Tyre Load Index x; Speed rating y?

[Raveydavey]

So I get the basics. A tyre with a 56 J rating should be stable up to 62MPH when loaded at 224kg.
Speed rating J = 100kph (62MPH)
Loading Index 56 = 224Kg

In attempting to be logical, this infers that a lower load should enable a higher speed, and a higher load would limit the speed further.
Am I thinking about this correctly?
If so is there a set formula for working this out? E.g. what would the weight need to be for the tyre to be stable at 70MPH?
I’m guessing the Loading Index is based on stationary weight?

Also, to save me lumping the bathroom scales down to the garage, does anyone have any ball park numbers for unloaded (i.e. without rider or kit) weight at the rear wheel and front wheel independently?

[HxPaul]

These are maximum weight and maximum speeds,you can load/speed at under these numbers,but not over.

[Raveydavey]

So what you are saying is that they are totally independent of each other? You could, in theory, have a 1Kg load and still only go to the max speed rating?

Wikipedia does seem to infer a link. It states that the speed rating"... indicates the maximum speed at which the tire can carry a load corresponding to its Load Index" It references 'European Tyre and Rim Technical Organisation Standards Manual 2010' for this statement but but the link provided doesn't work.

[Solid Air]

I've always understood it that the numbers are meant as a guide and that they work together, ie if you exceed the weight limit then reduce the speed accordingly and vice versa. Exceed both and you're asking for trouble

[HxPaul]

The speed rating on tyres is a hard and fast rule EXAMPLE - j rating means 62 mph,similarly the load rating is the maximum load you can carry on that tyre.If you reduce the load,the speed rating still applies ie.j rating still means the top speed is 62 mph.

[Solid Air]

The speed rating on tyres is a hard and fast rule EXAMPLE - j rating means 62 mph,similarly the load rating is the maximum load you can carry on that tyre.If you reduce the load,the speed rating still applies ie.j rating still means the top speed is 62 mph.

Thanks Paul, glad I posted my reply to find that out then. Fake news... it's everywhere these days and I can remember who told me that too, no names