2026-09-14

Last modified: 2026-09-14 20:45:44

• Metals inventory
• Cyclecar front wheel bearings

Metals inventory

I took measurements of all of the pieces of metal I have, so that I can avoid unnecessarily buying duplicates.

Transcription by gpt-5.6-terra in Codex:

Flat bar

Round bar

Round tube

Box section

Angle

Cyclecar front wheel bearings

I have a 2nd pair of pit bike wheels now, and my front wheel bearings arrived today. They are 20x35x9, this is a "non-standard size" and as such they are no-brand generic bearings off Amazon.

The original plan was to fit 2 of them on each side of the hub just to account for the fact that they are unknown quality and unknown load rating, however I assembled one like this and I had to hammer a 20mm shaft in to get it to go all the way through, and it wouldn't spin freely, it was over-constrained.

So I knocked those bearings back out and put them in the box of random bearings, and assembled both wheels in the conventional way, one bearing each side, using the remaining 4 bearings.

There is a spacer in between them. There is approximately 61mm from the outside of one bearing to the outside of the other.

I took one of the seals off one of the bearings that I'm not going to use so that I could look inside:

They have 10 balls.

The seals are marked "6003RS", and ChatGPT research is that apparently NSK's actual 6003 bearing (which has 17mm ID instead of 20mm) uses 10 balls of 4.762mm diameter each, so based on the marking on the seal and the number of balls it is probably a 6003-derived bearing but with the inner diameter enlarged. NSK's 6003 is rated for 6.6 kN dynamic load or 3.25 kN static load, which is well above what I intend to encounter.