How to best determine your bicycle size

"Which of your sizes do you recommend for someone of my height?"

Quick answer:
We need a little more information before recommending a good size for you. If you'd like to work a little more with us on that, go here. For the long answer, read on....

I'm 6' tall, what size shoes should I buy?

Obviously, nobody would order shoes like this. We know that 2 random people that are 6' tall are very unlikely to wear the exact same shoe size. Why would they automatically ride the same bike size?. It would be ridiculous for a shoe salesperson to even ask your height in determining a good shoe size for you, right? Maybe they could get a general sense.....6' tall...male.....probably between size 9 and size 13, but nothing really accurate, and certainly not worth paying $100 or more for the guess. Obviously, you would want them to consider the size and width of your foot. Really good shoe stores will consider your ankle width, and maybe your arch. So that's 4 measurements that count, and none of those measurements are your height.

How does this scenario relate to a bicycle?
Now you go online to consider a new bicycle, and the company is suggesting a size based on your height. How does that work? The answer: It doesn't work. Your chances of getting the right bike size this way are about the same as getting the right shoe size that way. As a result, thousands of people each year pay good money to buy poorly fitting bikes. Then, they either ride uncomfortably, or even worse, hang the bike in the garage and decide that bike riding is not for them. So, I think we've determined that you don't want to order shoes based on just your height, and maybe ordering an expensive bike that way isn't such a good idea either. If not by height, how should you determine a bike size for yourself?

Who are we to write about bicycle fit?
We're Rodriguez Bicycle Company. In case you don't know us, we've actually been building and fitting custom bikes for years now. years is a long time...longer than most in the bicycle industry. Most of our customers are not professional racers, but ordinary people who want to enjoy a comfortable, high-end bicycle. It only makes sense to innovate with them in mind. For decades, we've pioneered bicycle fit, and developed our own complete fitting system (software, fit machine, and fitting tools) to better serve our customers. Most other fitting systems, if not all of them, were designed around professional racing.
I've written a lot on bike fit over the years, and I'll attach some further writing I've done at the end of this article.
Why did I write this article?
Every year, I get several customers who ask me "I'm XX tall, which one of your sizes will fit me?" Usually, they've already determined that they should ride a certain size based on a height chart from some other bicycle website. I've probably already written this article 100 times or more in the form of emails to these customers, so I though it was about time to put it in a form I can reference more easily than trying to dig it out of my head. In fitting a bicycle, there are many more measurements to consider than when sizing for shoes. So what's height have to with it? Read on and see....

Now Back to our Story:
Important things to consider when determining your new bicycle size: Your body is a machine with many levers and pivot points, and so is your bike. Our goal is to get them adjusted and functioning as 1 machine. When all levers and pivot points are where they are supposed to be and working together, you will be comfortable and efficient. The length of each lever, and the placement of each pivot point effects all of the others. Inseam is important (and some shops get that right), but how about your femur length? Your femur length in relation to your inseam will determine where the placement of the pivot point (your knee) should be. This relationship will affect greatly the fore/aft placement of your bicycle seat (to get your knee in the right place). In turn, the seat fore/aft position in relation to the handle bars will greatly affect your reach to the handle bars.

Let's keep rolling
Foot length is also important (there's that shoe size again) as your foot becomes an extension of your leg when pedaling. Now how about torso length? This is probably the most important measurement, and also the least considered. Your reach to the handle bars is determined by your torso length (as well as other factors mentioned past and post this sentence). Probably 80% of fitting complaints come from improper reach to the handle bars. Arm length plays a strong role as well, and will determine how high or low your handle bars end up in your final fit. Now realize that all of these things play together. Your femur length affects your reach to the bars, so adjusting just for inseam and femur length will throw your bar reach out of whack. Changing your fore/aft seat position will also affect your seat height. It all plays together in determining what frame size will fit you best. If all of this were not enough, throw conditioning, riding style, and injuries into the mix. Now tell you think it's reasonable to expect a good bicycle fit from someone who considers just your height, or inseam?

Hopefully, I'm making some sense and you're getting an idea of how it all works together?

Wow! Writing this circular description might make it sound confusing, but it's really not if you've been doing it for as long as we have. Read on and I'll give a little more down to earth explanation of why all of this is important.

We can offer more sizes and custom frames at lower cost than other custom builders
It was years of custom bicycle building and fitting that drove us to our 20 Rodriguez sizes. We have multiple sizes for every height of rider, not just one. Our L and S categories take into consideration whether your height is in your legs, or whether it's in your torso. We fit around 90% of our customers on these 20 sizes, so I don't know how folks are getting good fits from companies offering just 5 or 6 sizes. How about a custom size? At Rodriguez, it's just $200 extra if you need a custom. This is because of our new manufacturing philosophy adopted in 2006 (but that's a whole different story).

If you are getting a size recommendation that considers just your height, how accurate do you think it could be? I, myself, have been fitting bicycles for 30 years, and I couldn't guess an accurate frame size based only on someone's height.

OK, so that's a lot of words, but what if you're a visual person like me?
How about a real life illustration of how people of the same height will require vastly different bike sizes? Below are 3 actual fit entries from our NEXT-fit database, with an imposed image of the size recommended from those measurements. Most manufacturers recommend a size based on the Seat Tube length, so that's the number that their 'size by height' chart is pointing you to. All 3 fits represent customers who purchased bicycles from us. All 3 riders are 5' 10" tall, and are male. Other than that, there are no similarities in their inseam, torso, arm length, etc.... All of these guys ride completely different frame sizes, and if they traded bikes, they would all give up cycling out of sheer discomfort. Pay particular attention to inseam, torso and arm measurements, and how it affects the seat tube and top tube lengths.

No need to worry. Just in case you're a 5' 10" Rodriguez customer, I've changed the names to 'Long Legs', 'Long Torso', and 'Medium Medium'. I don't want you all to think I'll publish your measurements online....and as far as we know, the NSA has no way into our database;-)

Rider 1 - Long Leg customer
Quick synopsis: Rider 1 has the long legs and arms of an 'assumed' 6' 3" guy, but then a torso measurement more like an 'assumed' 5' 6" guy. Most companies don't make a bike for someone of this build. He winds up with a 62cm frame with a short top tube.

Long-legged customer fit data

Rider 2 - Medium Medium customer
Quick synopsis: Rider 2 is a pretty good representation of the 'averages' that most companies use to build their sizes, and recommend them by the rider's height. If you happen to be these proportions (very few people are), then the 'sizing by height' method may work out fairly well for you.

Medium-medium customer fit data

Rider 3 - Long Torso customer
Quick synopsis: Rider 3 has the very long torso of an 'assumed' 6' 3" guy, but the arm length and leg length of an 'assumed' 5' 5" guy. Notice that his short arms put him with an overall reach to bars about the same as the first guy with the really short torso. Although his seat tube length is almost 10cm shorter, they ride the close to same top tube length, but rider 3's bars are much higher due to the shorter arms.

Long-torso customer fit data

How do we do it?
'Long Torso' and 'Long Leg' are kind of extreme examples, but they are indicative of many of the customers we work with every day. If either one of these guys purchased a bicycle online by selecting from a sizing chart determining their frame size by their height, they would both have really poorly fitting bicycles. It's important to measure your whole body in order to get the right size. Medium-medium guy would probably find that off the rack bicycles may fit him OK as far as 'sizing by height', but notice the seat tube angle required for his femur length. Even though his seat tube and top tube would be easy to find in a production bike, he will still end up making a lot of adjustment for his femur length, and then have to adjust for that. If it all seems overwhelming, don't worry, that's why we're here.

At Rodriguez, when we're fitting a 5' 10" customer, we have about 4 sizes that fit about 90% of them (that's true for just about any height rider as well). The other 10% (of which 2 of these guys are) will wind up paying $200 extra for a truly custom size. A small price to pay for a lifetime of comfort. We work with people online, and in person every day, all day, to get them the most comfortably fitting bike they can possibly have. We have video and written instruction online to help our long-distance customers get their measurements right.

Now, if you happen to be a magic bicycle fitter that can accurately fit customers to bicycles based on knowing just their height, give me a call, I may have a job for you. You see, I spend countless hours writing emails back and forth with our long distance customers to determine the proper size bike for them. It's extremely important to us that our customers love their new Rodriguez, and we think it's worth the time to get it right.

If you're considering a new bike, and you'd like to work with us online or in person to determine your next frame size, we'd be glad to oblige. We think you'll find that we're easy to work with, and we really love our customers....long-distance or local.

Links in this article and related links:

Rodriguez and Erickson bicycle logos