Question Cheap(ish) Amazon frames for frame mover?

Hi all, been weighing options/designs for my first build over the past few weeks, and this is a thought I had, which I couldn't find much info or experiences on. TLDR at bottom if you don't care for the details/thinking out loud.

So I want to build 2DOF to start out, and like the idea of having the pedals/wheel mounted directly to the seat. I keep starting to plan out a design in CAD so I can price out the steel I need to order for a frame. However I am 6'4" and ~240lbs so I am a bit nervous about trying to guess at distance/angle for the pedal box and wheel. So ultimately I keep looking at ways to add adjustment ability to the design.

This always comes down to a couple design options:

• square under seat with 2 rails coming out the front (similar to the DIY in the FAQ)
  • side rails will have double sized square tubing to allow length adjustment, as well as diagonal/vertical adjustment on the wheel
  • potentially more stable/rigid
  • probably weighs more
• square under seat, 1 wide rail coming out from under the center of seat, wheel post comes up between legs
  • same adjustment approach for wheel, unsure of rectangular tubing /sliding adjustment feasibility
  • probably lighter but less rigid

However the complexity of adding adjustment seems like a lot of additional work/materials that I am unsure is worth it. I also have not found/purchased an exact seat yet, though like the size options of some cheaper sparco or nrg seats. With that said the cost of just the seats is anywhere from $200-$400, and it seems like there are some pretty decent options on amazon for a steel frame + seat with a lot of the adjust-ability aspects figured out already. However all of the designs I have seen appear to rely on the floor to provide rigidity for the pedal box, but I am a programmer so not super well versed on materials or structural engineering so looking for some experienced opinions.

TLDR: There are some steel frames + seats on Amazon which look like they would be pretty suitable for the top portion of a frame mover setup. One I am looking at in particular is "Openwheeler GEN2 Racing Wheel Stand Cockpit" (new here so no links yet, just search on amazon) which looks like a good starting place and minimal additional metal could be added to stiffen up some parts. Is this a smart move to take or would I be better off welding up a whole custom frame to essentially do the same things but out of known gauge/strength steel stock?

it's to fragile to be a dynamic simulator part IMO

Thank you for the image. Upon watching a lot of videos/reviews of that exact seat, the pedal portion is definitely weaker than it appears and I agree with your assessment. I think it makes more sense to "do it right" and design/weld something myself since it can be made much stronger and more cost effective.

As mentioned though, figuring out the geometry for my size and weight seems like the hard part. At the moment my line of thinking is: I should just commit to a seat, take some measurements between my seat/pedals/steering wheel in my car, and then make the design fit those dimensions for the chosen seat? *edit* did see the dimensions thread/sticky btw, very helpful for this, just having a hard time figuring out what fits my long legs comfortably.

I am just having a really hard time justifying the cost of just a seat, that is probably not very comfortable, when I could apply that cost to other parts of the setup. However after looking into it, the weight savings of a race seat over a junk yard special make a lot of sense to me being 240lbs already..... just maybe not an extra $300 worth....

Another thought I have had, is to use my awful computer "gaming chair" (whoever thought putting race car seats on office wheels was a good idea....) since it has a hefty mounting plate on the bottom. But take it a step further, and use the mounting system on the chair itself to essentially hot-swap the chair between the office wheels base, and the sim rig. I haven't been able to find anything like this attempted anywhere yet, so it could make for an interesting build. Closest thing I have found: community/threads/my-2dof-motion-office-chair.11645/ (not an external link so I hope that's ok)

Sorry I am not trying to derail the thread immediately, but I am in the planning phase still and just looking for some second opinions.

Just a FYI. I have the OpenWheeler GEN2 Racing seat that you are showing.
I can tell you it is a very high quality product and an excellent platform.
If you live in the US the customer service is A+++.
They have sent me several extra pieces (steering wheel stands W/ knobs) free of charge shipped over night!
The distributor is Team HomeRacer
Right now I am in the final stages of completing this latest platform.
It is a 3 dof rig incorporating @noorbeast 's brilliant heave solution.
I may post a build article when finished.
I trimmed the factory video to show its adjustability and accessories that are indeed available from Team HomeRacer in Florida and some are distributed by Amazon.
I am 220lbs 6Ft and the rig is plenty rigid for my weight.
If you get the OpenWheeler I would be happy to help answer any questions you may have.

This is how I have started .. from a fixed chair all the way up to 4DOF.

https://www.xsimulator.net/community/marketplace/2dof-3dof-optional-descriptions-now-4dof.81/

Also if you're worried about the Open Wheeler frame being too flexible, it wouldn't be too hard to make a simple base frame for it out of a few aluminum extrusions or strut channels or something like that. That's basically what I did when I wanted to add some big transducers to mine.