Fit Recovery

Home » 2012 » February » 22

Daily Archives: February 22, 2012

What’s A Centimeter? It’s All In The Fit

I had a comment the other day in which a person wrote that he’s had a hard time with cycling because anything longer than an hour’s ride required the application of an ice pack to his butt afterwards.   Whatever his problem, and there is definitely something very wrong there, I thought I’d take a minute to illustrate the need of a good fitting.  Now, it’s important to note, that one can get away with a smaller framed mountain bike – in many cases that is even desirable but that’s a post for another day.

It just so happens that I have two road bikes – one that is exactly the proper size (right down to the crank arm length) and one that is too small, but only by a matter of two centimeters and I can say for a fact, the difference in comfort between the two is astronomical.

It is important to note here, that I switched the stems – the stem that came with the Trek was too long (16 cm) so Matt put that one on the Cannondale and put the stem from the Cannondale (9.5 cm) on the Trek to get me in the proper position so while the bar/seat positions will look close with the two bikes side by side, this certainly wasn’t the case when I was riding the Cannondale – the bar was in another 6.5 cm.  I took the second photo from a higher angle to illustrate the seat heights which are identical.  That angle distorted, through an optical illusion, the stand-over height of the top tube.  The difference between the two is significant, 5.25 cm (C’dale 78.75 cm, Trek 84 cm) or about 2 inches.  Also, the top tube on the Trek is almost 5 cm longer 57.875 cm vs. 53 cm (center to center).  In any event with both bikes side by side you can see that there is a substantial difference.   When the fact that the stems were swapped is added to the equation, the differences are remarkable – and that’s just between a 56 and a 58 cm bike.

So what I ended up with was that I had to fit my body into a space that was too small to accommodate it.  I had to hunch here, rotate my hips awkwardly there etc.  This caused a lot of unnecessary pressure on my shoulders and kept me from breathing properly because my lungs and diaphragm were crammed into a small cockpit.  With the Trek, I’ve got 66 cm from the bar to the sweet spot on my saddle, on the Cannondale I had 58 cm.

So, to sum this up, there was only a 2 cm difference in the frame size but that translated into 8 cm where it counted.  This is why, without a doubt, one should consult a professional first and I can tell you from experience, the online bike measurement tools don’t count the same – the one I used says, by my stats, that I should have a 175 mm crank, but my fit up definitively showed 172.5.  As well, the online measurement tool suggested a 59 cm frame with possibles of 57, 58, 60 and 61…  I imagine when I checked that before I bought that Cannondale I said to myself, jeez, what’s a half-inch for crying out loud…  It’s a lot.

So long story short, don’t do what I did.


As a post script, if I just went by what the online do-hickey suggested, and I didn’t know that all manufacturers size bikes a little differently, I could end up picking the wrong bike.  In a purely hypothetical scenario, say I had my eye on a Scott Foil 20.  I walk in to the local Scott dealer and tell the saleswoman to order up an XL frame (based on my 59 cm measurement from the online thingamajig), because we all know that you want the exact size or one cm down…  First of all, I can’t imagine a shop out there that would let anyone walk in off the street and order a $3,500 bike without pulling out a tape measure, but let’s say that happened or you buy it online…you get your 58 cm Scott a few weeks later, you’re happy as a pig in poo…until your first century when you discover that the bike hurts.  You raise holy hell with the website and take your new steed to your local shop only to find out that Scott bikes run small (I don’t know if they do or not, this is hypothetical) and you should have ordered the 61 cm XXL frame.  The next time you get a chance, check out Craigslist and note how many posts for high end bikes start out with “I found out this bike is too small/big”.  It’s a lot.