# OSL belt re-tensioning **URL:** \ **Category:** Hardware\ **Created:** [December 18, 2025, 10:07pm UTC](https://opensourceleg.discourse.group/t/osl-belt-re-tensioning/171 "2025-12-18T22:07:05Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![cangelid](https://avatars.discourse-cdn.com/v4/letter/c/5e9695/32.png) [@cangelid](https://opensourceleg.discourse.group/u/cangelid)\ **Post date:** [December 18, 2025, 10:07pm UTC](https://opensourceleg.discourse.group/t/osl-belt-re-tensioning/171/1 "2025-12-18T22:07:05Z")
I’m working with the OSL and need to **re-tension the belts** (for the knee/ankle). Has anyone had to do this before? If so, I’d really appreciate: - any **step-by-step instructions** you followed, - any tips on how you verified proper tension (e.g., method, signs of over/under-tension), - and anything to watch out for (alignment, slipping, noise, etc.). If there’s a doc, video, or internal note you can point me to, that would be amazing. Thank you! ---
**Author:** ![OSL\_Admin2](https://yyz2.discourse-cdn.com/flex036/user_avatar/opensourceleg.discourse.group/osl_admin2/32/106_2.png) [@OSL\_Admin2](https://opensourceleg.discourse.group/u/OSL_Admin2)\ **Post date:** [December 19, 2025, 11:39pm UTC](https://opensourceleg.discourse.group/t/osl-belt-re-tensioning/171/2 "2025-12-19T23:39:16Z")
Hey Chara, we currently have some [written tutorials on belt tensioning](https://opensourceleg.org/hardware/tutorials/belt_tensioning) available on the website. Let me know if you find this helpful or if there’s anything we could clarify or improve in the instructions. ---
**Author:** ![cangelid](https://avatars.discourse-cdn.com/v4/letter/c/5e9695/32.png) [@cangelid](https://opensourceleg.discourse.group/u/cangelid)\ **Post date:** [December 22, 2025, 12:02am UTC](https://opensourceleg.discourse.group/t/osl-belt-re-tensioning/171/3 "2025-12-22T00:02:45Z")
Thank you, Kiara, for pointing out the tutorial! If I understand correctly, the first step would be to disassemble the knee/ ankle joint to gain access to the belt and pulleys. Is there any way to do the belt tensioning without fully disassembling the OSL, or are there any workarounds to that? Any clarification or short video on that would be great. Thanks again for the help! ---
**Author:** ![ldevillez](https://yyz2.discourse-cdn.com/flex036/user_avatar/opensourceleg.discourse.group/ldevillez/32/71_2.png) [@ldevillez](https://opensourceleg.discourse.group/u/ldevillez)\ **Post date:** [December 23, 2025, 7:59am UTC](https://opensourceleg.discourse.group/t/osl-belt-re-tensioning/171/4 "2025-12-23T07:59:51Z")
Hello Chara Angelidou, You will need only to remove the actuator to tension the belt. Without the actuator you have access to the 4 screws of the shaft cap eccentric multi (2 on each side). You can remove those screw, tighten the belt by rotating the eccentric shafts and then put back the screw. Kind Regards, Louis ---
**Author:** ![cangelid](https://avatars.discourse-cdn.com/v4/letter/c/5e9695/32.png) [@cangelid](https://opensourceleg.discourse.group/u/cangelid)\ **Post date:** [December 30, 2025, 6:33pm UTC](https://opensourceleg.discourse.group/t/osl-belt-re-tensioning/171/5 "2025-12-30T18:33:33Z")
Thank you, Louis, for the clarification. Do you have any guidelines as to how I can tell that the belt has been properly tensioned? With the actuators removed, it is not very intuitive how much the eccentric shafts should be rotated. ---
**Author:** ![ldevillez](https://yyz2.discourse-cdn.com/flex036/user_avatar/opensourceleg.discourse.group/ldevillez/32/71_2.png) [@ldevillez](https://opensourceleg.discourse.group/u/ldevillez)\ **Post date:** [December 31, 2025, 9:42am UTC](https://opensourceleg.discourse.group/t/osl-belt-re-tensioning/171/6 "2025-12-31T09:42:11Z")
Hi ! You should still be able to move the joint quite easily with the tensioned belt. If the belt is not tensioned enought, it will skip and then you can tensioned it more. I think the OSL team use a 3D printed tool to tension the belt to reach the right amount.