I don't like just taking people's word for it. When Avoda put a curved face on an iron, I had to go test it out for myself.

So I tested it twice. First indoors on a launch monitor with an Avoda fitter, then for six months on the range and the course with my own two sets. Here are my numbers, the shot that paid for my irons, and who I think should actually pay for curved.

Six months, hundreds of balls, flat vs curved. Do curved face irons actually work?

What a curved face does

What's the point of a curve on an iron? Well, it's the same idea as your driver. The science of gear effect says that with a curved face, toe hits and heel hits self-correct back toward the target, and the effect gets bigger with more clubhead speed.

Avoda says their Origin curved face irons use progressive curvature: the 4-iron has the most, and the pitching wedge has the least, because the long irons are where speed is highest and off-centre hits are hardest to control. Avoda says the idea started on a range with coach Mike Schy hand-grinding a curve into a raw forging for one of his tour players. The guys at Avoda also told me the faces are CNC milled so everybody gets the same curve, which makes production a little slower.

Why robot tests can mislead

Something you need to know: most robot testing is done at about an 80 mph clubhead speed. My 4-iron swing speed averages about 96. Since gear effect grows with speed, a robot at 80 doesn't tell me what happens with my swing. I wanted real numbers, not robot numbers.

My indoor test results

I met up with my buddy Max Millet, the Precision Fit Avoda fitter for the Phoenix area. He brought his own curved set with specs very similar to mine, and I tested it against my flat-face set, starting with the 4-iron. Here's the deal with long irons: the number one issue isn't distance, it's sidespin.

On a five-ball test, the curved face had 38% less sidespin. Now, there's going to be a couple of you saying, oh, that was only five balls. Fair. So I did a 30-ball average of the exact same test, and it got better: 46% less sidespin with the curved, or put the other way, 86% more sidespin with the flat. The more balls I hit, the bigger the gap got. I also saw a bit more backspin and a more consistent landing with the curves.

The caveat: that was one indoor session with Max's set, not mine. So I went and did the long version.

Curved vs flat on the launch monitor. Absolutely redonkulous.

My 6-month on-course results

For six months, I hit hundreds of balls on a FlightScope Mevo+ with two sets built to my specs: my flat-face combo length Origin irons and my curved combo length Origin irons. Like for like.

The result: about a 30 to 50% reduction in unwanted sidespin on mishits, and by mishits I mean the ones that were slightly off-centre. The biggest difference was in the long irons. By the 7-iron and shorter, it's smaller, which makes sense: less curve, less speed and more loft. If you want the earlier indoor video, it's Curve Faced Irons: The Straightest Irons on Earth?

The shot that paid for my irons

A skins game. About 205 to 210 yards, pin over a bunker on the right, water right. Anything right is no bueno. I needed this one close.

I heeled it. I immediately thought, oh crap, it's in the water. Instead, it turned into what I call a protected fade. This shot had no earthly business going toward the hole, and it landed about six feet away. I knocked it in for eagle and won the only skin of the day. That shot paid for my irons.

That's the real benefit. Hit a fade off the heel and it fades, but not too much. You're not going to double-cross yourself, and those double-crosses get nasty. On a hole with water down one side, you've taken that side out of play.

Can you still shape it?

Can I curve a curved-face iron? Yes. Gear effect only kicks in when you hit the toe or the heel, so your shot-making stays the same. I hit one draw and one fade on camera to prove it. Boom shaka laka baby.

Indoors with Max, I could draw and fade it on purpose too. And yes, it still works with a coloured ball.

Do curved face irons still go straighter with a coloured golf ball? Yep, they do.

We know it goes straighter, but can you curve a curved-face iron?

Who should pay for curved

The honest caveats first. Curved costs more than flat, so check the current price. And there's a small adjustment: I tend to look at the heel of the club, so I was lining up the heel where I was aiming and had to adjust my eye.

Avoda's speed guide, using your 7-iron:

• 95+ mph: you can play flat, but they strongly recommend curved.
• 85 to 95 mph: either works, but curved is still the pick.
• Under 85 mph: both are fine. The gains are real but less noticeable, so it's worth testing both.

My take: decide your set type first. The most important factor with Avoda is choosing between combo and same length, and that's where most of the benefit is. That decision is in Same Length vs Combo Length. After that, it becomes a price question. The curves are better. But if the extra money is going to turn you off getting a set of same length clubs at all, get the flat ones.

Who's curved not for? If you're a slower swinger on a tight budget, the flat face gets you most of the benefit. The curve is the upgrade, not the foundation. Curved sets come in 4-PW or 5-PW, and makeups are covered in Set Makeups and the Long-Iron Question. You can see the curved and flat options here.

The fitting covers flat vs curved by speed too. Get fit online and let a real fitter look at your swing. I verified my online fit in person and got exactly the same specs; that's in Can You Really Get Fit Online?. The whole series starts at Same Length Irons Review, and my same-length page has my number.

Don't guess. Get fit. I bought all three of my Avoda setshrough their online fitting, and when I got fit in person later, the specs came back exactly the same. It takes a few minutes: a down-the-line 7-iron video, your height, your speed, and a real fitter emails your specs within 48 hours. Start your free online fitting →