Wheel sizing query

[Seagul]

I am looking at replacement launching wheels - when one 260mm x 85 mm wheel states 3.00-4, and another 260mm x 85mm wheel states 4.10/3.50-4.....what is the difference in the wheels......what does the 3.00-4 refer to?
Thanks

 

[Spi D]

It is a matter of giving different size info formats:

This is the most simple size marking. The first part, 3.00, is simply both the width of the tyre and the height of the sidewall of the tyre in inches. The second part, -4, is the rim diameter in inches. So a 3.00-4 tyre would fit a 4" diameter rim, be 3" wide and 3" tall on the sidewall. Therefore, the overall height of the tyre would be 10" (4" plus 3" plus 3").

In world of car tyres you see eg. 185/60-14 which means tyres width in mm, height of sidewall (aka 'profile') as a percentage of the width and rim dia inches. Mixing mm and inch this seems a bit weird too, but none the less is an international standard.

Your 3.00-4 would translate to 76/100-4 if used by same format because it would be 76 mm wide, sidewall height be 100% of width and rim size 4".