LanterneRouge

Hi all, sorry for the long-winded post, but maybe you can help me with some analysis-paralysis. I've flipped through the seat thread, but I was hoping to get some more specific info if there is some first hand experience out there. I am building an NB1 for endurance racing (LuckyDog and possibly ChampCar) and I have potentially very different driver heights to contend with. My primary concern to start is that my brother who will be one of the team's primary drivers, is about 6'3" and has a relatively long torso to boot (we also have pretty slim builds, so no "XL" seats ideally). In order to fit his helmet under the cage to regulations I am already adding a floor drop, planning to mount the main hoop to the parcel shelf, and bringing it up to the max internal height of a race spec thin fiberglass hardtop shell.

So with that said, next comes the seat itself. I have a handful of criteria and two seats that I'm wondering if anyone has any feedback on:

• Halo seat
• Reasonably large layback angle to get him a little more "crouched" and his head lower
• High enough back to give the suggested coverage up to at least mid-helmet for rearward neck support
• High enough shoulder strap holes (bonus if they extend low enough for the shorter drivers as well)
• Minimal "stack height" between the outside of the shell bottom and the inside seating surface, again, to keep him under the main hoop.

From trolling around online, looking at dimensions, and doing some back of the napkin math I've found two potential seats with some good features:

• Sabelt X-Pad
  • Price: not bad
  • Looks like 26-27 degree layback taking some rough measurements off the drawings
  • 900mm height is maybe ok, but seems like it might be on the edge of being too short?
  • Shoulder strap holes look very tall from the pics, maybe ok?
  • Unsure on stack height?
• Tillett C1
  • Price: ouch
  • Listed as 28 degree layback
  • 840mm height seems suspiciously low, not sure if that's accurate or what?
  • Shoulder straps look ok, but maybe not as large as the X-Pad?
  • Stack height seems incredibly low, probably the lowest I've seen, especially considering you can sit directly on the shell. Should help with fitting a tall driver under the cage regs?

The other issue is it looks like we can maybe go up to Wine Country at Sonoma to try the X-Pad the next time he comes to visit, but there doesn't appear to be a Tillett dealer in the Bay Area so without some first-hand knowledge I'm not going to feel confident purchasing online, especially considering the cost premium over the Sabelt.

X-Pad:


C1:

engineered2win

I had the B6 screamer and the dimensions look very similar to the C1. The only real difference looks to be the angle of the back is 2deg more upright on the C1. I had the 40cm wide seat and it just fits so perfect in a Miata. I'd still recommend the trans tunnel notch plate to get the seat centered to the wheel, but it could easily fit using the stock seat mounts with an adapter and not be hideously high like every other seat.

I'm 5'-11" with a 32" inseam and previously had a Cobra Suzuka bolted to the floor with the back almost touching the parcel shelf. I actually had to raise the B6 up 2" because I was sitting too low and couldn't see over the dash. You can see the bottom of the seat is below the side mounting holes. The seat is maybe 10mm thick, so in the most extreme setup w/o the padding your *** can be a half inch from the floorpan. Your biggest issue would be sub belt clearance. Put a couple pieces of cardboard on the floor pan and that will effectively simulate as low as you can possibly sit. I really like the B6; just wished it had a halo, which this solves. And it just wasn't tolerable for street use. Might have to pick one of these C1's up for track days once my turbo setup is complete.

That X-pad looks quite wide in the shoulders (dim C is 600mm), which will probably hit the B pillar and door.

LanterneRouge

Thanks, that's awesome feedback. So If I extrapolate a little from 5'11" with the seat raised 2" that's kind of equivalent to being at least 6'1" with the original seat location just to get the sightlines you wanted. And that's being conservative just adding the 2" of torso height to your height and assuming the same inseam.

For others who might find it useful I did get some feedback from Tillett that they've had driver's about 6'3" in the C1 with adequate helmet support with the caveat that of course it depends on the exact driver's torso proportions so no guarantees on that.

As far as the X-Pad, there was one example I found in the seat thread, but the owner wasn't particularly tall, so the fit info wasn't very useful to me. The seat did fit in the car, but as you noted, the shoulders were super tight to the cage and B pillar. You'd have to be very careful with your upper door bar placement to make sure there's no interference. Effectively, the upper door bar needs to sneak under the shoulder of the seat to reach the main hoop. Might be tricky in my case where the seat will need to be slammed against the dropped floor and would sit very low compared to the door bars.

Gee Emm

Don't extrapolate (that inseam may be quite different to your brother's - it is the torso that decides). If you want better advice/decision, get some data. FFS, just sit him down on a hard surface, and measure the critical height, probably from his tailbone tp the bulge in the back of his head(? wherever his helmet protrudes furthest back?), same for his and the shortest (torso) driver shoulder height. Job done, now go look at seat specs.

LanterneRouge

Seat specs don't really work that way. Manufacturers measure from the outside of the seat shell base and the measurement may be parallel with the seat back or normal to the floor plane. The angle can partially be corrected for, but nobody lists the actual seating surface to top dimension that I've seen. This is further complicated by the multiple angles in the seat back. These details make a difference.

I already have had him measure his seated height and done some calcs to estimate our heights in a race seat posture with layback. That was my first bit of research and data collection.

I was hoping to get some real world feedback as calcs and manufacturer specs can be deceiving. I'm obviously not going to use someone's height alone as a deciding factor, but the first reply was a helpful and he even provided his inseam to know his rough torso length.

Gee Emm

Ahh OK. And you have the data, thanks for the reply. Not having to do more than check our a couple of options when I bought mine, your fitment challenge is a whole another level!!

Good luck!

LanterneRouge

Yeah, I'm sure I am over-analyzing a bit, but figured if anyone on here had some experience with these two seats it never hurts to get some additional feedback.

It's also tricky because he lives 7 hours away, so I've had him take some measurements so I can keep progress going on the seating and cage design, but I'll know more when he has a chance to visit and just do some seat mock-ups on the drop floor and see where we end up..

Shmommy

Are you located near Los Angeles? Grid Partners has both seats on display last time I was there earlier this month.

I am 5' 10", average torso length, 230lbs, 36" waist. The C1 has a decent taller back than the B6 Screamer. The harness holes on the B6 were barely above my shoulders, so it was a no-go. The regulars were too narrow for my thighs and really squished them together, so they were a no-go. The C1 XL was about half to one inch taller back than the regular and fit me perfectly; halo was at the perfect position covering the side of the head instead of cheek down. The C1 XL bottom internal fit very close to my 16" Kirkey. Very rigid seats. However, I personally find shoulder bolsters (especially the ones that wrap around) to be better at upper torso retention; your upper body may move more under high-G.

While I sat in the X-Pad, I didn't pay much attention because I knew it wouldn't fit the stock sheet metal. All I remember is it was too narrow for my fat thighs; the bottom internal fit the same as the Tillett regular.

Other recommendation, the Sparco Circuit QRT has a fairly tall back. But the Halo is wide and IIRC some say it can intrude into the window space. Also apparently they now offer something like a Tillett B6 called the Ultra QRT.

LanterneRouge

Not really, I'm only about half an hour south of San Jose. If I end up down there I'll have to check out Grid Partners though. Thanks for the tip!

Appreciate the review. Good point on the shoulder bolsters. Part of what makes them so narrow and easy to fit also reduces the the upper support a bit. It wouldn't be the same as a full bolster, but I wonder if some friction tape/hockey stick tape on the upper torso/shoulder area would help a bit. At least compared to the slippery gloss surface.