I have been looking at ways to improve the design of my tracks.
The existing tracks have a flexible 3D printed insert to stop them stretching too much and provide the drive pins but there is quite a lot of friction between the rubber and the side walls of the wheels and also small bit of rubber from around the drive pins shown below gets into the gearboxes.
![Image](https://ohp8uw-ch3301.files.1drv.com/y4mhydh0ApkW2y7tceo15DUwTluelVqkJxYCbQ3-RYztxS4gwmkgbOLbFh0CDqadaLPtPJpSofKWMKDCofAUzwru2NIcgQk_2MrQPsLAtb94j0DsKR3gbobFCbUU9OyEY-aXK1Yfbx9wRc0XQUa9IlxRc08y3Dn6-YhqJYGUvHfeCBVbtbKzJ7VAnkoPSmEBMwZYJECSx6QcBdXo1_2SFBj5Q?width=800&height=600&cropmode=none)
So I have changed the design so only the 3D part runs on the wheels.
Here is the insert, the insert in the mold and the finished track.
![Image](https://ozpeda-db3pap001.files.1drv.com/y4m5_sU15oucXex_Co_M7DUZYBbiYTJb3_9npwh1KvvzCrG1S0YQYgu7AxHoS_pHSqV_xRHISbPbYweTLrGw4YT3sDEufHethOIL72wjZm3uYLkgTRMoZhvzWL3nEj-777Vyd_QybnDl_ZqCFmr-CIw2cOHuy_2Jiu89SSF-ryEMrDBnf6tVCrlUogx0DxxjDWCNAePkyIH5QPa0sHm8zr6gg?width=1080&height=810&cropmode=none)
Below is a close up of the insert showing how the rubber is molded through the three holes into the hollow drive pin area to ensure the tracks are held on firmly.
![Image](https://zafema-db3pap001.files.1drv.com/y4mHx1nKytbDgrvbdXBEAmun9LVngA3WKHnHku1FbMTAepT2NBwIV5aDaKAQMPd3-mFK8D-MkhVpvZzM5IBSMQ3VVyiEz-DRQbuNBB-3WOsPlGfdPjCoKUI62iE34mG9KMha4Y-Lx7lNxu0ORY6U_vVQJIr8Fhs8KFkeKINMR2Wo80jlmrXzGvpT1cJcAYgbQufj5VzyAgp6wTefA3XEGKUCQ?width=1080&height=810&cropmode=none)