door bars are worth every cent
 

I have a 1991 with 170k miles, so its the most flimsy of all Miatas. The car now feels like one piece of metal, rather than two subframes which twist around, it was so bad in my car that on 205 r-comps on 99 wheels I was lifting the front inside wheel on corner exit. The car now rides smoother and doesn't feel "over-sprung" anymore. The hardtop rattle at cruise is gone too.
http://i49.tinypic.com/58fib.jpg
I now must remove the RB rear bar and try a stock bar again because adding throttle causes front wash-out. If I had better dampers I'd just remove the rear bar and add valving but my Flex will jack with any more stiffness.

Yes, you should buy them. My car feels half its chassis age.

Short concise review, nice. But what does this mean? I first interpreted that as understeer, but then, changing rear ARB to a softer one would'nt cure that.

Does this only brace the chassis twisting and not longitudinal bending?

Bolted or welded in?

What brand?

Already have frame rails right?

Hard Dog bolt in bars right?

Great review and good to know it makes a difference. Boss Frog slams them so much I was waffling. Got a set coming for the holidays now.

I have said it before but a +1 from me on the door bars. I have the Hard Dog bolt-in set (with a roll bar) in my '99 and they really make a big difference. The door bars form a triangulated structure (with the floor pan/frame, and the chassis behind the seat forming the other two legs).

Yup, I've heard the door bars make more of a difference than the rollbar. I'll be picking some up hopefully before the season starts.

What seats do you have?

I've been putting off door bars because of potential seat interference, but it looks like they fit well with yours.

Can you measure hor far they sit away from the door sill? X inches in and X inches higher would be awesome.

Thanks for the input, hustler. I've been considering these for my 213k-mile '90 as part of a plan to get rid of the flimsy-factor.

Did you get yours directly from Bethania or elsewhere?

both
Bolted in.
hard dog
no overprice, heavy frame rails.
yes
The seats are Ultrasheilds from TDR. Those are new too. It all depends on how you do the mounts. The bars touch the door card all the way down.
Bought them from Gary with the seats.

Cool, i'll be getting a set soon too.

How do you like the seats? I really want a pair but, i've heard that they are not very comfy, especially for a daily.

For dual duty seats, take a look at Cobra Clubmans

Door bars are nice, but getting my 240 pound butt in and out of race buckets with the bar in the way almost makes me want to pull the door bar...... ALMOST :)

Quick release steering wheels make life easier though

I doubled the foam padding in the butt and added some lumbar and its just as comfy as the old sparco sprint. My hips AND shoulders fit in this seat which is nice. I don't know my measurements, but I'm 5'11, 31" waist, and weigh 184lb...the shoulders and thighs never fit right.

cuse your soo jacked :cjerk: lolol

Having setup cars with Hard Dog door bars and frame rail braces myself. I have to say the Door bars are like an order of magnitude more effective at stiffening than the frame rails even compared to a full butterfly.

On my car I have a Hard Core Bar and door bars. I also seam welded the chassis and welded in reinforcement plates at the roll bar and door bar attachment points. I also added my own version of under fender braces (more like Tucken 99 than Boss Frog) I have my own front and rear subframe braces My own front shock tower bar that triangulates through to the base of the windshield. I am also running FM frame rails but without the butterfly.

Of all of these things without a doubt the most effective chassis stiffener I have done is the door bars.

Bob

I'm jealous, Bob. I've only driven the car home from the shop, but it feels half its age now. I'm putting on the stock sway and hopefully going to the track this weekend. Hopefully the car won't be as sketchy because it was a little daunting at times through highspeed stuff. I really need aero...but that's for another car.

Yea I alwas ran the Racing Beat 1 1/8 hollow up front and as I got the chassis much stiffer I went back to running a stock bar in the rear instead of the 5/8” RB.

I recently installed ISC sways. 1 ¼” X 1/4” wall in the front. And 5/8” in the rear. Right now I have the rear on full soft and the front 1 hole from full stiff. But it is hard to compare directly to other bars because both front and rear have much more adjustment range than other bars and the arm lengths are much longer making them softer than they might seem.

Bob

Great to hear! This is the next purchase for my car.

Do you have install pictures, and do you think it stiffens the bosy more than frame rails?

This thread sucks...

...now I have to have them. I must cure my rattles at all costs. Better handling a plus as well.

Its so easy that they don't include instructions...because you don't need them. Its Mr. Potato head. I left mine on top of the carpet and drilled the first hole from the top, then guessed at the bottom holes and it worked the first time, everytime...unlike Panther cologne.

I don't know if it stiffens the body more than FM rails, but geometry is on the door-bar's side. A few posts above and you'll find this answer.

I get weird noises through the car now, especially with the poly rear-end bushings. The R&P noise resonates a bit more now, but that's expected.

Now I need to weld little tabs on my 1.6 rear subframe so I can attach the beatrush bar. I'm still toying with the idea of strengthening the PPF too because I know that poor little guy if not twisting, will eventually fail from fatigue.

Do it and report back. I have always wondered how much strengthening the PPF helped but have never seen anyone actual do it and report results.

Look at my build thread for some door bar pics.

https://www.miataturbo.net/forum/t36266/

+1 door bars more dramatic improvement than the butterfly.

After the door bars I changed my mind about replacing the miata with a Stook or a Boxster due to the wet noodle chassis shudder.

So is there anyone out there that still doubts the effectiveness of the door bar approach?
Forget about the safety arguement; even if it is an issue, my Momo buckets are taking care of that.

can someone post non-shitty pictures of them installed?

Here ya go.

Suspension

Loving this thread. Moving into my first house on Dec 18 and then the 6 pt roll bar and frame rails are going on (and the new suspension).

Already answered. Yes. The only reason I know of to get rails instead of door bars, especially if you already have a roll bar, is that some do not like having door bars in the cab for whatever reason. There is a long discussion about it at miata.net. Otherwise, considering the cost/stiffness ratio and the weight/stiffness ratio, the door bar is better IMO.

Some more door bar pictures here:
https://www.miataturbo.net/forum/t37096-2/

great
thanx

Nascar bars or bust!

Sounds like I can pull my FM frame rails and sell em when my door bars show up! They did exactly zip for stiffening that I could tell. The shock tower brace was a more noticable change that the fm rails.

Really? I think that's the first time I've seen someone say the frame rails didn't make a noticeable difference.

I already had an HD roll bar in and a triangle shock tower brace. The rails really didn't make a noticeable difference in driving feel. There is a difference when jacking the car up so I know they work but it wasn't significant enough for me to tell on the road. The strut brace was an bigger change.

Of course my wife accuses me of being insensitive. I guess this could apply to my driving too. :giggle:

I would consider leaving them in since they will save your stock rails from speedbump induced bashing especially if your suspension is lowered.

Nice to see you're bolting more stuff on. However front wheel lifting is hardly from a floppy chassis me thinks.

Still, full cage > door bars.

You can feel the body twist in 3rd gear, on the loud pedal. This car is very old.

I had no clue that a 15-point cage was more rigid than door bars. Thanks for the enlightenment. lol

Full cage = death in a street car! It's a consideration only for track cars in my book unless you dress like the Stig to go to the grocery store.

Damn you trendy fuckin' bastards.

When I had expendable cash to spend on chassis stiffening everyone said frame rails were the way to go, and some of ya'll even talked me OUT of door bars.

Don't get me wrong, I love my frame rails...but now I'm gonna HAVE to get door bars as well. I'm going to stop listening to you guys before end up broke (and divorced).

sell the ------ frame rails and get door bars. I'll be in Houston in January if you want to go for a ride...in my lap.

This thread is going to cost me more money.
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How long after gospeed gets his door bars do we wait before seam-welding our cars?

About 6 months.

What ever happened to this?

https://www.miataturbo.net/forum/t39221/

What happened? Big suprise. The newb with 23 total posts proposing building them never came through.

I still think someone with a tubing bender could reproduce these very easily for dirt cheap.

If I knew someone with a tubing bender locally i'd make them my damn self.

Welp...glad to hear that you're a happy camper now. I am also glad you're liking the Ultrashields and the "new" seat bracket design. After mocking the Lemon's and doing mine, I can now drive for more than an hour without the notorious butt knuckle cramp.

Roll bar or door bars?

Pick one.

Rollbar first

rollbar first since doorbars arent gonna to save your life

Why not have the door bars and the frame rails? It would help triangulate the center of the chassis.

Good deal...working internship on north side...can meet for "lunch."


lmao at mgeoffriau and cueball. Ya'll's some mean fucks. :bowrofl:

Nothing like laughing out loud in the library. People studying for finals look like they wanna dismember me.

I actually ordered a set of these to make them myself $52.99

Jegster 940008 Jegster Pro Street Door Bars

They would work really nicely I think. Might even create a slightly better ergonomic installation than hard dog if done right.

I still have them. But in the end I got lazy and ordered directly from Hard Dog. I needed a harness anyway so I added door bars to the order. So I have the Jegs bars just sitting in the shop.

Bob

I hav both. I think they complement each other nicely.

Bob

What he said.

I may be interested in buying those off you some day if they continue to sit around. I'd like to put in the door bars at the same time that I finally seam weld the door sills. Did you ever test fit them or anything to see how they really fit?

I would think only if you had the butterfly brace to tie the rails together. Otherwise there is nothing additional triangulating the two frame rails for horizontal plane stiffening.

I kind of layer them up next to the car. but to really fit them in place good would require iterative cutting off of the ends and hoping to nut cut too much off in the process. I never got around to that and they are still uncut.

Bob

In my professional opinion as a chassis structural engineer a flat plate on the bottom of the car will do next to nothing for stiffness. a flat plate to resist parrelelogramming like where one rail shifts forward and the other one shifts back will also do next to nothing in this case as well because I don’t thing that is a weak mode for the chassis to flex in.

Closing the bottom of the transmission tunnel in a structural way such that it makes the trans tunnel behave like a big tube rather than an open channel will do quite a lot. But you still have that torsion bar concept going on like where the material in the middle of a torsion bar adds minimal torsional stiffness. Hollow bar and a solid bar of the same OD have very similar torsional stiffness and yet the hollow one is ¼ the weight. The trans tunnel being in the center of the car isn’t as effective as material further away from the centroid like near the sills.

The stiffness that the FM butterfly adds to the chassis is mostly from its effectiveness at closing off the bottom of the trans tunnel making it behave like a tube. The problem I see is it could be designed allot better and be lighter than what it is to do this. It needs to bolt to the car near the edge of the tunnel not out by the frame rails. The later model factory braces are much better at doing this than the FM peace. I saw it as way to much weight for the benefit.

Bob