{"id":1780,"date":"2025-07-09T14:20:58","date_gmt":"2025-07-09T12:20:58","guid":{"rendered":"https:\/\/wp.stromer-tech.info\/?post_type=ht_kb&#038;p=1780"},"modified":"2026-05-31T11:44:22","modified_gmt":"2026-05-31T09:44:22","slug":"crank-arm-loose-falls-off-cannot-be-loosened","status":"publish","type":"ht_kb","link":"https:\/\/wp.stromer-tech.info\/en\/knowledge-base\/kurbelarm-locker-faellt-ab-laesst-sich-nicht-loesen\/","title":{"rendered":"Crank arm loose... falls off \/ cannot be loosened"},"content":{"rendered":"<h3 class=\"wp-block-heading\">Crank arm falls off<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\" id=\"74fb7724-2b82-49c6-9a1a-ffffe026f8cd\">One problem that is less expected is the loosening or loosening of the left crank arm on cranks with ISIS mounts. It is not a Stromer-specific problem and also happens with other brands. The problem announces itself and does not happen immediately.<\/p>\n\n\n\n<figure class=\"wp-block-video\"><video height=\"540\" style=\"aspect-ratio: 540 \/ 540;\" width=\"540\" controls src=\"https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer-Kurbelarm-lose-Video.mp4\" playsinline><\/video><\/figure>\n\n\n\n<h5 class=\"wp-block-heading\" id=\"db989d0e-4930-4a86-bc99-a84e41d53c59\">Cause<\/h5>\n\n\n\n<p class=\"wp-block-paragraph\" id=\"aee7ad12-660c-4e35-a70e-60b36b06e6b3\">The cause is usually the assembly. The screw lock applied at the factory is not very tight, so that the crank can come loose even if it is fitted correctly. Furthermore, the M17 screw connection is sometimes incorrectly greased (because this is sometimes the case with other cranks).<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Repair<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The left crank arm's construction is self-extracting, and it doesn't require any special tools to remove it. You can loosen the arm counter-clockwise with an 8mm Allen wrench. <\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The M27x1 pull ring must be loosened clockwise, against the arrow. <\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"768\" src=\"https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Kurbelschraube-_mit_Abzieher_Gossamer_T52_Isis_Kurbelsatz-1024x768.jpeg\" alt=\"\" class=\"wp-image-11250\" style=\"width:400px\" srcset=\"https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Kurbelschraube-_mit_Abzieher_Gossamer_T52_Isis_Kurbelsatz-1024x768.jpeg 1024w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Kurbelschraube-_mit_Abzieher_Gossamer_T52_Isis_Kurbelsatz-300x225.jpeg 300w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Kurbelschraube-_mit_Abzieher_Gossamer_T52_Isis_Kurbelsatz-768x576.jpeg 768w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Kurbelschraube-_mit_Abzieher_Gossamer_T52_Isis_Kurbelsatz-50x38.jpeg 50w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Kurbelschraube-_mit_Abzieher_Gossamer_T52_Isis_Kurbelsatz-1536x1152.jpeg 1536w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Kurbelschraube-_mit_Abzieher_Gossamer_T52_Isis_Kurbelsatz-2048x1537.jpeg 2048w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Kurbelschraube-_mit_Abzieher_Gossamer_T52_Isis_Kurbelsatz-16x12.jpeg 16w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Kurbelschraube-_mit_Abzieher_Gossamer_T52_Isis_Kurbelsatz-60x45.jpeg 60w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Kurbelschraube-_mit_Abzieher_Gossamer_T52_Isis_Kurbelsatz-100x75.jpeg 100w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">Tight <em>= Tighten \/ Crank clockwise, the puller clockwise<\/em><\/figcaption><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">The thread of the crank screw and in the axle must be degreased and cleaned. Afterwards, the crank screw or the thread in the axle can be fitted with a little Loctite 242 and fastened with the torque specified on the crank screw.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">See also <a href=\"https:\/\/youtu.be\/gsDEP5Ljd3E\" target=\"_blank\" rel=\"noreferrer noopener\">Video1<\/a>&nbsp;| <a href=\"https:\/\/www.youtube.com\/watch?v=pRdoIwVMShM\" target=\"_blank\" rel=\"noreferrer noopener\">Video 2<\/a> | <a href=\"https:\/\/youtu.be\/mxAj-zbynPI?si=QHJ_pMFma0a5m2pb\">Video 3<\/a><\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"937\" src=\"https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/a1ece2a4-c478-4c62-9443-849bc56a8652.jpg\" alt=\"\" class=\"wp-image-1782\" style=\"width:600px\" srcset=\"https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/a1ece2a4-c478-4c62-9443-849bc56a8652.jpg 1024w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/a1ece2a4-c478-4c62-9443-849bc56a8652-300x275.jpg 300w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/a1ece2a4-c478-4c62-9443-849bc56a8652-768x703.jpg 768w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/a1ece2a4-c478-4c62-9443-849bc56a8652-50x46.jpg 50w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/a1ece2a4-c478-4c62-9443-849bc56a8652-60x55.jpg 60w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/a1ece2a4-c478-4c62-9443-849bc56a8652-100x92.jpg 100w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n<\/div>\n\n\n<h3 class=\"wp-block-heading\">Share<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The <a href=\"https:\/\/www.ebay.ch\/itm\/358285728909\">Puller<\/a> consists of four parts, an M17 screw with an 8mm internal hex, an M27x1 retaining ring, a MW497 domed spacer, and a MW080 spacer.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"901\" height=\"689\" src=\"https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Kurbelarmverschraubung_links_M17_mit_Selbstabzieher_M27x1.jpg\" alt=\"\" class=\"wp-image-10531\" style=\"width:400px\" srcset=\"https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Kurbelarmverschraubung_links_M17_mit_Selbstabzieher_M27x1.jpg 901w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Kurbelarmverschraubung_links_M17_mit_Selbstabzieher_M27x1-300x229.jpg 300w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Kurbelarmverschraubung_links_M17_mit_Selbstabzieher_M27x1-768x587.jpg 768w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Kurbelarmverschraubung_links_M17_mit_Selbstabzieher_M27x1-50x38.jpg 50w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Kurbelarmverschraubung_links_M17_mit_Selbstabzieher_M27x1-16x12.jpg 16w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Kurbelarmverschraubung_links_M17_mit_Selbstabzieher_M27x1-60x46.jpg 60w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Kurbelarmverschraubung_links_M17_mit_Selbstabzieher_M27x1-100x76.jpg 100w\" sizes=\"auto, (max-width: 901px) 100vw, 901px\" \/><figcaption class=\"wp-element-caption\">The spacer disc MW080 mounted on the axle side is missing in the picture.<\/figcaption><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\"><strong>AL<\/strong>\u00a0stands for\u00a0<strong>Aluminum<\/strong>\u00a0- these rings are available in different materials (e.g., also steel for Shimano cranks), and AL denotes the aluminum version, which is typically used for FSA or other aluminum bottom brackets.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>LH<\/strong>&nbsp;stands for&nbsp;<strong>Left Hand<\/strong>&nbsp;(Left hand) \u2013 this means that this ring is a&nbsp;<strong>Left-hand thread<\/strong>&nbsp;(counter-clockwise to tighten). This is common for bottom bracket\/crankset components on the left side of the frame so the connection doesn't loosen on its own from pedaling motion.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/wp.stromer-tech.info\/en\/knowledge-base\/chainring-bottom-bracket-wear\/\">See<\/a> also PROBLEMS \u2013 chain (-wheel) \/ pulleys and belt \u2013 <em>\u201aWear: Chainring \/ Bottom Bracket (<strong>Spare parts<\/strong>(\u2018<\/em><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Crank arm cannot be released<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\" id=\"6e7c8d86-1c33-4951-9a80-5774176ab133\"><strong>Solution variant 1<\/strong>: Drive a few meters.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\" id=\"832fa61f-c5f2-40d4-827a-79a1d2215ba0\"><strong>Solution variant 2<\/strong>Treat the crank from behind with a little rust remover (e.g. WD 40) and then leave to work for 24 hours. Alternatively you can use Coca Cola - no joke. Then lightly tap the crank arm around the bottom bracket axle with a rubber or soft-face mallet - the crank should then come loose.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\" id=\"320ffffa-21ca-4570-98d5-6a20f5433ed5\"><strong>Solution variant 3<\/strong>Heat the crank arm around the crank axle with a hot air gun - the crank should then loosen.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\" id=\"dce47871-ebf9-4b1e-ba91-c9c37d7b5f57\"><strong>Solution variant 4<\/strong>Use a professional squeegee.<\/p>","protected":false},"excerpt":{"rendered":"<p>Kurbelarm f\u00e4llt ab Ein Problem, das man weniger erwartet, ist der sich lockernde bzw. l\u00f6sende Kurbelarm links bei Kurbeln mit ISIS-Aufnahme. Es ist kein stromerspezifisches Problem und passiert auch bei anderen Marken. Das Problem k\u00fcndigt sich an und passiert nicht von jetzt auf sofort. Ursache Die Ursache ist meistens die&#8230;<\/p>","protected":false},"author":1,"comment_status":"open","ping_status":"closed","template":"","format":"standard","meta":{"footnotes":""},"ht-kb-category":[211],"ht-kb-tag":[522,524,523,521],"class_list":["post-1780","ht_kb","type-ht_kb","status-publish","format-standard","hentry","ht_kb_category-p-diverses","ht_kb_tag-fsa-gossamer","ht_kb_tag-isis-aufnahme","ht_kb_tag-selbstdemontage","ht_kb_tag-self-extracting"],"_links":{"self":[{"href":"https:\/\/wp.stromer-tech.info\/en\/wp-json\/wp\/v2\/ht-kb\/1780","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wp.stromer-tech.info\/en\/wp-json\/wp\/v2\/ht-kb"}],"about":[{"href":"https:\/\/wp.stromer-tech.info\/en\/wp-json\/wp\/v2\/types\/ht_kb"}],"author":[{"embeddable":true,"href":"https:\/\/wp.stromer-tech.info\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/wp.stromer-tech.info\/en\/wp-json\/wp\/v2\/comments?post=1780"}],"version-history":[{"count":40,"href":"https:\/\/wp.stromer-tech.info\/en\/wp-json\/wp\/v2\/ht-kb\/1780\/revisions"}],"predecessor-version":[{"id":11452,"href":"https:\/\/wp.stromer-tech.info\/en\/wp-json\/wp\/v2\/ht-kb\/1780\/revisions\/11452"}],"wp:attachment":[{"href":"https:\/\/wp.stromer-tech.info\/en\/wp-json\/wp\/v2\/media?parent=1780"}],"wp:term":[{"taxonomy":"ht_kb_category","embeddable":true,"href":"https:\/\/wp.stromer-tech.info\/en\/wp-json\/wp\/v2\/ht-kb-category?post=1780"},{"taxonomy":"ht_kb_tag","embeddable":true,"href":"https:\/\/wp.stromer-tech.info\/en\/wp-json\/wp\/v2\/ht-kb-tag?post=1780"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}