How To Choose The Right Size Mountain Bike | Frame Geometry Explained

Mountain bike frames come in all different shapes & sizes, but choosing the right size for you is crucial in ensuring a fun, safe and comfortable riding experience for years to come! Doddy runs you through some key geometry measurements to help you know how to find the right frame size so you get the perfect bike fit!

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[shadesofgrey]

There are thousands of videos out there explaining what measurement does what, but what people are actually asking is, what measurement they actually need. Like great, correct reach is awesome, but what is the correct reach? What do I need to measure to figure out what the correct reach is for me? All this video says on that topic is "go to a bike shop". Not helpful at all.

[davidjuhos]

Gotta say, the thumbnail on the video is on point. Very engaging, but not clickbaity. This is what I like to see!

[zoubtube]

I need to give a shout out to lee McCormack from lee likes bikes on this topic. He came up with a way to measure your "personal" reach, he calls is a RAD number. I've tested it on myself, and about a dozen people with resounding success. The theory behind it is solid. Every person has a max personal reach to where they can use their primary muscles groups for strength. once you pass this limit you 'll be left using your smaller muscle groups, which are significantly weaker. this works back to you mentioning equilateral triangle. your max strength and agility is within the max limits of the triangle

it very simple to do. I highly recommend trying it. It might feel odd at first but give it a bit and overall control and balance will improve significantly, especially on rough terrain and jumps . there is a YouTube video that explains the steps, and so far he has been right. Reach is pretty much all that matters with modern bikes and I have to agree with him, most people are riding modern bikes that are to Large for them. you really are better off sizing down if your in between sizes.

[conrod]

Just gone from a large trek remedy to an xl Nukeproof giga, and it is so so much better for me, way more room, and when climbing my knees and quads aren’t killing me, and the front end is properly weighted.

[chrisridesbicycles]

Doddy, could you dig a bit deeper into this topic and maybe do a video with a bikefitter? I have the feeling that the „modern“ geometry thing is overshooting at the moment and every brand wants to have the longest and slackest bike. If you have long legs this can be a pain because bikes are either too long or the seat tube is too short.

[snbsmtb]

Great video Doddy!! Learnt some stuff today!! Love these videos!!

[danielrichter]

Epic video and great timing, I was literally just thinking about this😂

[georgepeterson]

I unknowingly bought a small used bike and it wore me out very quickly on a moderate trail. Now that I have the correct sized new trail bike the same trails are incredibly easy for me. Frame size matters lol

[Andy-copn]

Love the Y bike. Back in the day we used bar ends to make up for the short cockpit

[Michael-bsyu]

A size bigger will help spread the wheels and just run smaller stem. Use to do this racing BMX. I fit a pro but ran XL and XXL frames with short stems. Gave me more room in front to move around. This was back then. Now I actually fit XL BMX frame. In-between in most cases @5'-7"

[billjohnson]

Did a fun check, got the geometry of my large Scott ransom and checked it with a range of other brands and found that i would be either a large or medium depending on manufacturer.

[richardjensen]

After choosing 27.5" 17 inch medium frames the last 3 times, I took a chance and did large 18.5 inches (5 foot 8 or 173 cm tall). Only two rides on it so far, but I'm already REALLY liking the larger frame. Wow. So much more room to move around on the seat. And unlike the smaller frames, I don't feel the need to constantly actuate the dropper post on smaller elevation changes. Just keep it at the same seat level, move a bit on the seat and keep pedaling. So nice to just cruise like that instead of trying to get the right seat height on a smaller frame. Don't really notice much of a handling difference, maybe a tad slower turn-in but the benefits of a larger frame really seem to outweigh any loss of handling sharpness.

[liamadamson]

im 6"1 with a 28" inseem and everyone told me to get a 20" frame, i had to have the seat slammed just to ride it and i found it very uncomfortable, now i ride an 18" 29er and im so much happier with it as it gives me room to actually adjust the seat

[amandan]

Thanks! The reach explanation helped me very much. That would explain why my height falls into a Medium frame, but I have long arms and my reach would fall into the large category.

[lee-annmurphy]

I'm 165 cm tall and bought a small orbea 29er full suss 420 reach and also purchased a medium nuke proof scout 27.5 also 420 reach love them both it's surprising how different they both feel

[Ridegucci]

Thanks, Doddy, I have been thinking about this recently I am currently riding an SC nomadv4 and wanting to try out an SC megatower to do everything bike vs building the new v5 Nomad for the park, shuttle days, and 5010 for everyday riding. My height is 165cm and I am in between the S and M which I think makes my Nomadv4 very hard to climb as it's too short I have tried to lengthen the stem watching from your previous GMBNtech videos and made the ridding characteristics of the nomadv4 changed. From the previous 29ers I have owned that you have pointed out that the rear wheel eats up your back side which made me switched from the 29er to the 27.5 especially ridding techy stuff like what we have here in New Zealand. Thank you for this video Bingaman. what your thoughts? megatower that does all bike or nomadv5 and 5010? await for your reply

[f.s]

I'm about to build a NS Eccentric Cromo 29. It's size large hardtail with good wheel clearense. Building it as mullet so a fatter back tyre can be used is a good idea or not?

[rhammitt]

Question his what measurements do you need to find out what reach you need. The RAD measurement doesn't work for everyone. I bought a bike based off my RAD and it ended up too small and I wish I had gone for the size up instead.

[mjbbell]

I need to test out a large frame when I have enough to upgrade from my medium 2017 Whyte T-130s

[KamenMinkov]

11:59 I remember when mullets were a thing with 26 at the front and 24 at the rear - like 15 years ago.