This is a noob question, but I have done my due diligence and spent the entire weekend reading articles on slowtwitch , so I have half of an understanding why we want to measure stack and reach.
I even got fitted and turns out my measures are :
Reach = 410 @ stem of 110mm → Total 52cm
Stack = 600 @ 20 mm of spacers - → Total 600 + X (missing info height of arm rests)
I have been browsing for dozens of bikes, I can quite easily find the reach I need, but for the stack it seems they always running a bit smaller. For example, even the largest frame for a Cervelo P3 is still only 588mm, and the reach for such large frame is way longer 446mm. https://www.cervelo.com/en_US/p3
When we did the fitting session I don’t remember the measure form the top tube (stack) to the arm rest , because I suspect some of these frames have shorter stack because they compensate with aero handlebars which can extend much higher than a regular clipon aero bars (for example, ENVE SES Aero Bar has a Max arm rest height of 75mm) whereas clipon aerobars seem to sit much lower than or not to have this ability to extend up.
Also I would like to have angled pads on the aerobar and I wanted to ask you if “tilt blocks” is something that can be attached to any aerobar, or if I need to buy a specific aero handlebar
I really like this bike, and I wish I could buy/build the same https://www.youtube.com/watch?v=fb2Oiz31Sbs
So I guess my question is, when I am browsing for my future girlfriend, to what degree is the stack relevant if I compensate with armrest height ?
Any suggestion would be greatly appreciated.
What you were measured for… that 620 stack and 520 reach… is your pad stack/reach.
The Cervelo numbers you mentioned are the frame stack/reach.
So the frame stack/reach plus your bar/stem configuration gives you pad stack and reach (where your aerobar pads end up).
So using the Cervelo size 56 as an example. It has a frame stack/reach of 540/425. In order for you to hit your 620/520 number you would need a bar/stem config that would rise up 80 mm and extend out 95 mm. The size 58 is 559/437. So you would need 61 mm more stack and 83 mm more reach from your bar/stem config.
Those numbers where for the frame too. I don’t have the pad stack/reach. I guess that’s the problem (?)
Those numbers where for the frame too. I don’t have the pad stack/reach. I guess that’s the problem (?)
I highly doubt that’s frame stack/reach numbers unless you’re like 6’7".
A couple of good Slowtwitch resources here: Check out this article with a great graph of stack and reach of different riders plotted. While this doesn’t mean the fit is great, the numbers at least fall within the standard trends you expect to see. Now you’re kind of ignoring the effect that a stem will have on your stack and reach. The numbers you’re seeing for frames are just the frames. If you use this stem calculator and plug in something basic, like 100mm +6 stem with a 10mm topcap, you’re already gaining 68mm of stack. That would make the stack numbers on your 61cm p3 already 656, before including the minimum stack height of the actual bars and pads. For a bar like the TriRig Alpha one, the minimum stack is 55mm. You can see how you’re already getting way to high for your setup. You can imagine it’s much easier to add and remove stack using armpad spacers rather than replacing your bike every time you need to change your stack. Now the issue with a lot of bikes with people who ride relatively long and low positions, as it would appear yours is, is that bikes often don’t have geometry too match. You need too size down as to not exceed your minimum stack height, but then end up with a frame too short. It could be that the p3 is too short for you but we would need a bit more information there, like were your measurements taken to pad center or pad rear.
Thanks GMAN, I’m 6’3’'. I though stack and reach always refer to the frame size, but maybe not. Sorry.
Unfortunately there is kind of a breakdown of communication there. As frame makers can’t know what type of bar/stem you’ll put on a bike, they can only give frame stack and reach. For a fit, the only thing that matters is pad stack and reach though. This can be achieved in a bunch of ways on any bike pretty much, but you’re obviously not going to want to run a 150mm or 30mm stem for handling reasons so it’s up to you (and the fitter potentially) to choose the frame that allows adjustment both higher/lower and longer/shorter in the future as well as accommodating the current position. This is all made much easier with a highly adjustable bar as well. The Enve bar that guy has on his p3 is nice, but the Alpha One is pretty much the most adjustable out there and would allow the tilt in the pads you’re looking for. The 51SS bar will do that as well (though not quite as well).
To riff on what Ben mentioned… a 58 cm Cervelo P3 with the TriRig Alpha One can get you to 620/520.
To riff on what Ben mentioned… a 58 cm Cervelo P3 with the TriRig Alpha One can get you to 620/520.
As could a 56cm frame most likely, depending on where the pad reach was measured to again. But the 58 would seem like a safer bet in this case.
I’m 6’-2" and my stack and reach are 592/435 mm respectively. I ended up with a Felt B14 size 61 which has a stack of around 600mm but with a reach of 444mm. I was going to recommend Felt as an option but for some reason Felts new B14’s (and IA series) only go up to a size 58 now, guess there wasn’t enough sales on the 61’s.
Thank you for the replies. I appreciate the inputs, but now I am more confused than before. I looked up at a picture I took before the fitting and they used an EXIT Fit bike. I am pretty sure this only measures the ctack/reach to the frame toptube. The seatpost angle was 76 (if I remember correctly), but I don’t know the measure from the top tube of the frame to the armpads. The FIST method doesn’t measure this, which makes me wonder why… partially the answer I remember reading is that there are so many variables when you start adding components to the frame that they suggest this would become too complex, but at this stage even after getting my stack and reach I still don’t know what bike I would fit on.
I’m totally confused now. Sorry. 
I’m 6’-2" and my stack and reach are 592/435 mm respectively. I ended up with a Felt B14 size 61 which has a stack of around 600mm but with a reach of 444mm. I was going to recommend Felt as an option but for some reason Felts new B14’s (and IA series) only go up to a size 58 now, guess there wasn’t enough sales on the 61’s.
Are you also confusing frame vs pad stack/reach? I don’t see how someone 6’2†should be riding a bike that big unless you have a 38†inseam or 7 foot wingspan. ðŸ˜
Frame reach + stem length doesn’t give you the bar reach, there is some trig involved (I’ve made a calculator for this https://www.velogicfit.com/frame-comparison)
Frame reach/stack + Stem/spacer reach/rise + aerobar offset/stack gives Pad XY
Your fit info is pretty much worthless without Pad XY, or at least Bar XY and exact aerobar setup.
Further - 410 frame reach is much too small for you - the assumption of a 110 stem would put you on a 51, instead of the at least 56 you need to be looking for.
As far as aerobars go - it this is your first tri bike - clipons are a good solution as they’re easily modified if you wish to experiment with your position (which is likely as you get used to riding in the aero position).
Then once you have your position dialled - upgrade to a high end bar that matches perfectly.
If you wish to get a top end bar from the beginning - don’t get something that doesn’t tilt. You have options from:
Profile Design (I work with PD on aerobar design)
Zipp
Vision (newest generation)
Tririg
51 Speedshop.
The Enve SES bar tilts but is no longer made and is very limited on width adjustment.
What you want is the scope to easily make position adjustments in small increments in every direction. Tririg Alpha One wins for stack with the mono riser but other bars are better on x and z adjustments.