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Understanding the Road Bike: The Handlebar Stem


Most people riding a bike won’t think twice about the stem on their bike, after all, it’s just a stem right?

Well, yes. And no.

The stem that came on my Venge, other than having to be flipped to take away the rise, was perfect. So perfect, when I upgraded the stem to carbon-wrapped aluminum (lighter than carbon fiber), I got the same rise and length as the original.

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The impeccable fit of my Venge presented a huge problem when it came to riding my Trek 5200 though. Riding the Venge feels so good I had to try to get my Trek’s setup as close to the Venge as possible.

What made this tricky was the Trek has a larger frame, 56 cm for the Venge versus a 58 for the Trek and to make matters worse, the geometries are quite different, compact versus standard frames. This meant if I was to get the reach close to the Venge, the only place to add or subtract reach is in the stem.

So here’s the deal…  Common wisdom today holds a few things about pedaling a bike efficiently.  We’re talking about a road bike here so please keep this in mind – a triathlon bike is entirely different.  That in mind, common wisdom holds that the pedal axle should be almost directly over the pad of your foot, just behind your toes (I don’t know the actual spot though the owner of our local shop did).  From there when the cranks are parallel to the ground, your front knee should be plumb (level – but up and down) with the end of the crank arm.  If your knee isn’t plumb, you move the saddle forward or back to make it so.  Simply put, assuming you’ve got the saddle height right, this is where your saddle stays.  To adjust the cockpit (handlebar) reach, about the only thing you can do is change the stem (this isn’t entirely true, you can roll the bars up or down, or raise and lower the hoods, or move the spacers around to raise or lower the bar but those are smaller adjustments – the big moves require a stem change).

A while back I upgraded the handlebar on my Venge from the alloy bar that came with the bike to an S-Works carbon fiber aero version.  I loved the Venge’s handlebar and hated the Trek’s original “ergonomic” bar so I swapped them out.  This presented a problem:  The reach and drop between the two bars was off.  The drop was something like 15 mm shallower but the reach was almost ten or so millimeters greater on the Specialized bar.  The stem on the Trek was really short though (70 mm).  Keeping a long story shorter, I ended up going through three stems before finally settling on an 80 mm Bontrager stem (I started with a 70 to match the original stem length.  Then I tried a 100 and split the difference with the 80).  The adjustments were made entirely by feel (I’d ridden something like 6,000 miles on the Venge since I’d purchased it so I knew what I wanted to feel on the bike).

In any event, here’s where all of this becomes important…  The stem, along with the reach of the handlebar drop, controls the reach in the cockpit.  Too much reach and you end up being pulled to the front of the saddle and you find yourself out of position and uncomfortable.  Worse, too little reach and you have to arch your back to fit into the cockpit.  Arch your back two things happen:  Your core crunches up which makes it harder to breathe and your hips have to rotate up which makes it harder to pedal when your hands are on the hoods or down in the drops.  This is where the rubber really meets the road, as they say.

The cockpit reach is what makes an amateur cyclist look like an amateur because you can’t possibly look cool and collected after 85 miles when you’re back is arched and barking and you’ve spent the last 85 miles breathing shallow because you can’t fill your lungs all the way.  Not only that, your hips have been over-rotated which puts a lot of pressure on your lower back…  This can be worked around or ignored for 20 or 30 miles but when you hit the wall at 85 miles, the cumulative effect can make for a rough last fifteen miles.

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Before

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After

I had the Trek sized up next to the Venge by a professional fitter to see if there was anything I could do different to get the Trek closer to the Venge in terms of fit.  It’s not perfect but it’s a lot closer to what suits me than what’s in the “before” photo.  After all of the numbers were crunched there were a few millimeters here and a few millimeters there but I just can’t get the Trek any closer.  What’s important though, is that I’ve got the “feel” close enough that it doesn’t bug me to ride the Trek anymore.

Finally, I want to go back to the hip rotation bit for a second because this was a big change to how I ride a bike.  The hip rotation was a game changer as far as long-distance comfort and being able to breathe better on the bike went.  I used to ride as if I were sitting straight up and down atop the saddle.  Then I would arch my back to get arms down to the handlebar.  What happened is my lower back ended up taking a lot of the shock of bumps (if I hit one) and my core was compressed ever so slightly which crunched my diaphragm so I couldn’t fully fill my lungs.  Once I bought my Venge and got used to a little more stretch (it took more than a year before I changed my Trek) I noticed that when pros ride, most of them aren’t perfectly flat in the drops, but their backs (except for a rare few) are almost perfectly straight.  Even the cat 2 and 3 racers ride with a straight back.  Noticing this led to me trying to mimic that look – and to my realizing that my hips needed to rotate down so I could straighten out my back.   And that led to less stress on my back (bumps are distributed along my whole back rather than just the lower) and improved lung capacity.

Now, if you’re a thinking cyclist, you may be thinking, “Well the setup was wrong on your Trek in the first place and that led to a slightly poor position on the bike”.  You’re right.  And wrong.  Originally I was fitted to the Trek in a more upright riding position because the knee-jerk setting for a bike is in that position because it’s thought to be a little more comfortable.  I don’t necessarily agree with that but who am I?  I started messing up with my setup within a month of bringing the Trek home.  I lowered the handlebar, changed the angle of the hoods and changed the angle of the handlebar itself.  What I didn’t do was take my bike to the shop to have an expert make the adjustments.  In short, I ended up stumbling on the proper setup because I bought a new bike – on the Trek, the cockpit length was set for me to ride the bike more upright but I changed everything else so I could ride lower.  The longer stem and greater reach on the bar meant I wasn’t scrunched into my cockpit.

Put simply, the bicycle stem is an incredibly important piece of equipment when it comes to properly fitting the bicycle to the rider – and we didn’t even get into rise!  Perhaps I’ll save that for a later post as this one’s already long enough.

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10 Comments

  1. Could you contact me at cudworthfix@gmail? I have a couple bike questions related to the Venge. And trust your judgment.

  2. Dustin John says:

    That is a sexy bike. I know nothing about bikes but I love the way it looks.

  3. Archetype says:

    Great post Jim! You’re technical and stats geek too! 😉

    I like that you fiddle with the setup, I do the same and have been since I began riding in 04. Although I have not gone to a shop for a ‘bike fit’ And I will probably never do so. I set my bike up to fit ‘me’ and for comfort first, productivity second- (hey at nearly 51, I don’t need to be laid out like a pro! 😀 and incidentally they typically ride frames 1 or 2 sizes smaller than normal, hence the long 120-140mm stems)

    I am pretty comfortable on my steed now and have a better understanding of each and every point and adjustment on the bike. 11 years of reading, trial and error has helped as well. I also stumbled on the Bicycling article last year which was an eye opener and also helped with my foot position.
    http://www.bicycling.com/culture/people/heretic-will-see-you-now

    Another mention about stems is that they do affect the steering arc of the axis, subsequently slightly increase or decrease the ‘quickness’ of steering (as does handle bar width)

    I probably tinkered with my setup 2 or 3 times during 2015 to compensate for various physical issues. Our bodies are in constant flux and as we age, the ‘fit’ should change albeit slightly to adapt to our changing bodies. At least that is what I agree with…and as always, it different for every single rider.

    Geo

    • bgddyjim says:

      Indeed.

      I’ve got a 56 cm frame and should be on a 58/59… I have a 100 mm stem and am stretched out perfectly (I can’t imagine going much further than that. I’ve also got an older 54 cm Cannondale and it took forever to get that one set right. I’ll check that article out, thanks man.

      • Archetype says:

        Yea, the 100mm is a perfect length for me too. I started with an 80, then a 90 and settled on the 100, I took out one of the spacers (the 5mm) left the 10mm in from under the stem with good results in reach, comfort and steering quickness

    • bgddyjim says:

      Interesting article, man. Wish I could disagree but I have experienced that, to an extent, and there’s something to it.

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