Giro
Register II MIPS
Everyday adult helmet with MIPS and a simple dial fit.
Universal Adult, 54–61 cm
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Universal Sizing Guide
Bike Frame Size Chart
This bike frame size chart translates your height and inseam into centimeter, inch, and letter-size labels for road, mountain, and gravel bikes. Because a frame size is a label rather than a universal body measurement, different riding disciplines use distinct numbering formats. Use height first to establish your baseline size, then confirm inseam and standover clearance for the exact model you plan to ride.
Road cm
Alpha
MTB inches
48 / 50 cm
XS / S
15–16 in
52 / 54 cm
S / M
16–18 in
56 / 58 cm
M / L
18–20 in
60 / 61 cm
L / XL
20–22 in
Height
Take shoes off and stand tall, looking straight ahead. A helper should rest a flat object on the crown of your head, then run a tape from the floor to the underside of that object. Save the number in inches and centimeters — charts use both.
Inseam
Stand tall and barefoot with feet slightly apart. Ask a helper to measure vertically from your crotch to the floor. Keep your legs straight and feet flat.
Universal Frame Sizing and Label Reference
Starting centimeter, inch, and letter-size labels by rider height. Confirm the range with the road, mountain, or gravel chart and the exact model.
Size
Height
Inseam
XS / 47-49 cm / 13-14 in
5'0"-5'5"
26-28 in inseam
S / 50-52 cm / 15-16 in
5'5"-5'8"
28-30 in inseam
M / 54-56 cm / 17-18 in
5'8"-5'11"
30-32 in inseam
L / 56-58 cm / 19-20 in
5'11"-6'2"
32-34 in inseam
XL / 60-62 cm / 21-22 in
6'2"-6'5"
34-36 in inseam
Size
XS / 47-49 cm / 13-14 in
Height
5'0"-5'5"
Inseam: 26-28 in inseam
Size
S / 50-52 cm / 15-16 in
Height
5'5"-5'8"
Inseam: 28-30 in inseam
Size
M / 54-56 cm / 17-18 in
Height
5'8"-5'11"
Inseam: 30-32 in inseam
Size
L / 56-58 cm / 19-20 in
Height
5'11"-6'2"
Inseam: 32-34 in inseam
Size
XL / 60-62 cm / 21-22 in
Height
6'2"-6'5"
Inseam: 34-36 in inseam
Road Bike Frame Size Chart by Rider Height
Centimeter-based frame size recommendations paired with rider height and cycling inseam ranges for road cycling.
Size
Height
Inseam
48
155-163 cm
69-74 cm
50
161-167 cm
73-77 cm
52
164-171 cm
74-79 cm
54
169-178 cm
77-82 cm
56
176-184 cm
81-86 cm
58
181-190 cm
85-90 cm
61
188-198 cm
89-95 cm
Size
48
Height
155-163 cm
Inseam: 69-74 cm
Size
50
Height
161-167 cm
Inseam: 73-77 cm
Size
52
Height
164-171 cm
Inseam: 74-79 cm
Size
54
Height
169-178 cm
Inseam: 77-82 cm
Size
56
Height
176-184 cm
Inseam: 81-86 cm
Size
58
Height
181-190 cm
Inseam: 85-90 cm
Size
61
Height
188-198 cm
Inseam: 89-95 cm
Mountain Bike Frame Size Chart by Rider Height
Letter-size frame recommendations optimized for off-road standover clearance, stability, and trail control.
Size
Height
Inseam
XS
150-160 cm
67-72 cm
S
158-169 cm
71-77 cm
M
167-178 cm
76-82 cm
L
176-188 cm
81-87 cm
XL
186-198 cm
86-93 cm
XXL
193-204 cm
91-98 cm
Size
XS
Height
150-160 cm
Inseam: 67-72 cm
Size
S
Height
158-169 cm
Inseam: 71-77 cm
Size
M
Height
167-178 cm
Inseam: 76-82 cm
Size
L
Height
176-188 cm
Inseam: 81-87 cm
Size
XL
Height
186-198 cm
Inseam: 86-93 cm
Size
XXL
Height
193-204 cm
Inseam: 91-98 cm
Gravel Bike Frame Size Chart by Rider Height
Gravel and all-road frame labels by rider height and inseam. Confirm standover and reach before copying a road size.
Size
Height
Inseam
XS
155-164 cm
70-75 cm
S
162-172 cm
74-79 cm
M
170-179 cm
78-83 cm
L
178-189 cm
83-89 cm
XL
186-197 cm
87-94 cm
Size
XS
Height
155-164 cm
Inseam: 70-75 cm
Size
S
Height
162-172 cm
Inseam: 74-79 cm
Size
M
Height
170-179 cm
Inseam: 78-83 cm
Size
L
Height
178-189 cm
Inseam: 83-89 cm
Size
XL
Height
186-197 cm
Inseam: 87-94 cm
Starter kit
Helmet, light, lock, bottle, and a pant-leg strap. Size the bike here; buy the complete adult bike at a shop.
NiteRider
Swift 300
Compact USB headlight for commuting and dusk rides.
Handlebar mount, 300 lumens
View on AmazonPrice and availability on Amazon
Kryptonite
Evolution Mini-7 with 4′ cable
Hardened U-lock plus a cable for wheels or a locked-together pair.
Fits most road, gravel, and hybrid frames
View on AmazonPrice and availability on Amazon
CamelBak
Podium Chill 21 oz
Insulated squeeze bottle for everyday rides.
Fits a standard ~73 mm cage
View on AmazonPrice and availability on Amazon
Green Guru
Narrow pant-leg strap
Upcycled inner-tube strap that keeps a pant leg off the chain.
Adjustable hook-and-loop, about 16 in long
View on AmazonPrice and availability on Amazon
As an Amazon Associate we earn from qualifying purchases. Affiliate disclosure.
Bike size calculator
Find a starting size
If the chart shows cm, inches, or S/M/L, enter your height and inseam to see which size fits.
The sizing process
How to Choose the Right Bike Frame Size
Step 01
Measure Your Total Height
Stand barefoot with your back against a flat wall and measure from the floor to the crown of your head in centimeters or inches.
Step 02
Measure Your Cycling Inseam
Place a book firmly between your legs against your pelvic bone and measure the distance from the top of the book spine straight down to the floor.
Step 03
Identify the Label System for Your Bike Type
Check whether your intended bike uses centimeters (common for road bikes), inches, or letter sizes (common for mountain bikes).
Step 04
Check Standover Clearance
Compare your inseam to the bicycle frame size chart standover height to ensure safe clearance when straddling the top tube.
Step 05
Confirm with a Calculator or Brand Chart
Use a bike frame size calculator or manufacturer geometry table to verify reach, stack, and cockpit fit for your specific model.
Understanding Frame Dimensions
How to Choose the Right Bike Frame Size
Frame size is a label system, not a body measurement. These checks keep you from moving a number between bike types that do not share one.
Take your own measurements4 checks
Frame Size Is a Sizing Label, Not a Body Measurement
A frame size is a label, not a body measurement. Road bikes are traditionally measured in centimeters based on seat tube length, mountain bikes in inches or letter sizes (S, M, L), and hybrid bikes frequently use either system. Knowing your bike frame size by height gives you a reliable starting range, but individual brand geometries vary.
Check: Note which label system your bike type uses before comparing numbers.
How to Measure Bike Frame Size and Standover
Understanding how to measure bike frame size begins with checking the seat tube length from the center of the bottom bracket to the seat tube collar. In addition to frame size, measure your cycling inseam to verify standover clearance over the top tube. Road and gravel bikes generally require 1 to 2 inches of clearance, while mountain bikes require 2 to 4 inches for off-road control.
Check: Measure inseam in cycling shorts, then keep 1–2 inches of standover on road and gravel.
Road, Mountain, and Hybrid Labels Are Not Interchangeable
A 54 cm road bike frame size chart recommendation does not translate directly to a 54 cm hybrid or gravel frame. Road bikes feature longer top tubes designed for an aerodynamic posture, whereas mountain bike frame size chart recommendations prioritize lower top tubes and upright control. Always evaluate sizing within the specific bike category rather than transferring a single number across styles.
Check: Compare inside one category: never move a 54 cm label across bike types.
What to Do When You Fall Between Two Sizes
If your height and inseam place you between two sizes, your upper body proportions and brand geometry serve as the tie-breaker. Riders with longer torsos or arms generally fit better on the larger frame for adequate reach, while riders with shorter reach benefit from the agility of the smaller frame. Use height first, then confirm inseam and the exact model before deciding.
Check: Take the smaller size whenever the larger one pushes your reach out.
Related guides
Choose the right chart for your bike
Once you have a starting size, compare the chart for your bike type or exact model.
Complete bike size chart
Explore comprehensive sizing tables covering road, mountain, gravel, hybrid, and commuter bicycles.
Road bike size chart
View detailed centimeter-based road sizing guidance with standover and reach considerations.
Mountain bike size chart
Find the ideal mountain bike frame size in inches and S-M-L labels for trail and XC riding.
How to choose a bike size
A comprehensive guide on measuring your body, evaluating frame geometry, and testing for proper fit.
How to measure a bike frame
Measure seat tube length, effective top tube, and standover on the frame itself.
Gravel bike size chart
Review gravel and all-road frame sizing charts built for endurance comfort and mixed-surface control.
Questions
FAQ
Quick answers to common bike-sizing questions.
How do I use a bike frame size chart?
Find your total height on the chart to identify your baseline size range in centimeters, inches, or letter sizes. Then cross-reference your cycling inseam to ensure proper standover clearance on the specific bicycle frame size chart for your bike type.
What is a bicycle frame size chart?
A bicycle frame size chart is a standardized reference table that matches rider height and inseam measurements to manufacturer frame sizes. It helps cyclists identify the right frame dimensions for comfort, pedaling efficiency, and safe handling.
Is a frame size chart by height enough?
A frame size chart by height provides an accurate initial estimate, but height alone does not reflect torso length or leg proportion. Confirming your inseam and reviewing manufacturer geometry ensures the bike fits your reach and standover requirements.
How do I measure bike frame size?
To measure bike frame size, measure from the center of the bottom bracket axle to the top of the seat tube where the seat collar sits. Because modern frames often have sloping top tubes, manufacturer geometry tables and standover height are more dependable than seat tube length alone.
Should I use centimeters, inches, or S/M/L?
Road bikes typically use centimeters, mountain bikes most often use inches or S/M/L letters, and hybrid bikes use either format depending on the brand. Always refer to the sizing convention specified by the bicycle manufacturer.
What size bike frame do I need for my height?
Your bike frame size by height depends on the riding category; for example, a rider at 5'10" (178 cm) typically rides a 54–56 cm road frame or a medium/large (17–19") mountain bike. Use height first, then confirm inseam and the exact model.
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