Stack / reach

vqdriver · #1 02-08-2020, 12:54 PM

How do you guys measure your stack and reach? Is there a diy tool for this? Everytime I try it seems even a little bit of wiggle or lean can throw off the numbers and it's not reliably repeatable.

robt57 · #2 02-08-2020, 01:11 PM

Bike level, measurements plumb. Measure top of head tube to the ground [X], measure BB/C to the ground[Y], Measure axle to the ground[Z].

Z-Y=BB drop. X-Y=Stack

Unless I had a brain fart typing that, there you go.

Lets put reach in there. X from BB center. Bike level use a plum bob or a 4' framers level.

I suggest always start with said 4' level making sure the ground is level. You can make a plumb bob with a nut tied to a piece of string. Carerful not to pendulum the swinging nut with any momentum/force and denting anything you care if it gets dented!!!

macaroon · #3 02-08-2020, 01:24 PM

Use a calculator

http://www.bikegeo.net/

Plum Hill · #4 02-08-2020, 03:19 PM

I set my bike on a hard level floor with the rear wheel in a corner of the room. Bike needs to be as vertical as possible without falling over and wheel(s) blocked to keep from rolling. There are a number of ways to do this; figure what works the best for you.

For reach, measure wall to HT top centerline (A) and wall to BB centerline (B). A-B=Reach.
For stack, measure floor to HT top centerline (A) and floor to BB centerline (B). A-B=Stack.

rePhil · #5 02-08-2020, 04:29 PM

The GCN way: https://www.youtube.com/watch?v=psbu9OH69sI&t=65s

https://www.youtube.com/watch?v=wfx3LqsCFSA

Dave · #6 02-09-2020, 09:23 AM

If you don't own a frame with the measurements listed by the manufacturer, I'm skeptical that they can be measured accurately enough to be of real value.

I matched the setup of my new Colnago to my old LOOK by setting the saddle height the same, then the setback the same, using a plumb bob, then setting the bar height the same, and finally setting the saddle tip to center of bars the same. Of course the same saddle is used on both bikes. With many stems only available in 10mm increments, you can only get so close and may have to decide between identical saddle tip to bar, or same saddle setback, or splitting the difference between the two.