Giro
Register II MIPS
Everyday adult helmet with MIPS and a simple dial fit.
Universal Adult, 54–61 cm
View on AmazonPrice and availability on Amazon
Trek bike size chart
Trek Alpha Sizing Chart by Height and Inseam
Match Trek XS, S, M, ML, L, and XL alpha sizing to rider height, inseam, and legacy 50, 52, 54, 56, and 58cm road frame labels.
Trek system
Alpha sizes XS/S/M/ML/L/XL plus 50-58cm road labels.
Read by height
Trek's height range beats the size label.
Cross-brand
Match by height range, not by label.
Find your Trek size
Trek road alpha sizing chart: XS, S, M, ML, L, XL in cm
Trek's brand-level road chart pairs S, M, ML, and L with a legacy frame size in centimetres; XS and XL are model-specific and carry no brand-level band. Trek also publishes per-model tables, and the same letter can pair differently there, so confirm on the model page before translating a size.
Trek alpha
Road frame size
Rider height
Height cm
XS
Model-specific
Model-specific
–
S
52 cm
5'5"-5'9"
165-175
M
54 cm
5'7"-5'11"
171-181
ML
56 cm
5'10"-6'2"
177-187
L
58 cm
6'0"-6'4"
183-193
XL
Model-specific
Model-specific
–
Trek alpha
XS
Road frame size
Model-specific
Rider height
Model-specific
Height cm
–
Trek alpha
S
Road frame size
52 cm
Rider height
5'5"-5'9"
Height cm
165-175
Trek alpha
M
Road frame size
54 cm
Rider height
5'7"-5'11"
Height cm
171-181
Trek alpha
ML
Road frame size
56 cm
Rider height
5'10"-6'2"
Height cm
177-187
Trek alpha
L
Road frame size
58 cm
Rider height
6'0"-6'4"
Height cm
183-193
Trek alpha
XL
Road frame size
Model-specific
Rider height
Model-specific
Height cm
–
Trek size chart by bike type
Road uses Trek's brand-level sizing guide. Gravel, mountain, and hybrid show a representative current model so the inseam and standover values are tied to a real, verifiable geometry.
Trek road size chart
Trek's official sizing across all current road models. Source: Trek US sizing guide, reviewed 2026-04-24.
Trek size
Height
Height cm
Standover cm
Fit note
S / 52
5'5"-5'9"
165-175
73.4
Riders under 5'5" should look at Trek model pages with 44, 47, or 50cm frames
M / 54
5'7"-5'11"
171-181
75.2
Most common mid-size road range
ML / 56
5'10"-6'2"
177-187
76.8
Half-step between M and L
L / 58
6'0"-6'4"
183-193
78.6
Confirm reach and stack on the model page
Trek size
S / 52
Height
5'5"-5'9"
Height cm
165-175
Standover cm
73.4
Fit note
Riders under 5'5" should look at Trek model pages with 44, 47, or 50cm frames
Trek size
M / 54
Height
5'7"-5'11"
Height cm
171-181
Standover cm
75.2
Fit note
Most common mid-size road range
Trek size
ML / 56
Height
5'10"-6'2"
Height cm
177-187
Standover cm
76.8
Fit note
Half-step between M and L
Trek size
L / 58
Height
6'0"-6'4"
Height cm
183-193
Standover cm
78.6
Fit note
Confirm reach and stack on the model page
Trek gravel size chart
Representative model: Checkpoint ALR 5 Gen 3. Source: Trek Checkpoint ALR 5 Gen 3 official sizing tab, reviewed 2026-04-24. Trek gravel sizing varies by model; see model pages for exact geometry.
Size
Height
Height cm
Inseam cm
Standover cm
Fit note
XS
4'8"-5'2"
143-158
67-74
73.5
Shortest Checkpoint ALR fit; check standover
S
5'2"-5'5"
158-164
74-77
76.5
Small road-adjacent gravel range
M
5'5"-5'10"
164-177
77-83
78.9
Common mid-size gravel pick
ML
5'10"-6'2"
177-188
83-88
80.9
Trek's between-size for taller mid riders
L
6'2"-6'4"
188-194
88-91
82.9
Compare ML if reach feels long
XL
6'4"-6'8"
194-203
91-95
85.9
Largest Checkpoint ALR fit
Size
XS
Height
4'8"-5'2"
Height cm
143-158
Inseam cm
67-74
Standover cm
73.5
Fit note
Shortest Checkpoint ALR fit; check standover
Size
S
Height
5'2"-5'5"
Height cm
158-164
Inseam cm
74-77
Standover cm
76.5
Fit note
Small road-adjacent gravel range
Size
M
Height
5'5"-5'10"
Height cm
164-177
Inseam cm
77-83
Standover cm
78.9
Fit note
Common mid-size gravel pick
Size
ML
Height
5'10"-6'2"
Height cm
177-188
Inseam cm
83-88
Standover cm
80.9
Fit note
Trek's between-size for taller mid riders
Size
L
Height
6'2"-6'4"
Height cm
188-194
Inseam cm
88-91
Standover cm
82.9
Fit note
Compare ML if reach feels long
Size
XL
Height
6'4"-6'8"
Height cm
194-203
Inseam cm
91-95
Standover cm
85.9
Fit note
Largest Checkpoint ALR fit
Trek mountain size chart
Representative model: Marlin 4/5/6/7 Gen 3. Source: Trek Marlin 4 (57361), Marlin 5 (57363), Marlin 6 (57365), and Marlin 7 (57367) Gen 3 official sizing and geometry tables, reviewed 2026-09-30. 2XS is the 26" Marlin 4 size; XS to XL are shared across the four; every trim publishes the 2XL band, and Marlin 5 and Marlin 7 publish geometry for it. Trek MTB sizing varies by family; XC, trail, and enduro models can differ.
Size
Height
Height cm
Inseam cm
Standover cm
Fit note
2XS
4'5"-4'9"
135-145
64-68
—
Marlin 4 only, on 26" wheels
XS
4'9"-5'1"
145-155
69-73
65.8
Suited to younger or shorter riders
S
5'1"-5'5"
155-165
74-78
69.2
Small adult MTB fit
M
5'5"-5'10"
165-177
79-83
74.7
Common mid-size MTB range
ML
5'8"-5'11"
173-180
81-86
75.9
Between-size for taller mid riders
L
5'10"-6'2"
177-188
84-89
77.1
Standard L MTB fit
XL
6'2"-6'5"
188-195
89-91
79.1
Tall riders; check reach on model page
2XL
6'5"-6'8"
195-203
91-97
81.6
Tallest band; Marlin 5 and Marlin 7 publish geometry for it
Size
2XS
Height
4'5"-4'9"
Height cm
135-145
Inseam cm
64-68
Standover cm
—
Fit note
Marlin 4 only, on 26" wheels
Size
XS
Height
4'9"-5'1"
Height cm
145-155
Inseam cm
69-73
Standover cm
65.8
Fit note
Suited to younger or shorter riders
Size
S
Height
5'1"-5'5"
Height cm
155-165
Inseam cm
74-78
Standover cm
69.2
Fit note
Small adult MTB fit
Size
M
Height
5'5"-5'10"
Height cm
165-177
Inseam cm
79-83
Standover cm
74.7
Fit note
Common mid-size MTB range
Size
ML
Height
5'8"-5'11"
Height cm
173-180
Inseam cm
81-86
Standover cm
75.9
Fit note
Between-size for taller mid riders
Size
L
Height
5'10"-6'2"
Height cm
177-188
Inseam cm
84-89
Standover cm
77.1
Fit note
Standard L MTB fit
Size
XL
Height
6'2"-6'5"
Height cm
188-195
Inseam cm
89-91
Standover cm
79.1
Fit note
Tall riders; check reach on model page
Size
2XL
Height
6'5"-6'8"
Height cm
195-203
Inseam cm
91-97
Standover cm
81.6
Fit note
Tallest band; Marlin 5 and Marlin 7 publish geometry for it
Trek kids size chart
Wheel-size based fit for Precaliber and Wahoo. Source: Trek Kids' Bike Buyer's Guide, Precaliber guide, and Wahoo Path FAQ, reviewed 2026-05-17.
Wheel size
Age
Height
Inseam
Trek models
Fit note
12"
2-3
3'0"-3'3"
15"-18"
Precaliber 12
Training-wheel or first pedal-bike range
16"
4-6
3'5"-4'0"
16"-22"
Precaliber 16
Beginning riders who are older or taller
20"
5-8
3'9"-4'6"
19"-25"
Precaliber 20 / Wahoo Path 20
Intermediate kids ready for more control
24"
8-11
4'1"-4'11"
23"-28"
Precaliber 24 / Wahoo Path 24
Older kids with solid handling skills
26"
13+
4'8"-5'2"
25" and up
Wahoo Path 26
Tall youth riders in Trek's Wahoo Path range
Wheel size
12"
Age
2-3
Height
3'0"-3'3"
Inseam
15"-18"
Trek models
Precaliber 12
Fit note
Training-wheel or first pedal-bike range
Wheel size
16"
Age
4-6
Height
3'5"-4'0"
Inseam
16"-22"
Trek models
Precaliber 16
Fit note
Beginning riders who are older or taller
Wheel size
20"
Age
5-8
Height
3'9"-4'6"
Inseam
19"-25"
Trek models
Precaliber 20 / Wahoo Path 20
Fit note
Intermediate kids ready for more control
Wheel size
24"
Age
8-11
Height
4'1"-4'11"
Inseam
23"-28"
Trek models
Precaliber 24 / Wahoo Path 24
Fit note
Older kids with solid handling skills
Wheel size
26"
Age
13+
Height
4'8"-5'2"
Inseam
25" and up
Trek models
Wahoo Path 26
Fit note
Tall youth riders in Trek's Wahoo Path range
Trek hybrid size chart
Representative model: FX 3 Disc Gen 3. Source: Trek's shared city sizing table (FX 2 Disc Gen 3, 35003) and the FX 3 Disc Gen 3 geometry table, reviewed 2026-10-05. FX, FX Sport, Verve, and the FX+ and Verve+ e-bikes publish the same height and inseam bands; the sizes each frame offers are what differ. Verve and FX Sport top out at XL. Standover is the FX 3 Disc frame.
Size
Height
Height cm
Inseam cm
Standover cm
Fit note
XS
4'10"-5'1"
147-155
69-73
67.3
Shortest FX frame; standover climbs 212 mm to 2XL
S
5'1"-5'5"
155-165
72-78
70.4
Reach grows 10 mm from XS while standover grows 31 mm
M
5'5"-5'9"
165-175
77-83
73.8
Most riders start here
L
5'9"-6'1"
175-186
82-88
79.9
Largest standover jump in the table, 61 mm over M
XL
6'1"-6'6"
186-197
87-93
84.8
Reach peaks at 398 mm here and at L
2XL
6'6"-6'8"
197-203
92-95
88.5
Only FX reaches this band; Verve and FX Sport top out at XL
Size
XS
Height
4'10"-5'1"
Height cm
147-155
Inseam cm
69-73
Standover cm
67.3
Fit note
Shortest FX frame; standover climbs 212 mm to 2XL
Size
S
Height
5'1"-5'5"
Height cm
155-165
Inseam cm
72-78
Standover cm
70.4
Fit note
Reach grows 10 mm from XS while standover grows 31 mm
Size
M
Height
5'5"-5'9"
Height cm
165-175
Inseam cm
77-83
Standover cm
73.8
Fit note
Most riders start here
Size
L
Height
5'9"-6'1"
Height cm
175-186
Inseam cm
82-88
Standover cm
79.9
Fit note
Largest standover jump in the table, 61 mm over M
Size
XL
Height
6'1"-6'6"
Height cm
186-197
Inseam cm
87-93
Standover cm
84.8
Fit note
Reach peaks at 398 mm here and at L
Size
2XL
Height
6'6"-6'8"
Height cm
197-203
Inseam cm
92-95
Standover cm
88.5
Fit note
Only FX reaches this band; Verve and FX Sport top out at XL
Trek hybrid frames keep reach nearly constant across the range: FX reach moves 9 mm from XS to 2XL while stack climbs 110 mm. Size a hybrid by standover and stack, then treat reach as the tiebreak. FX Sport is a different frame from FX and sits 37 mm higher at M.
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.
Start with height. If two sizes overlap, use cycling inseam to choose.How to measure
Trek sizing system
Trek labels follow height range — confirm with inseam and standover.
Trek now publishes road and mountain sizing in alpha labels (e.g. S, M, ML, L, XL) and pairs them with the legacy frame size in cm where applicable.
Trek M is not always equivalent to 54cm across models. The 54 number is a frame size convention; the alpha label is the official fit reference.
When comparing across brands, match by published height range first, then confirm with reach and standover on the model page.
Fast Trek answers
Quick answers for common Trek size searches.
These answers summarize the Trek road and mountain tables above so riders can resolve common XS, S, M, ML, L, and XL sizing questions before opening a specific model page.
Trek mountain bike size chart for 5'0" XS or small
For a 5'0" rider on the Trek Marlin Gen 3 chart, start with XS. Trek lists XS for 4'9"-5'1" and S for 5'1"-5'5", so 5'0" sits inside XS rather than S.
Confirm inseam and standover before buying; a short inseam can make XS more important than height alone.
Trek road alpha sizing XS S M ML L XL
Trek road pages commonly show alpha labels beside legacy frame sizes. On this chart, S maps to 52cm, M to 54cm, ML to 56cm, and L to 58cm; XS and XL appear on specific model pages outside this core 52-58cm road range.
Use the height band first, then confirm the exact model's reach, stack, and standover.
Trek road frame sizes 50 52 54 56 58
Trek road bike frame sizes 50 52 54 56 58 overlap with alpha labels. On this brand chart, 52 is S, 54 is M, 56 is ML, and 58 is L; 50cm appears on smaller model-specific charts.
If you search Trek road bike size chart M 56 cm, check both M / 54 and ML / 56 because Trek uses ML as the half-step between M and L.
Is Trek ML between M and L?
Yes. Trek ML is the half-step between M and L, useful for riders around 5'10"-6'2" who do not fit cleanly into either side.
Compare ML against both M and L when reach or standover is close.
Trek vs Giant vs Specialized at the same height
Road sizing only. Bands match Trek's brand-level road chart; riders under 5'5" should look at Trek road models with 44, 47, or 50cm frames. Mountain and gravel use brand-specific systems (such as Specialized S-Sizing) — confirm on each model page.
Height
Trek
Giant
Specialized
5'5"-5'9"
S / 52
S
52
5'7"-5'11"
M / 54
M
54
5'10"-6'2"
ML / 56
M/L
56
6'0"-6'4"
L / 58
L
58
Height
5'5"-5'9"
Trek
S / 52
Giant
S
Specialized
52
Height
5'7"-5'11"
Trek
M / 54
Giant
M
Specialized
54
Height
5'10"-6'2"
Trek
ML / 56
Giant
M/L
Specialized
56
Height
6'0"-6'4"
Trek
L / 58
Giant
L
Specialized
58
Popular Trek models
Open the model page, then confirm exact geometry on each Trek product page before buying.
Between Trek sizes
Use Trek's ML step when you fall between, then check standover.
Pick the smaller Trek size
When standover is tight, your inseam is on the short side of the range, or you want a sportier, more aggressive fit on Domane, Madone, or Checkpoint.
Pick the larger Trek size
When standover clears safely and you want a more upright, longer-distance position. Confirm reach is not too long for your torso.
Use ML if Trek offers it
Trek's ML is a half-step between M and L for riders who fall in the overlap. Compare standover and reach against both adjacent sizes before locking it in.
Trek bike FAQ
Short answers for choosing a Trek frame before purchase.
What size Trek bike do I need for my height?
Use Trek's official height range first, then confirm with inseam and standover. Most riders land within one or two adjacent Trek sizes; the calculator narrows it to the best match.
Is a Trek M the same as 54cm?
No. Trek pairs M with 54 for legacy reasons, but the height range and the model's geometry are the source of truth. Different generations of the same Trek model can pair M with anything from 52 to 56, so trust the published height range over the cm number.
How does Trek sizing compare to Giant and Specialized?
Brands draw their height ranges differently. A rider near 5'9" might be a Trek M, a Giant M, and a Specialized 54. Use the cross-brand table on this page for a starting point, then check the exact model geometry before buying.
What Trek mountain bike size should a 5'0" rider start with?
Start with XS on Trek Marlin Gen 3 sizing. The published XS height range is 4'9"-5'1", while S starts at 5'1", so a 5'0" rider should check XS first and confirm with inseam and standover.
What do Trek road alpha sizes XS S M ML L XL mean?
They are Trek's fit labels. On this brand-level road chart, S corresponds to 52cm, M to 54cm, ML to 56cm, and L to 58cm; XS and XL are model-specific edge sizes. The height range and exact model geometry are more reliable than the label alone.
What size Trek hybrid bike do I need?
Trek hybrid bikes share one published height table. A 170 cm rider falls in M, which Trek lists for 165-175 cm and an inseam of 77-83 cm; FX reach barely changes across the range, so standover and stack decide the size. Verve and FX Sport top out at XL while FX reaches 2XL.
How do Trek road bike frame sizes 50 52 54 56 58 map?
For Trek road bike frame sizes, 52 usually maps to S, 54 to M, 56 to ML, and 58 to L on this chart. A 50cm Trek road frame is usually a smaller model-specific size, so compare the exact Domane, Madone, or Emonda chart before buying.
Data sources
Verified Trek references on this page
Road, gravel, mountain, and kids charts were reviewed between April and September 2026. The hybrid table was added in October 2026.