I have an existing bike that is setup very well for me.

I am building a new bike using the components from the old one and am trying to preserve that setup as much as possible.

Things I've measured:

1) Rear of saddle to split in stem (where the face plate bolts on) -- I'll be using the same bars and shifters (to measure reach)
2) Nose of saddle to center of BB (horizontally -- ie, setup of saddle setback relative to center of BB)
3) Saddle height from BB along seat tube
4) Saddle tilt
5) Saddle to bar drop

The 2 frames have different geometries, so this probably won't work, but I figure it's worth a shot.

Am I missing anything?

Thanks,
Bob

Check out this thread: https://www.bikeforums.net/showthread...f-Measurements

The poster in Post #9 mentions a Park Tools measurement sheet ... they're good. Have a look at them, print them out, and fill in the measurements.

sounds complete to me- check bar height from ground if using same tires, more accurate, especially with sloping tt

I like that Park tools chart. Thanks for sharing. What I have been doing till now is stand the two bikes up side by side and try and match the saddle position and handlebar position on both. I did not think of what would happen if a bike got stolen. Though recently, when I damaged one of my bikes in a crash, I started thinking along these lines. A formatted chart is a good idea.

I think you're pretty right with this - just one minor point:

If the seat tube angles are different, this won't be correct, so it's best to measure up from the BB vertically. If you put a spirit level along your saddle, you can measure setback (#2 in your list) using a plumb line and measure vertically from BB to where it intersects with the level.

It should work PERFECTLY if you get all the measurements right.

Having all the measurements on paper (I still use an Excel spreadsheet) also came in handy recently when we ordered Thorn touring frames from SJS Cycles. It's nice to have that information at our fingertips.

Great stuff. Thanks!

Bob

I'm about to try to match a new build as well, and just had a thought. Would differing rake/trail geometries wind up creating subtly different fit requirements?

I mean, if the handling or shock-absorbing characteristics of a frame are different, or handlebar shape/width, crank length, or even the Q factor in the new cranks... would your dialed in fit on bike "a" be so surely ideal on bike "b?" Just a thought experiment.

This is true, but by copying the measurements from original bike to new bike should still give you a really good starting point. I did the copy measurements thing a few years back when I got a dedicated road bike to along with my multi-tasking CX bike. After riding the road bike a few times, I did tweak the seat a little bit and ultimately flipped the stem over lowering the bars, but the initial setup still allowed me to just get out and ride without having any discomfort or needing to pull out an allen wrench every half mile.

check the crank length

it is kind of crude, but i definitely use photos to assist in my setup. i will take a picture of the old bike on a trainer in my garage/basement. i mark the location of the trainer and the camera, or i just keep both still until i get all of the parts switched over. i then take another picture of the new bike. i use GIMP (free) to overlay the images and adjust the transparency. this works really well for me in terms of adjusting things that aren't so easily measured like bar tilt, shifter angle, saddle setback, and saddle angle.