Giro
Register II MIPS
Everyday adult helmet with MIPS and a simple dial fit.
Universal Adult, 54–61 cm
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Trek Mountain frame
Trek Marlin Size Chart
Marlin runs XS to XXL in Trek's mountain alpha sizing, and the frame switches from 27.5-inch wheels on XS and S to 29-inch wheels from M up. Trek publishes the same rider height and inseam table for the 2026 Marlin 4, 5, 6 and 7 Gen 3, so these bands answer for all four; this page carries the Marlin 5 Gen 3 table and geometry. The brand-level Trek mountain chart adds the 2XS band Marlin 4 publishes on 26-inch wheels.
- Frame sizes
- XS–XXL · 7 sizes
- Rider height
- 4'9"–6'8"
- Height (cm)
- 145–203 cm
- Stack / reach · M
- 609 / 440 mm
Marlin size finder
Which Marlin size covers your height?
Height gives you one size, or two when the published height ranges overlap. Stack, reach, and standover settle the overlap.
ft
in
Enter your height and the Marlin size that covers it is marked in the tables below.
How to measureHeight gives the starting size. Standover and reach confirm it.
Height ranges
Where each size starts and ends
Height ranges for every Marlin size, 141 to 207 cm overall. XS: 145 to 155 cm. S: 155 to 165 cm. M: 165 to 177 cm. ML: 173 to 180 cm. L: 177 to 188 cm. XL: 188 to 195 cm. XXL: 195 to 203 cm.
- XS145–155 cm
- S155–165 cm
- M165–177 cm
- ML173–180 cm
- L177–188 cm
- XL188–195 cm
- XXL195–203 cm
141 cm174 cm207 cm
Size chart
Marlin size by height
Rider height and inseam are Trek's published sizing table for the Marlin 5 Gen 3, and the 2026 Marlin 4, 5, 6 and 7 Gen 3 publish the same bands. Marlin 4 also builds a 2XS band for 135–145 cm, which this table does not cover. Trek labels the tallest band 2XL on the sizing chart and XXL in the geometry table.
Size
Height
Height cm
Inseam
Fit note
XS
4'9"–5'1"
145–155 cm
69–73 cm
Smallest Marlin 5 size, on 27.5-inch wheels with the lowest standover in the range.
S
5'1"–5'5"
155–165 cm
74–78 cm
Last size on 27.5-inch wheels; M and up move to 29-inch wheels.
M
5'5"–5'10"
165–177 cm
79–83 cm
First 29-inch size; the stack and reach above are for this size.
ML
5'8"–5'11"
173–180 cm
81–86 cm
Half step over M: 5 mm more stack and 15 mm more reach.
L
5'10"–6'2"
177–188 cm
84–89 cm
Middle of the top three sizes; check reach before stepping up from ML.
XL
6'2"–6'5"
188–195 cm
89–91 cm
The inseam band is only 2 cm wide here, so inseam decides more than height.
XXL
6'5"–6'8"
195–203 cm
91–97 cm
Tallest Marlin 5 size, with the highest standover. Trek labels this band 2XL on the sizing chart.
XS
4'9"–5'1"
145–155 cm
Inseam 69–73 cm
Smallest Marlin 5 size, on 27.5-inch wheels with the lowest standover in the range.
S
5'1"–5'5"
155–165 cm
Inseam 74–78 cm
Last size on 27.5-inch wheels; M and up move to 29-inch wheels.
M
5'5"–5'10"
165–177 cm
Inseam 79–83 cm
First 29-inch size; the stack and reach above are for this size.
ML
5'8"–5'11"
173–180 cm
Inseam 81–86 cm
Half step over M: 5 mm more stack and 15 mm more reach.
L
5'10"–6'2"
177–188 cm
Inseam 84–89 cm
Middle of the top three sizes; check reach before stepping up from ML.
XL
6'2"–6'5"
188–195 cm
Inseam 89–91 cm
The inseam band is only 2 cm wide here, so inseam decides more than height.
XXL
6'5"–6'8"
195–203 cm
Inseam 91–97 cm
Tallest Marlin 5 size, with the highest standover. Trek labels this band 2XL on the sizing chart.
Start with height. If two sizes overlap, use cycling inseam to choose.How to measure
Marlin trims
Marlin 4, 5, 6 and 7 sizing
Trek sizes the 2026 Marlin line from one table. Marlin 4, 5, 6 and 7 Gen 3 all use the rider height and inseam bands above, and the frame geometry matches size for size; only the sizes Trek builds each one in differ.
ModelSizes Trek publishesWhat to know
Marlin 4 Gen 3 57361
Sizes: 2XS, XS, S, M, ML, L, XL, 2XL
The only trim with the 2XS band (135–145 cm) on 26-inch wheels, which Trek writes XXS in its geometry table. Geometry is listed up to XL.
Marlin 5 Gen 3 57363
Sizes: XS, S, M, ML, L, XL, 2XL
The sizing table and geometry above come from this trim.
Marlin 6 Gen 3 57365
Sizes: XS, S, M, ML, L, XL, 2XL
Same sizing table; Trek's geometry table for this trim stops at XL.
Marlin 7 Gen 3 57367
Sizes: XS, S, M, ML, L, XL, 2XL
Same bands and the same frame numbers as Marlin 5, the 2XL size included.
Trek's earlier Marlin 8 carries the same height and inseam bands and the same published sizes as Marlin 4, from 2XS to XL. It is not in the 2026 line-up, which runs Marlin 4, 5, 6 and 7.
Geometry
Marlin geometry by size
Stack, reach, and standover for every Marlin 5 Gen 3 size, taken from Trek's published geometry table by column name. The 2026 Marlin 4, 5, 6 and 7 Gen 3 share these frame numbers.
Size
Height
Stack
Reach
Standover
XS
4'9"–5'1"
563 mm
390 mm
658 mm
S
5'1"–5'5"
572 mm
415 mm
692 mm
M
5'5"–5'10"
609 mm
440 mm
747 mm
ML
5'8"–5'11"
614 mm
455 mm
759 mm
L
5'10"–6'2"
618 mm
470 mm
771 mm
XL
6'2"–6'5"
637 mm
495 mm
791 mm
XXL
6'5"–6'8"
651 mm
520 mm
816 mm
XS
4'9"–5'1"
- Stack
- 563 mm
- Reach
- 390 mm
- Standover
- 658 mm
S
5'1"–5'5"
- Stack
- 572 mm
- Reach
- 415 mm
- Standover
- 692 mm
M
5'5"–5'10"
- Stack
- 609 mm
- Reach
- 440 mm
- Standover
- 747 mm
ML
5'8"–5'11"
- Stack
- 614 mm
- Reach
- 455 mm
- Standover
- 759 mm
L
5'10"–6'2"
- Stack
- 618 mm
- Reach
- 470 mm
- Standover
- 771 mm
XL
6'2"–6'5"
- Stack
- 637 mm
- Reach
- 495 mm
- Standover
- 791 mm
XXL
6'5"–6'8"
- Stack
- 651 mm
- Reach
- 520 mm
- Standover
- 816 mm
XS4'9"–5'1"
Stack563 mmReach390 mmS5'1"–5'5"
Stack572 mmReach415 mmM5'5"–5'10"
Stack609 mmReach440 mmML5'8"–5'11"
Stack614 mmReach455 mmL5'10"–6'2"
Stack618 mmReach470 mmXL6'2"–6'5"
Stack637 mmReach495 mmXXL6'5"–6'8"
Stack651 mmReach520 mm
How neighboring sizes compare
If two sizes both fit, compare reach and standover rather than assuming the larger size is more comfortable.
How to measure a bike frame- Size stepStackReachStandover
- XS → S+9 mm+25 mm+34 mm
- S → M+37 mm+25 mm+55 mm
- M → ML+5 mm+15 mm+12 mm
- ML → L+4 mm+15 mm+12 mm
- L → XL+19 mm+25 mm+20 mm
- XL → XXL+14 mm+25 mm+25 mm
Starter kit
Helmet, light, lock, bottle, and a pant-leg strap. Size the bike here; buy the complete adult bike at a shop.
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Kryptonite
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Narrow pant-leg strap
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Bike size calculator
Find your Trek Marlin size
Enter your height and inseam for a Trek mountain bike, then compare the result with this Marlin chart.
Sizing notes
Why height alone is not enough
Riders with the same height can need different sizes because inseam, torso length, flexibility, and preferred handling differ.
3 checks
Reach grows faster than stack across the Marlin range: XS to XXL adds 130 mm of reach but only 88 mm of stack, so stepping up lengthens the cockpit more than it raises the front end.
S to M is the largest single step, adding 37 mm of stack and 55 mm of standover, and it is where the frame switches from 27.5-inch to 29-inch wheels.
Trek publishes a height band and an inseam band for every size. Where the two disagree, compare standover against your inseam before choosing the larger size.
Sources
Confirm the exact bike after you have a starting size
Every number on this page comes from the sources below. Check the exact model year there before you buy.
Data reviewed:
Compare
Compare before buying
A size label does not mean the same thing across brands. Compare published geometry before you choose.
Related guides
More Trek and mountain sizing
Once you have a starting size, compare this frame against the Trek chart and the mountain guide.
Trek bike size chart
Compare Marlin against broader Trek size guidance.
Mountain bike size chart
Check mountain sizing by height and inseam before choosing a frame.
Questions
Marlin size chart FAQ
Short answers for Trek Marlin sizing.
What size Trek Marlin should I ride?
Start with the Trek height band: XS for 145–155 cm, S for 155–165 cm, M for 165–177 cm, ML for 173–180 cm, L for 177–188 cm, XL for 188–195 cm, and XXL for 195–203 cm. Then confirm inseam and standover for the size you land on.
Is a Trek Marlin M the same as a 54 cm road bike?
No. Marlin sizes are letters with no published centimetre label, so a Trek road 54 does not carry over. Marlin M covers 165–177 cm with 609 mm of stack and 440 mm of reach; compare those numbers against any road bike you already ride.
What size Marlin fits a 5'10" rider?
5'10" is 178 cm, which falls inside both Trek's ML band of 173–180 cm and L band of 177–188 cm. M stops at 177 cm, so a 5'10" rider is above it; compare ML with L, where L adds 4 mm of stack and 15 mm of reach.
What size Trek Marlin 6 do I need?
Marlin 6 uses the same published table as every 2026 Marlin: XS for 145–155 cm, S for 155–165 cm, M for 165–177 cm, ML for 173–180 cm, L for 177–188 cm, XL for 188–195 cm, and 2XL for 195–203 cm. Pick the band your height falls in, then check the inseam and standover for that size.
Is a Trek Marlin 7 the same size as a Marlin 5?
Yes. Marlin 5 and Marlin 7 Gen 3 publish the same height and inseam bands and the same frame geometry, so a Marlin 7 in M is 165–177 cm with 609 mm of stack and 440 mm of reach, exactly like the M size above. Take the same size in either trim.
What size is a Trek Marlin 8?
Marlin 8 is an earlier trim and is not in Trek's 2026 line-up, which runs Marlin 4, 5, 6 and 7. Trek published the same height and inseam bands for it and the same published sizes as Marlin 4, so start from the sizes above.
Does the Marlin ML size fit between M and L?
Yes. ML covers 173–180 cm with 614 mm of stack and 455 mm of reach, which is 5 mm more stack and 15 mm more reach than M. The M to ML reach step is the smallest in the range at 15 mm, tied only by ML to L; every other step adds 25 mm.