Dynamic Mountain Bike Fit

On this page I share knowledge from working with thousands of mountain bike riders over the years. While most riders love the fits they get with the RideLogic system, everyone is different, and your ideal setup might differ. That’s totally cool. Once you find a setup you love, I encourage you to use the RideLogic measurements so you can re-create that awesomeness with your next bike. Please keep reading below.

Dialed Book

$24.99 ebook
$34.99 print book

This book explains the whole RideLogic dynamic MTB fit philosophy, gives you tons of helpful info and includes access to the online calculators. Model your bike’s fit before you spend thousands of dollars!

Membership Site


Get full access to the entire RideLogic dynamic MTB fit universe, including the online rider/bike calculators. Once your bike is dialed, practice the skills and training programs that make you a truly great rider!

Enjoy a free month with the code FREETRIAL.



I’ll help you dial in your current bike or choose and dial in your next bike. Do this before you spend all that money. This is especially useful if you think you’re between sizes, or if you have unusual proportions. 

Hi all!

Mountain biking is currently in an amazing, fun revolution. Bikes are evolving. Trails are evolving. And riding styles are evolving. All for the better. What a great time to be in this sport.

What hasn’t changed (until now) is how we fit bikes to riders. Most people are either using old-fashioned static road/XC fitting techniques, or they’re following industry trends, or they’re guessing.

When your mountain bike fits your body and riding style perfectly, riding is incredibly comfortable and fun. When your bike doesn’t fit you properly, riding is still fun! (Because MTB is rad.) But it’s less comfortable, and you struggle to do the things you want to do.

In my skill work with many thousands of riders, I see that most riders are on bikes that are the wrong size and/or are set up improperly. This bums me out! I know how hard it is to ride a bad setup, and I know how amazing it is to ride a dialed setup.

So I’m doing what I can to help.

– Lee

Static sitting fit vs. dynamic standing fit

In a traditional bike fit, you sit on a trainer in a studio and they make measurements. There might be lasers and computers! But the fundamental logic is as old as bikes: How to best position you for seated pedaling. They set your seat position relative to the pedals, then they position the bars relative to the seat. The goal is a neutral, comfortable-enough position for making power in the saddle.

If seated pedaling is what’s most important to you, this is the way to go.

A RideLogic dynamic MTB fit focuses on out-of-the saddle handing. We position your bars relative to your feet. This is critical for technical/expressive riding. Independently, we position the saddle relative to your feet. The saddle-to-bar relationship is incidental.

If out-of-the-saddle handling is important to you, this is the way to go. We’re talking about manualing, hopping, pumping, dropping, jumping, cornering, descending and all-around shredding. If you just want to feel safer, this is also your best bet.

Here’s why so many people are on ill-fitting bikes

A few things are happening out there. Which of these apply to you?

Most of us just don’t know any better. The majority of riders aren’t in touch with their bodies or their bikes, and they simply don’t know how their bike setup is affecting them. No value judgement here, just an observation.

Bike fits are done in the saddle, but most of the fun happens out of the saddle. The traditional bike-fit philosophy is out of line with how people ride mountain bikes.

Seat tubes have gotten steeper. The industry has done a wonderful job convincing us steeper seat tubes are better for pedaling (and they are on very steep seated climbs), but the real reason seat tubes got steeper is packaging. In order to fit big wheels, long travel suspension and short chain stays, bike designers steepened the seat tubes to make room. This makes the seated cockpit shorter, which led to this change:

Frame reaches have gotten way longer over the past few years. Examples: A 2017 large Specialized Stumpjumper has the same reach as a 2021 small. A 2017 medium Transition Patrol has the same reach as a 2021 small. In some ways the extra length is a good thing, but once it’s too long for your body, your riding experience suffers. Keep in mind: People have not gotten taller.

The bike makers’s sizing charts have not been updated to reflect the new frame reaches. Many of us — most of us — would be smart to go down a size. At 5’8″ I’ve ridden mediums since 1988, but now, on many bikes, I’m a small. On a lot of the new bikes, all of the sizes are too long! If you’re a short person, and especially a smaller woman, it’s getting very hard to find bikes that fit properly.

Handlebars have gotten too wide. Back in the day, we cut our bars to 20 inches (510mm). That was too narrow! Nowadays, bars tend to be too wide — especially for small- and average-sized riders. This affects your ability to control your bike, and it causes excess wear and tear on your shoulders.

And let’s not forget:

Many dudes over-estimate their height. Of course this doesn’t apply to you, but many men — other men — say they’re taller than they actually are. I’m an honest 5’8″. Most guys my height report 5’10”. When you over-report your height and ride a new bike, the bike can be WAAAAY too long for you.

But there’s good news:

If you’re a tall person, be stoked. Bikes finally fit!

Richie Rude, a world class MTB enduro racer, is 182cm tall (almost 6 feet) and chooses to race a medium Yeti SB150.

The Yeti sizing chart puts him on a large.

Geometry that properly fits people certainly makes them faster and more comfortable but isn’t always immediately appreciated by riders because they’re used to something different. That’s human nature. It takes time to acclimate to anything new.”

– Dave Weagle, the “DW” in DW-link, one of the most respected MTB designers in the world

We are making our bikes longer because that’s what the market demands, but the people who work here, and the people we size at demos, and our elite racers, are going down a size. If a top pro can’t control a longer bike, a normal rider can’t.

– Chris Cocalis, founder of Pivot Cycles, in a Bike Rumor podcast

How do you know your bike fits poorly?

I help lots of riders with bike fit and riding skills. These days, 80-90 percent of riders are on bikes that are too big. So, statistically speaking, your bike is probably too big.

A fast and easy way to check is the RideLogic on-bike test. You can see it in this sweet video:

How does it feel when your bike setup is too long for you?

Weak technical climbing. Whenever you’re out of the saddle trying to make big power up a thing, your arms are bent. This compromises the power chain between your hands and feet, and you can’t generate your full power. A classic symptom: You’re attacking a technical uphill section, and you hunch down and go for it … and your legs are pedaling fine, but then it gets steep and they just kind of stop pedaling. The issue isn’t a lack of strength; it’s the broken chain. Your brain doesn’t want you to rip your arms off, so it cuts the signals to your legs.

You have trouble cornering. Berms don’t count because medicine balls can turn in berms. I’m talking abut real, proper flat turns. The bike feels unwieldy, and your front tire often washes out.

You struggle with all the tricks. Manuals, hops, jumps … they’re all harder than they should be. Part of that might be technique, but bike setup has a huge impact.

Shoulder pain. When your grips are too far away from you, that puts extra stress on your shoulders. The same can be said for too-wide bars, which is also very common.

Heavy, hurting hands. Few riders have great mobility. Even fewer can reach the bars on a too-long bike while staying balanced on their feet. This shifts their weight forward, where they get a royal beat-down.

You and the bike just don’t vibe together. It can be hard to express exactly what’s going on, but the bike just doesn’t feel right. You spent a lot of money on it, and you’re committed, so you love it! But, in private, you’ll admit you felt better on your old bike.

What are the components of a great dynamic MTB fit?

When all of these factors fit, your bike feels incredible.

Riding style. If you’re just hanging on and letting the bike do the work, fit doesn’t much matter; get the longest bike you can. However, the more you ride dynamically — manualing, hopping, jumping, dropping, technical climbing, gnarly descending, corner carving — the more you’ll value a dynamic MTB fit.

What if you just want to ride without fear? A bike that’s too big is terrifying! A properly fit bike makes everything way easier, safer and less scary.

Frame size, most notably frame reach. When you look at the sizing charts, ignore the letters (S, M, L) or numbers (1, 2, 3) and focus on “reach.” That’s the only sizing number you need to worry about. Once you know your ideal frame reach, picking a bike is easy and stress free.

RAD. Rider Area Distance is the distance from your bike’s bottom bracket to its grips. This forms a lever, and you use this lever to control your bike. When your bike RAD fits your body, the bike feels great. When it doesn’t, well … your bike doesn’t feel quite as great. Your bike’s RAD is a function of the frame reach, frame stack, stem height, stem length, bar rise, bar setback (how far your hands are behind the stem clamp) and spacers under your stem.

RAD angle (aka RAAD). This is the angle of your RAD line relative to level. Put simply, a higher angle gives you a taller, shorter cockpit that feels great on technical descents. A lower angle gives you a lower, longer cockpit that feels good on smooth climbs. Most of the time, we shoot for a moderate angle.

Handlebar width. The correct bar width gives you awesome range of motion and strength, plus it’s good for your shoulders.

Bar, stem and spacers. It’s all about creating the optimal RAD and RAD angle for you. We start with the frame reach and stack, then we fine-tune with your bar rise, bar setback, stem height, stem length and spacers under the stem.

Crank length. The more proportional your cranks are to your leg length, the better. Unfortunately, most bikes come with the same crank lengths. That’s like everyone wearing the same size shoe.

Saddle position. This is key for powerful, efficient and comfortable pedaling.

We are here to help!

Picking the perfect size bike, and dialing it in for your body and riding style, is trickier than ever. Here are some resources to help you out:

Dialed Book

$24.99 ebook
$34.99 print book

This book explains the whole RideLogic dynamic MTB fit philosophy, gives you tons of helpful info and includes access to the online calculators. Model your bike’s fit before you spend thousands of dollars!

Membership Site


Get full access to the entire RideLogic dynamic MTB fit universe, including the online rider/bike calculators. Once your bike is dialed, practice the skills and training programs that make you a truly great rider!

Enjoy a free month with the code FREETRIAL.



I’ll help you dial in your current bike or choose and dial in your next bike. Do this before you spend all that money. This is especially useful if you think you’re between sizes, or if you have unusual proportions. 

Also check out our RideLogic.bike site:

Dial In Your Bike – Basic. $10 one-time fee. This online course gives you just the basics. It’s a great place to start if you have average proportions.

Dial In Your Bike – Pro. $50 one-time fee. This online course gives you the complete RideLogic dynamic MTB setup, including access to the online calculators. Essential if your proportions are not average.

31 replies
    • Lee says:

      Hi Brett,

      I’m not ready to make a pronouncement, but I find drop-bar bikes ride great when the RAD fits in the drops.

      My Specialized AWOL fits like that, and it rips.

      • Tj says:

        I never thought of that, but it sounds sensible.
        I am going to go out and check my gravel bike!

        In general, on mtb’s I find RAD-plus gives a comfortable, opened-up torso and arm position. (Depending on saddle position).

        Hoods (cruiser position on drop-bar bikes) are always going to have a much bigger RAD than the drops, so if your drops are set at RAD, for shredding, your hoods will be at RAD plus, great for cruising, and you are ready for some great drop bar rides.
        Also, your bar tops will be close to RAD again (higher than drops, but closer), but with much steeper RAAD angle. No wonder that feels good for powerful climbing!

  1. Timothy says:

    Hello, Lee:

    Just watched (3x) the sweep video you made with Alex. Quick question about the SQ Labs bars. Why not the 311 v2.0 bar? Have you ridden with it yet? I like the idea that it has the forward sweep at the center so the reach stays somewhat constant with a “normal” bar, or my current bar designed by Torquemada.

    Background, I just got my first “real” mtb. I had a slight delay because I changed the size of the bike down to an L based on your RAD calculations. Only two rides so far, but I am so glad I did not go with an XL. The factory bar has 6° backsweep and my hands went numb and tingly a few times during the hour-long rides. I’m your age, and have had surgery in both shoulders as well.

    Let me know if you’d rather I post this on the YouTube video page, but I wanted to specifically direct it to you, not Alex.

    Thanks for all you do, your videos and riding concepts have changed the way I ride!

    • gato ryak says:

      “Why not the 311 v2.0 bar?” For me, two reasons: 1) length = 740 mm; 2)From SQlab product description – “The handlebar may not be used at bikeparks and for downhill-bikes.”

      On the other hand, 30X: 1) length = 780 mm; 2) 30X is rated for gravity-riding.

  2. Mike Hammer says:

    Hey Lee! I love the videos you do with Alex. I’ve been hooked since the start. Ever since the “rad” videos it’s been in the back of my head. I just watched a video by Better Mountain Rides where he discusses how your system helped him and he mentioned the book Dialed. So I came here to get it.
    Last year I got a 2019 Giant Trance 2. I’m 5’10” and it’s a medium. I’ve tried so long and struggled with manuals and bunny hops. I’m sure it’s bad technique but bad size didn’t really occur to me until the other day. I think I’m of odd proportions. Standing neutral, I can’t reach the bars too well. I’m always riding leaned far forward..my hands always go numb. I’m hoping this book gives me the insight I’m looking for. My rad number tells me the bike is too big. It was the first NICE bike I’ve ever owned. I’ll probably never have another $3100 to get another.. so I’m wondering if I got bars with a bigger rise, could I turn them in to get closer to where I want to be? I’m going to check out the book. If it truly is helpful, like I think it’ll be, I’m going to bring it to the bikeshop and let the owner read it.
    And also Lee, if you’re ever out east doing a bike event or class, I’d love to attend. I’m from Pennsylvania near Valley Forge National Park. I don’t know if you ever take the show on the road but I’m just throwing that out there?. God bless brother. Keep doing what you do.??

  3. Erik N says:

    I’m getting tired of crashing – I want a bike that fits. So I’m going to need to learn some RAD stuff. But I’m a little confused. Does the DIALED book cover everything that’s in the “Dial in your Bike – Pro” course, just in written form? Or does one cover more than the other?

  4. Terry Rolan says:

    I am a bit confused. In your book “Dialed” it says to find RAD, multiply height in in centimeters by 4.47 (page 15). In the video, it says height in cm by 2.5 (9min 37 sec). Which is it?

      • Dakhil says:

        Indeed. What I’ve done is calculated optimal reach using height in cm x 2.5, then used that figure along with the optimal RAD to determine the optimal stack of a given bike. Basically, knowing your ideal RAD and Reach numbers, you can use the Pythagorean Theorem to determine the stack needed on a bike with the proper reach number in order to yield your ideal RAD number.

        I admittedly have not tried this yet, but the video and tips immediately gave me peace of mind that I have been correctly sizing down for the past few years, even when bike shops urged me to go with their manufacturer size charts. Where I am at now is coming to understand that since I use my bike in both standing and seated mode, it makes perfect sense that I struggled to make my previous bike fit well.

        My previous bike was within my ideal reach range, but had what I felt was too long of an effective top tube length, purely a product of the seat tube angle and head tube angle. Had I realized that both reach and ETT mattered for my riding, I would not have purchased that bike before looking for others with similar reach but a shorter ETT. In the end, I bought SQlab 30X bars, shortened the stem by 10 mm, and played with riser bar and spacers to get a better-feeling cockpit.

        Having begun demoing new bikes, I’ve already found that my optimal reach (455 mm) matched with an ETT around 620 mm takes care of both seated and standing riding. It’ll be much easier to yield my optimal RAD by having the stack dialed in with riser bars and spacers, and using the SQLabs bars that bring the grips right in line with the stem. In the end, it may not be perfect, but the way I’ve felt riding larger bikes over the years seems to fall in line with what Lee has been trying to educate us about, and I am going to try my best to dial my fit in solidly when choosing a bike. It’ll take some actual riding to be sure I went the right way, long-term, but I am confident it will work out or be well worth the experiment!

  5. Nick says:

    Hi, Lee!
    Thank you very much for the book ‘Dialed’, it is very helpful.
    I have a question though. Is RAD and RAAD measurements are performed with sagged bike or not? I’ve found this moment crucial for hardtails.
    Thank you!

    • leelikesbikes says:

      RAD is unaffected by sag.

      For dual suspension bikes I model the RAAD unsagged; the difference at sag is minor.

      For hardtails, determine how many degrees the fork will sag (about one degree per 20mm of sag). Say your fork will sag 40mm and you want a sagged RAAD of 58 degrees. In the calculator, model the bike unsagged at 60 degrees.

  6. Zac says:

    Wouldn’t it be possible to take your personal RAD at home, where you mark the wall with a pencil with hands down straight, and then compare that to the RAD geometry of a frame? Which would be middle of BB to top of headtube. I’m thinking this as many bikes are not in stock right now and it would be easy to rule out a whole bunch just by looking a frame RAD compared to my personal RAD.

    This could be more accurate than multiplying height by 2.5 and should be easy to figure out since most manufactures give stack and reach numbers. All we would need calculate is the third side of the triangle. The formula would change as bars are higher than top of headtube, but maybe something like look for a frame RAD that is 2-3 inches less than your personal RAD?

    Could this be a RAD’er way to do it?

    • leelikesbikes says:


      Some XC riders prefer a lower RAAD (aka RAD angle) than, say, enduro riders, but the logic is all the same.

      I for one run the exact same foot-to-hand relationship on every bike I ride, including XC. This way I only have to master one set of muscle memory.

  7. Bernie Negus says:

    Hi Lee
    I have bought many copies of ‘Mastering mtb skills’ with Brian Lopes, and your book ‘Dialed’.
    I have photographed myself in the ‘attack position with all weight on feet’ on several bikes.
    On bikes closer to my ideal RAD I have noticed that my chin is over the headset, and those with a longer RAD that my chin is several centimetres behind the head set.
    Is that a consistent finding with correct RAD?
    Or can using attack position be misleading?
    What is the ideal place for chin?
    Once correct RAD is found can you get ‘attack position’ fine tuned by adjusting stem and bars to place your chin in an ideal spot?
    Over stem? Over headset? Behind headset? Elsewhere? Irrelevant?

    • leelikesbikes says:

      Hi Bernie,

      Do not worry about where your chin is relative to a part of your bike.

      1) Never focus on that while riding.

      2) That relationship changes all the time.

      If you get the RAD and RAD angle (RAAD) you want, all will be perfect.

      Don’t use attack position for anything if you can help it. I’ve learned a lot since I used that term in the 2004 book; nowadays we’re all about solid bike fit, hinging and dynamic movement.

      I hope that helps!

  8. Ben Jenson says:

    Hi Lee. Loved your dialed book. I was looking at getting a new bike, and I found a really good deal on a Medium Sized. The bike I am looking at is a 2018 Intense Sniper XC. It has a wheelbase of 1152, Top tube of 609, and a 444 Reach. (All in mm.) I am 6’2″ so was wondering if this bike would be too small for me. What things could I do to make it bigger? (Longer stem, etc.)


  9. Jeff Jones says:

    Can you believe my naivete? I posted this question when I still thought Lee knew more than every pro XC team in the business. You can follow and see that this idiot belief didn’t last long. I know snake oil. This guy sellin’ yaw’l snake oil.

  10. Greg Biggers says:

    I am convinced of the RAD sizing system. Turns out, I’ve been riding bikes that are too large for me all my life!

    Lee, how do we take a RAD measurement and use it when looking at bike geometry charts? Do you have a cheat for how to estimate the RAD from a geo chart?

    My RAD is about 725mm, and I think many size small frames are probably still too big for me.

    Help! How do I use this info when shopping from home?

    • Greg Biggers says:

      Ok, I am trying geo chart reach and stack as approximations for the RAD triangle. Are there even any full-sus bikes that fit a RAD of 725? I know I’m not large, but 5′ 4″ is not tiny!

  11. Chris says:

    The thing that confuses me about measuring RAD is arm length. The shorter your arms, the longer your RAD measurement on the wall measuring system. But I would think that if you have long arms, you are going to need a longer reach (i.e. more RAD). Thoughts?

    • Greg Biggers says:

      Chris, the thing is— RAD is about the relationship of your hand position and the bottom bracket (not the seat). I think Lee’s RAD system has nearly nothing to do with your seated reach.

      I’m still trying to figure out how much (if any) to skew my preferred RAD measurement based on seated pedaling, which I still do quite a bit.


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