Wednesday, December 12, 2012

Becoming my own bike fitter

I haven't posted in a while, I know, but things have been busy, I've been riding a lot, travel for Thanksgiving, then I got sick, etc....

In a follow up to the last post, I earned a little extra cash by doing some editing work and decided to investment in a Salsa Size-O-Matic II fitting stem, to work towards that process of refining my fit.  I also figured it would be a good tool to have if I keep up with this fitting thing and go on to help other people with their fit.  It came it late last week and after getting over a cold this weekend, I decided to start playing around with it a couple of days ago.

However, I wanted to be systematic about any changes I was going to make, and to make sure that I recorded setups before I started changing them.  So, my first step was set the bike up on a borrowed trainer, level out the axles (turns out my old archaeology textbook was the perfect size to prop up the front wheel), and go about accurately measuring my current position.  I used the technique laid out by Steve Hogg in this article, and these were the results of my measurements:

Seat Height:   820mm
Seat Angle: +1 degree
Seat Setback (measured to nose of saddle):  13cm
Seat Nose to Handlebar: 60cm
Seat to Bar Drop:   0cm
Bar Angle: +16 degrees
Brake Lever Height:  13mm
Just for good measure, I recorded the components for future reference:

Seatpost Setback: 40mm (Nitto S-84)
Saddle: Specialized Comp Road (Riva?)
Stem: 100mm, minus 10 degrees (Felt w/ adj. shim)
Bars: Felt "2.2" (44cm width at hoods)
Cranks: Sugino XD2 double, 170mm, 107mm BB

There were a couple of suprises here, such as the fact that my handlebars were level with my saddle (when measured directly above the midpoint of the rails, as Hogg recommends).  I had never really measured before but visually, it had always seemed like my handlebars were slightly below my saddle, perhaps because I have my saddle nose angled up a couple of degrees.

After taking and double checking my measurements a couple of times (some of them definitely require some technique, especially the setback measurement), I went about starting to give myself a fitting session, at least how I would start to go about one.  I changed into my riding shorts and shoes.  The first test I did was to test my saddle position through a balance test.  This type of test is recommend by a few different fitters (Peter White and Dave Kirk, among others) but I followed a detailed procedure, again recommended by Steve Hogg in this article (scroll down to the section marked "point of balance").  The procedure is to warm up well, then to start a hard-ish effort (I don't use power meters or heart rate, so I just went by feel).  Move your hands down into the drops (on road bikes), and then, when you're ready, take your hands off the bars and swing them back towards your hips.  The theory of the test is that if you are balanced properly, you should be able to hold this position without using your arms, without a marked effort from your torso muscles, and without feeling like you're sliding forward off the seat.

My second surprise came when I discovered myself falling forward during the balance test with my current position.   I guess this surprised me because I am surprised by how much setback it turns out I really need.  The Casseroll has a fairly slack seat tube angle--72.5 degrees (not super slack by any means, but no track bike either)--and is fitted with the seatpost which features, in my searches, the greatest amount of setback available in a conventional seatpost: the Nitto S-84 at 40mm.  My seat is fairly centered on the rails, maybe slid a touch towards the rear.  So in terms of commonly available equipment, my seating position, it would seem, falls in the super-setback, Greg Lemond territory of things.  And yet I was finding myself still falling forward, suggesting that more setback is in order.

So in the interest of experimentation, and having confidence that I could return to my original position if need be, I slid the saddle back on the rails by a centimeter--basically to the forward limit of the seat rails--and re-attempted the balance test.  The test was much more successful with this position, although I can see where practice and developing an eye and feel for this comes into play.  I was basicallly able to hold position without real effort with the new saddle setting, but I could definitely feel *something* happening in my torso as I swung my hands from the drops back to my hips.  After trying it a number of times, I concluded that it was probably just my body adjusting to the new hand position and slightly re-balancing.  Not what I would call a large effort from the torso muscles to hold balance.   So it seems like the sweet spot is somewhere around 14cm of setback for me, at least with my current saddle.

All of this makes me wonder what puts me out there on the bell curve when it comes to setback.  I definitely have long legs for my height (~96cm pubic bone height, last time I was measured at Riv), but the relationship between leg length and setback is iffy at best, and my legs aren't that long.   The one dimension that is outside of the bell curve for me is foot length--I have ginormous feet: size 15US/ 50 Euro.  It makes sense that large feet would push my balance point back, since if they were too under me they could be pushing me up and forward.  So maybe that's it.

However, with the saddle slid back, it was readily apparent that my reach to the handlebars was now far too long--it was a strain to reach anything but the tops of the bars.  So, I popped off the stem (yay for removable faceplates) and popped on the new Size-0-Matic, and began trying shorter stem lengths--70mm, 60mm, and 55mm (the minimum stem length possible with the Size-O-Matic, and probably a minimum for commonly available stems).  Off the bat, nothing popped out as being "right," but it was getting late and I wanted to wrap up so I didn't try anything for super long.  Nothing felt as comfortable as some bikes I can remember, specifically ones with shorter top tubes, a feeling I've been seeking in some of my bike fit experiments.  So I'm beginning to think that that particular feeling might not be achievable on the Casseroll, between the longish top tube (61cm) and the extra reach from the seatpost offset needed.

Where does that leave me?  Well, still pining after a frame that is large enough to get the bars at a decent height, a seat angle that allows me to get enough setback with commonly available seatposts, and a short top tube--definitely 59cm or less, preferably in the 57 range.

At the same time, I probably won't give up on the Casseroll just yet.  After all, I can ride it fairly comfortably as is.  I'd like to do another longer session on the trainer with the seatpost moved back to around 14cm of offset and something like a 70mm stem.  In doing so, I would evaluate the position using some of the functionality criteria Hogg describes in his article on bar positioning--namely, the ability to extend my neck, the ability to ride in the drops for extended periods of time, etc. It may not feel like some of the shorter top tube bikes I've ridden, but is it good enough for long rides?  Shorter than that, and I'd be concerned about weird handling on the bicycle.  I'm reminded of one bike I saw in my old shop, a woman's lightweight aluminum road bike with a 40mm stem intended for downhillers fitted!  I also wonder if a different set of bars with less reach would make a significant difference.  Once again, I am tempted to try the Soma Highway One, with 75mm of reach.  

All of this brings up the difficulty of trying to learn bike fit.  Obviously, I'm beginning to see there's a lot of judgement and learned feel involved.  I'm using myself as my first test subject, and I have precious little to go on as to what the feeling is that I'm looking for--the memories of certain bikes (ridden at times when I was in a much different place, perceptually and physically), and the descriptions of a cagey Aussie who obviously knows what he's talking about.  I'd love to get a set of professional eyes to help me out, and perhaps to go on and learn some of the finer points of bike fitting from, but I find it hard to gain enough confidence in a fitter from their website.  Nobody around the Bay Area has as much info online as Hogg does, especially about their overall fitting philosophy, and that makes me reluctant to drop a couple of hundred dollars on any of them.

Has anybody out there had a good bike fitting in the Bay Area, especially one focused on balance and functionality?


  1. Hi Jeremy,
    Any chance we could get some pictures of what you did to measure your bikes fit parameters in a repeatable way? I read your link to the Hoggs article but I would have liked to have seen how you implemented the techniques he suggested.

    1. Hi Dave-- I've got some pictures of the process on my flickr account here, but since I don't have four arms I don't have any of me actually taking measurements. Maybe next time I do it I'll have Meg take some.