A client of Daryl Fitzgerald's sent him a video. The rider had a 20-kilometre time-trial loop he did every other Tuesday — a fixed, repeatable test of his own form. Fitzgerald watched the clip and said one sentence: your saddle's a touch too high. The rider dropped it by about seven millimetres. Same loop, next Tuesday. He went a minute quicker.
A minute. Over 20 kilometres. For seven millimetres of saddle height and around three watts of difference. No new wheels, no training block, no aero helmet — just a fitter's eye and a hex key. That story, which Fitzgerald told on the podcast, is the whole argument for why he thinks saddle height is the one thing most amateurs should get right before they spend money on anything else.
Why saddle height is the change that counts
Fitzgerald fits World Tour riders at Science to Sport, so he's seen every expensive marginal gain there is. And his pick for the highest-impact, lowest-cost change available to an ordinary rider isn't aerodynamics or equipment. It's the height of the thing you sit on.
The reason is that saddle height does three jobs at once. It sets how fully your leg extends, which governs how much force you can put through the pedal. It sets your pedalling efficiency, because too high and you rock and reach, too low and you bury your knees. And it sets your comfort, because a saddle even slightly too high slides you forward and back across the nose with every stroke. Get it right and all three improve together. Get it wrong — and most amateurs have it a touch too high — and you're quietly bleeding watts, efficiency and comfort on every ride. It's the first thing our bike-fit guide tells you to check, and Fitzgerald would put it ahead of almost everything else.
That "too high" tendency is worth dwelling on. Riders creep their saddles up over the years chasing the look of full leg extension, or because a too-high saddle feels powerful in short bursts. But the cost shows up over hours and over a season: reaching for the bottom of the stroke, hips rocking, the back and hamstrings taking strain they shouldn't. The seven-millimetre drop that bought a minute wasn't a freak result. It was a rider who'd drifted too high being brought back to where his body actually works.
A millimetre at a time
Here's where Fitzgerald gets emphatic, and where most self-fitters go wrong. When you do adjust your saddle height, you move it one millimetre at a time.
"Don't be scared," he said, "but don't go five or 10mm at a time. Go one mm at a time. It may only sound a little bit, but you'll definitely feel the effects."
This matters more than it sounds. The instinct, when you decide your saddle is wrong, is to make a decisive change — drop it a centimetre, settle the matter. But a centimetre is enormous in fit terms; it blows straight past the right position to a different wrong one, and because you changed so much at once, you've no idea what actually helped or hurt. A millimetre at a time is slow, almost frustratingly so. But it's how you home in on the genuine sweet spot rather than bouncing between extremes, and it's how the pros do it. Patience is the technique.
Fit is individual — even the rules
The most important thing Fitzgerald said, though, was a warning against treating any fit advice — including his own — as a universal law. Because the same conversation that crowns saddle height also contains a story that cuts against the grain of a lot of modern fit dogma.
He's had elite athletes back home in South Africa go to shorter cranks and lose 20 to 30 watts immediately. His response wasn't to insist the cranks were right and the rider would adapt. It was to say: put your old cranks back, do the same session, and they were straight back to normal. The shorter cranks, which help so many riders, cost these particular athletes real power. So he reverted them, no ego, no theory.
Hold that next to the (entirely sound) advice you'll hear elsewhere that most riders benefit from shorter cranks. Both things are true, and that's the point. Fit is individual. A change that transforms one rider can rob another, and the only way to know which you are is to test it on yourself, on a repeatable effort, and read the result honestly. The body gets a vote, and it doesn't always vote the way the rule book predicts. This is exactly why we're cautious about one-size-fits-all advice on position and aerodynamics too — the trade-offs land differently on different riders.
The danger of copying the pros
There's a trap that sits right next to all of this, and Fitzgerald's crank story is the warning against it. Amateurs love to copy what they see at the World Tour — the slammed stems, the extreme saddle setbacks, the very short cranks that have become fashionable. The logic seems sound: if the fastest riders on earth do it, it must be faster.
But the pros arrive at those positions through years of adaptation, exhaustive testing, and bodies that bear almost no resemblance to most amateurs'. A position that lets a 60-kilogram professional with elite hip mobility hold an aggressive aero tuck for five hours will fold a middle-aged amateur in half after twenty minutes, costing them comfort, power and probably their lower back. The elite athletes who lost 20 to 30 watts on shorter cranks are the perfect illustration: even at the very top, where you'd expect the "rules" to hold most reliably, the individual response overrode the trend. If a shorter crank can cost a World Tour rider real power, the fashionable choice is clearly not universal.
The honest version of bike fit is unglamorous. It's not about looking like a pro. It's about finding the position where your body produces the most sustainable power in the most comfort, and then testing your way toward it patiently. Sometimes that lands you somewhere that looks nothing like the magazine photo, and that's fine. The clock and your own legs are the only judges that matter, which is the same principle behind weighing aerodynamics against comfort rather than chasing one at the expense of the other.
Saddle height first, but not saddle height only
Saddle height being the highest-impact single change doesn't mean it's the only thing that matters — it means it's where you start. Once it's dialled, the next fundamentals are worth the same patient attention, because they interact with it.
Cleat position is the obvious one. Where your foot sits on the pedal changes your effective leg length and how the load travels through your ankle and knee, so a cleat that's badly placed can make a correct saddle height feel wrong. Fore-aft saddle position — how far forward or back you sit — changes how your weight loads the pedals and where your knee tracks over the foot. Reach and bar height govern how much of your weight goes through your hands and how open your hips stay. None of these is independent; move one meaningfully and you may need to revisit the others, which is precisely why Fitzgerald and every good fitter work methodically rather than tweaking five things at once.
The discipline that ties it all together is the same one he applied to saddle height: change one variable, test it on a repeatable effort, and judge it honestly before touching anything else. It's slower than a weekend of guessing, but it's the only way to build a fit you actually understand rather than a pile of adjustments you're afraid to undo.
How to use this yourself
You don't need a World Tour fitter to apply Fitzgerald's method. You need a repeatable test and some discipline.
Find an effort you can repeat under similar conditions — a local loop like his client's, or better still a controlled indoor session where you can hold the variables steady. Note your current saddle height to the millimetre. If something feels off — reaching at the bottom, rocking, numbness, a sense you're never quite on top of the pedals — try dropping it a single millimetre and ride the same test. Then judge it on how you feel and what the numbers say, not on theory. Repeat, one millimetre at a time, until it clicks.
It is the least expensive, least glamorous performance work in cycling, and on Fitzgerald's evidence it can be worth a minute over 20 kilometres. Most riders will spend more than that minute's worth of money on a part that does far less. The hex key was always the bargain.
Hear Daryl Fitzgerald's full breakdown on the Roadman podcast. For the complete approach, read our bike-fit guide, and bring your position questions to the community on Skool.