I have a long torso in relation to my legs so I wonder if this captures it better

 

Even if long enduro bikes had similar RAD, their long wheelbases would make techniques require more force to pull off. That's part of the benefit of the long wheelbase, to make the bike more numb to input forces, like a rock or other obstacle smashing into the wheel. When the bike feels calmer, you feel like you have room to go harder.

The bike is built to be optimized towards a certain kind of riding. Building around a # like RAD, HA, ETT, STA, or whatever has its own trade-offs. If I downsized because the RAD was too long, it'd probably compromise the seated position's comfort, perhaps leading to excess pressure on the hands and butt. Since the RAD is correct, I'd and the reach is familiar, I'd be left to blame something like the steep STA or maybe accuse modern geo as going the wrong direction since it makes choosing a bike with proper RAD in your size very hard.

 

I think one of the points Lenosky makes is the recent fascination with long and slack, enduro-influenced geometry has made it harder to find bikes that fit in a traditional, well-rounded sense. Too much enduro-specialization sacrifices all-around performance.

 

Not necessarily. Bikes have longer reach, but stems are shorter too. 35-50mm stems are the norm, compared to 80-90mm a decade ago. And even longer before that. This ~40mm difference is in the ballpark of the difference in reach.

RAD is an approximation, reach + stack to the handlebars paint a more accurate picture. For example, on one of my bikes my the bar was too high, not RAD too long. Shorter stem would have the opposite effect of lowering the stem (but they both would have the same RAD effect).

 

I think this is way to serious a bike related topic to be in the OC. I'm now going to have to go off and check all of these dimensions to see where my latest build sits. Although completely different geo to my hardtail, I sized the frame so that I could keep seat clamp to centre of bar and bb to centre of seat clamp the same as my hardtail without the use of an offset post. I have achieved that and yet the two bikes assume completely different seated feels.I'll come back with more detail later.

Other than that, all I can say is all of my bikes have always been RAD to the MAX

 

If I only ride downhill or jump then RAD is prob great but I don’t. Pedaling on bike with RAD fit sucks. My bike is RAD++.

 

I think the height based formulas aren't accurate enough. There was a video Lee was in where he showed how to measure RAD directly and I found this much more useful because it accounts for everything (height, arm length, inseam, etc). At 6'5" my calculated RAD is way smaller than my actual RAD. I was surprised to find that my gigantic XXL Santa Cruz is about 1" below my RAD. Also, his bar width calculation says my max bar width would be 860mm!

 

I suspected my bike was a bit long from how it felt at pump tracks and flat corners and stuff. So I did the on the bike check by paying super close attention to this part of the video of where the knuckles are supposed to be (behind the middle of the grips) and how to do your posture with the on the bike check, and confirmed that my knuckles were about 40 cm below the center of the grips:

I think the on the bike check is the best way to go to see if your bike setup is too long vs all the measurements and multipliers, as you can't mess anything up except your posture. I used barstools with some plastic beneath the pedals to prevent damage. Once you are convinced by the on the bike check, and want to move forward, I found that measuring my height really carefully in cm made a difference for the next step, because I had rounded up my height in inches and stuck with that number for a long time, even though it wasn't quite right.

For me, the multiplier formula for RAD is a few mm too large vs the on the bike check, but there is "rider and bike calculator" available on his site if you sign up for a free month that agreed with the on the bike check pretty closely, and helps you pick out a stem and handlebar if you can use the handlebars that people have measured setbacks for (some good ones for me there). I swapped to a 30mm stem and 15mm rise handlebars and the bike feels easier to corner and hop, and it felt fine on a steep loose trail. But, I had waited until my stock handlebars and stem were 3 years old, and I wanted to replace them anyways for safety, since they had hit the dirt many times.

As far as the recommendations for bars over 800mm in width for people a few inches over 6', he answers this question a lot, and says that bigger number is just a max for people, and usually people go a little bit below the max, like with RAD. I went with 800mm instead of the ~830mm recommendation, even though 820mm bars exist, because I couldn't find a 30mm stem that was rated for more than 800mm bars.

 

pages of this discussion

 

I've watched these videos and like everyone here got to thinking how does my current bike fit me? Well I did the ladder test and the RAD equations and my bike came up pretty much spot on. My bike felt like a great fit from the first day of building it. Now I think these equations are good for your average trail riding especially tech and tight switchback trails. Which are my typical trails, I find that for where I ride a wheelbase of less than 1200mm is the best. Now for fast flow trails I could see a longer wheelbase and reach being more advantageous.

 

In reading both threads I see a consistent misunderstanding of what RAD is and how to measure it. I bought the book "Dialed" and it definitely explains this in detail.

That said, the book includes recommended reach measurements that are outdated. Reach is relative to the seat tube angle and older bikes at 72*, for instance, have shorter reach than a 75* STA new bike with longer reach.

RAD is simply the distance between BB and the top-center line of the handlebars. Regardless of your bike design, it's supposed to be the same. RAAD, or the angle of your RAD, is adjustable considering whether you are a DH or XC rider, but RAD should be the same.

In studying the book I shortened my stem to a stubby 35mm AND threw some backsweep in to get down to the shorter RAD I needed on a bike with 505mm reach. It feels great--the idea is that your bike is more maneuverable and you have some slack in your arms to handle terrain and cornering better. Too stretched out and you can't control the bike adequately.

 

In reading both threads I see a consistent misunderstanding of what RAD is and how to measure it. I bought the book "Dialed" and it definitely explains this in detail.

That said, the book includes recommended reach measurements that are outdated. Reach is relative to the seat tube angle and older bikes at 72*, for instance, have shorter reach than a 75* STA new bike with longer reach.

RAD is simply the distance between BB and the top-center line of the handlebars. Regardless of your bike design, it's supposed to be the same. RAAD, or the angle of your RAD, is adjustable considering whether you are a DH or XC rider, but RAD should be the same.

In studying the book I shortened my stem to a stubby 35mm AND threw some backsweep in to get down to the shorter RAD I needed on a bike with 505mm reach. It feels great--the idea is that your bike is more maneuverable and you have some slack in your arms to handle terrain and cornering better. Too stretched out and you can't control the bike adequately.

Reach, as measured by all bicycle manufacturers, has absolutely no relation to the seat tube. All reach measurements are obtained by drawing a vertical line up from the center of the bottom bracket and a horizontal line back from the center of the top of the head tube. The horizontal distance from top center of the top tube to where it intersects with the vertical line drawn up from the bottom bracket is the reach. Just look at any frame geometry schematic on any website.

 

I think mtb "fit" is a scam. Bikes fit trails to a pretty large degree.

Crazy low, slack bikes pop up around the time that flow trails get huge. Low bb's rip on flow trails. "Back country" used to be kind of popular, and a 14" bb was great for crawling over huge rocks on an unestablished trail.

If OG nasty slow chunk trails get popular again, someone will "revolutionize" fit again and bikes will change. We'll all wonder how we ever rode LLS bikes.

 

I think mtb "fit" is a scam. Bikes fit trails to a pretty large degree.

Crazy low, slack bikes pop up around the time that flow trails get huge. Low bb's rip on flow trails. "Back country" used to be kind of popular, and a 14" bb was great for crawling over huge rocks on an unestablished trail.

If OG nasty slow chunk trails get popular again, someone will "revolutionize" fit again and bikes will change. We'll all wonder how we ever rode LLS bikes.

Have to laugh at the whole thing...

Frankly, my slack, high BB bike with a stack that doesn't require slumping over to grip the bar does me dandy! I hate the hell out of having to call AAA to get a bicycle that high centered on a speed bump in front of the corner package store...

 

43yo noob recently began jumping and such, all very tame small stuff. Working on manuals and wheelies. 6'3" on XL Hardtail that was rad+ by the recent joy of biking video approach. I went with a shorter stem, bars with more back sweep, and moved some of the spacers around. Ended up slightly rad- and I am enjoying the change. No issue feeling cramped in cockpit pedaling and am able to generate noticeably more torque. Will I fiddle with it some more, yeah that's part of the fun, but count me as a rad fan.

On related note, did anyone notice how high Lee kept his seat when working the technical climbs in the video this week? I realize his understanding and ability is 1000x mine but that's not my approach to those sorts of things. Get that seat out of the way I'm probably using 10x more energy while he's 10x more successful lol, but still, drop the dropper for more chi bud.

Joy of biking videos have been solid for me in my learning stages.

 

I like my enduro bikes with an ett of 600 and my trail and xc bikes at 640mm.

 

My RAD is about 80cm actually measuring myself. One bike is just about spot on...the other bike is about 1cm short. I measured my GF and she is about 78cm. The RAD on her bikes are both about 81cm.

The thing is that out of the four bikes in the garage...the one that has the longest reach...measured the shortest. All bikes have a 50mm stem. The Ripley V3 LS and Spesh Stumpjumper (411 and 413) both have fairly short reaches...but both have the longest RAD. The V1 Evil Following (feels like it fits me best) has a 419 reach and Banshee Spitfire V2 has a reach of 430. All bikes are mediums.

I'm also thinking about trimming my bar down from 760 to 740.

 

I'm going to have the unpopular opinion about reading what you someone says in a fit that works for everyone. it doesn't fit everyone. Everyone is built differently.

If you're interested in getting fitted, go pay a reputable fitter for mountain bikes and get fitted for your bike. This way they can SEE you and how you move. Not just plug in random numbers from a formula online and this is your fit.

The RAD concept fit is a one-size fits all, and does not take into account any mobility issues you may have, weird things that go on with your body, nor does it take into account a seated bike position. I know, because I've done this with Lee before (had several in-person sessions with him, including the whole step ladder thing), and it still ended up not benefiting me. Lee's got a good idea, but it doesn't match a lot of the newer geos, so he suggests sizing down. I ended too crunched up, which did nothing to help my spine or hips. Don't assume that this is one-size that fits you. He looks for specific movements on the bike, but he doesn't watch the way your spine and hips behave on the bike even when you do this in person. Nor does every person my height want to run 740mm bars and a 40mm stem, ugh.

Full disclosure: I like Lee, and I think he's a fantastic skills teacher. He taught me how to pump, and helps me refine other things (I have another clinic with him in a couple weeks). But I did tell him he's not allowed to ever talk bike fit with me, so we agree to disagree on his RAD principle.

 

I'm going to have the unpopular opinion about reading what you someone says in a fit that works for everyone. it doesn't fit everyone. Everyone is built differently.

Fitting a bike is very much like trying on shoes. The size charts, construction, style, value, and reviews might all seem right but you don't really know anything until you slip 'em on, lace 'em up, and take a couple steps.

 

I’m tired of thinking about bike measurements, so I’m just gonna go ride my bike and see how it goes.

 

I’ve really come to the conclusion that RAD just doesn’t work for me.
I have a degree in biomechanics, and am a sports/ortho physical therapist, so I can follow the logic of what Lee says, but neither of my bikes are even in that same zip code as my calculated RAD.
I’m 5’9”, my measurement with the marker in hand on the wall is IIRC 735mm. Both my FS and my hardtail have a RAD of something in the low 800s! Neither has a long reach- the HT is a 450 reach, the FS is a 445. I’m running 50 and 55mm stems with 780 bars. To get my bike fit down to the suggested RAD, I’d be in my 5’5” wife’s bike, or I’d be running a 32mm stem with flat bars, and I’d be slamming my knees into the dropper lever.

I’ve done the ladder-test and the bars are juuust short of being comfortably in hand, I’m also really comfortable on both my bikes, so I don’t sweat it.

 

I've really come to the conclusion that RAD just doesn't work for me.
I have a degree in biomechanics, and am a sports/ortho physical therapist, so I can follow the logic of what Lee says, but neither of my bikes are even in that same zip code as my calculated RAD.
I'm 5'9", my measurement with the marker in hand on the wall is IIRC 735mm. Both my FS and my hardtail have a RAD of something in the low 800s! Neither has a long reach- the HT is a 450 reach, the FS is a 445. I'm running 50 and 55mm stems with 780 bars. To get my bike fit down to the suggested RAD, I'd be in my 5'5" wife's bike, or I'd be running a 32mm stem with flat bars, and I'd be slamming my knees into the dropper lever.

I've done the ladder-test and the bars are juuust short of being comfortably in hand, I'm also really comfortable on both my bikes, so I don't sweat it.

Did you do the wall test with your legs straight? They didn't explain it in the video but once you get into your riding foot position, straighten your legs.

 

Interesting the timeliness of this topic. I bought a new mtb back in January, a 2020 SC Tallboy C V4 size large. I was able to take it for a brief test ride and found it fit very well. Shortly after that I start seeing this topic of RAD on Joy of Bikes and a few others. I'm somewhat OCD and this sent me into analysis mode. I found my new bike was bigger than my RAD. I only had a couple of rides on it and starting thinking my re-entry to mtb after some years away was already flawed. I'm pretty anal about my fit and tried a shorter stem (40mm vs 50mm) which made my bike very twitchy. I decided to ignore this RAD stuff and just ride and find my skills are coming back, albeit slowly. I had the opportunity to ride a bike that was my RAD size, I hated the fit, it felt very cramped. I am 5'11" and have 33.5" inseam and a very big wingspan.

Just like all the other formula driven bike fits it doesn't work for everyone. I'm sure some of you read Greg LeMond's book back in the 80's and set their seat height to inseam*0.883. I know I did until my knees told me otherwise.

 

I think the body measurements, aside from your height, are too easy to mess up. Is the pen level, are your hands the right distance apart, are you knees straight, are your shoulders packed? Etc etc. Just do the step ladder test with your bike if you feel like it is hard to pump, jump, turn, or your back hurts after a few hours riding. If you are mostly an XC, non technical rider, this stuff doesn’t apply as critically, same if you are a more passive rider, looking to sled down the hill.

 

I think the body measurements, aside from your height, are too easy to mess up. Is the pen level, are your hands the right distance apart, are you knees straight, are your shoulders packed? Etc etc. Just do the step ladder test with your bike if you feel like it is hard to pump, jump, turn, or your back hurts after a few hours riding. If you are mostly an XC, non technical rider, this stuff doesn't apply as critically, same if you are a more passive rider, looking to sled down the hill.

The RAD does not take into account seated pedaling. Enduro and XC both do it, and for me, that's where it kills me. My RAD is a lot smaller than where I'm comfortable uphill or seated pedaling.

It also doesn't work for me because it forces me into a much more cramped position that my spine seriously objects to, even on the pump track.

I wouldn't say DH riders are necessarily passive either-RAD is a fine that works for some folks, but it's not for everyone.

 

Seems to me that as bikes getting longer, RAD is more important if you are trying to do the things that require you to have leverage over the front end. If you are not able to generate a ton of torque on a BMX, that's fine only a small amount of torque is needed to pull a manual. Modern geometry enduro with 180mm travel bike, If you want to have more control over the front end, more ability to "PULL UP", manual, wheelie, drop off ledges with control at slower speeds. Having that leverage makes it require less energy to accomplish. If you're bombing smooth downhills holding on for dear life, that's different.

Also the "it doesn't feel right" argument is sometimes flawed imo. We get accustomed to a bike and then that feels right, change geometry, stem length, spacers, where the levers are... feel is impacted. Decide you like it for one reason or another it will feel right over time. Decide you don't like it for one reason or another and "it doesn't feel right".

Pick up something with some weight off the floor close to your feet. Now try to do it with it gradually further and further away from your feet. Leverage decreases as that distance increases plain and simple. If you have enough leverage to pop up tough climbs, manual without exerting everything you can, yank a J hop you are proud of, u good. Riding a bike giving you enjoyment, NICE!

 

Agree, feel means almost nothing, not buying the "RAD is too short for my spine and climbing." I've shortened my RAD from what thought it should be before to the measured distance of about 30mm closer to me, and the bike climbs great. Now I can corner more confidently and lift the bike more easily. With steeper seat tube angles (or virtual STA by sliding your rails forward), it's not necessary to weight the front end as much and you can climb in a position that handles better.

Lee rails about super-long reach these days, but I wish he'd also mention that reach used to be much too short. There's nothing good about a bike with a 90mm-120mm stem--something was wrong with bikes a few years back, and now they're much better fits.

 

Sure, you can have that conversation with my PT on how bad a cramped position is for my spine and hips. I also can't ride bikes with too steep of a SA either.. same problem. The RAD works if you're gonna ride out of the saddle the whole time, but that's not realistic for 95% of the people out there.

Lee has always been railing about super long reach for years. It's not just these days, but for a long time. Back when he created his fit, people were regularly riding on 60-80mm stems, so he created this fit system to compensate for that, and back then it made a lot of sense, and it worked fine for me up until I got my first long/low/slack HA/steep SA bike in 2017. His fit was also good before the steeper SA too. Now we're pretty much on 35-50mm stems for the most part, and most bikes have their designs compensate for that.

Lee and I have an agreement: I can take skills lessons with him, and I think he's really a great instructor. But he cannot at all discuss bike fit with me. We agree to disagree on fit, and I respect him for that.

 

Curiosity got the best of me. I bought his guide and will play around with it later. Though I suspect it's going to be tough with my build. I'm 5'11" with a 6'6" wingspan and I suspect no calculator out there is going to work with that.

 

Wow, that is a wingspan! Are your legs long as well? That would be an interesting fit.

 

I think the main issue is in how it's measured. The height guideline is way too general. You need to measure RAD more directly. The wall method seems like it should be pretty accurate. I'm not sure how people are ending up feeling so cramped or running their bars upside down. I'm on a 76° STA bike with the seat slid forward and still feel very comfortable running a bit RAD-. Now if I went by the height calculator it would be a totally different story.

 

Isn’t the internet great. How else people would have a chance to debate about a fit theory?

Watching the little kids with no upper body strength doing amazing on bikes that some might consider are too big for their size and weight almost half of their body weight pretty much convinced me that if the bike feels good then just ride it unless you get paid to ride then do what sponsors tell you.

Personally I can’t imagine to be able to do anything well if it doesn’t feel good.

 

Personally I can't imagine to be able to do anything well if it doesn't feel good.

There are plenty of road bikers that go against that mantra. Zero spacers for the proper look and 8 cm drop from saddle to bars.

 

The premise of RAD is based on getting the bike just short enough so you have better leverage to manual, row, pump, etc. If your riding style doesn’t use those things a lot, RAD isn’t going to benefit you as much. It does potentially sacrifice some stability by putting you on a shorter wheelbase.

 

I see it as a matter of specificity training.

The old-school MTB position, especially with XC-style bikes, mimicked roadie positions. It's a common custom for riders to transfer their fit from one bike to the other. This allowed mtbers to take advantage of road training and the comfort/fit associated with it.

The new school bikes changed things. Longer WB and steeper STA allows them to ride mountains better, both down and up. It's a different position that requires time to become more efficient at it, not too unlike how a TT or triathlon racer has to train in their own unique position to optimize their efficiency rather than train on a regular road bike. Their bikes offer an advantage that's worth the change.

These RAD guys enjoy BMX/pump-track riding and want to transfer it to MTB as much as possible. I suppose they're trying to appeal to riders who want to be "rad" too, getting these kind of skills. It's like they want to be reliant on these skills, rather than be reliant on modern bike geo. I understand the logic, that the skill can be transferred to a wide variety of bikes and are impressive to watch. Being overly reliant on modern geo makes you unwilling to ride lesser bikes.

These guys are like saying, "the closer the bike row movement is to a deadlift, the better." I argue that the long wheelbase makes the modern bikes difficult to use these techniques on, not the reach or whatever. 430mm reach with a 1250mm WB bike is a lot different than the same reach with a bike with 100mm shorter WB. Lee is 174cm (5' 8.5") and he's deciding between small and medium bikes. The difference between them is like 25mm reach and 25mm WB, so I bet they'll notice an improvement in kung-fu, but I worry about the fit of the small. Banging knees against the shift/dropper levers when pedaling doesn't sound like a fun time. I argue that they'd like a short WB with modern reach better, like a Forbidden Druid, Canfield Tilt, GG Trail Pistol, etc.

IMO, forcing the BMX handling feel (short WB) results in bikes like the Kona Honzo (OG, not ESD) and Canyon Stoic. They're like big BMX/DJ bikes or maybe like a slopestyle bike. The '21 Spec Status is probably their kind of bike (they might even like the old-school pedaling characteristic). It's akin to how forcing road bike fit resulted in the old XC bikes. What they refer to new/modern bikes are those that are more optimized for mountain-like terrain, which has been developed due to enduro racing. No surprise that they don't need all the features that make mountainous riding easier, based on where they show their riding footage.

 

These guys are like saying, "the closer it is to a deadlift, the better." I argue that the long wheelbase makes the modern bikes difficult to use these techniques on, not the reach or whatever. 430mm reach with a 1250mm WB bike is a lot different than the same reach with a bike with 100mm shorter WB. Lee is 174cm (5' 8.5") and he's deciding between small and medium bikes. I worry about the fit of the small... banging knees against the levers when pedaling doesn't sound like a fun time.

I wonder what size Stumpjumper he rides. I can't tell of its a small or medium. He's got a tiny slammed stem on there. From some of the videos I've seen...I can see why he likes that deadlift position. Alex from JOB is building up a small and medium bike to see which one he prefers.

I watched a few of his videos trying to see how he came up with his RAD fit. From a few of the videos...I can see why he likes that "deadlift" position.

I put a 40mm stem on my GF's bike ( Medium Ibis Ripley V3 LS)...from a 50mm. I don't know if its in her head...but she's telling me that she likes the shorter stem more.