Raising Seat Height

  1. My model of MX-5 is: __RF
  2. I’m based near: __Coventry
  3. I’m looking for technical help or recommendations on: _ raising the driver’s seat height on my RF . I have read a post recommending using washers and a longer bolt to raise the seat rail . Is there any reason why I could not use pieces of square steel or alumimium tubing_under the seat rails to give a more stable base for the seat ?

Hi. I am sure someone more technically minded will give you a definitive answer soon but until then, my concern with using aluminium in this way would be strength in the event of an impact. Any tube would be better with very thick walls.
Washers would be unlikely to crush although the bolt might sheer.
Steel would be stronger than aluminium in most situations.

Most of the structural strength in an impact is the seat belts, they hold you and your seat in place. The seat rails need to be strong enough to hold the seat if it’s empty so it doesn’t become a projectile. You obviously want it strong enough not to let you twist or be thrown free. It needs to hold up more from you catapulting backwards post impact, but in my MX5 I sit back flush to the bulkhead so that would do the job for me.
See kit car regulations if you want to know more.