Yet another rider on a bike that’s too big

Hi Lee,
I’ve recently purchased your book Dialed to help me try to understand better where I’m at with my current mountain bike, all the changes in frame geometry (not to mention suspension) in the past five or so years, and now the changes literally in how people ride.
I’ve been riding a long time, which may be part of the problem. I’m a 50 year old woman who got her first mtb back in the days of the 26″ wheel. I rode and raced xc for years, mostly on a singlespeed 29er. And then I got into a really big wreck – I don’t race anymore. Still riding though and I love all the suspension being offered by manufacturers now. Last year before shit hit the fan I bought myself a Pivot Switchblade. I just love it. But… when I went to test ride the demos, the XS felt ridiculously small, uncomfortably so. My husband said it looked like I was on a kids bike. The small felt pretty good. The deal is, I am 5’2″. The size chart says I’m totally within the range for the XS, not even on the cusp of small. So, based on my initial impression, I went and bought the small anyway because I just didn’t like how the XS felt.
Fast forward a year of really learning how to ride my amazing new bike – I can ride so much more stuff I can’t believe it. But, there are times on the trail, mostly steep or technical or both (up or down) where I suddenly feel like I’ve got a shitton of bike underneath me and it just feels really unwieldy, hard to manage, clumsy. I started looking into sizing and the fact that I’d colored out of the lines by buying a larger bike than Pivot recommended for my height, which lead me to your book.
I measured from my knuckle to the floor in the stance you specified. 77cm. Bike from BB to midpoint between grip throughline, 80cm. SO… does this mean that I truly am on a bike that’s too large? According to the equation you also suggested, (height x 4.6) = 724.5. Is this so much l lower than my knuckle to floor measurement because my legs are long?
Anyway, do you have any advice? I realize a long travel 29er isn’t going to be a spry, ‘playful’ type of bike and I really should be on something more like the 5.5 – but size will still matter for that if I decide to buy another bike (cringe).
Thanks for such a good manual for evaluating frame fit!
Best regards,
Lisa


Hi Lisa!

Thanks for reaching out. Yours is an increasingly common situation.
Thoughts:
– Unless you have very long legs coupled with short arms, your personal knuckle height/RAD is probably a lot less than 77cm. Most people make these mistakes when measuring: 1) Shoulders are hunched upward. 2) Elbows are bent. 3) Wrists are bent. Your RAD is already way less than your bike’s RAD, and I’ll bet the difference is even greater than you’re measuring
– The small is way, way, way too big for you.
– Guess what else? The XS is also too big for you! It might have looked and felt tiny, but I’ll bet you’re used to a traditional fixed-position XC/road type setup. The ideal MTB setup is a lot shorter.
– For the bike you have, all you can do is shorten the stem all the way to a 30-35mm and install bars with extra setback like the SQlab 30X (I run these bars).
– A size XS will fit better, but you’ll still need to do the bar and stem.
– In a perfect world, the reach of your next bike will be a bit less than 400mm. (The Switchblade in S is 430; in XS it’s 410.) The way bike geo is currently trending, that leaves you few choices.
I can give you further assistance by watching you on your bike. If you like, you can set up a remote coaching session for this.
What do you think?
Lee

 

5 replies
  1. John Fontana says:

    Lee,

    I want to join this discussion after watching your video on bike sizing. you say that height x 2.5 will give you the reach distance for a dialed in bike. Then you show that the RAD is really what you are interested in which is the distance from the crank to the bars and demonstrate the perfect RAD as being when feet on pedals (crank) to bars (clenched fist with the bike standing vertical) is the perfect distance and that it is the RAD. This would be the hypotenuse of the right triangle made from the reach and the stack. My height is 168 CM. The distance from my feet to my fist (around the bars) is just over 30 inches. Wouldn’t the 30 inch measurement be the perfect RAD for me? if we do your math of 168 (my height) x 2.5 then we get a reach of 420mm. Yet the bike I’m looking at has a reach of 440mm and a stack of 621mm. This would be a hypotenuse of 761mm, just 1mm different from my RAD measured from my feet to my clenched fist (30 inches or 762mm). By your estimated calculation the bike would be too big, but the calculated RAD would be correct. I’m confused. Can you help me understand this apparent discrepancy?

    Thank you in advance,

    John

    Reply
  2. leelikesbikes says:

    Hi John,

    For everyone else, here’s that video:
    https://www.youtube.com/watch?v=HyppZOpHocM&t=4s
    It’s pretty good in a lot of ways, but mistakes were made. Unfortunately, we can’t fix them and upload a new version of the video.

    1) It’s so hard to do short, free videos like that. We want to provide useful info, but not too much. Some people like you want more detail. Based on the YouTube comments, for a lot of people that was too much detail. You can learn all the good stuff via the resources at https://www.leelikesbikes.com/dynamic-mtb-fit

    2) You’re right that your knuckle height is also your neutral bike RAD. Hence the sweet ladder test.

    3) Bike RAD is a function of many things: frame reach, frame stack, head angle, stem height, stem length, bar height, bar setback, height of spacers under the stem … and even crank length, shoe thickness and pedal thickness.

    4) The hypotenuse of frame reach and stack is *not* RAD. That number ignores the role of the other factors listed above. If you pick a frame whose hypotenuse matches your knuckle height, and you choose to ride with a stem and bar, the bike’s RAD will end up too long for you.

    5) When it comes to choosing a bike frame, reach is the best number to look for. That’s why we drilled into that and gave those free multipliers.

    Does that help?

    Lee

    Reply
    • Joseph Farrugia says:

      Lee,
      point #4 you make about Reach/Stack hypotenuse seems super important to me;
      but at the same time makes me confused about your suggested multiplier for calculating optimum Reach (height x 2.5); which seems incorrect?
      Eg: at 168cms tall I would get around 420mm Reachmeasurement; however considering the Stack height for most bikes on the market with that Reach size (420mm or thereabouts); the hypotenuse would already equals the “body RAD”; which would make the bike’s RAD too long.

      Therefore I would be better served by going down a size, with less Reach (eg: 400mm), correct?
      Thanks in advance if you find time to reply; you have done soooo much for so many people around the world; I’m from tiny little Malta (Europe).

      Reply
  3. Rick Tan says:

    Hi Lee,
    Great website and the Joy Bike videos are great as well. I started reading and watching the videos and a lot of it makes sense. I’m coming from a road bike background where you don’t move around the seat much. And definitely come from a ‘keep the rubber on the road’ background.

    I’m in the same situation as Lisa’s. I bought a Pivot Switchblade Small before the COVID mess and I am now unsure about my decision about the size. With the 29inch wheels, I cannot stand flat on the ground and still have air between the top tube and the man-parts. Perhaps changing to 27.5inch wheels will help with standover height. Is 2 to 4inches of space between you and the top tube (for standover) a safety requirement?

    Regarding the poor fit of bikes from bike manufacturers, what is the reason for that? Surely they have ‘average’ body dimension data that they can get from reputable sources with which to build the bikes with. Or are they catering to their sponsored riders, who are likely at the extremes of the bell curve.

    Rick

    Reply
    • Lee says:

      Crotch frame space is nice. Not a requirement but nice.

      The makers are all chasing the same trendy numbers. The anthropometric charts are being ignored.

      To really dial in your bike for your body and riding style, check out the book Dialed or the site http://www.llbmtb.com

      Reply

Leave a Reply

Want to join the discussion?
Feel free to contribute!

Leave a Reply to John Fontana Cancel reply

Your email address will not be published.