[slotloco]

You guys are just not trying - really.  They even give instructions. Seriously, now i should start my 2020 posts with something nice, but you fellas need taking out back for a slap with several wet bus tickets, and be told to stop being "winging ****"
You are in serious danger of being sent back to elementary slot-school, where you learn what a trigger is, and why cars fall off, and wives have access to count your collection number on a weekly basis - and that would be an unmitigated disaster. You could even yourselves get laughed at by the continentals who eat technical data BEFORE breakfast, and have been known to drink tyre oil while chewing through a flexible chassis for appetisers.

It took me all of 5 minutes to work out what does what, and why.
They are providing the data in a every size fits all sort ofd format, so you can work out the result of almost anything to anything.

- You have to remember, people want to fit all types of tyre to all types of rim - and not just Slot.it rims.

So let me tell you the easy way.
1) Learn what wheel is on your car - oh come on, you can do that if you really try.
2) Decide what formula you want - Oh I know decisions are hard, its almost as bad as deciding what chocolate to take from the tray
3) read along the line for the wheel until it is below the formula you want, and an outside diameter you can live with.

In reality, most of us live our entire slotting lives on just 2 or 3 lines and in two or 3 columns.

4) Steal the kids/wife's highlighter and mark the 2 or 3 tyres you actually use on the chart., and make intersecting rings between the tyres and wheels with a biro.
5) Cease with the hard thinking and go pour yourself a nice IPA or dark, or a shot of those lovely aromatic vinos the colonists down under send you.

There . . . . now don't you feel better, you have the tyres and you have the drink, and you have a new found focus for all that pent up tyre rage, the condescending twat who wrote this post.

BTW, some resellers also put the O.D. of the tyre when fitted to the range of rim diameters, just to make life and re-checking even easier.
eg

F22 compound
DWG 1171 mould size
Approximate diameter on hubs prior to trueing
15.8mm hubs 19.7mm
16.5mm hubs  20.3mm
16.9mm hubs   20.6mm
17.3mm hubs 21.0mm

And CMOTD - don't you people glue and true your tyres?
F22 are snot hard to true. MUCH easier to glue and true N22- code is PT1171N22, or they have the new PT1207N22 due out any day now as well, for a slightly tighter loose fit and smaller OD.
- But it all depends on your club rules and on what sort of surface you are working with.