It is easiER for sure once you get stack and reach. Not a walk in the park though. Each company presents the info a little bit different.. some not at all.

I like charts with ranges of different configs. because you can tell for each frame for each pad (low pad, high pad) what your pad stack and reach is..

here is the older shiv http://www.specialized.com/.../SHIVStack-Reach.pdf

here is the speed concept: http://www.slowtwitch.com/...C_FitGuide_final.pdf


Do you have a price range? You posted some old bikes, is that because you are shopping used or because the fit database has a bunch of old stuff in it?

I would love to hear more about this Felt recommendation.

when i had a guru fit i received a 12 page print out of every bike that would fit me and how it would need to be adjusted to hit my fit coordinates--that was a year or two ago--maybe they dont do that any more, but i would ask.

Yeah, trying to keep it under $1500 for now. I am in the process of selling motorcycle, boat and lake house so things could change but then my top would be $2500 to $3000. More interested in getting a bike that fits and getting aero for my first tri bike.

i think they were tryng to sell them something in stock instead of something that fit him....... That is a red flag...

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Jonathan Caron / Professional Coach / ironman champions / age group world champions
Jonnyo Coaching
Instargram

yup...time to name the shop so we can roast them!

---

Superfly Coaching
http://www.superflycoaching.com/eric

IL PIRATA VI GUARDA

That sounds like a super duper high front end. Like hybrid bike high.

I thought the guy giving me my fit was really engaged and helpful. The whole vibe from the store was good too. Looks like I just need to make an appointment for a follow up for a list for all the bikes in the industry. I guess I just got hyped up cause I saw what I thought was a great deal on a used bike here (2011 slice 3 ultegra $1150 shipped).

I really don't know what lengths are normal for what though, so I'm not sure why the Felt (54cm) measurement seems to have raised some curiosities. Which were similiar to a Scott Plasma that was recommended too.
Scott Plasma 10 / 20
Stem: 120mm
Stem angle +6
Spacers 50mm
Frame Reach: 400mm
Frame Stack: 530mm

and also on the list was Scott B series 56cm
Stem: 90mm
Stem angle -6
Spacers 50mm
Frame Reach: 420mm
Frame Stack: 554mm

but again I'm pretty new and not familair with industry standards on sizing so I don't know if these are reasonable or not.

It's galvanizing questions because it seems ridiculous to "recommend" a bike that has a known stack/reach but then ADD 5 cm's of spacers (to the steerer tube, which is probably beyond what is technically "max" allowed on a steerer tube), a super long stem, AND and up angled stem.

Things that would be helpful if you want more specific advice in the ST community:

1) A picture of the fit (I'm sure a $200+ Guru fit contains some pictures, no?)
2) What type of saddle you were fit on
3) Your ride history, goals, and races for this year

People take money from others for fits like that. Its mind blowing.

At some point, you'd think common sense would prevail. Like, "hmmmm 5cm of stack and upward angled 120mm stem...maybe the frame could size up? Maybe theres a better bar option? Maybe I shouldnt be a fitter?".

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"One Line Robert"

"2011 Slice: 54cm Stack 50.9 Reach 39.8"

there is no way this works.

would you like me to show you exactly how to tell which bikes will work based on HX: 489 and HY:645?

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Dan Empfield
aka Slowman

Yes!

First off, Thanks! Secondly, I would be grateful. Thanks again!


edit: spelling

this is pretty simple, and the tools are all here on slowtwitch.

first, one must stipulate to the geometry of the aerobar used during the fit. so, let's pretend it was a zipp vuka. it's probably 60mm of pad height above the centerline of the pursuit bar. let's say the bar center sits over the pursuit bar squarely. i don't know if it does or doesn't. but, when you're up on that guru (or any) fit bike, you're getting fit and the output of HX:489 and HY:645 is based on that pursuit bar. if you were fit on a pursuit bar that had 50mm of pad height, your HY would be 655mm. if your pursuit bar on the fit bike was 35mm of pad height your HY would be 660mm. do you see that? if you don't see that, don't say that you do. stop now, say you don't see it, and i'll explain it in another way. it's critical that you understand this paragraph.

now, if, and only if, you're willing to assume the very same aerobar, or another aerobar with the same geometry, as the one used during the fit session is also going to be on the bike you end up with, then let's proceed.

we need to find the stack and reach of the frame you're looking for. in order to do that, we need to reduce the X and Y from the pursuit bar center to the X and Y of the frame, at the head tube top (which is, by definition, stack and reach). we need to calculate a little mini X and Y of the front end of the bike, from the head tube top to the pursuit bar center (aka the stem clamp). in order to do this we have to pick a front end we want on that bike. an elegant front end that looks good, will make the bike handle well and so forth.

i'm going to say a 90mm stem, -17° pitch, and only 10mm of total spacers + headset top cap. this means that the wind sees the frame, or aerobar pedestal, rather than upturned stem and headset spacers.

we take these values over to this calculator and plug them in. we get a frame with the following stack and reach, rounding to the nearest 5mm:

stack: 615
reach: 410

we've got problems here. that's a very short reach, very tall stack. so, i'm going to repent of my decision to go to a 90mm stem, and instead use an 80mm stem. this is fine for tri. tri bikes like shorter stems than the same person would choose for his road race bike. this now means:

stack: 615
reach: 420

see what i did there? the length of the position is the frame reach + the stem length + other stuff, such as putting the pads in a forward/rearward set of holes, and so forth. i need less length, so i'm shortening the stem.

i hope you can see why that older 54cm felt will not work. it's about 10cm too low. however, a newer geometry felt B series in a 56cm size has this:

stack: 556
reach: 420

we can also look at a size 58cm:

stack: 576
reach: 435

if we go with the 56cm, we're going to need to pedestal those armrests 60mm. that's a lot. if we go with the 58cm, we'll only need to pedestal them 40mm, but we will have to put those pads back into a different set of holes (the pad cradles tend to have holes about 15mm apart).

what's the difference? two things. first, if you choose the smaller size frame the pursuit bars will sit lower, but more back toward you. if you choose the 58cm frame the pursuit bars will sit 20mm higher, but 15mm further in front of you. the difference between these two sizes is zero in terms of how the aero position fits you, because you're normalizing your position for the changes in frame height and length. the difference is in how the pursuit position fits you.

secondly, the 58cm bike is going to be longer. more front/center. more wheelbase. do you need that larger base of support?

the OP is a slightly better fit on these Felt B series than on a Cervelo. here's a P2/P3 in size 58:

stack: 559
reach: 437

he needs height, and he's got more height with the felt. here's a shiv in size L

stack: 565
reach: 425

here's the shiv in XL:

stack: 590
reach: 445

lots of height in the XL. but a lot of length.

let me throw a little wrinkle in here. road bikes have less reach and more stack than tri bikes. here's a Felt AR in size 61cm:

stack: 617
reach: 417

road bikes can work if you can get the saddle forward enough, and if you have enough standover height.

the thing is to make sure that the fit is correct. i make my subjects work very hard during a fit session. it's a workout. i want to make sure they simulate the work they'll be doing on the road. this is a tall position, and not very stretched out. is this really the correct position?

the analysis above is just math. these are the calculators that are built into the F.I.S.T. system. when i first wrote about, identified, named stack and reach back 12 or 13 years ago it was with the above in mind. but these are very precise methods by which we accurately prescribe complete bikes based on your position. but it will accurately prescribe the correct bike for your shitty position. garbage in, garbage out. you have to make sure the the position is correct.

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Dan Empfield
aka Slowman

Wow, that is very eye opening. These are not the same sized bikes I thought I needed last week at all. Got some light bulbs going off and its starting to make sense, but I'm in the process of going through some of your past articles and digesting it all. Figure I need to inform myself more before I go forward. Thanks!

Yea, that.

please bear something in mind. this is often overlooked, but is critical. all the numbers i'm quoting you are based on the aerobar you used during the fit session.

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Dan Empfield
aka Slowman

I got fit on the GURU about a month ago and was given a list of 5 bikes that would fit.

I need to re-read some of this myself and make sure that I'm looking at the right bikes too.

I'm coming from a road bike that I've done a few tris on and want to make sure I get the best fitting bike possible for me.

Thank you for the information.

Yeah so as a synopsis would it be safe to say (and I'm generalizing here) ... that a frame has a static stack and reach.
I don't have a static stack and reach its dependant on the intricacies of the cockpit.
Then my final cockpit has its mini frame and reach that can be changed here and there until I have the final setup.
Which then ends up being the frame SnR + cockpit SnR = the "effective" stack and reach?

what i'm saying is that you could break a tri bike position down into 3 components:

1. x and y from the bb to the head tube top (stack and reach)
2. x and y from the head tube top to the handlebar clamp
3. x and y from the handlebar clamp to the top of the armrest pads, midway between tip and tail

what we do know is that if you add values 1 and 2 together we get the metrics you provided, which GURU calls hx and hy (the x and y from the bb to the handlebars, hence the "h"). if you get positioned on a purely custom fit bike, or a shimano fit bike, you get the same values. these aren't GURU values, they are values. they are system independent.

if i want to find a product solution that fits up underneath you, i could mess with the front end config and every time i mess with it (pitch the stem differently, lengthen or shorten the stem) the resulting stack and reach of the frame i'm looking for changes. that's the exercise i went through above.

however, there are additional things i can do. i can mess with the aerobars. i can pedestal the armrests. i can slide the extensions back and forth in their clamps, and assuming the pads are clamped to the extensions they'll move back and forth accordingly.

but the hx/hy output is based on a particular aerobar on the fit bike when you were fit. if those pads sit 60mm above the handlebar clamp, okay. if they sit 30mm above it, also okay. but i have to bear that in mind when i'm looking for solutions. if you said, "great! i'll get a cannondale slice!" that's fine. but this bike comes with a visiontech trimax bar, so if you followed the math above but didn't account for the difference in pad height between the bar used during your fit (a zipp or profile with a 60mm pad height?) and the 35mm visiontech, if you got that bike mail order and set it up according to the math above your position would be 25mm too low. compounding this, the visiontech bars don't pedestal worth a spit, so you can't really fix it.

(this is why i asked nytro if they'd swap out aerobars when they sell their slices through the mail and confirmed it's a yes.)

the above is pretty easy math when you understand how the system is constructed. but you'd be surprised how many fitters just still don't understand it.

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Dan Empfield
aka Slowman

 
I'm trying to wrap my head around all of this myself. I understand where the numbers come from, the aerobars make a difference in the HY/HX.

When I plug in my numbers it just looks off. My reach seems low.

I'm 5'11 and have a 32" inseam....if that matters.

The Aerobar I was fitted with was the T4+ with pad height of 45mm

HY 612
HX 456

Most of the bikes recommended had 70-80mm stems with 40-50mm spacing. When I tried to adjust the stem/spacing in the calculator the reach seemed way low.

I'm wondering if the spacing was there in order to let me get more flexible and then remove some?? I have no clue.

P3 was recommended

54 70mm stem -6 angle 55mm spacers

Big decision,so any insight would help me and the OP

x2

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Advanced Aero TopTube Storage for Road, Gravel, & Tri...ZeroSlip & Direct-mount, made in the USA.
DarkSpeedWorks.com.....Reviews.....Insta.....Facebook
--

" My reach seems low. "

reaches can not be low. and, when you say reach you need to tell me if you really mean reach. reach is a term of art. it's the distance from the bb to the head tube top in the horizontal axis.

all that said, if you plug in the front end you mention, the 70mm stem, etc., and if you assume 15mm of total headset top cap, you get stack and reach of about 400x565. the 54cm cervelo has 411x522. so, you'd pull the front end back slightly, and then you'd add about 40mm of spacers. yes, it's 55mm if you assume no headset top cap but you've got to assume something. so we'll assume 15mm.

the spacers in the calculator refer to headset spacers. you really want to minimize that, and get your height from pedestals under the armrests.

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Dan Empfield
aka Slowman

Guess I've been doing too much reading. I read somewhere that the reach should be higher with my height. I'm still new at this whole thing so, not well versed.

I figured that it was based on human size...height (inseam) reach (torso, arm length)...I see it's more complicated than I originally thought.

The spacers is what had me concerned, as you mentioned you want to keep that as low as possible.

So here's another elementary question....which is more important? Stack or Reach? Find a frame that fits closer to stack and adjust reach?

I was just worried that maybe the frame should be a little larger to do away with some of the spacing.....however obviously I have no idea.