16 replies to this topic

[Brian129]

So I am just wrapping up the little things. Finishing up the front seat mounts, and working out the final little issues.

So last night I bolted my seat all the way in. There are two bolts that run through the rear of the seat into the rear seat humps( which have been slit, and pounded flat against the floor, so the back of the seat is on the floor. Sean at miatacage said this was the way they do it.). I then have a metal brace that looks like a H that bolts to the bottom of the seat in front of the rear mounting points, and bends down to bolt into the for cross bar.

Anyway, the seat is as far back as I see I can make it. And I have leaned it back trying to get my head down. Even to the point of having to relieve the side of the shoulder wing to clear the main hoop.
The seat is an ultrashield pro road race in 16", I have already chopped a large section of foam out of there bottom of the seat pad to try to get lower.

I am 6'2" with about a 32" inseam. Weight 235 right now but need to be like 205.
Anyway so I sit in the bolted down seat and I am hitting my head against the bottom of the main hoop now. This is without a helmet on too. And no padding on the bar. If I slouch in the seat I can get under it, but then I have a large gap behind my back, which is not going to work as tightening the belts against air won't be good.

When I was working on the cage and everything I did not have the front brace in, and the seat was loose in the car, so it seemed like it was working, and now it's not. I really don't know what to do. I guess I should have just dropped the car off and taken the $4000 hit. bacause now I'm about $11k deep in a car I can't drive. The only advice I get from my dad is " there's golds gym, maybe if your less of a fatass you'll fit in the car." I can't see where losing a few pounds will lower my head 1.5 ".

[38bfast]

If you take the seat out of the car and sit in the car do you fit? If the answer is yes then you will need to fabricate the seat to emulate that fit. We have cut the bottom out of seats to increase the amount of flat that is parallel to the floor.

[Keith Andrews]

Take it over to Tom Fowler/OPM.  He may be able to make it work or tell you what will work.  

[Todd Lamb]

I'm 6'3" and fit in some really tight SM's - I'm sure there's a way to make you fit.

[Ron Alan]

So it sounds like the bottom of the seat is flat on the deck correct? An you've pulled out the padding correct? And when you put the seat in a position so your head wont contact the main hoop you are to close to the wheel and or pedals? I'm going to assume yes to all. Guys with long Torso's always seem to have the toughest time in these cars...but its definitely doable. Maybe your main hoop design is just a little to far forward? Or not close enough to the hard top? You mentioned Sean so if its a Miata cage I'm sure these arent the case...so here is a solution i've seen guys take...which is not legal!!! And i'm sure i'll get flamed for posting this...but modify your floor pan down to get the height. There are several cars in our area that have done this with no issues from tech or other competitors...maybe just lucky but in the end its what it took to drive the car for some. Again, exhaust all other options first but if this is what it takes to run around in the back to mid-pack for awhile...I cant imagine anyone will care. Ok regulars...please dont send me hate mail. Cutting the actual seat...hmmm?? 

 

As Todd said...it absolutely is done all the time...and some just resort to being all up on the wheel NASCAR style!

[mdavis]

Like Todd I'm 6'3" and fit with a miatacage in my 01 and that's a roomy cage compared to what I have in my 99 and still fit.  Brian Wisler has driven my 01 and he's at least 6'4" 200+ and fit fine.  In both of those cars the seat is bolted directly to the floor- ultrashield spec miata seat in the 01 and a momo in the 99.  My guess is that if you got rid of that "H" shaped brace, notched out the transmission tunnel, and got a different seat you'd fit fine.  It might just take one of those 3.

[Jim Drago]

The only issue I am concerned about is if you laid the main hoop in a plane that is directly over your head? Most lay it back a little for this reason.
Before you get too concerned..

what seat do you have? You will likely need to go to an aluminum seat and bolts directly to the floor in the back and raise the front a little to get the desired incline. Also remove the front seat brackets and the rears completely, you need all the room you can get.

No brackets on the seat, direct to the floor.

If you have any pictures, post them or email.

Installing seats in these cars can be and often is a full days job.

BTW 6'3 275 and fit fine
Jim

[svvs]

I'm actually kind of surprised your head is right below the main hoop as well.

 

A lot of us tall guys wedge into these cars, and it's a pain.  The first time I went to mount a seat....I gave up and drove 2.5 hours to Planet Miata.  Spent half a day with their fabricator getting into and out of the car, but that seat was in the perfect spot when he was done with me.

 

It's all been said here, but the list is good.

 

Blast out the rear humps (drill the spot welds) and that front cross member part.

 

Modify the trans tunnel.....either with a cut out and re welding material in, or with a BFH.  If you go BFH and the top is on the car...wear muffs.  I actually used an air hammer/chisel with a blunt end.

 

Something that hasn't been mentioned here is playing with lean back to get your head lower.  If you need to get clearance for knees to steering wheel...use an extender to bring the wheel closer to you.  I have a 3" or 4" extender on mine so I can have proper foot work without rubbing on the wheel with my knees/thighs.

 

You'll get in there somehow.  Good luck.

[Bench Racer]

If possible post some pictures of the cage, with steering wheel, wearing helmet, with and without you seated.

There is a straight forward SCCA Spec Miata rule, "The floorpan must remain in it's original position."  Having other classes talk about our driving and double dipping is one thing, we don't need them talking about the illegal Spec Miata cars they see. 

 

 
 

[Danny Steyn]

Brian129.

 

There is more to this than getting your seat to fit. If, as it sounds to us, your main hoop is directly above your head, I would tell you that I would NEVER drive that car. Sure you can get it to fit, but the point is, what happens in the event of a crash? Having the main hoop directly over your head is a serious concern. Most builders have the main hoop offset to the rear of the seat, so that the chance of the head contacting the hoop is reduced

 

[Brian129]

It is a ultrashield aluminum seat
Yes the humps are down in the back, the h brace bolts to the front cross bar just for holding the seat up, it stops before going under the rear of the seat.

The mainhoop was installed back further then the miatacage instructions call out,, but no it's not directly over my head, just hitting the top edge of my helmet.

Here's some pics

[Mark McCallister]

I think your cage is right, you just need to mount the seat about 3" further forward than that.  Your knees are going to bend, but that's OK, you want to be close to the controls.  It's a Miata not a Fiat.  :-)

[Danny Steyn]

Yup Mark has it right - that seat needs to move forward significantly to give you some safety clearance between your soft head and the hard roll cage.

 

And Brian, just so you know, I took a big hit several years ago, going in backwards into a concrete wall at Mid Ohio. Car stopped dead from 60mph, All the rearward momentum was transferred into the seat so badly that it pulled up the floor pan and my head made contact with the roof. The shell on my $1,000 Aria GP5 helmet was crushed and my helmet dinged the roof. My head hurt and I was out of sorts several weeks after that hit. If my head had hit the hoop I doubt I would be able to type this.

 

So take this seriously. There is at least one top national contender sitting out this season due to head injuries sustained with his helmet making contact with the roll cage (not hoop but side bar).

 

So do not gloss over this stuff. 

[jschwarz]

I'm 6'2" and its tight. You will def need to recline the seat a bit to make sure your height isnt too high. Not the best position but i think it works. hammer the floor flat and get rid of all the OEM mounts on the back. Spend some time on this and it can be done. Getting in and out will be the fun part!

[38bfast]

As I said before you need to increases the flat on the bottom of the seat. The part of the seat that sits parallel to the floor pan. You will cut about 1" off the bottom of the seat and then reeled in a larger flat. Also remove the foam from the bottom as well as some under the thigh area. Again sit in the car without the seat if you fit then you can fabricate the seat to emulate the fit. It should drop you down a concidirable amount. I have done this several times for my very tall customers.

[SaulSpeedwell]

What Ralph said!  Try seat magic first!

 

At 6'3", 180lbs, 34" inseam, after many custom suits and custom seats, I have learned that the thickness and depth of your back/torso and glutes is a HUGE deal.  Beerbellies don't affect your "packaging" in a car as much as those other items, and the sum of glutes/torso can even trump height and inseam!

 

An inch of glute/thigh thickness is close to the same as an inch of "height"/headroom.

An inch of upper back/torso depth is, like, 0.5"+ of fore-aft plus 0.5"+ of "height"/headroom.

 

Always custom fit you and your seat in the car as early as possible in construction, and don't commit to a steering wheel position (inches of dish, spacers, length of stub for quick disconnect) until AFTER that.

 

Like Ralph says, the prob with those U-S seats in a Miata is they rest on a sharp corner.  You need tthe part under your butt to be flatter/more parallel to the floor pan before it "kicks up" in front of your butt to support your thighs.  If you compare your U-S to a Kirkey "Drag" Seat, I can almost guarantee the Kirkey will sit 2"+ lower for the same rake angle and similar "fit".  Then you can bolt on shoulder supports if you need them.

 

Look at the drawings and pictures online, hope this helps.

[38bfast]

I did not want to bring up what Saul said but for others future rereferance. Step one in a build, fit the seat and driver then build the cage around the seat. I know for you it too late now.