Looking for forum members' input (bike fit data)

[ergott]

Originally Posted by wallymann

cool. i updated my data and added a comment clarifying that spec.

As did I. I usually keep records to bar center back when 31.8 wasn't standard.

[Mark McM]

Originally Posted by fa63

Based on what has been entered in so far, I think some interesting patterns are starting to emerge. Perhaps the one that stands out the most to me is the fact that cycling inseam does not appear to be a significantly better indicator of saddle height than just the rider height (Chart 1 vs. Chart 4). The fact that it is more difficult to measure inseam than height could be factoring into this, but interesting nonetheless (to me at least).

Well, there are a number of factors that neither height nor leg length account for that affect saddle height. These include foot length, shoe sole thickness and pedal cleat stack, saddle shape, and pelvis shape and tilt.

Unfortunately, none of the measurements in the table are fully direct measurements of bike fit dimensions, so there will always be measurement error bands. For example, BB to saddle top isn't really a measure of effective saddle height, nor is peddle top to saddle top, for that matter. Missing are the effects of cleat stack height and shoe sole thickness. Likewise, saddle to handlebar tops isn't a full measure of reach, because handlebar reach and brake lever shape also effect total reach. While pedal and handlebar dimensions might easily be included in the measurements, far less easy to measure are the effects of saddle shape, which interacts in a more complex way with the cyclist's anatomy. Perhaps the only way to get a true measure of cyclists fit is to measure the cyclist themselves (from a fixed set of anatomical points) while sitting on the bike.

[fa63]

Those are all very valid points. Plus cycling is a dynamic activity and these are all static measurements, but I think having this data is interesting and insightful nonetheless.

[drewellison]

I have yet to enter my data, but I have good intentions to do so. Maybe this weekend.

Just for fun, I think I'm going to set up one of my bikes at the "average" setup for my height, just to see how I'd feel if I were average. That means I'm going to have to slide my saddle back about 1.5 cm and drop my bars by 2.5 cm.

I hope I don't hurt myself.

[fa63]

I would try the increased setback, but probably not the increased drop. The average in that case doesn't mean much, as you can see from the scatter in the data

[drewellison]

Originally Posted by fa63

I would try the increased setback, but probably not the increased drop. The average in that case doesn't mean much, as you can see from the scatter in the data

I'm sure that's good advice. My back was hurting just thinking about making those changes! I was sure a visit to my chiropractor was in my near future.

I will definitely try the setback setting, for fun, at least, if not for serious consideration.

And yes, I might make the change in stages, or at least take it easy on a few rides just to get the feel for it.

That's the problem with having n+1 bikes. You make a fit change on one, then you have to do it on all the others, or keep track of which ones you've changed and make those changes over time. Arrgghhh!!!

[fa63]

Giving this a bump, in case anyone else would like to contribute (see link to the spreadsheet in my first post in this thread).

[fa63]

Here is a quick chart summarizing the findings so far:



On average the saddle height is virtually the same across the spectrum, but the pros reach a little bit (1-2 cm) longer...

[gregblow]

can you update the spreadsheet? i don't see anything. thanks

[fa63]

It works for me. Here is the link again:

https://docs.google.com/spreadsheets...it?usp=sharing