I've been into cycling for decades—riding with grade-school buddies, kicking around in college, then city commuting in Boston, Paris, Barcelona, New York, and now Seattle. Somehow only in the last 10 years, when I became a volunteer mechanic at a bike-centric Seattle nonprofit, did I think about adjusting anything more than the seat height. Now I’m diligent about making sure I have the right bike and that it’s fit for my body and my riding style.

I wish I could have figured that stuff out sooner, so for this story, I wanted to gather expert advice on the basics of what people should look for and what questions to ask when buying a bike. (My colleague Michael Venutolo-Mantovani has more advice if you’re going that route.) After that, I’d take my own bike to a professional fitter and go deep into the nitty-gritty of bike fit to find out what it means to have a tailored ride.

I start with no bike at all. I walk to meet Rebekah Ko, the community resources director at Seattle's Bike Works, the nonprofit where I volunteer. Ko previously ran the sales floor as general manager at the city's Mend Bicycles, and for the purposes of this story we pretend like I am in the market for a bike that I'd use for transportation and general kicking-around fun. We make sure it’s unlike my own bike, so I won't be comparing the two in the back of my mind.

Bike Works sells new bikes and refurbished older bikes, and after a round of questions about what I was looking for, particularly about how and how often I planned to use it, Ko wheels out a Trek Multitrack 7200, a sturdy hybrid likely from the late aughts. This Trek is upright and handsome and silver and blue, with a short wheelbase, flat bars, grip shifters, and a big, squishy seat, all of which are very different from what I'm used to.

“Hybrids are a soft landing ground for many people looking to get into cycling,” she explains.

She checks for about two inches of standover clearance between me and the top of the frame. She then has me put a thumb on top of my left hip and extend my hand out flat in the air next to it, setting the initial seat height just beneath it. With Ko bracing the bike, I hop on, so she can fine-tune the saddle height, making sure I have a slight bend in my knee with the pedal at its lowest point.

"That slight bend helps make sure we are engaging the larger muscles—the glutes and the thighs—where the power comes from," she says. "It also helps keep pressure off of the knees."

From there, it’s time to grab the bars, which can typically be raised, lowered, and pivoted. We then adjust the brake lever angle to make sure my hands rest on them in a relaxed position.

Ko makes sure I look comfortable, not overreached, without locked elbows or a pinched neck, not scrunched into what some call “meerkat position,” with a straight back and the wrists and elbows very bent like you're peering over the top of them.

After these adjustments, it’s generally a good time for some preliminary stock-taking, as you'll hopefully be spending a lot of time on this bike. So how's your keister feel? If the saddle feels wonky, consider a different one. If it feels good, it’s time for a test drive.

I hop on the Trek and pedal around a parking lot, first noticing that giant squishy seat, which is kind of weird … but kinda fun! It fits the bike’s vibe, and I like it. The brakes are nice and grabby. The whole thing feels surprisingly nimble.

From there, I head up to the street and take it around my neighborhood. It’s a beautiful day, and I feel confident dodging potholes and navigating traffic on narrow streets. I feel secure when I need to stop quickly, and I like the perspective shift of the upright hybrid. For a minute I forget that I am working or analyzing how the bike feels. I’m just happily gliding through my neighborhood on Ferdinand Street, passing under my favorite maple trees.

Returning to the shop, I note to Ko that my knees are a little bowlegged, and she raises the saddle a bit, bringing them back in a more natural position.

At this point a rider should take the whole thing into account. There's a bit more fussing that could be done, but if this is clearly not the bike, it'll be apparent now.

"It takes spending time on a bike to know what you want. It's OK not to know right away. Spend some time on it. Trust your body. Cycling and fit is intuitive," she says, establishing her bar for success. "I want to encourage you to ride your bike."

Going Pro

A professional bike fitting is for a different customer base yet shares a lot of DNA with what Ko has shown me.

For it, I bring my own bike—a steel “all-road” ride with nice, fat tires that's comfortable on both streets and gravel—to Jenny Iyo at the Upward Physical Therapy clinic in Seattle's Ballard neighborhood. Ayo is a cyclist and a doctor in physical therapy, and most of her clients come in to address something particular like knee pain, lower back pain, shoulder and back discomfort, hand or foot numbness, or saddle discomfort. Some of her clients are referred by their health care providers and others pay $275 out of pocket, a competitive rate for such a consultation in Seattle.

First thing she does is sit me down and ask lots of questions. Are there any specific issues or discomforts I’m experiencing on the bike? Is there anything I’d like to learn about bike parts or pedaling technique? What is my typical ride like: distance, elevation, road surface, loaded or unloaded?

She then does a series of assessments to check for mobility, flexibility, and strength. I touch my toes—or almost, as I have tight hamstrings. She tests leg strength. She puts me face down on a table in a “Superman” position with my arms and legs lifted off the exam table, then tells me to hold it there for one minute, which feels like it’s going to be a lot of time, but I prevail. This helps her look for head and neck discomfort that might reappear while riding. She asks what I want out of the session, which is to make sure my bike is as optimized as possible for years of happy, comfortable riding.

Combining that information with my typical riding speed, what some call “party pace,” and usual riding distance—between 10 and 30 miles, with occasional longer rides—she determines my fit type. I am after what she calls an “endurance road” fit, with a more upright posture than a road racer and a gentle bend to the elbows.

Body Language

Out on the clinic floor, she puts my bike on a trainer, slides shims under the front wheel to make sure it’s even front to back, and puts a level on the saddle. The pitch of the saddle impacts how much weight you put on it and how stable you feel, she explains. You generally want it perfectly flat.

She measures from the center of my stem bolt to the back of the saddle. She compares the width of my shoulders to the distance between my brake hoods (where you rest your hands on drop bars). She suggests I try slightly wider bars, which would likely leave my arms and my whole body in a more natural, more comfortable position.

Having watched me walk out to the floor, she turns her attention to my feet on the pedals, making sure that they mimic my gently duck-footed stride.

“Wait a minute,” I interrupt, "duck-footed?”

“Well,” she counters, “how about out-toed?”

Ai ai!

Using a large protractor called a goniometer, she measures angles, like my knee when my foot is at the bottom of the stroke, and hangs a plum line from the inferior border of the patella of my forward knee when my cranks are parallel to the ground. She finds that my bike already fits pretty well, but here it’s a bit off. That plum line should fall close to the center line of the pedal spindle, or just behind it, but mine is notably far back for my style of bike, something she corrects by sliding my saddle forward.

"The idea is that you are trying to set up your leg in a position to push down on the pedal so that the big glute and quad muscles are optimized," she says, echoing Ko. “Millimeters matter, though. We make tiny adjustments."

While there are specialty devices charmingly referred to as “ass-o-meters,” she confirms that my saddle is the right size using a charmingly old-school technique. Saddle size is based on the distance between your sit bones (the pelvic bones in your keister) and by having me sit on a rectangle of corrugated cardboard, then rubbing the length of a piece of chalk across the surface where I sat, two oval depressions appear where my sit bones pushed down. Measuring the depressions from center to center gives her my sit bone width: 115 millimeters. For foam saddles, her rule of thumb is to shoot for one that’s about 20 millimeters wider than that, so about 135 millimeters in my case.

Position of Power

This brings us to what bike nerds call the “cockpit”—your handlebars, stem, brakes, and (usually) shifters. The positioning of these components is what Iyo refers to as “a conversation between the bike fitter and rider.” After our conversation, she finds that I was riding more upright than most endurance road riders do and works to tilt me forward, in part by dropping my bars down a bit.

This is also where we began to address one of the bigger questions on my mind: riding posture. As someone deep in the heart of middle age, I think about posture a lot, correcting my slouch dozens of times per day. On my bike, I do the same thing, frequently going from a curved back to ballerina-straight and am hoping these adjustments to the bike could help encourage good posture.

“Good posture on a bike isn’t necessarily what we consider good posture,” she says, and we learn that in this case it isn't the bike that needs adjustment.

While Iyo's adjustments make my bike feel expertly dialed in, her bigger insight is to change how I sit on the saddle. To explain what’s going on, she grabs a pelvis anatomy model and sets it on my saddle. Upright, the sit bones on the model nestle comfortably into the cushiest part of the seat, but then she tips it forward, like I was doing with that straight-backed style, and the weight transfers off of the sit bones and onto the perineum. In other words, I have been moving my weight from where it should be to the tender spot behind my privates.

With me on the bike, Iyo has me position my pelvis correctly and hold it there as I lean forward, while keeping a gentle bend in my elbows. I realize I need to work at it, build strength even, but I can tell this is where I should be. This is not what I was expecting from a fitting, but it’s by far the most important change she suggests.

Bike fitting is an investment, but if you ride a lot it's likely worth it, even if you have to pay for it out of pocket. Getting an assessment and suggestions from a pro puts you in the right position and gets you as comfortable as can be. I've come to like tinkering with my bike adjustments, but I never would have figured all of this out by myself.