Carbon Density/Strength for fishing rods.

I'm doing some minor repair work on a mate's barbel rod and I'm very conscious of the very high weight/density of the carbon for such a slim blank as well as the beautiful quality and finish of the blank.
It's a 12ft 1.75lb stepped-up jobby with a lovely tip action that turns into an absolute brute just over a third of the way down. I realise that you would expect this type of material quality at such a price but I'm struck by just how very different it feels to rods that I have and have worked on in the £70 to £150 range.
When you see rods advertised that have 24t, 30T and 40T carbon.... What are the makers referring to?
Is it a relative tensile or compression value?

Wow Lark,I don't really know,I just tend to pick a rod up,test the action,lightness,feel,power and go fishing,I notice on the cadence website they go on about 30 and 40 ton carbon,who knows,lol.

I believe it's tensile strength.

Some info here: Fishing Rod Blank manufacture

wetthrough said:

Some info here: Fishing Rod Blank manufacture

Click to expand...

Amazingly, by my normal standards, this makes perfect sense. No single element governs the overall performance or capability of the rod blank to perform in a specific fashion. Really interesting read, cheers.

whitty said:

Wow Lark,I don't really know,I just tend to pick a rod up,test the action,lightness,feel,power and go fishing,I notice on the cadence website they go on about 30 and 40 ton carbon,who knows,lol.

Click to expand...

This is what threw me working on this rod - it looks as though it should be very light, but the lattice type weave of the carbon (instead of the more common spiral wound rods, which tend to be very light) is very complex and the rod blank just seems to handle much heavier - very dense and rigid. The butt section is like a steel rod!

CLICK HERE might help

The mechanical properties is also worth consideration, there are very very light rods being made with nano-technology that offer more strength along more supple/fast action to the lowest section/s.
I suspect the tonnage is like drop forging steel, the more compression the stronger but stiffer the mechanical properties of carbon, where the feeling of being well under gunned develops a more intense playing of a fish.
When it comes to scientific jargon there is much license given for the sales pitch, most rods are often understated in there overall power capabilities. Working on the basis of a minimum threshold for consumer ratings, my Shakespeare run of the mills are rated at 10lb line but easily play 15lb straight through, because I wanted to find out for myself.