Buy a hollow pool noodle and split it lengthwise, some further modification may be required
for example
https://www.amazon.co.uk/Noodle-Hollow-Swimming-Rehabilitation-Children/dp/B07P5YBG56
prefer a ready-to-buy bike product but thanks
https://www.customriders.com/4062/products/united-bmx-x-bicycle-union-frame-top-tube-pad-full-colour.aspx?currency=GBP&chosenAttribute=MIBI01&gclid=CjwKCAiAtK79BRAIEiwA4OskBu39I-xK_bPzINedNoJzKIe3_Mm4v0ZMAkyU0gejSQqMvPlirYXyCBoCpQ0QAvD_BwE
@Albb started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
Buy a hollow pool noodle and split it lengthwise, some further modification may be required
for example
https://www.amazon.co.uk/Noodle-Hollow-Swimming-Rehabilitation-Children/dp/B07P5YBG56