brickhouseracing

February 14, 2013

A little bit about bike fit & setup

Filed under: Around the shop — Andrea @ 9:19 am

What started as a review of two handlebars had me thinking that, in the process of talking about the two bars, I should answer a couple of questions about bike fit. So, I’ll split the post, and you’ll get the bar talk tomorrow…

1. Picking the right size bike and making little tweaks:
What you see here are two Niner carbon hardtails- a Small Air9 Carbon and a Medium Air9 RDO:

IMG_0491

Why did I choose a medium bike when I bought an Air9 RDO? A) I was being a little impatient, and the small was not immediately available when they were released, and B) Two water bottle cages on the medium. How did I know that the medium frame would fit? I used the commonly-overlooked geometry measurements of Stack and Reach. These two measurements have the largest impact on how high/far away your handlebars will be in relation to your butt.
When I see someone ask, “what size bike should I get?” they can simply compare these two measurements with their current ride and get a very good idea. They can also help you figure out what length/rise/orientation stem they’ll need to make the new bike feel just like the old bike. In my case, I used these two measurements to figure out that with a shorter, negative rise stem (80mm, -17deg), I can get my handlebars in the same place in relation to my saddle when compared to the small frame (which, btw, is very cozy using a 100mm, -6deg stem). Here are the actual S/R measurements for the two frames:

size

I’ve got to throw in a pet peeve of mine here: Standover height is a bunk measurement. Depending on your proportions and a bike’s geometry, you may/may not be able to “stand over” a bike that fits you (or doesn’t fit you). Totally the absolute LAST thing you should even think about considering when it comes to bike fit. Still, people are so blasted stubborn about standover that bike manufacturers are forced to do things like make their size-small seat tubes so short that you only get a water bottle cage on the downtube. STOP IT, PEOPLE.
I know what some of you are thinking… “You’d think differently if you were male blah blah testicles blah blah” Guess what, guys- A) Stop acting like it tickles if I hit my crotch on my top tube, and B) if you wreck in a way that is going to put your tender boy parts in contact with your top tube, chances are, that’d happen whether or not the standover height was “OK” when you’re standing around in you tennis shoes in the bike shop. So, stop reading the outside of the bike box and listen to your mechanic.

I digress.

2. Flat bar vs. Riser bar:
The other tweak I’ve made between my small and medium frame was to flip the medium handlebar over. Both Niner flat bars are actually built so that you can run them “up” or “down” (the down position drops the bar 5mm). This brings me to another question I see all the time- “why would I want a flat/riser bar?” It depends on where you want your hands in relation to your saddle. Once your proper seat height/setback is determined (which, btw, should be done totally independently of your handlebar height/reach), you can use a flat or riser bar (in conjunction with spacers under the stem, stem dimensions/orientation, etc.) to put your hands at a height that’s comfortable for you. I like my bars essentially even with my saddle. That’s not comfortable for everyone- some people like them higher/lower. There’s nothing wrong with either way unless it’s not comfortable for you.

3. Other random tweaks?
Once you’ve got everything dialed in, you can work on the details. Bar width? That’s up to you, but always experiment with wider before you get to chopping things down. When you do start cutting, just go a little at a time- like 5mm each side at a time. Turns out, you can always take more off, but it’s pretty dang hard to put it back on if you go too far. I’ve found that 666mm is my “sweet spot.”
Also included are other things like setting the inboard/outboard placement and angle of your brakes/shifters/lockout, grip angle (if you’re using non-round grips), and bar-end angle (if you’re using bar-ends). I use Ergon grips on everything. I use bar-ends on the hardtails because I love climbing out of the saddle, and they give me both comfort and leverage to do so. When I got my geared bike set up, I realized that I like to have my lockout inboard of everything. However, this put my left shifter/brake lever out of comfortable reach. So, I made a modification to my left grip, which I eventually carried over to my SS because I liked the lockout position so much:

IMG_0488

IMG_0489

IMG_0490

That prettymuch covers the front end of your mountain bike. In the next couple of days, I’ll do a writeup on the differences between the standard carbon bar and the RDO bar.

 

 

3 Comments

  1. 666 is your “sweet spot”. Go figure :)

    Comment by Shelby — February 14, 2013 @ 9:38 am

  2. Sudden dismounts, not wrecking, are the importance of standover. Is it the be all end all? Nope. But I will never ride a bike where my crotch will suddenly rest on the TT if I suddenly dismount.

    Comment by Mike — February 14, 2013 @ 4:54 pm

  3. I’ve swapped back and forth over a Small / Med Trek Superfly SS, and while I agree 100% having 2 spots for Bottle cages is awesome and that set-up can be handled accordingly with proper “Cockpit” measurements / fit. I’ve ultimately settled on the Small size, due to the shorter overall wheelbase on this ride. Most of the Upper Midwest riding is tight tech stuff in the trees (like east coast) and I found the shorter wheelbase increased the overall comfort / fun factor. So when sizing bikes look at that measurement also.

    Comment by Yoshi — March 13, 2013 @ 6:39 am

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