This sizing guide helps you find your ideal Argon 18 Sum, an all-rounder race bike. Its aggressive geometry places you in a lower and more stretched-out position. Consider the Argon 18 Krypton if you want a more comfortable (endurance) geometry.
There are six Argon 18 Sum frame sizes available for cyclists with heights from 4’11” to 6’7″ (150 to 200cm).
| Rider height (cm) | Inseam (cm) | Rider height (in) | Inseam (in) | Argon 18 bike size |
|---|---|---|---|---|
| 150 – 163 | 70 – 76 | 4’11 – 5’4″ | 28″ – 30″ | XXS |
| 163 – 170 | 76 – 79 | 5’4″ – 5’7″ | 30″ – 31″ | XS |
| 170 – 175 | 79 – 82 | 5’7″ – 5’9″ | 31″ – 32″ | S |
| 175 – 185 | 82 – 86 | 5’9″ – 6’1″ | 32″ – 34″ | M |
| 185 – 192 | 86 – 90 | 6’1″ – 6’4″ | 34″ – 35″ | L |
| 192 – 200 | 90 – 93 | 6’4″ – 6’7″ | 35″ – 37″ | XL |
Other factors to consider beyond height
The chart above is just a starting point. There’s more to a good fit than height beyond the sizing chart.
Here are important things to consider from my previous experience working at the bike shop, helping hundreds of customers get their right bike size.
Argon 18 sizing vs. other brands
Argon 18 bikes come in XXS, XS, S, M, L, and XL sizes.
These provide a rough indication of the frame size, and they may not be consistent across other bike brands. What constitutes a size S in an Argon 18 could be different in another brand that uses a similar sizing, such as Giant or Specialized.
Just relying on these values alone can be misleading.
Understand the stack and reach measurements
If you currently have a bike that fits you well and is comfortable, use that as a reference point.
Find out its Stack and Reach measurements and compare them against the Scott Addict RC’s measurements. Then, pick the closest size.
- Stack is the vertical distance from the bottom bracket to the top of the head tube. Stack height influences how high your handlebars will be relative to your saddle. A higher stack leads to a more upright riding position, which can be more comfortable, especially for longer rides, older riders, and those with less flexibility on the lower back.
- Reach is the horizontal distance from the bottom bracket to the center of the head tube. It determines how stretched or compact your riding position will be. A longer reach results in a more stretched-out, aggressive riding posture, while a shorter reach promotes a more upright position.
The Stack and Reach measurements can be found below.
Measure your inseam
Measure your inseam and compare it against Argon 18’s inseam chart above. Here’s how to measure your inseam correctly.
- Remove your socks and shoes.
- Stand with your feet 6 to 8” apart, back flat to the wall.
- Place a book between your legs, with its spine facing up until it touches your crotch.
- Slowly move away from the wall while keeping the book in place.
- Measure the distance between the floor and the book’s spline.
Here’s a video demonstrating how to do it.
What if you fall between sizes?
It’s common to find yourself falling in between two bike sizes. The most common mistake among cyclists is choosing a frame that’s too big. Here’s what to consider.
- Body proportions. If you have long legs and a short torso, consider going down a frame size. For a short-legged (shorter than average inseam), long-torso rider, consider going up a size.
- Flexibility. If you’re less flexible, a more relaxed, endurance-oriented frame such as the Giant Defy Advanced may be better.
Test ride before you buy
Visit your local Argon 18 dealer to try both sizes to get a feel for what suits you best. Most large dealers can provide a test ride if they have a bike in your size in their demo fleet.
Argon 18 Sum frame geometry (2020-2023)
The geometry chart below applies to all Argon 18 Sum frames from the following:
- Years: 2020, 2021, 2022, 2023
- Models: Argon 18 Sum Pro
- Frame material: Carbon
Each of the measurements is explained in detail in this article.
| Frame Size | XXS | XS | S | M | L | XL |
|---|---|---|---|---|---|---|
| Top Tube (mm) | 503 | 520 | 538 | 557 | 578 | 600 |
| Seat Tube (mm) | 395 | 425 | 460 | 505 | 550 | 595 |
| Seat Tube Angle | 75º | 74.5º | 74º | 73.5º | 73º | 72.5º |
| Head Tube (mm) | 69 | 85 | 101 | 126 | 152 | 180 |
| Head Tube Angle | 71.2º | 72.1º | 72.7º | 72.7º | 72.7º | 73º |
| Chainstay (mm) | 410 | 410 | 410 | 410 | 410 | 410 |
| Wheelbase (mm) | 967 | 972 | 975 | 990 | 1006 | 1020 |
| BB Drop (mm) | 69 | 73 | 77 | 77 | 77 | 77 |
| Standover Height (mm) | 676 | 700 | 727 | 766 | 804 | 841 |
Bernard Lu has 7+ years of experience working in a bicycle shop, overseeing the retail and workshop operations. He’s a qualified bicycle mechanic who understands a cyclist’s needs and speaks the same cycling lingo.
If you meet him at the cafe, he will happily talk to you for hours about all the intricacies of bikes and cycling tech. Just buy him a coffee next time you see him.