I live in the US. In South Carolina. I wanted the primo build and decided to order it. The size of the rails was listed and i went with the 1 inch since i live in the. US and wanted it tough. Thinking 1 inch in US should be a stadard size. That is the 24.5 mm size. Seems i was wrong. Big box stores , plumbing , and electrical supply houses. None had a 24.5 mm OD pipe or conduit. I have started checking supply houses that are over 100 miles from me. This is just a friendly warning to others source your rails first . And have them in hand before you order your kit.
1 inch is 25.4mm and you want tubing, not pipe/conduit.
If you need to order online, Metal Supermarkets and MetalsDepot are probably the most popular.
Also, if you have a Summit Racing, Jeggs, or Tractor Supply Co. near you, you can get 1" DOM tubing from them.
Never thought about Tractor Supply. Thanks for the tip. I was about to try and order online for some.
Sorry. i inverted the numbers . Yes 25.4.
Just about any metal supply shop should have it. Just like @kcny said you want to ask for tubing (which is measured by outside diameter), not pipe/conduit (which is measured by inside diameter). But you are right that I haven’t ever seen it at a big box home supply.