Originally Posted by
Kontact
Hilarious edit!
The way virtually everyone measures bikes involves setting setback with a vertical level or plumb bob, and then setting the handlebar drop and reach from the saddle also using a level. They do it that way because almost no one owns a 4 foot framing square that reaches from the floor to the saddle or bars. And if you use a framing square you'd need to put reference marks on the floor so you can move the square around, and you still won't be able to directly measure things like handlebar angle or saddle angle. And the floor has to be evenly not level - which they rarely are - or the framing square will keep changing what it shows as vertical.
But then you still haven't solved the problem of transferring fit off the Kickr bike because that fit is actually level, despite the slope of the floor it is sitting on. So you're going to be collecting those numbers with a level and applying them with a framing square.
All of which are doable, but involve a lot of problematic steps where measuring and arithmetic errors can come in because there are two techniques using two different sets of tools.
After seeing all the different ways my colleagues could mess it up, I built a level track for the bike's tires with a moveable grid board that centers on the BB location without losing level. Then you can observe setback, stack and reach directly for each component and even mark those locations on the grid with chalk. Pull the source bike out and you can read off the numbers or put a second bike in and move the components to match the marks.
Well I'm glad you are amused, but this has actually been a useful thought process for me. I do now realise you are right about the potential issues with using a plumb bob to measure saddle setback if your floor happens to be on a slope. So I will eat some humble pie for you there and thank you for explaining your reasoning. It does make sense now.
The method I actually use for transferring a setup is pretty simple. I use a floor and wall as a reference and for saddle setback I rest my back wheel against the wall, measure the distance of the BB and saddle to the wall and subtract the two. But I do happen to have an inclinometer to check that the floor and wall are actually square. I also measure my road bike and Kickr bike on the same floor and against the same wall to minimise any reference error. I have also measured the saddle setback with a plumb bob on various floors around the house and get the same answer within a mm. So I guess my floors are flat enough, as I would have thought most hard screed floors are.
For bar drop I measure the saddle height and bar height vertically from the floor and subtract. I'm sure you would agree that a slight slope would not really matter using this method.
For reach I simply measure directly from saddle to the hoods. So the floor doesn't matter at all.
Saddle height I measure directly from BB centre to centre of saddle. Again floor slope is irrelevant.
I therefore have 4 simple measurements to transfer and only saddle setback requires a consistent reference plane. So I don't think it's very hard to accurately transfer a setup from my Kickr Bike to road bike. The biggest mistake I've ever made in this process is not having my Kickr Bike set to zero deg tilt before measuring!
I'm now curious how much on the piss your floors must be? I've just been checking all our floors with an inclinometer and they all level within the 0.1 resolution of my inclinometer.
I would also genuinely like to hear some critique of my above method and what errors would arise.