Bike stack and reach determine how a bike fits your body and riding style, helping you avoid discomfort, improve power output, and enhance control right from your first pedal stroke.
By dialing in these two critical measurements, you’ll prevent soreness and injuries—so you can spend more time enjoying the ride and less time recovering.
Ill-fitting clothes and shoes usually result in discomfort and pain. The same goes for bikes. Buying a new bike is paramount to picking the correct size. The proper bike ratio will improve your riding performance. It will also save you from many nights of body pains and injuries.
Knowing two critical points on your bike (the reach and the stack) will tell you which bike will fit you. Except that it wouldn’t be that easy if you don’t even know what stack and reach are.
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We gathered the most trusted information from professional bikers and bike researchers. This will enlighten you about the stack and reach ratio, how to choose the right bike and many more!
Stack and Reach Ratio
Biking is one sport where you’re in the same statistical bent position most of the time. If you get the reach wrong, it may add up to discomfort, pain, and injuries.
What are bike stack and reach, and how does it affect your riding experience? Stack and reach are used to give you a pretty accurate perspective on whether your bike’s going to fit you or not. These are calculated using the bottom bracket as the base point.
The reach is how far from the bottom bracket the head tube is. The stack is how high the bottom bracket is from the head tube. Reach is the horizontal distance; the stack is the vertical distance from the bracket to the head tube.
Why They’re So Important
Whenever you ride on a bike dynamically, whether it’s jumping or dropping, you’ll be in an attack position. If you have the perfect bike fit, you’ll be completely comfortable on the bike.
You won’t over-stretch your body, and you’ll be able to take your hands off the bars avoiding a fall forward or back. In short, the perfect bike size gives you better balance.
Stack and reach aren’t just valuable for making your riding experience better. Every bike manufacturers have their take in sizing. Some bike manufacturers use terms such as S, M, L, 52s, 56, etc.
Having your stack and reach measurement can help you compare two frames and decide which works for you. This is especially helpful for riders who are in between two sizes like medium to large.
If you want to compare bike stack and reach between two frames, use our calculator to see which bike is taller or longer: Compare Bike Stack and Reach Calculator (A vs B Fit Tool)
Forget About Top and Seat Tube Length
Top tube length and seat tube length have been the go-to metric to get bike size estimates. These measurements will give you a good idea of whether you can get your saddle or handlebars in the right place or not.
The only problem with using this metric is it won’t give you an exact bike fit. For instance, comparing bikes with the same top and seat tube length may vary in their stack and reach measurements.
Measuring Stack and Reach
Now that we know what and why it’s essential, it’s time to figure out how to measure it. We’ll describe how you can measure stack and reach and how you can make some adjustments.
You can find your bike’s stack and reach measurement by looking it up online. Or let’s measure it together manually.
To start, measure the center of the bottom bracket axle back to the door. Then measure from the bottom bracket axle down to the ground. This will give you the origin of the bike’s reach and stack measurements.
Get the stack by measuring the top of the head tube down to the floor and subtracting the bottom bracket height.
Measure the reach from the frame’s bottom bracket extending vertically up from there through where it meets with the head tube at its center point.
Actual Stack and Reach Measurement
Do you ride a bike holding on to the top of the head tube? I don’t know about you, but most bikers don’t. Earlier, we referenced the standard measurement of the reach and stack from the center of the head tube. But we’ll give you what we call “the actual” stack and reach sizes.
We’ll adjust the actual stack and reach measurements on the bottom bracket to the middle of the grip. Knowing your actual reach and stack measurement will help you customize your bike and allow you to compare different bike dimensions, stacks, bars, and stems.
Preparing your Bike
First, make sure your bike wheels are straight to get the correct measurements. Next, get a tape and draw a straight line across the middle, then carefully place it from end to end of your grips. The line will serve as your reference point for the measurement. You can now measure your actual bike stack and reach.
Actual Stack
Measure the center of the grip down to the floor, then subtract the bottom bracket measurement that we’ve gained earlier.
Actual Reach
Measure the point from the line on the tape to the saddle to get the reach measurement.
Typical Stack & Reach Ranges
- Road bikes: Stack ~520–600 mm, Reach ~370–410 mm
- Endurance/comfort frames: Stack often above 580 mm
- Performance/aggressive frames: Reach toward the upper 390–410 mm range
Some fitters reference a stack:reach ratio to gauge how upright versus aggressive a frame is, but there’s no one “perfect” ratio—individual flexibility and bike type always win out.
How do Stack and Reach Affect Speed and Comfort?
While the stack measurement increases, you get a more upright and relaxed position. Bikes designed for comfort and longer biking hours usually have a higher stack distance. Higher reach positively correlates to a more aerodynamic and aggressive position. Higher stacks are common on bikes designed for faster rides like road bikes.
- Stability: A bike with a higher stack and shorter reach tends to be more stable, making it excellent for beginners or those who prioritize comfort over speed.
- Responsiveness: A longer reach, on the other hand, positions the rider in a more aggressive stance, making the bike more responsive, especially during sprints or climbs.
- Maneuverability: The combination of stack and reach also affects how easily you can maneuver the bike, especially in tight corners or when navigating through traffic.
Detailed Fit-Performance Trade-Offs
- If stack is too high, you’ll sacrifice aerodynamics.
- If stack is too low, a closed hip angle can sap power and lead to discomfort.
- A reach that’s too long also closes the hip angle and strains your back.
- A reach that’s too short makes you feel cramped and hampers handling.
Stack and Reach Limitations
Bike geometry isn’t restricted to stack and reach. The stack and reach measurements disregard other essential factors like the bike’s seat angle in terms of fit. For this reason, it’s necessary to understand the different measures of a bike that will contribute to the riding experience. Knowing just the bike stack and reach ratio may be helpful but limited. Here are additional limitations of the stack and reach:
- Stack and reach fail to look at the shape of the handlebar, spacers and stem length and angle.
- Stack and reach ratio disregard headset. Add the headset to the listed stack dimension if you intend to use a frame with an external bearing headset.
- Fails to deal with frame’s seat-angle limitations.
Brand-Specific Geometry Tendencies
For example, Giant frames often come with more generous stack, whereas Specialized tends toward lower-stack, aggressive geometries at the same reach.
Get Help from a Professional
It’s overwhelming to understand all these concepts at first. We recommend you get a professional fit before you decide on buying a bike. This guarantees that you won’t be guessing when investing in a new bike. Also, experienced fitters can help you figure out your positioning coordinates while exploring other essential factors, including cost, durability, and ride qualities.
How To Change Your Bike To Fit You
What if you don’t like the way your current bike feels but can’t buy another bike? The good news is you can modify some of your bike’s dimensions by changing the following:
- Spacers above and below the stem.
- Change the stem to be shorter or longer.
- Choose a stem that has a rise.
- Shift to flat bars or increase bar’s rise
- Increase the sweep if you want to be pushed a little back on the bike
- Decrease the sweep to be pulled a little forward.
You can consider many factors that alter the reach (forward and back) and your stack height (up and down). There’s no right and wrong bike stack and reach measurement. It would highly depend on the rider’s comfortability and riding preference—experiment on how you want your ride to feel. Are you new to biking? Check out our article on the biking basics to kick-start your journey in the cycling world!
References
- Velo. (2021, December 14). Gravel bike geometry 101: How trail, stack, and reach affect fit and handling. https://velo.outsideonline.com/road/road-racing/gravel-bike-geometry-101-how-trail-stack-and-reach-affect-fit-and-handling/
- Tuvalum. (2024, July 2). What are the Stack and Reach of a bicycle and why they are important. https://tuvalum.eu/blogs/news/what-are-the-stack-and-reach-of-a-bicycle-and-why-they-are-important
