the planet require them. It needs to be one of the early mods every novice Miata driver does: rollbar, shift knob, vent rings, door blocks. Not necessarily in that order.
Go get your set. It’s one of the biggest bang for the buck modifications you can do to a Miata.
I’ve received a few questions about the door blocks and thought I’d address them on this post to help folks out.
Sorry about the wall of text below.
Q: There have been complaints about increased force required to close doors. Some guys have to slam the door pretty hard to get it to latch. Do you have any problems with this?
A: For me, the door effort oscillates between zero extra effort required and “some” extra effort required. It seems to depend on my parking situation. In my flat garage, my NB has zero extra effort required to close the doors. They latch easily. If I park somewhere with a less even terrain, there might be an extra shove required to get the door to close.
The first couple times this happened, I was a little concerned. One time while parked in a mall parking lot, I whipped out my ratchet and re-adjusted the passenger door bushing which seemed to be sticking. I got the slam effort dialed out and went home happily. When I got home and was parked in the garage, the door required some effort to close again. I re-re-adjusted the door block to work correctly on a flat surface and haven’t really thought of it since.
I’m attributing this effort to chassis flex. My NB is pretty flexible. Sharka, my NA, is a lot stiffer. I’ve not had any problems closing the doors on any parking surface with Sharka.
This is my own experience with my own cars. Will it be different on YOUR car? Probably. I can’t say for sure. I can only relay my experience with my own two Miatas.
Q: Some cars have problems with the lower door edge sticking out after installation of the GS door bushings. Do you have this issue?
No, I do not. Both of my cars have the same door alignment as before.
I asked Ken (owner of Garage Star) about this and he mentioned loosening the door mounting bolts and re-aligning the door itself. He did this for a local customer and the lower door poke issue was solved.
It seems to me that you might be able to massage the stock door cup into shape if it’s not allowing the door to close with the bushing installed. A bit of a nudge with a large pliers or channel-lock might get the clearance necessary. Or shaving a bit off the front edge (edge you see when the door is open) might allow the door to close without the lower edge poking out. But this is all just a guess since I never had a problem on my installation and did not test them in an attempt to fix.
Q: You are manipulating people into buying these so that you can get a kickback.
This one shocked me. It came from one of the various Miata forums. A moderator actually typed it. I’m not sure if I wronged him somehow or if he just doesn’t like toy robots. Anyways, here is my answer.
A: I have zero financial interest in this product. I posted about the Garage Star door bushings because I truly liked them and was astounded by how well they worked. The experience I posted is 100% true for my own small fleet of two Miatas. I am not receiving any royalty or “kickback” from the sales of these or any other non-revlimiter product that I’ve reviewed. I make and sell my own parts, but I don’t “review” them on here. I post about their existence and let others write reviews of my own products.
All reviews you read on this blog are my own personal opinions. I’ve never been bought off or asked to write a positive review. The great majority of my product reviews are positive because I research the hell out of everything before I buy. In the few circumstances I’ve found a product to be poor or disappointing, I’ve posted as such in my reviews.
I might have given in to hyperbole toward the end of this review what with the statement “100% of Miatas need these.” I enjoy writing about cars and attempting to be witty. Not every car is the same and, very likely, not every car will benefit. My NA did not benefit greatly. However, I could feel a pretty noticeable difference over large bumps and road imperfections like train tracks. If I’d only installed these on Sharka, my review would likely have been much different, but it would have still been a positive review.
I wrote about this part as an enthusiast in hopes of helping other enthusiasts. That’s it. No other reason.