Tire fit/clearance gauge for 559/584/622 ( 26"/650b/700c)

Whether you're contemplating a change of wheel size, or just want to know the maximum tire size that will fit in your frame or fork with your current wheelset, this tool will remove the guess work.* 

Based on the idea of the checker developed by Hahn Rossman, no longer sold by Compass/Rene Herse, and modeled by Aiber, but adapted to be more friendly for 3d printing.

[update 11/11/24: Hahn Rossman sells a newer version of the original design: https://www.rossmancycles.com/toolsparts/tire-fit-guage https://forum.customframeforum.com/t/tire-checkers-and-crank-gauges-back-in-stock/1157 )

Instructions for use are the same as the original tool. Great write-up here: https://www.roadbikerider.com/hahn-rossmans-ingenious-tire-clearance-checker/

Instead of using the long hook & extension (gauge) piece that's too long to print as a single piece with most 3d printers, and which is really designed to be cut from stouter plastic or metal, I adapted the concept for use with 3/16" solid metal rod that can be easily sourced at a hardware store for under $5.

The hook and indexing end pieces can be glued to the rod with superglue, gorilla glue, or whatever permanent glue you have laying around.

You have a couple options for the hook: 12mm or 20mm hook with a series of inserts to reduce the hook to 15/12/10mm to accommodate the most common standards for QR Skewers and Thru Axles. (10mm will work on a 9 or 10mm dummy axle for QR. The .5mm slop won't be an issue if you're respecting proper tire clearance)

Each wheel size requires a separate tool, with the length of the metal rod being critical:

• For 26" (559 BSD), cut the metal rod to 269.5mm
• For 650b (584 BSD), cut the metal rod to 282mm
• For 700c (622 BSD), cut the metal rod to 301mm
• To calculate the length of rod needed for a different wheel size, take the BSD, divide by two, and subtract 10.7mm (the length added by the hook).

I've included tire gauges in: 32/35/40/48/50/56mm and can upload additional sizes if requested. Alternately, the Onshape project is available for you to copy and modify here. Simply change the diameter of the circle on any of the tire gauge tabs to create a different size.

'* Tire sizing can be a minefield. Stated/printed width does not always equate to measured width, and internal rim width can influence actual measured width of a tire. Tires are generally made to measure the stated width on the design rim. Finding out what inner width of the design rim can be impossible, but a general rule of thumb is that for each mm wider or narrower the internal width of a rim gets, tire size increases or decreases by 0.4mm Bicycle Rolling Resistance can be a helpful resource as they publish actual tire width and use the same rim inner width or 17.8mm for all their testing.

Based on the idea of the checker developed by Hahn Rossman, and modeled by Aiber, but adapted to be more friendly for 3d printing. 

 https://www.roadbikerider.com/hahn-rossmans-ingenious-tire-clearance-checker/

Instead of using the long hook & extension (gauge) piece that's too long for most 3d printers, and which is really designed to be cut from stouter plastic or metal, I adapted the concept for use with 3/16" solid metal rod that can be easily sourced at a hardware store for under $5.

Modeled a hook and indexing end piece to glue to the rod and made tire gauges to fit the indexing end.