What size mountain bike frame do I need? Yes, that’s the big question.
Ordering bikes online is becoming more and more popular due to there not being any shopkeeping or warehouse costs, making the prices better.
And don’t worry about the old wisdom of trying a bike before getting it, that is quite definitely overrated. And very highly. Salesmen say this just as a means to get you to invest in a bike. It really doesn’t have to do that much with finding the right bike size for yourself.
You should try your bike first! FALSE
Another reason is that salesmen know that there are decent bikes on the online market and the option of getting to sit on one gives them an apparent edge over that market, but in actuality, it isn’t by any means necessary to choose a bike with the right size.
Related: Best Mountain Bikes Of 2023
There are many good methods to choose a good bike. I’m going to highlight SEVEN METHODS to help you measure a bike.
Feeling more confident? Good. There are actually three different ways to pick a size: you can calculate it or use the bike size charts below. Let´s start with the easiest. The bike size is measured from where the seat post starts down to the crank. You can also use the bike height chart.
#1 – Mountain Bike Size Chart
What mountain bike frame size do I need?
It’s easy!
Your height / Bike Size
- 4’11” – 5’3″ = 13 – 15 inches
- 5’3″ – 5’7″ = 15 – 17 inches
- 5’7″ – 5’11” = 17 – 19 inches
- 6’0″ – 6’2″ = 19 – 21 inches
- 6’2″ – 6’4″ = 21 – 23 inches
- 6’4″ and taller = 23+ inches
Or you can use the mountain bike frame size chart below…
Need Professional Fitting Service? Order From Amazon!
Or you can use the…
#2 – Bike Size Calculator
- Take off your shoes and stand with your legs 6″ – 8″ (15-20 cm) apart. Measure the height from the ground up to where your legs come together.
- Be sure about the bicycle type you want to choose: Mountain bike, city bike, or road bike. You can read about the different bike types here.
- Now you can take your calculator and quickly find the right size:
Right mountain bike sizing– Leg inseam (cm) x 0,66 = Your frame size
For example: If your leg inseam is 76cm, then your right mountain bike size is 50 cm (20”)
Review: Best Gravel Bikes To Buy
#3 – Chart
| Rider Height | Suggested Mountain Frame Size | |||
|---|---|---|---|---|
| Feet & Inches | Centimetres | Frame Size (inches) | Frame Size (cm) | Size |
| 4’10” – 5’2″ | 148cm – 158cm | 13″ – 14″ | 33 – 37 | X-Small |
| 5’2″ – 5’6″ | 158cm – 168cm | 15″ – 16″ | 38 – 42 | Small |
| 5’6″ – 5′ 10″ | 168cm – 178cm | 17″ – 18″ | 43 – 47 | Medium |
| 5’10” – 6’1″ | 178cm – 185cm | 19″ – 20″ | 48 – 52 | Large |
| 6’1″ – 6’4″ | 185cm – 193cm | 21″ – 22″ | 53 – 57 | X-Large |
| 6’4″ – 6’6″ | 193cm – 198cm | 23″ – 24″ | 58 – 61 | XX-Large |
Source: Evanscycles.com
Voilà!
Extra: Right Saddle Height
Right saddle height has a very important role. If it’s too low, you won’t have enough power in your feet. In mountain bike racing, I have experienced that when the saddle falls one inch down from its normal position, I lose about 25-50% of my force.
Stopping to fix it can cost me my position and about 15 seconds too, but then with the correct saddle height, it’s not that hard to catch up with the group and even get all the way to the next group ahead. So the right saddle height plays a huge role!
The easiest way to find that height for you is to
- Lean against the wall with your elbow sitting on the bike (or let someone help you as shown in the picture)
- Push your leg down to the lowest point keeping it parallel to the ground.
- Move your saddle up or down until you have a small bend behind your knee. It should be something around 30° but don’t worry too much about finding that exact angle.
Go out and ride. Does it feel good? If not, then adjust. Also, you can adjust the seat forward and backward.
Related: Check Out The Best Fat Tire Bikes
Bicycle Guiders’ TIP:
When you have found the right height for yourself, you can use a marker or a sharp object to mark the right position for your saddle as some of them can sink down a bit with time. Some bikes also come with height lines written on the post, that you can check and remember once you’ve found the right one for yourself.
EXTRA
- Fourth Sizing method: Amazon Fit Guide
- Fifth Sizing Calculator: Competitive Cyclist Fit Calculator.
- Sixth – Jenson USA Bike Fit Calculator (Beta)
- Extra – Professional Bike Fitting Service – Order From Amazon!
What If I Got My Bike Size Wrong?
Then tell the merchant, who can easily exchange your bike for the right one. If you don’t want to do that, then you can try the following things:
- move your saddle forward or backward
- buy a longer or a shorter stem. It will change your body position
- buy a longer seat post
Give it time to get the feeling right. I remember when I got my first 29er mountain bike. It felt like a ship and seemed difficult to ride it in narrow trails or the forest. But I’ve become so familiar with it and can ride with full ease and skill, that when I sit on a 26″ mountain bike it seems so completely ridiculous how tiny it is.
If you don’t know, what to buy, then read those reviews below
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Hello!
I’m trying to decide what size for REI’s co op 2.1 DRT. There is no info on frame size just reach and stack and I’m unsure what those are?
I’m female 5’9” 145ish lbs and my legs are a few inches longer than my torso. I’m having a difficult time deciding because I am in between sizes and the Medium comes with 27.5 in tires and Large has 29s. I plan to ride lots of trails in desert and forest areas. I will try both out if possible but any advice would be greatly appreciated! c:
Medium : 453 reach , 594 stack
Large : 478 reach , 617 stack
My inseam: 33in
My arm length from top of arm to wrist : 26in
Not sure if this helps lol
Hi Tess,
Stack is the vertical distance from the center of the bottom bracket to the midpoint at the head tube. Reach is the horizontal distance from the center of the bottom bracket to the middle of the head tube.
The rule of the thumb is this: find a recommended frame for your size. For example, the medium is a recommended frame size for you. However, there is no perfect fit when it comes to our bodies. That is why bike fit is still important. For people with longer arms then you can make an adjustment in terms of the stem length or your saddle fore and aft etc.
All this info about frame size but not a word on wheel size.
Example: which is for a taller person, a 19″ frame with 27″ tires or a 20″ frame with 26″ tires.
To get the right size bike you need to consider both .
I feel you need to explain the relationship between the two
Hi Angryhippi,
Thanks for the feedback. We will look into this. However, if you look at all the bike sizes from different websites, the frame is always the standard.
Hey Dave, I’m 5’4″ 31 inch inseam. Everything steers me to a small frame but they just feel so small and compact. The bike I’ve looked at is the Santa Cruz Hightower. Suggestions
Hi Claire,
You fall on a small frame recommendation. There are other things to consider other than the recommended frame size and this is where bike fit comes into play. For example, you can always adjust the bike fit by getting a longer or shorter stem, the saddle fore & aft, stem height, and also handlebar sweep or angle. So, don’t worry if the frame seem so small. You won’t know if it is comfortable until you try it and get a proper bike fit. In fact a smaller frame (in general) gives you more control of the bike.
Doesn’t make sense. I’m 6’2 so should have a 21 inch mtb but my inseam is 33″ so I should have an 18″-19″ mtb.
I can never get the right size bike which is comfortable for riding
Hi Rick,
You are not the only one. The chart can provide you with the standard size for your height but that is not the end of it. You need to make adjustments in terms of saddle fore & aft, crank length, stem length etc. That is why a bike fit is recommended. I once bough a smaller frame that my recommended size but after making changes in the stem, saddle, handlebar etc, no issues felt.
26frame cycle wheel and 26wheel size
Then how it’s is medium or large I need make taller
Hi Rahul,
Do mean to make the bike fit your size? I assume you are taller than the recommended frame, but do correct me if I am wrong. You can make adjustments like increasing the saddle height, moving the saddle back, and increasing your stem length. However, getting a proper bike fit is more effective.
Thanks for a wonderful article. This is really helpful! I’m 5’5″ in height and cosidering purchasing an RB and MTB. Should I get both small size?
Hi Chris,
Just choose a frame that’s medium size-for both. Then consider getting a proper bike fit. Good luck! Do let me know what happens.
Hi Jeff – great article – but I’m still a little confused and stuck between size decision!
I’m 5′ 9 with a 31 inside leg and I think this means I should be looking for a L mountain bike, however the bike I’m looking at seems a little high from a standover perspective, it’s an On-one Scandal from here:
https://www.planetx.co.uk/i/q/CBOOSCGX/on-one-scandal-sram-gx-mountain-bike
Do you think the L will be fine or better with M? The M is 16.5″ and L is 18″.
Hi David,
A large frame is best suited for you. 18″ is perfect. Do make adjustments on the stem length and saddle fore & aft if you can.
I’m 5,7 w/ 30”” inseam. Can I ride a 13” trek navigator 3.0
Hi Tina,
5’7 belongs to the medium size under the road bike category. I am not sure what you mean about the 13″ but your frame sizes are 54-55 cm.
Hello, I already ordered Marin Bobcat Trail 3 XL frame size , im 6.13 tall 205lbs.. Do you think it´s gonna be good size for me?
This size chart make me feel good but im overthinking about that..
https://www.marinbikes.com/bikes/2021-bobcat-trail-3
Hi Jakub,
Yes that size can accommodate you because it still falls under your height. Make sure to have a bike fit for those little adjustments that will make your riding experience a comfortable one.
i have a trek fuel ex 8. large frame. my seat height is just over three inches higher than my handlebars. feels very awkward. all my weight feels like its on my arms. i have a lot of trouble with front tire washing out
Hi Tim,
Try to lower the seatpost and test the ride. You also need to adjust the saddle angle. Having a perfect horizontal saddle angle will prevent your body weight being pushed to your hands.