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
Mountain Bike Reviews
- NEW! Best Electric Mountain Bikes
- Best Cheap MTBs
- Top 11 Best Full Suspension Mountain Bikes
- Best Mountain Bikes Under $500
- Under $1,000
- Under $2000
- Best MTBs
Twitter
Facebook
Google+
LinkedIn
Hi Jef, I am Bryant 5’3 in height and I’m planning to buy a MERIDA 29ers MTB small frame. Is this the right size for me. Thank You
Hi Bryant,
There is really no issue with wheel sizes. Only frame sizes. So yes a small frame is suited for you. Do get a bike fit too so you can make changes as to stem length, seat post height, saddle fore and aft etc.
Say I’m buying a Trek Marlin 7 for someone and they’re 5’10”, will the size L be an alright fit?
Hi Lilian,
That is absolutely correct!
Hello Jeff,
Seeking a bike for my wife 5’7”
Probably a hybrid bike. Would a medium frame work for her height?
Thanks for answering.
Taj
Hi Taj,
Yes that is a perfect frame size for her.
Hi Jeff. I’m 5’10” -33inseam.What Giant Talon size will be good for me M orL 29 or 27,5 wheel size.
Hi Waldemar,
A frame size around 17″ / 18″ under the large category is good for you. As for the wheel sizes, they have advantages and disadvantages. Bigger wheel size means less nimble, but good for rock gardens. They also carry a lot of mass. Smaller means easy to control. But it is really up to you and your preferred riding style.
Hello jeff. im 5’10 in height and I’m looking for a 29er frame what size should i get?
Hi Neil,
You should get a frame size around 17″ / 18″ and it’s under the large category.
Hi, Planning to buy Java full suspension MTB. Im 5’9″ (175-176cm), Inside crouch length is 30inch, hip to foot is 40inch.
Should I go for 18 Large 29er? or 17 27.5tyre?
Hope to hearing from you brother.
Hi Gem,
Your height overlaps between medium and large. Your sweet spot is actually 17” with 27.5.
Hi Jeff,
I’m planning to buy a trek marlin 7 but I’m not sure what frame size I should get. Some say I should get medium ( 17.5″) or medium large ( 18.5″ ). I’m 5’8 with an inseam of 33″. Which size should I buy?
Hi Joseph,
You still fall under the Medium category(16” / 17″). If you look at the old school measurement your inseam should fall under the XL category(18.5) hence the confusing results. I’d say you base it on the former and just make seat adjustments like seat height as well as the fore & aft.
Hello jeff. Im 5’10 in height and using a 17″ or medium 29er mountainbike and it feels like that all my weight is leaning infront of the bike. It feels uncomfortable all the time and hurts my arms and lower back. Should i switch to large 19″ frame? Thanks and rs.
Hi Hernan,
First let me address the weight going to the front of the bike. You can resolve this by adjusting the saddle tilt. A saddle nose that’s tilted down will push all your body weight to the front resulting in pain. Another issue is the bike size. You fall under the 17″ / 18″ large category. So yes that. An also contribute to the discomfort. 19” is too big for you.
Hi Jeff. im 5’5″ and my current xc bike in size medium trek marlin 7. im planning to buy Nukeproof reactor 27.5. Based from trek, I’m medium but in Nukeproof site I’m small. Can you help me decide what size should i buy?
thank you
Hi Byron,
With your height they can overlap. Your sweet spot is a size 16” frame.
Hi Jeff! Great article! Need your advice please. I’m 5’6 and I believe my MTB frame should be a medium size but I’m checking out Merida bikes online and it appears I should get a small according to their charts. Need your advice please, thank you!
Hi Vince,
Glad to be of help. Each bike site has its own category and sometimes they overlap. However, do check the frame measurement. As long as you don’t beyond the 16” / 17″ frame sizes then you are ok.