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always licking the glass
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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. :p 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.
 

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I'd say you have relatively long legs too. What are you riding now?
I'm riding a Large Megatower. So far, I really have no complaints and haven't gotten to messing with cockpit other than rotating the bars and moving the levers etc. But I also kinda wonder "what if?" and like to geek out on stuff sometimes. I'm treating it as an experiment that may or may not pencil out in performance, but I'll better understand my interaction with the bike.
 

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always licking the glass
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Yeah, there are too many variables to make one formula work every time, and this one isn’t focussed on seated pedaling.

I think the step ladder test is a good starting point for people who don’t feel quite right on their bike, since a professional fit might not work out either, and can be expensive, but perhaps better informed.

The sled comment is not aimed at DH riders, who can be very active and mobile on their bikes, but was more of a lazy way to say, sizing down won’t work for people who feel really tied to the longest wheelbase they can work. Personally, I haven’t sized down on my modern bike, just tweaked my reach and stack down a bit, and widened my handlebars at the same time, which can counteract the steering effect if simultaneously going to a shorter stem.
I would agree not all pro fits are equal. There are some really crappy fitters out there too, which is why you have to find a reputable one in your area and if you can afford it. That's the hard part right? So yeah, then RAD does make a decent starting point.

The problem is people don't take RAD as a guideline--which is what they should do. Because because everyone references it, they think it's the Word, and never question.

There are other people who are other outliers: based on this formula, how would someone who's under 5' be able to fit? You'd want them on a kid's bike? What about the super tall people out there who are 6'4" and higher? And other folks with mobility issues...
 

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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.
 

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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.
 

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I've never seen a rad kid with a RAD+ fit. The wheel size and weight might be proportionally larger, but their bikes are generally better fit than ours.

This stuff is hardly conjecture, and Lee has good reasons for saying that RAD- is fine, but RAD+ is dangerous.

I think you're trying to muddy the waters but you're just incorrect.


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.
 

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always licking the glass
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View attachment 1929197

I've never seen a rad kid with a RAD+ fit. The wheel size and weight might be proportionally larger, but their bikes are generally better fit than ours.

This stuff is hardly conjecture, and Lee has good reasons for saying that RAD- is fine, but RAD+ is dangerous.

I think you're trying to muddy the waters but you're just incorrect.
Are you saying strictly for children or adults or both?

I ride RAD+, assuming this means greater than your RAD number. Doesn’t appear to be dangerous.
 

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View attachment 1929197

I've never seen a rad kid with a RAD+ fit. The wheel size and weight might be proportionally larger, but their bikes are generally better fit than ours.

This stuff is hardly conjecture, and Lee has good reasons for saying that RAD- is fine, but RAD+ is dangerous.

I think you're trying to muddy the waters but you're just incorrect.
A typical BMX bike has a head tube angle around 74 to 76°, does Lee's RAD formula work in that realm? Most mountain bikes never had head tube angles steeper than 71° typically.
Kids tend to ride what they have, I know I did. Back the BMX craze of the mid 70's I wanted a BMX bike my parents said you already have a bike. I did what most kids did, scavenge and save and made my banana seat Huffy into a BMXer. I could wheelie for miles.
 

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A typical BMX bike has a head tube angle around 74 to 76°, does Lee's RAD formula work in that realm? Most mountain bikes never had head tube angles steeper than 71° typically.
You definitely want your bmx to fit smaller than your trail bike. BMX is the extreme end of low stability and high maneuverability. I'm 6'5" and came from BMX, when I was shopping for my first mtb I thought a medium with 430mm reach felt fine. The shop had to talk me into an XL. Lee is a great mtb coach but I wouldn't trust him for bmx sizing.

I will say with those steep HTA's and tall bars, BMX bikes aren't as far off in fit as the wheelbase would suggest.
 

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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.
When it comes to road bike fits...some fit for aero and output...some fit for comfort. If you're racing crits...you don't want that upright position. You're sacrificing power by sitting bolt upright.

The thing with the human body is that it can adapt...even to an extremely poor fit. I've done enough social rides too see a lot of poor fits. Friend of mine was one of them. He kept saying that it feels "comfortable"...it was comfortable until it injured his knees. I've also seen mountain bikers with the saddle pushed so far forward that their rear is hanging off the back of the saddle as they bounce along spinning at 120rpm. Some people don't know they have a bad fit until someone tells them they do...that or wait for an injury.

One of the early sales I did when I worked in a bike shop was a 56cm road bike to a 5'3" person. I asked if they are sure that they want that size. I also asked the manger if I should sell them that bike. He said I asked all the right questions and if that person insisted that they wanted that size...there is no problem selling them what they want. That person put the money down and bought the bike. Never seen them again. I'm 5'8"...my road bike is a 54cm...some other manufacturers I would ride a 52cm. Sizing a road bike isn't as ambiguous as a mountain bike.
 

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When it comes to road bike fits...some fit for aero and output...some fit for comfort. If you're racing crits...you don't want that upright position. You're sacrificing power by sitting bolt upright.

The thing with the human body is that it can adapt...even to an extremely poor fit. I've done enough social rides too see a lot of poor fits. Friend of mine was one of them. He kept saying that it feels "comfortable"...it was comfortable until it injured his knees. I've also seen mountain bikers with the saddle pushed so far forward that their rear is hanging off the back of the saddle as they bounce along spinning at 120rpm. Some people don't know they have a bad fit until someone tells them they do...that or wait for an injury.

One of the early sales I did when I worked in a bike shop was a 56cm road bike to a 5'3" person. I asked if they are sure that they want that size. I also asked the manger if I should sell them that bike. He said I asked all the right questions and if that person insisted that they wanted that size...there is no problem selling them what they want. That person put the money down and bought the bike. Never seen them again. I'm 5'8"...my road bike is a 54cm...some other manufacturers I would ride a 52cm. Sizing a road bike isn't as ambiguous as a mountain bike.
My comment about roadies was sarcastic humor. I realize bikes are fit particular ways for particular purposes. I road raced back in the early 80's, just club level stuff but bike fit became somewhat of an obsession. I bought Greg Lemond's book back in 87 and used the fit formulas he used from Cyrille Guimard. I forced myself to try to use that method for a while, what I realized is I didn't want to ride as much because the bike was no longer comfortable to ride.

A friend of mine is a road mileage junkie sometimes putting in 200+ miles on a weekend. His bike fit gave him thousands of pain free miles. He wanted to get to the next level and went to a "pro" fitter. After that Charlie wound up with neck and and hand pain that took him off the bike for a few months. Each bike fitter applies a theory but until they can step inside someones body they can't feel what is going on. I'm 55 so I am speaking from a little bit of life experience.
 

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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.
 

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My comment about roadies was sarcastic humor. I realize bikes are fit particular ways for particular purposes. I road raced back in the early 80's, just club level stuff but bike fit became somewhat of an obsession. I bought Greg Lemond's book back in 87 and used the fit formulas he used from Cyrille Guimard. I forced myself to try to use that method for a while, what I realized is I didn't want to ride as much because the bike was no longer comfortable to ride.

A friend of mine is a road mileage junkie sometimes putting in 200+ miles on a weekend. His bike fit gave him thousands of pain free miles. He wanted to get to the next level and went to a "pro" fitter. After that Charlie wound up with neck and and hand pain that took him off the bike for a few months. Each bike fitter applies a theory but until they can step inside someones body they can't feel what is going on. I'm 55 so I am speaking from a little bit of life experience.
I didn't go get a fit on my road bike till I started feeling pain. I went full roadie and was doing about 80 to 100 miles a week. It was in my left lower back and the pain would shoot down my left leg. The ride the weekend after the fit was like a revelation. I was riding and climbing with more power and endurance. My saddle turned out was too low and too far back. He also switched me to a longer and lower stem. Moving me forward also let me ride in a lower more aggressive position. I asked about the lower bar position and comfort. He says as long as can ride without discomfort...I'm ok. I've used that same saddle position on all my mountain bikes. It been about 10 years now. No leg or lower back pain. I did move the bar on my road bike up since the fit though. I went from a -17 to a -8 rise stem. I don't ride the road bike like I used to.
 

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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.
 

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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.
 

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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.
 

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always licking the glass
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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.
So basically to turn your trail bike into a dirt jumper. Which makes total sense since Lee does 95% of his riding at Valmont.
 
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