Forgiveness · High MOI
High-MOI Putters,
Stable on Every Strike
MOI is a putter's resistance to twisting on a mishit. Ashdon builds it into the shape — for a wider sweet spot than a traditional putter.
Moment of inertia — MOI — is a putter's resistance to twisting when you don't strike the ball dead center. The higher it is, the more a mishit still rolls true. Ashdon builds MOI through geometric mass distribution: using the putter's shape — triangles, arcs, perimeter edges — to position mass at the extreme outer boundaries of the head rather than concentrating it in the center. Every gram of weight is placed where it creates the most moment of inertia.
Pushing that mass to the edges expands the effective hitting zone dramatically. Where a traditional putter's sweet spot is about the size of a penny, Ashdon's geometric architecture creates a much larger zone — big enough that even mishits stay on line and on pace. You don't have to find the center; the center finds you.
The same geometry that raises MOI also keeps the face square, reducing torque by 87% versus conventional putters. Every head is CNC-milled from solid 303 stainless steel and 6061 billet aluminum to tolerances tighter than ±0.001″, and every model is designed to conform to USGA and R&A rules.
The Physics
What Actually Raises MOI
Moment of inertia is measured in grams per centimetre squared, and the "squared" is the whole story. MOI depends on how much mass a head carries and how far that mass sits from the center — but distance is squared in the calculation, while mass is not.
In practice that means moving a gram twice as far from the center raises MOI four times as much as adding a gram at the center. Weight is the weak lever. Geometry is the strong one. This is why two putters can weigh exactly the same and behave completely differently on a mishit, and why simply making a head heavier is close to the least efficient way to make it more forgiving.
It is also the reason Ashdon builds forgiveness through shape. Triangles and arcs push mass to the outer boundary of the head as a consequence of the form itself, rather than by bolting weights onto a shape that was drawn for looks first.
| Lever | Effect on MOI | What it means |
|---|---|---|
| Distance of mass from center | Squared | Double the distance, quadruple the contribution. By far the strongest lever. |
| Amount of mass | Linear | Adding weight helps, but only in proportion — and it changes the feel of the stroke. |
| Where the mass is placed | Directional | Heel and toe weight resists side-to-side twist. Rear weight resists opening and closing. |
Who Gains Most From High MOI
High MOI is worth most to golfers who miss the center of the face regularly — which is nearly everyone, but some more than others. If your putts tend to finish short and right, or short and left, without an obvious read error, you are likely losing speed to head rotation at impact rather than misreading greens.
It matters less if you strike the center consistently. A head that twists less also reports less, and a practised putter who reads their own contact loses a genuine tool. That is the honest trade, and it is why Ashdon builds both blades and mallets rather than treating one as the upgrade.
The Collection
Engineered for Maximum Forgiveness
Bermuda Triangle Caribbean Blade
$299.95
Roundabout Ballistic Missile G-360 M6 Mallet
$349.95
Bermuda Triangle Ballistic Missile G-360 M5 Mallet
$349.95
Roundabout Mallet
$299.95
Roundabout Guided Missile M3 Mallet
$299.95
Bermuda Triangle Grand Bahama Mallet
$299.95
Bermuda Triangle Blade
$299.95
Roundabout Blade
$298.98
Bermuda Triangle Long Island Mallet
$299.95
Roundabout Guided Missile M4 Mallet
$299.95
High-MOI Putters, Answered
What is a high-MOI putter?+
MOI — moment of inertia — is a putter’s resistance to twisting when the ball is not struck exactly on the sweet spot. A high-MOI putter resists that twist, so an off-center strike still rolls straighter and holds its pace. It is the single biggest driver of forgiveness in a putter.
What is geometric mass distribution?+
Geometric mass distribution means using the putter's shape — triangles, arcs, perimeter edges — to position mass at the extreme outer boundaries of the head rather than concentrating it in the center. This dramatically increases the moment of inertia (MOI), which is the putter's resistance to twisting when the ball isn't struck exactly on the sweet spot. Higher MOI means straighter roll, more consistent distance, and fewer three-putts from slight misses.
Does higher MOI help on off-center putts?+
Yes — that is exactly what MOI is for. By distributing mass along the outer edges, Ashdon expands the effective hitting zone dramatically: the sweet spot is larger than the penny-sized zone on a traditional putter, so even off-center contact rolls truer and travels farther. You don’t have to find the center — the center finds you.
Are Ashdon high-MOI putters USGA approved?+
Yes — with one clarification on the terminology. The USGA doesn't approve or endorse equipment; it evaluates clubs for conformance to the Rules of Golf. All Ashdon putters are designed to conform to USGA and R&A equipment rules and are legal for tournament play at all levels. The high-MOI models are covered on the same basis as the rest of the line. The Roundabout Series geometric head design was first patented in 1994 (U.S. Patent US5599241A, expired 2014).
How is putter MOI measured?+
MOI is quoted in grams per centimetre squared (g·cm²) and describes how strongly the head resists rotating about its own vertical axis. It is a function of two things: how much mass the head has, and how far that mass sits from the center. Distance counts far more than weight — moving a gram twice as far from the center raises MOI four times as much as adding a gram at the center. That is why head shape, not head weight, is what really drives forgiveness.
Is a higher-MOI putter always better?+
No. High MOI reduces how much the head twists on a mishit, which also reduces how much the strike tells you. A player who strikes the center consistently and uses that feedback to self-correct can genuinely prefer a lower-MOI blade. High MOI is most valuable to golfers who miss the center often, play on inconsistent surfaces, or want their bad putts to finish closer. It is a trade, not a straight upgrade.
Does a high-MOI putter help with distance control?+
It helps with distance control on mishits specifically. When the head twists at impact, some of the energy that should have gone into the ball goes into rotating the head instead, so the putt comes up short. A higher-MOI head twists less, so an off-center strike loses less speed and finishes nearer the hole. On a perfectly centered strike, MOI makes no difference to distance at all.
Do I need a mallet to get high MOI?+
A mallet makes it easier, because a wider, deeper head has more room to push mass away from the center. But head shape is the means, not the goal — what raises MOI is where the mass sits, and a well-engineered blade can carry meaningfully more MOI than a poorly designed mallet. Ashdon builds MOI into both, which is why the blade line is not simply the less forgiving option.
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