ive read that lighter is better for obvious reasons when it comes to rod blanks. but what does the butt diameter and tip size say about a particular rod blank. ive noticed many different size butt diameters on rod blanks with the same power,length and line ratings. does a smaller number mean lighter, more sensitive, better? or is there no correlation? thanks, mark

No, you can't go by diameters alone - the wall thickness and material involved all play a role.

Diameter is a major factor, moreso that wall thickness alone. But even then, it is possible to get the same stiffness in a thick walled, small diameter blank as you have in a thin walled, large diameter blank. The smaller diameter, thicker walled model will be more durable, but will also be much heavier for the same stiffness. It all comes down to the attributes that the designer was aiming for and knowing which design will provide them.

The most powerful rod blank I have ever owned has a butt diameter of less than 3/4 inch, but it will cast over 12 ounces of weight. Conversely, I have blanks with butt diameters of over an inch that won't handle more than an ounce. It's the total combination that determines the power or stiffness involved, material, diameter and wall thickness.


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I've generally found the rod tip dia is smaller in more expensive or better quality rods.
The smaller dia makes the tip respond faster and feel lighter. Good for sensitivity and hook set.
The butt dia is where the power of the rod comes into play.
Larger diameters will generally mean stiffer overall rod with the ability to handle more weight , heavier line and give a large edge on fish fighting ability.
Thicker walls can be used to add power but at the expense of increased weight.
Small tip, large butt, light weight all play together to provide the best rod.

Modulus changes are used to reduce weight in the butt section and increase durability in the tip section. Tip diameters of multi modulus blank will typically be slightly larger due to the use of lower modulus materials in the tip section - increased durability and "softening" in some cases are postitve attributes.

The greater the difference between the butt and tip diameters the faster the action will be. The less difference between them the slower or less fast the action will be.