These are for TPU only, they don't work well with hard filaments because they are completely ridged if you don't print TPU. These are very robust and will fit most vehicles.

I have a bunch of sizes and you can mix and match and just print which ever ones you need, or print them all to see what size fits best. There are 3 shaft sizes, skinny, normal and wide to fit various size holes and there are 6 base sizes, 30mm, 25mm, 20mm, 17mm, 14mm and 10mm. Also, you can scale any of them to produce custom sizes if you need.

PRINT SETTINGS:
TPU only
Print slow, like 20-30mms
.20 or .24 layer height works with no supports

3 wall loops
Infill type doesn't really matter, there is hardly any infill on these

If you would like to leave a tip for my hard work you can do so here :D  https://www.paypal.com/ncp/payment/Y5DRF7PN8S5AJ