Might be stating the obvious (to some) but something I didn't realise until I started trying to pick tyres for aftermarket wheels is that the profile figure - e.g. 40 - is 40% of the width.
So for a 255/40/17 tyre - diameter is 255mm, profile / side wall is 102mm (40% of 255), and radius is 17inches.
Learning this made it all make a lot more sense to me. I also have this graphic to refer to. Can't recall where I found it but it's now saved on my desktop!
I also wanted a chunky looking tyre with a solid side wall and after going 245(F) / 265 (R) , have since switched back to 235(F) / 255 (R) as I found the handling was noticeable more boggy and I use the car for fast road and track use. For ref, these tyres are on 18" BBS LMs.
By
sumshiftyguy ·
It is the year 2032, and a father and his son walk the streets of lower
Manhattan.
Approaching the site where the WTC used to be in the end of the 20th
century, the father sighs and comments, "to think that right here used to
be the Twin Towers..."
The son, not understanding, asks his father: "What are the Twin Towers?"
The father smiles and looks at the son, and explains, "The Twin Towers
were
two huge buildings that used to be here until 2001, when the Arabs
destroyed them."
The son looks up to his father, and asks, "And what are the Arabs?"