What Size Mountain Bike Do I Need?

What Size Mountain Bike Do I Need?

The best mountain bike for you needs to be the appropriate size for your height and inseam. You can determine the appropriate frame size by measuring your height and inseam measurements.

A good fit is a pivotal factor when selecting a bike in terms of comfort. A comfortable bike will improve your riding ability and keep you safe when you’re driving through rough terrain.

It would be best if you never bought a new bike until you’ve learned the importance of getting your height’s best size and how to modify the bike’s parts to make them better suited to your measurements, requirements, and preferred discipline.

The right fit and a properly set up bike make it easy to take on tracks at a very high speed, but a too-small bike can cause twitching, nervousness, and discomfort on long rides.

In this article, you get insights into what size mountain bike you need. Let’s dive in and see!

Table of Contents

What Size Mountain Bike Do I Need?

Every rider knows that every bike rides and feels different, even though they have the same numbers on paper.

The sizes of bike frames listed by manufacturers can confuse. The dependable guideline is lists the seat tube length; however, even that differs since some are estimated to the highest point of the seat tube, and some at the center of where the seat tube meets the top tube.

In many cases, bikes are listed as Small, Medium, and Large, with XS or XL at each end.

In recent years, manufacturers have been listing bike sizes according to reach figures instead of the top tube and top tube lengths.

In other words, they have managed to extend the bike’s wheelbase, top tube, and reach figure while shortening the stack heights and seat tube lengths. When seat tube lengths are short, shorter men and women can ride bikes with long reach figures because the seat height can be adjusted lower, allowing them to ride larger bikes.

When buying a bike, it’s crucial to consider top tube and seat tube length since the seat tube length determines the base seat stature that can be set, and the top cylinder length generally decides how loosened up the rider will feel on the bicycle.

There is no one perfect answer to determining the size of your frame because, like many other things on your mountain bike, you can adjust your stem, handlebar, and saddle to make a poor fit feel comfortable. You should always consult the manufacturer’s size chart, which specifies a height range for each bicycle frame size.

The table below shows manufacturers’ size chart for your guidance on mountain bike sizing.

What Size Mountain Bike Do I Need

Bike SizeFrame SizeRider Height
Extra-Small13-14inch5ft-5ft 4inch
Small14-16 inch5ft 4 inch-5ft 7 inch
Medium16-18 inch5 ft 7 inch-5ft 10 inch
Large18-20 inch5 ft 10 inch-6 ft 1 inch
Extra Large20-22 inch6 ft 1 inch plus


Top Considerations When Choosing A Mountain Bike Size

Here are the factors to consider when choosing a mountain bike size.

Be Sure First To Check The Manufacturer’s Size Chart.

You can pick a size from a manufacturer’s range of basic sizes. Different companies have different ranges, so a small bike from one manufacturer may differ in size from another. Be sure to check out the basic guidelines before you buy your own bike.

Proper Calculation Of The Bike Size

Here are the steps to calculate your bike size accurately.

  • First, remove your shoes and stand with your legs about 15-20 Centimeters (6-8in) apart.
  • Place a book between your legs as if you were on a bike.
  • Using a measuring tape, find the distance between your pubic bone and the floor.
  • Remember, sizing systems vary between companies but also between types of bikes. When you calculate your bike size, remember which type you want. For example: Mountain bike: leg inseam (cm) x 0, 66 = frame size. If, for example, the inseam of your legs is 76cm, the right mountain bike size is 50 Centimetres (20in).

Measure The Seat Tube Length And Examine The Standover

The Seat Tube Length And The Standover

Your bike’s seat tube should be long enough to leave you a suitable standover gap and sufficient standover clearance. To find this, measure from the middle of the axle holding the crank arms together to the top of the seat tube.

Test the standover of your bike by straddling it over its top tube. Take your bike as high as possible, and then ask a friend to measure the distance between your tires and the ground so that your bicycle is at the proper height for you.

Saddle Height And Crank Length

Saddle Height And Crank Length

Most bicycles come with 175mm or 170 mm cranks, which are fine for many users. However, if your legs are short, the cranks might be difficult to turn without your knees bowing exorbitantly at the highest point of the stroke, which brings about some unacceptable muscles being utilized.

You may also benefit from a longer crank if you’re tall so that you can make the most of your proportions.

Generally, it is advisable to set a saddle at a height that maximizes efficiency and power. If it’s too high, it will result to the rocking of your hips back and forth, wasting energy; if it’s too low, the adequate power you need may not be delivered by your muscles.

Your saddle height should be adjusted so that your highest heel is on the pedals at the bottom of the pedal stroke and your calf is fully extended so your knee will not lock out. To get more clearance, lower your saddle a few inches.

 Check Top Tube Length And Reach

Top Tube Length And Reach

Also important for the comfort and efficiency of riding a bike is the top tube length. You should know where the handlebars should fall to enable the proper fit and the length of your torso. You can do this by measuring the length of your torso and arms.

If you’re not sure the length of your top tube, measure from your knuckles to your collarbone and from your pubic bone to the hollow at the base of your neck. Add the results and divide them by two. Add four; this is the perfect length.

The top tube length will show you how the bike feels when you’re sitting, but reach tells us more about how the bike feels when you’re standing up. This feature is particularly relevant when you’re descending but also indicates a bike’s size.

The position of a cross-country cyclist may be stretched out, though an amateur who has never taken a bicycle in rough terrain may like to be more upstanding for additional solace and with less weight on their hands.

Comfort, control, and efficiency are often sacrificed when determining your reach. It’s important to find what works best for you, but do not span out or hunch too much, as this can cause back problems.

How To Make Extra Fit Adjustments On Your Mountain Bike

How To Make Extra Fit Adjustments On Your Mountain Bike

If you want your bike to be more comfortable, make some extra adjustments. To make these extra adjustments, follow these steps.

Seat Angle And Effective Top Tube Length

Because the cranks (or bottom bracket) are never located below the saddle, you can lean forward without placing undue weight on your arms.

Since the seat tube lies at an angle, the saddle will be situated behind the bottom bracket, determining how balanced you feel seated.

It’s possible to measure this angle overly strongly, but fortunately, the range of angles is usually rather narrow, so this is typically not that crucial.

If we compare two bicycles with the same ETT length but distinct seat tube angles, the slacker-angled bike will feature a forward-sloping bottom bracket, and the opposite is true for the tighter-angled bike.

The result is that two bicycles with equal reach may handle differently based on your weight is distributed. Inexperienced riders often slide the saddle way back, which is psychologically reassuring while also making the strength of the steering vague and preventing the suspension from compressing effectively.

As you sit forward, you’ll maximize the use of the fork and tread on the front tire, and there will be better handling of the bike.

This all assumes that the reach is correct for you. It is advisable to mark your saddle with a plumb line; the line should cross the chainstays almost exactly halfway between the bottom bracket axle and the rear wheel axle.

Foot Position And Cleats

Foot Position And Cleats

If your pedals are flat or platform, your foot usually rests conveniently on the pedal axle. Nevertheless, pedals without clips are more difficult to adjust; the best way to get started is to place the cleat directly beneath the ball of your foot.

When you have gotten the perfect spot, do forth, and back adjustment – minor adjustments can alter which muscles are used and how smoothly you pedal.

Cleats should align with your feet’s natural angle, which is easily visible when using flat pedals.

Most clipless pedals have a built-in float, which allows the foot to accomplish a natural angle, making it a great choice when you are not sure of what’s best for you.

Practice with the final pedal setup. Once you get this right, the flow of the pedal stroke will feel fluid without any twisting of the ankles, knees, or hips.

Getting in the sweet spot takes several rides, but it is worth the effort – when you get there, draw a circle around the cleats as a reference whenever they need to be replaced.

 Adjust The Height Of Your Seat

Adjust The Height Of Your Seat

Use your measurements and a tape measure to determine the seat tube length of your bike. Start by measuring the circumference of the seat tube at the pedal crank attachment point. Then, measure out the seat height using your inseam.

The seat post bolt should be loosened with a wrench. Swivel the seat post up or down into the correct position. Then tighten it with a wrench. Make sure the saddle is level with the upper end of the tape measure.

Adjust The Handlebars Of Your Bike

Adjust The Handlebars Of Your Bike

Use a standard wrench to loosen the bolt at the base of the handlebars. Lean your upper back under the handlebars so that your arms form a 90-degree angle with your upper back.

Set your forearms at a 45-degree angle to the handlebars. Adjust the handlebars either up or down so that they are level with your saddle. Tighten the bolts around the stem of the handlebars.

Mountain Bike Fit And Size For Women

Mountain Bike Fit And Size For Women

Women-specific mountain bikes and geometry have only recently been introduced to the world of mountain biking. However, if you look closely, you’ll find that some brands use the same frames as men’s or unisex equivalents, adding just a few touches, including finishing kits tailored for female riders.

Anyone particular model does not fit all ladies, and some riders might prefer a universal bike.

Various features are common among these bikes, such as lighter springs, thinner grips, narrower bars, and women’s saddles. But women aren’t the only ones who can benefit from this thinking; men can also if they have narrow shoulders or small hands.

In general, women have distinct measurements to men at a given height, so some brands have altered the profiles of their bikes so that they are more appropriate for female riders based on body geometry data and riders’ feedback.

Mountain Bike Fit And Size For Kids

Mountain Bike Fit And Size For Kids

Even for kids, some regulations apply, although there are also a few extra things to keep in mind.

Bike sizes are usually determined by the size of the wheel, from 12 inches to 26 inches. Also important is the top tube’s width and reach.

However, unlike adults, a child needs to reach the floor when seated to stay safe and in control.

Make sure the brakes are easy to use and can be squeezed easily even with weaker hands. As for the gear shifters, look for twist grips because ergonomics can be easily handled by many kids.

Another neglected component gears, as many bikes are equipped with full-sized chainrings and adult-length cranks. Instead, look for smaller gears so they can handle the steep climbs.

Problems Caused By The Wrong Size Mountain Bike

Problems Caused By The Wrong Size Mountain Bike

Choosing the wrong mountain bike size, whether it’s too small or too large, can make you not enjoy the journey as much as you would like or cause injury.

An ache or pain can be caused by the bike’s setup or other factors. So, consult your doctor if it persists after riding and is not relieved by the adjustments discussed here.

Pains and aches on a bike may be caused by inadequate muscle support. To relieve these, you need to ride more and work on your core muscles.

Here are the common bike-related problems and their causes.

Knee Pain

A saddle that is too high or too low can cause knee pain, as can shoes that are not properly. Some cyclists like a pedal/cleat combination with freer float, which reduces pain in the knee.

Back Pain

Back pain is usually associated with inadequate core muscle support when cycling, so changing your handlebar position and your reach to the bars might help. Some riders have found that shifting the stem an inch or two up or down will cure lower back pain. Back pain can also be indicative of a sloppy bike frame.

Pains In Shoulders/Arms/Neck

Often, this occurs when you have too much space in front of your bike or when you have too much space behind it, making your shoulders curl and making it impossible to hold the bar properly.

If you suffer from either shoulder pain or neck pain, it could be either you have a too small or big bike. Different bar shapes can boost your comfort. Some riders find a bar with an increased backsweep or upsweep improves their performance.

Hip Problems

Bicyclists often experience hip problems because the saddle is too low, too high,  too far back or forward, or not providing appropriate padded support.

Top Tips For Buying Your Mountain Bike

If you’re an experienced MTB rider looking to get trails-ready or if you’re new to mountain biking, see what to look for when picking the right bike. The following tips will help.

Make Sure The Size Is Right

The right frame size is superior to everything else. However, avoid depending on the highlighted size because it has become increasingly inaccurate. For instance, there is no standardized idea of what large means. For instance, one company’s large size may not match another’s medium size.

Instead, make sure that the bike is the right size for you by checking the reach and stack measurements. Don’t hesitate to go longer than with a road bike.

With a long front triangle, you can weigh the axle further forward and keep your front wheel in place so you don’t get sucked into your bars on impact. This also helps with climbing because it keeps your wheel planted.

If you go too long, you won’t have enough clearance for a standover. Only a couple of centimeters are needed. Keeping the seat tube short allows for better standover and maneuverability but maintains full pedaling height without exceeding the Seatpost. 29er bikes have taller front ends, and you can adjust the bike’s position with stems, bars, and seat posts.

Choose A Wheel Size

The 650b wheel size is available in 27.5in or 29in diameters (xc and trail), but the wide-rimmed Plus size and recent interest in 29in downhill wheels confuse the matter.

29ers will undoubtedly become more common in the coming years – together with appropriate tires and frames – but right now, you have the choice between big hoops for giant distances, or smaller, stronger ones to smash trails.

While plus sizes can be great for hardtails, they are sensitive to tire pressure, and it is still unclear if they will stay longer.

Choose Hardtail Or Full-Suss

Choose Hardtail Or Full-Suss

Full suspension bikes have expensive rear shocks, bearings, links, and manufacturing processes, so this means you’ll likely get a better parts specification on a hardtail at the same price. You’ll also have less maintenance and fewer problems too.

Furthermore, full-suspension bikes are now more advanced than ever, which means their advantages outweigh their disadvantages. The need to start with a hardtail before upgrading to a big bike is a myth, so preference is the key here.

Weight Shouldn’t Be A Focus

While weight is important, off-road performance is slightly more important. Steering accuracy, cornering confidence, and speed all suffer when random rocks, roots, and ruts are lurking behind you. It’s better to carry a little extra weight and avoid the hedge. And stay out of the workshop, too.

Watch Out For Flashy Trinkets

You don’t need a top-notch rear derailleur to buy a good bike: some of them are up-specced to help sell the bike. A good rear derailleur is important, but so are cranksets, shifters, and even the chainrings.

Suspension Quality Is More Important Than Quantity.

You should review the forks and shocks on the bike you are interested in buying and check the manufacturer’s website to get exact models. Original equipment (OE) units are far different from similar-looking aftermarket ones, so be sure to get the best.

Invest In Future-Proof Design

Be sure to check out the most popular axle diameters and spacing in addition to the head tube and bottom bracket diameters – a dropper post (for changing saddle height on the fly) will be tough to find in the smallest size for example.

Although internal gear hose routing makes for stealth-like droppers, it also loses noise and maintenance.

Don’t Spend All Your Budget

It is wise to set some funds aside to invest in a dedicated trail helmet with greater coverage, stronger construction, and a decent peak. You may also need a backpack, sunglasses for warding off flying debris, and cleats and clips to use on mountain bikes.

In addition, you may want to replace your tires, either because their original equipment tires have softer, cheaper compounds or because they have heavier steel beads than their aftermarket counterparts. You may also wish to modify your gear ratio and almost certainly modify the shape and size of your cockpit.

Final Thoughts

If you intend to buy a mountain bike, it’s crucial to select the ideal size to enhance your safety and comfort. Check the general manufacturers’ guide to determine the right size for you. Lastly, get on the bike and ride it to make sure it suits you. If you are not comfortable, you can readjust it if needed. If you are a beginner, go for an affordable bike.




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