Correlating Fit Stack/Reach to Bikes

Look at the chart of stack and reach and you can see what brand, model and sizes are close to your ideal. Ideally the bike will have close stack and reach for you not one or the other.

Your stack seems awful high relative to your reach.

Stack can be adjusted by using spacer to add to stack, reach can be changed by stem length.

Felt data for all Felts in 56

 Large Speed Concept

 Reach is similar....425 for Felt and 426 for Speed Concept.

Stack is different Felt 525 and Speed concept is 541...both you need a lot of spacers to get to 601.

Thanks for the info.  I've poked around on the table before and was looking at it after my fit.  The 601 stack has me a little irked.  I'll have the videos of the fit process and more data tomorrow.

Still seems funny that I could ride a 56cm Felt and have it "fit."  I ride a 60cm Trek roadie right now, but maybe that doesn't fit me (never got a fit for it).  I feel like I could spend hours dissecting fit data and not feel the least bit more intelligent about it.

Anyone else out there that has some really high stack numbers?

Reach is reach and doesn't change unless mismeasured or you grow.

Stack is more subjective.

Hope this image can help you....

Imagine you in your aero position...I use my right hand with my thumb being my leg reaching to the pedal towards the ground. and have my forefinger be my torso. Keep the tip of your thumb in same position and angle same between thumb and finger and rotate around tip of your thumb. You'll see angle and reach stays the same but the stack varies depending on the position. Really as you move forward your angle will open up a bit to keep your fore finger level with ground.

So you can see the angle and rotation makes a different in stack.

They may have recommended both those brands as they sell them? Stack can be effected with spacers on aerobars and what the stack is on them as well as spacers.

I would ask the fitter about the stack. Have you ridden tri bike before? Road bike with aerobars?

I have worked with 4 fitters since 2004. Reach always is close but stack has changed. I dropped my stack quite a bit this year when working with a new fitter....I dropped to 9 cm drop from 2 with other fitter. Part of fit is science and another part is art and different fitters have different philosophies.

Thanks for the replies - been very helpful so far.

Never ridden a tri bike before, but I did put clip on aero bars on my road bike previously.  I took them off after about a month because I couldn't get used to them, and didn't really understand a lot about fitting.  I just kinda threw em on and thought I should be going faster.

It looks like Blue or a Cannondale Slice would get me a pretty high stack and reasonable reach.  Speed Concept could also work.  The bike shop I went to sells Felt, Trek, and BMC.  He was pretty understanding that I wanted what fits me, and not necessarily what they sell.  I've really had my eye on Felt, but the more I look at the Slice, the more it grows on me. 

For what it's worth, I had a fit on a GURU Dynamic Fit Unit about 2 months ago.  I never got the actual print out of my data, but I think my stack was in the 580-585mm realm, while reach was a little shorter than my current 438mm.

What are the disadvantages of having a lot of spacers to get my stack, besides it looking goofy?  Does it dirty the aerodynamics?   

Spacers change the way bike handles and you are changing the way it was designed. I would really poke around on the stack and reach articles and do some studying so you understand it better. There are plenty of articles you can read.

Yes it most likely will effect aerodymanics and increase your drag.

Are those numbers for stack and reach for your CONTACT points, or the frame?

For instance that 601 stack may be to the arm pads so it would include spacers and the stack build in to the aerobars.

If so, then you need to find your frame with your aerobars in mind.

For instance, there might be 40mm of stack build in to the bars/stem you buy so you would look for a frame with 581mm stack or LESS (because you can add some spacers).  Oh, and don't forget to add in the height of the headset top cap.  Some are up to 10mm.

I don't want to disappoint you, but for beginner athletes these highly precise "fits" are great revenue generators for shops, but they often don't provide a lot of useful info. Why?

Well, for one, 'stack and reach', which was at one time a pretty good way to compare framesets, is now slowly becoming obsolete. For example, you can't use stack and reach to effectively analyze or compare your fit across many of the newer bikes with integrated stems and cockpits (including many of the Trek Speed Concepts). And then to add to the problem, many of the manufacturers of these new bikes seem to use a different convention to measure their frames.

But even if you have your desired stack and reach numbers for a conventional tri frame, there is another issue that your fit has not addressed. Even regular tri bars, aerobars, and cockpits have very big differences on where your contact points are relative to the stem's bar clamp, i.e., the height and fore-aft placement of the armrests; the length and angle (and width) of the aerobar extensions; the shape, height, and fore-aft positions of the gripping sections of the basebars. The differences in bars are often a lot more than the differences in stack and reach between similar-sized frames. Even similar-looking saddles are quite different as to where your rear end finds a home on them. So just a saddle brand change can result in your sitting almost 1-2 cm more forward (or aft).

Finally, your fit numbers are not static numbers. Especially for beginners, as you start to ride and then ride more, your flexibility will change, your comfort preferences will change. Even the tri events you select and prefer will affect your fit. You might find one fit great for a 25 mile bike leg, and find another fit better for you for a 112 mile bike leg.

So what should you do to move forward?

Well, for one, use your 'stack and reach' fit numbers as a just a ballpark guide. If they indicate that you need a taller frame (relatively high stack), don't go buy a super long frame. If you need a longer frame (relatively long reach), don't go get a super tall frame. But once you select your frame or bike, let your comfort and experience guide you. Don't worry if you're riding with a slightly different reach or stack than what was prescribed. Start riding and training, listen to your body, and have some smart and experienced athletes look at your position as it evolves. You can even post a pic on a forum like this.

Not disappointed at all, but I do appreciate the feedback.  I felt like I got a lot out of the fit besides just my stack and reach numbers.  I definitely understand that the numbers generated today aren't static and would likely change from one fit to the other.  I really needed a ballpark guide, and it seemed (at the time) the only way to get one was to pay for a fit.  At least, that's what is highly encouraged around these parts.  I've been on a road bike for 3 years that I haven't ever been fitted on, and wanted to make sure I at least started this process on the right foot.

 The stack/reach are based on the frame stack/reach and not contact points.  I have all the data from the fit, and I'll look at it more after work.  It includes the data that addresses aerobars position, position of the arm rests, angle of grips, width, etc.  I know these can and will change, but it should at least give me some sort of a base and help account for differences in cockpits.

I even have a nice little video of the fit I could post up, but I think it may be protected on YouTube currently.  I'd love to have some other opinions on it before I go all in on a bike. 

Ok. so you can try to find a tall and narrow bike, but you won't find one with a 601mm stack.  So you will need to increase the bike's stack using spacers.  If you can find one with a 580mm stack and 430-440mm reach then you are fine to add 20mm of spacers.

It would help to see your fit video.  It's probably 'private' in that only users that have the direct link can see it.  But you can provide that link here.

Here's the link: http://youtu.be/qxP5DVp_c9E

I'm at work and YT is blocked, so I can't check it.  I watched it on my phone:

0:00 - :30 - preliminary fit.  Threw me on and made a few adjustments
0:30 - 1:00 - adjusted fit
1:00 - 1:34 - The 'final' fit on the fit bike that corresponds to the above stack/reach.

Your thoughts are greatly appreciated! 1:00 - 1:34 of the video is likely the most relevant, as that was my final position where he took all the measurements.  

Yeah, that looks quite reasonable.

As the other fellow mentioned, the fit can/will change over time as you get more aggressive, race different distances...

But what you have there on the fit bike is a perfectly valid place to be right now, so go ahead and go for it.

Did his fit spec a 100mm stem?  You can also fudge your reach 10mm up or down if you adjust to that with a longer or shorter stem than he spec'd you with.

Hey JRL, if you don't mind I've got some questions for about your fitting.   I've never had a fit either, but have made many adjustments over the years and I'm thinking a new Tri bike for next season.  I was thinking about getting a fit done at either Emery's or W&S.  So, on with the ?s.

How did you like your fitting at Wheel & Sprocket?  Do you feel you got your monies worth from the fit?  What made you feel that way?

Thanks!