Question about RAD bike-setup number


I wanted to discuss your RAD number idea a little more.  I read your article on Pinkbike and used the suggested ratio to calculate my RAD number and then went out to the shop and checked all my bikes.  It was interesting.  My BMX and 4X/dirt jump bike both were spot on the number.  My medium Yeti SB66 with 50 mm stem was 20mm longer and my Specialized Epic WC was 70 mm longer.  I found this interesting as did not set up any of these bike with RAD.  I got to thinking and have an additional question.  Both the BMX and dirt jumper you ride standing up all the time.  However with the Yeti and Epic I spend and increasing amount of time sitting and pedaling.  I put a long seatpost in the dirt jumper and got my saddle position set and that made the reach to the bars feel way to close for seated riding.  Your thoughts?  As a side note one thing that I have noticed in the past on my bikes is that I tend to tuck the front wheel in corners as apposed to a front wheel slide.  Could this be due to to much weight on the front wheel?  Also with regards to “new” bikes out there I would typically be a size M, but with longer reach numbers maybe I need to look at size S as you suggest.

In any case, thanks for you input as always.  You have been great to both Susan and myself in the past.  I have also gotten the pump track built in the back yard, so if you ever make it up to Spokane you have a place to stay and rip some laps. 

Greg S


Thanks for reaching out.

You’ll find a lot more detail in the Dialed book and on the site.

Put simply:

Using RAD, your seated cockpit will feel shorter than you’re used to. The solution is to hinge your hips and get into your normal riding position, then bend your arms. No matter where your bars are, you shouldn’t lean onto them. 

It does sound like you have too much weight on the front end. See above.

Have fun out there,


7 replies
  1. Phil Barnes says:

    Hi Lee,

    I also read the RAD article on pinkbike and have a few questions. I am about 6.5 feet tall, probably 6’1 with shoes. The thing is I have about a 36″ inseam and a +1 ape index. Is there a way to factor in these elements when using the RAD multiplier? Also, should I factor in my ready to ride height plus the pedal thickness when calculating my RAD number? Thanks for the feedback.

  2. Chee says:

    Hi Lee,
    Happy New Year! I am about to buy a new bike (Evil Offering). Unfortunately there is no dealer with a demo anywhere close to where I live. Does your online calculator has an option of plugging in the numbers from Evil’s website and tells me which size would work with my RAD? Right now I am riding a medium Stache with Pacenti’s 20mm stem. I think a small is still to big. I would like to know before committing a lot of money for something the wrong size.

    • Lee says:

      Chee, yes! Using the RideLogic Rider and Bike calculator you find your ideal measurements then tweak the bike geo until the numbers line up. It’s an easy way to experiment with different bike sizes *before* you buy.


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