Giro
Register II MIPS
Everyday adult helmet with MIPS and a simple dial fit.
Universal Adult, 54–61 cm
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Geometry
Stack, reach, and standover
Compare Bike Stack and Reach
Size labels such as 54 or Medium do not mean the same cockpit on every brand. Stack, reach, and standover let you compare published geometry in millimeters.
- Stack:
- Vertical distance from bottom bracket center to head tube top.
- Reach:
- Horizontal distance between the same two points.
- Standover:
- Ground to top tube. Measurement position varies by brand.
Pick two or three bikes
Choose two bikes, or add a third. The comparison URL can be shared.
Choose two different bikes to see stack, reach, and standover side by side. A third bike is optional.
Looking for size labels by height? Open bike size comparisons.
Example
Trek Domane SL 5 vs Specialized Roubaix
A medium-size endurance road comparison using the published stack, reach, and standover numbers. Use the pickers above to compare other bikes.
Measurement
Trek Domane SL 5
Specialized Roubaix
Bike type
road
road
Size
54
54
Stack
575 mm
585 mm+10 mm
Reach
374 mm
381 mm+7 mm
Standover
754 mm
766 mm+12 mm
Stack-to-reach ratio
1.54
1.54
Bike type
Trek Domane SL 5
road
Specialized Roubaix
road
Size
Trek Domane SL 5
54
Specialized Roubaix
54
Stack
Trek Domane SL 5
575 mm
Specialized Roubaix
585 mm+10 mm
Reach
Trek Domane SL 5
374 mm
Specialized Roubaix
381 mm+7 mm
Standover
Trek Domane SL 5
754 mm
Specialized Roubaix
766 mm+12 mm
Stack-to-reach ratio
Trek Domane SL 5
1.54
Specialized Roubaix
1.54
A higher stack-to-reach ratio is typically a taller, more upright cockpit. A lower ratio is typically longer and racier.
Trek Domane SL 5 geometry on the brand siteSpecialized Roubaix geometry on the brand site
Numbers last checked 2026-09-12.
Full size comparison
Trek Domane vs Specialized Roubaix SizeStarter 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
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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
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CamelBak
Podium Chill 21 oz
Insulated squeeze bottle for everyday rides.
Fits a standard ~73 mm cage
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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
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FAQ
Short answers for comparing published bike geometry.
What are stack and reach?
Stack is the vertical distance from the bottom bracket center to the top center of the head tube. Reach is the horizontal distance between those same points. Together they describe frame height and length better than a size label such as 54 or Medium.
What is standover?
Standover is the vertical distance from the ground to the top of the top tube. Measurement position varies by brand. If a brand table does not list standover for the compared size, that measurement is shown as not listed.
What does stack-to-reach ratio tell me?
Divide stack by reach. A higher ratio is typically a taller, more upright cockpit. A lower ratio is typically longer and racier. Use it with the millimeter numbers, not instead of them.
Can I compare a road bike with a mountain bike?
Yes. The numbers still compare cockpit height and length. Riding position, handling, and size labels will not map one-to-one across bike types.
Where do these numbers come from?
Each bike links to the brand geometry page we last checked. Confirm the exact model year on that page before buying.