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,

Hi Lisa!

Thanks for reaching out. Yours is an increasingly common situation.
– 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?


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