I read this last night and measured my RAD on my new Waltworks. It was pretty much spot on. My Switchblade was 50mm too RAD and my Les 20mm too RAD.

There’s no such thing as too RAD in my book but I’m happy my new custom frame is bang on!

Thinking about buying Lee’s Dialled book as I’m very interested in making bikes works the best they can for me and in bike fits in general.

 

Front Center and RAD are not at all related, don’t lump them together in any way.

Also, I think he loses some people on how to actually measure the distance. Bottom bracket to grips, parrellell to an invisible center plane isn’t the easiest measurement to get right.

Lee’s complete method includes a bunch of body measurements, which are also easy to get wrong.

It can all add up to unnecessary confusion.

My favorite implementation of a RAD check is to drag a couple picnic tables around so you are able to set your bike up with a pedal on each tabletop. The bike is free to pivot around the bottom bracket... the. Stand on the pedals and “row” the bike toward your hips as you stand up straight. (I’m sure this was an inspiration for the riprow...)

Lee’s RAD and RAAD dimensions make a lot of sense when combined with proper images of how a person looks when using full range of motion on a bike, compared to a person at the top of a deadlift style motion (shoulders packed, bar across thighs)

Your hand position with the bike rowed into you, should look and feel like you’ve just locked out at the top of a deadlift. If the bike feels short or long in this position, you MAY find benefit in playing with longer or shorter RAD dimensions.

Pinkbike commenters were quick to point out the angle of the RAD and it’s importance. Lee hits on this with RAAD, and it sounds like he’ll be coming to his own defense with a better description soon that includes this.

I like Lee’s stuff a lot. I’ve been riding off-road for almost 20 years and have been a certified instructor for the last four. Lee’s methods are slightly different from what you’ll find from a typical instructor.
His unique focus on row and anti-row movements seem to have influenced his observations on fit and fitness ala riprow.

I think it’s great to have someone putting new words to old problems relating to both technique and fit.

And Lee is probably correct that SOME people are riding bikes too long for them. I frequently see 5’8” people lamenting over whether they should be on a Large or XL frame... the answer is probably Medium - unless you’re just along for the ride and don’t wish to have any influence over what that mysterious contraption below you is doing.

 

I did not measure my bikes to find where I fit with Lee's numbers. I usually come to the conclusion that most of these fit formulas work as a neutral starting point, but not as hard fast laws. Hell, I still think saddle height and KOPS work as a good starting point for a novice rider. In Travis's example, if he corrects to Lee's formula, will he need to slam his saddle back most of 2" to get back to his preferred riding posture, and what will that do to alter his weight distribution on the bike?

 

I just measured my 3 main bikes in my garage and all three have about 4-5cm too much RAD for me if I use the simple calculation in Lee's article.

 

Chris Porter has a similar method. I would imagine those who are coming in too long for Lee's method will be very close to Chris's ideal measurements. Chris uses a larger multiplier for a longer bike, shocking, I know.

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The measurement process seems to be overly complicated, honestly. Especially if you dive into the full calculations of "ideal" RAD that make fewer assumptions.

But when measuring things out, my bike (which feels pretty good to me) has about 2cm longer RAD for me than Lee's calculation in the article. That said, I recently made a handlebar change (a little more rise than I used to have) and have felt like dropping it down a touch would feel better. Also worth noting, I have longer arms than avg for my height, so slightly longer RAD than the simple calculation supplies is probably also a good thing.

 

It should also be noted that Lenz Sports use Lee's method when fitting their bikes up for customers.

http://lenzsport.com/bicycle-fit/

 

I go strictly by ETT and reach as far as bike fit goes. 590-620 ETT and 420-460 reach. I know those numbers will fit me comfortably both seated and in the attack position. Angles don’t matter as much especially since specific categories of bike have their specified ranges. Angles depend on the bike I’m looking for. Not really convinced that steep actual seat angles make climbing better or easier to be honest. I have a Slash with a real slack seat angle and an SB100 with a steeper seat angle and climbing sucks with both of them. Yes I hate climbing. All climbing sucks but is a necessary evil.

 

I go strictly by ETT and reach as far as bike fit goes. 590-620 ETT and 420-460 reach. I know those numbers will fit me comfortably both seated and in the attack position. Angles don't matter as much especially since specific categories of bike have their specified ranges. Angles depend on the bike I'm looking for. Not really convinced that steep actual seat angles make climbing better or easier to be honest. I have a Slash with a real slack seat angle and an SB100 with a steeper seat angle and climbing sucks with both of them. Yes I hate climbing. All climbing sucks but is a necessary evil.

Curious - how tall are you? Inseam and arm span?

 

While I know Lee is very popular, I don’t think his fitting system fits everyone.

For me, it caused me to be too cramped, putting too much stress on my hips and midback. It also made my bike feel too twitchy for me (shorter stem, narrower bars).

I ended up sizing up frames when I figured out a lot of my fit problems were due to riding something too cramped and small for me.

I do like his row/anti-row mechanics, and think there is some validity in that. But his fit? Not so much.

 

While I know Lee is very popular, I don't think his fitting system fits everyone.

For me, it caused me to be too cramped, putting too much stress on my hips and midback. It also made my bike feel too twitchy for me (shorter stem, narrower bars).

I ended up sizing up frames when I figured out a lot of my fit problems were due to riding something too cramped and small for me.

I do like his row/anti-row mechanics, and think there is some validity in that. But his fit? Not so much.

That's similar to what I told him on Pinkbike. He may put you in a position for max biomechancial leverage but that does not necessarily mean it is the best position. Whether it's what you experienced or if the bike is designed in a way that does not require maximum leverage. For example, a longer, slacker, more stretched out bike is going to require much less core and upper body strength to resist going over the bars versus its inverse.

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Are we measuring middle of grip/end of handlebar to middle of bb?

 

I measured from the center of my crank spindle to the center of my bar at the stem. This is my 140mm medium trail bike with 430mm reach

I got about 779mm with a 50mm stem. I'm 5'8"...just shy of 174cm.

I just measured my XC bike and got 800mm with a 66mm...its got a 414mm reach.

Lol...I think I measured wrong.

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Measured the Evil I built up in March.

I went and measured my "RAD" on both my bikes.

Using LLB's formula...I got ~774mm for my RAD.

I'm 5'8" (173cm) 145lbs. 30in inseam long-ish torso.

Evil Following Medium, ~810mm RAD

Syntace Flatforce 55mm and an Enve M6 7.5mm rise and 9 deg sweep trimmed to 760mm. One 2mm spacer under the stem.

608 Stack and 419 reach.

Banshee Spitfire Medium, ~810mm RAD (kinda surprised that both bikes were the same)

Thomson X4 40mm and an Enve RSR 23mm rise and 9 degree sweep trimmed to 760mm. No spacers under the stem with a Cane Creek Slamset.

596 stack and 430mm reach.

 

The RAD recommended for me is about 740. Every single bike I own has a rad of 810 to 830. I am not sure it is actually possible to achieve that RAD on any of my bikes.

I am curious as to where he got his recommended fit numbers from. I do not think there is a single professional who is running a bike anywhere near those dimensions.

 

It sounds to me that he came up with this fit method through experience.

 

That and through applying RipRow learnings. I think it has validity but ignores the effects of geometry in chasing maximum leverage.

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I bought the ebook this morning and read it my my garage with my new Waltworks in front of me. I am within a few millimetres on all of Lee's recommendations which is good to know, pretty interesting too for me at least. I even noted what Lee says about bar and saddle position, his recommendation is to have the bar slightly lower than the saddle which is something I adopted for the first time on this bike. I made comment the other day about it feeling weird but something I would get used to. Exactly what Lee says on the subject.

I have had numerous bike fits over the years, I know what works for me I guess too, so all my bike builds generally start with a few key dimensions and I go from there. Lee air's on the side of a traditional bike fit I think, but he's actually made it easier to follow and quantify so that people can work out what should work for them too.

I suppose it makes sense that I am where I should be. I had lengthy discussions with Walt and other's when we were building my frame, I wanted to go long because everyone was banging on about it like it was the be all and end all, but Walt reigned me in and suggested a length that would be about the limit of what my dimensions should be at. He was right, I'm getting benefits I can feel but I'm not stretched out or hindered in any way.

 

I read those fit suggestions and I found them to be pretty asinine and inches too short.
However I bet it's in the ballpark for my wife.

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I read those fit suggestions and I found them to be pretty asinine and inches too short.
However I bet it's in the ballpark for my wife.

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Interesting. I'm female and I found them to be too short for me.

I think there are several other factors at play that this doesn't include like ape factor and body proportions.

 

So my RAD number is 818 and my bike is 860. I can't imagine how crunch up I would be if my bike was at my RAD number. I'd probably need to lower by stem and shorten my bars. Two things that I'm not likely to do. I tried running a lower stem and felt too my like I would go OTB on steep spots. I run a 760 bar and like the ride feel with that bar. I read through the PinkBike comments and that was entertaining.

 

So my RAD number is 818 and my bike is 860. I can't imagine how crunch up I would be if my bike was at my RAD number. I'd probably need to lower by stem and shorten my bars.

RAD has nothing to do with handlebar width. It is the hypotenuse of the horizontal and vertical distance from the center of your BB to your hands. Measure from the middle of your cranks to the midpoint between your grips. Because most handlebars had upsweep, backsweep, and rise, this spot is probably behind the center of your handlebar.

I thought my bike would be way "too long" but I ended going from 70 to 50 mm and using a wider bar to get my bike to fit by Lee's RAD measurement and it's been great since this summer.

 

Interesting. I'm exact with my RAD# at 800 and 800 on both my single speed hardtail and full suspension. Both frames are also custom to my numbers. It reminds me of my math sometimes. I have the correct answer but I can't tell you how I got there.

 

I'm a little old school probably in thinking that ETT (from the seat to the stem) is the best measurement. I went from a large Stumpjumper with a reach of 442mm to a large Patrol with a reach of 475. But since Transition also steepened the seat angle, the ETT is actually about 7mm shorter on the Patrol (611 vs 618mm). I haven't measured, but I suspect the RAD is way shorter on the Stumpy than on the Patrol... even though they fit the same.

 

I'm old school too. Just give me. 24" TT and I'll get to where I'm going.

 

The quest to determine ideal bike set-up using formulas is an attempt to make the complex and subjective into something simple and measurable. There are so many factors. To name a few:

Joint-to-joint lengths - cripes, how many would that be?'
Weight distribution
Distribution of strength among muscle groups
Neural factors, such as balance, movement sensation, etc
Types of forces encountered for the kind of riding one does
Positions of the stars

His criteria are height and gender. That's it.

Then also, there are myriad ways to set up a bike to reach the same RAD. Are they all equally beneficial?

From the post: "As your bike RAD gets closer to ideal for you, your bike will start to feel better. When you get to the last 10mm, then the last 5mm, then to perfect, something clicks. Your bike just feels right."

Ultimately, in his own words, it boils down to what feels right.

P.S. RAD on my own two oft tweaked bikes (Salsa Pony Rustler (MTB) and Salsa Fargo (Gravel) were both right about 95 cm - well above the "ideal" RAD. I guess, I'm one of these: "Most riders don't know any better".

There are simpler ways to get to a starting point. Then, adjust to your liking.

 

Well over the supposedly optimal "RAD". Damn and I was having so much fun!...

I'm guessing its not obvious but to suggest that there is a formula one could use to determine the one optimal setup for a bike is pretty ridiculous.

 

Lee discussed handlebar width in a previous article. RAD measurement assumes you're riding a modern bike with a reasonablely short stem and with a rational handlebar width for your proportions, not "hotdog" bars with the grips crammed next to the stem.

 

His handlebar width in that article is also way off. No way can I run ~840mm bars, can't remember the exact number but it was obscenely large. I understand what he is trying to do and academically it makes sense. In practice I think it is a big miss though due to geometry differences changing the leverage needs of the rider.

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Yup, then throw in the other important factors like:

Terrain
Riding style
Preferences

Even if his formulas are based on a thousand use cases of individuals (which apparently it is) AND he separated and analyzed each of these other extenuating factors (which he didn't) it still would not be possible to determine the perfect fit for any one individual based on this formula. Because one's bike happen's to fall into the range of what is considered acceptable by this formula and you happen to enjoy riding said bike does not suddenly make it "correct".

 

Agreed. I also noticed, if you see Lee on his bike in pics or videos it appears to fit smaller than racers (enduro & DH) fit on their bikes. It doesn't look too small for a trail bike but he does seem to have a narrower hip angle than you see on racers. Anyone else notice this?

 

Interestingly, this actually came out really close.
I did my best to measure my bike and got 78.5 cm.

I’m 5’9” (176cm), so my RAD is something like 786mm

Given that I *just* bought a new fork (same A2C) but added 10mm more of spacer under the stem and found I climb and descend faster and with more confidence, it seems like this works for me, on a singlespeed.

 

Out of curiosity I measured my bike from the crank spindle to the virtual point between the grips. His recommendation (based on the article) would see me at 761mm, whereas I was actually almost 100mm longer. Instead of 76cm my RAD is closer to 86cm. I can't imagine moving my bars down and back 10cm.

 

He has a lot of his students turn their handlebars upside down (especially if they have a rise) and/or trim them, and slam the stem to the head tube to get them in the correct RAD.

 

I measured up my Sawyer and was very surprised to see the RAD exactly where Lee predicted. I did no math in my set up, totally instinctual but I'm happy see someone else agrees with my preference, lol.

 

Both my bike are way longer than the recommended RAD and I can't imagine them being shorter. Not my cup of tea.

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