Old 08-03-16, 08:01 AM
rm -rf
don't try this at home.
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Originally Posted by Fly2High
So if I would like to look into racier bike, will I just have to go on trial and error or pray the salesman isn't trying to SWAT (Sell What's Available Today)?
Is there anything useful from the fitting that could help? Would the seat height or something be reusable?
Just to recap, here's stack and reach measurements:

It measures from the crank axle to the top headset, center-to-center.

It's for comparing frames. You have your current bike's stack and reach, and also have the stem and bars stack and reach. And you can count the spacers under the stem (10mm is the standard height, and there are 5mm, 2mm, etc, short spacers) to add onto the stack number. And you know your stem's length and angle.

EDIT--this bike stem calculator compares two stem setups and shows the change in height and reach between them. Very useful.

When I was shopping for a new bike, it's stack was 8 mm higher, and the reach 5mm shorter than my current bike. So i knew I could go from a 90mm stem to a 100mm on the new bike (adding a net 5mm more reach), and drop one 10mm spacer to get close to my current fit. And this new bike was a 55cm, the old one was 54cm, so I could ignore that sizing difference, since stack & reach compares them way better.

So, if you want a lower, more stretched out, "racing" bike, you can compare the differences on stack and reach to see how much the frame affects your riding position. And then different stems (using the calculator linked in the previous post) and bars, determine if you can get your hand positions where where you want them.

Or, for riders whose current bike is too low, they can see if the new bike frame will allow for a high enough position without adding too many spacers. (usually 30mm or 40mm is the maximum spacers on carbon fork steerers.)

Originally Posted by Fly2High
Love the advice. seriously.

When I read all these threads on bike selection I have come to what can only be the wrong conclusion in that for each person there is only one reach and stack. Clearly there must be many. I came to this conclusion because in fitting a bike, there appeared to me to be a finite range the spine should be at, a defined reach a person has and since one's legs are not plastic, a fixed seat height and stack related. Clearly I am incorrect in this thinking. It also seemed to me that some just do not fit certain types of frames no matter the amount of gymnastics attempted.

So if I wanted another endurance geometry, I could use the determined reach and stack for a bike that fit but clearly, it will do no good if I wanted a racier geometry. Over the last year and a half, I have been becoming more flexible and might like to try something racier since I wasn't when I purchased my current bike.

Am I relegated to trial and error or can anything be salvaged from the current numbers to get a direction to a suitable less endurance minded frame?
Range of fittings
Sure, riders can use a range, but a wrong size frame means adapting by more spacers, short stems, and other non-optimal means. Then if the rider wants a minor adjustment later on, it might be difficult to do, since it's already at the edge of a reasonable size range.

And a rider can use a wrong size bike, but they may not be fully comfortable on the hoods and drops.

Racing setup
First, have you contacted your fitter? Advice on a racier frame might be free, included in your original fitting.

It's hard to say how much lower and farther forward you need. You can roughly estimate it by kind of half-holding the hoods or drops, and sliding your hands farther ahead. Is is a minor change or a very large difference?

Lowering the bars
Is your stem angled up now? Flip it, and even get a cheap longer stem with more angle (or even an adjustable stem for this test) and try it out. Performance has a 120mm adjustable. You could see if the longer stem, angled way down, gives you a good position. You'd be able to ride it for a while, instead of at just a single fitting session. Any spacers under the stem? Try moving them above the stem (you don't want to cut the stem down.)

Compact bars

A lot of bikes come with compact style bars. These have a shorter reach distance to the shifters, and the drops aren't as far down. This style works great for a lot of riders. Compact bars let me ride in the drops comfortably. Typical measurements are 80mm reach and 120 mm drop.

You may want more traditional bars with a longer reach and a bigger drop.

Last edited by rm -rf; 05-07-17 at 08:17 AM.
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