UCI Handlebar minimum width tool

Remix of the UCI handlebar width gauge as shared by them in the 3d printing model repository found on this page. A two piece tool that allows a mechanic to check a bike's handlebars for compliance on two parameters:

• Overall width of the bars more than 400mm

• Distance between the brake levers of at least 280mm.

This is covered in Article 1.3.022 of the UCI rules.

Use of this gauge is simple. If the gauge fits over the widest part of the handlebars, they are not compliant as they must be at least 400mm wide. If the gauge fits between the brake levers, that is a pass, as they must be at least 280mm apart. It is important to understand that the gauge clearing the large dimension is a failure, and clearing the small dimension is acceptable.

The basic design is a good one - it's a two piece design that allows the otherwise quite large tool to fit in toolboxes and be printed on most print beds. However, the model has several issues that I've addressed in this remix:

• The male dovetail on the left piece would print with supports, this is unnecessary. I've adjusted the dovetail so it still interlocks securely but does not need supports for printing.

• The female dovetail on the right piece has been adjusted to work with the above adjustments.

• The text is in a very thin font and is printed quite deep. I remove the UCI's own font and replace it with text that will print better.

• The UCI logo prints quite deep which isn't necessary.

• The stripes of the UCI logo were 0.09mm and would never show up. I thicken them up so that a slicer using Arachne will render them. This is admittedly a very minor thing but it just looks better. 

• The shapes at the center intersection had overhangs which were removed by the addition of chamfers - this prevents the need for supports at this point.

• I removed the original male/female notches which didn't fit well together and replaced them with holes for 10x3mm magnets which hold the two pieces together FAR more effectively. This also adds the capability to stick the tool to your refrigerator, as you can see in the photos. 😆

• There are two nubs at the outside ends of the tool which are offset when they are stuck together. I believe this is to separate the halves more easily, but this area had overhangs, so I fixed that. The addition of the magnets also reduces the need for these.

• I added a chamfer to the top and bottom surfaces to make it a little nicer without sharp edges.

• On the 280mm side, I added the text "CLEAR = PASS" as a reminder that the gauge fitting between the levers is a good thing.

• On the 400mm side, I added the text "CLEAR = FAIL" as a reminder that if the gauge clears the ends of the handlebar, they are too narrow and out of compliance.

• and finally, I add my own logo and that this is a remix. Don't hate me for wanting a little credit on the amount of work this needed.

Print instructions

Find a printer that will fit - the left side piece is 249.5mm so it'll just fit on a 250mm print bed. The right side is smaller at 239.5. Remember that if you have a slightly smaller print bed, orienting the part at 45 degrees (or somewhere around there) to the print bed may be just enough for this to fit. Unfortunately, I couldn't get it to fit a 180mm bed no matter how I tried.

I sliced it at 0.2mm for a 0.4mm nozzle, and printed it with three shells and 20% infill. Pretty much any settings will work. As mentioned in the fixes list, if you run a slicer with Arachne enabled or turn on thin walls, the stripes of the UCI logo will show up. This may not be a big concern for you but I figured if they put the logo on there, might as well print it accurately.

Optionally, source 4 10x3mm magnets and press them into the holes. It should be a press fit and not require any glue. If you do find it needs glue, I'd double check the finished 280 and 400mm dimensions to make sure your printer is printing accurately. The 280mm side should measure 279mm and the 400 should measure 399 - they include a 1mm tolerance.

Speaking of tolerances - the dovetail is a close fit coming off my printers, and after a couple assembly/disassembly iterations it does loosen up. When it's been particularly tight, I find a drop of lube will help ease the process a bit more. I haven't had to resort to sanding or filing, but do be aware that it will be a quite close fit, and I can't control how well your printer will or won't render this interface.