Tldr; Does anyone have reccomendations on tools for getting precise bike fit measurements.
I’ve looked at the abbey tools fit kit ( Fit Kit ) but it is out of stock.
Longer preamble: I redid my bikefit a few months ago and we moved my saddle on my SL8 as far forward as it would go. We talked a bit about whether or not it should move even further forward, but that would require a 0 offset post.
I think I want to try that 0 offset, but I have moved away, so I can’t go back as part of my fit follow up.
I’d like to find an idiot proof tool that removes the possibility of me taking inconsistent measurements as I start to adjust things on my own.
No tool is idiot proof, as accuracy depends more on the user and the process. A 30 dollar tool well used can be better than a 300 dollar tool poorly used. You could probably make that change with just a tape measure, but plenty of other options like the Ryden tool can be found on fitkitsystems dot com.
Personally, I just put my bike with the rear wheel perpendicular to a wall (e.g. ever so slightly leaning against an adjacent wall).
Where the wall meets the ground is (0;0) of the X/Y axis system.
I measure the coordinates of all important points of my bike, and afterwards I recalculate everything in relation to the bottom bracket position.
If you then measure the coordinates of the bottom bracket of your new bike using the same method, you can easily calculate where all points need to be on the new bike to replicate your position.
The more precise you can position your bike and measure the coordinates, the better.
There’s the possibility of some parallax errors due to this method of measurement, but for greater precision, something like the Ryden Tools or the options from Fit Kit Systems would work better to reduce significance of those variables.
I have the non-Pro version of the Ryden tool. I’ve learned how to make it work, but I think there are some pain points. If I had to buy it again, I’d get the Pro version.
The ruler is flexible. With some practice, you’ll learn how to keep it straight. I think the Pro version uses a metal ruler, so I expect it to make measurements more consistent.
The friction-fit coupler that holds the two halves of the ruler can crack if you disassemble the tool between uses. To their credit, Ryden sent me a replacement. The Pro addresses this by using thumb screws.
A digital level is much easier to use than a smart phone. I attach mine to the Ryden with 3M Command picture hanging strips (i.e. adhesive velcro, but with less play). The Pro version has a digital level attachment available.
In the past, I’ve used the Specialized BGFit XY Tool. It looks like it would be more precise, but in the end, it was cumbersome having a scaffold bolted to the bike while making adjustments.
I’ve got an Ergon TF1 and their fitting box - lets me get close enough to my reference bike - it has a few design choices that make it very easy to work with, e.g., the spirit level has an indent along the long side so it can fit to the paper template that goes off the bottom bracket to measure offset).
Tools are only as good as the person using them. I’ve tried the ryden tool but I find it to be imprecise b/c of the flex in it. Ive not tried others but im yet to find anything cost effective to try. The closest I’ve found is this company in Italy but the cost is still too high. I also don’t like tools that work off polar coordinates (personal thing) like the velo angle.
For me at the end of the day the best thing for home use has continued to be a tape measure, plumb bob and an 80mm tool. A self leveling level can work if you are mindful of parallax effect and align it so it intersects the pedal spindles (set to 12 & 6) and bottom bracket.
For measuring the saddle angle there is no good way, just be consistent with how you do it. For me the easiest method is measuring across the full length of the saddle, but some people are good at eyeing the middle third.
Nearly every measurement you would want (bar x/y, bar drop, grip reach, setback, etc) is doable with some practice and consistency. The only tricky thing is if you decide to try different saddles. There’s a few ways you can do it: just use difference of the lengths, use the 80mm tool, lay them on top of each other and align the sitting area, measure from the stem to the sitting area.
I definitely recommend CMH Designs 80mm tool. He also has other tools to help including the crank arm tape holder. For saddle angle I bought a digital level and use an ipad or something else rigid to span the entire length of the saddle to adjust or replicate. It may not be good to use with different saddles but should be useful to set back to the desired angle.
I have the non-Pro version of the Ryden tool and encountered the same issues. The flexibility of the ruler really makes me question the repeatability of measurements. I switched the the CMH 80mm tool, shimano crank tool with magnet and a measuring tape. It’s a much better solution.
Agreed. the CHM tool and shimano crank insert with the magnet, along with a measuring tape. The rigidity of a a metal measuring tape makes it very accurate. It works so well and you can easily travel with it too.
Hopefully this will be in the market in the next 6 months. Laser guided X/Y that measures off of BB center, making it repeatable to virtually any bike…
I agree with earlier posters that for a change of seatpost you could most likely make due with a tape measure and a plumb bob (a bolt or nut tied to a piece of string will do).
When I recently wanted to transfer the touch points (seat, pedals, handlebar) of one bike to another I used a laser level with the crosshair centered on the BB and a tape measure. Lean the bike against the wall in such a way that it almost falls over, put the start of the tape measure on the part you’d like to measure (e.i. the 80mm saddle width point), hold the tape measure horizontal and read the dimension at the point where the laser line intersects the tape measure. Simple, fast and accurate enough.
+1 for the CMS designs 80mm tool. With a plumb bob, a laser level, tape measure, and level, you are mostly good to go to transfer measurements between configurations.
One note from the world of data science: When measuring your position, you’re shooting for precision (i.e, I can repeatedly arrive at the same measurements) rather than accuracy (i.e., the “true” number of all your measurements.) Although those might seem equal, they are not. The OP got the distinction right.
The tools above are very useful in precisely capturing position for later changes. You would need something else entirely if you wanted to accurately determine your position. This is the realm of laser trackers and other cool doodads in a fitting studio.
The most useful tool I’ve bought in a long time is one of these cheap self leveling crosshair lasers.
Need to set saddle setback from the BB? Line the laser up with the crank centerline, and measure your saddle nose to the laser. Different saddles? Measure from the BRP to the laser.
Want to measure saddle to bar drop? Line the laser up with the bars, measure from the saddle straight down to the laser.
Lever/Control Stack/Reach? Put the laser crosshair just behind the brake hood and measure from the BB in both dimensions.
