Should you join a chain gang?

Hello All
Thank You a lot for this article and comments. Iam mechanical designer and my next build will be on chain. Based on this I refreshed my university education and made some research with basic calculations. Please check it, mainly chain riders and please let me know Your feedback on this theory.

At first european 05B are more or less in the same strength category like ASA25 and 06B is equal to ASA35H. What is very iportant for us is the pitch of chain which is together with tooths define diameters of sprocket. And diameter on wheel should be so small as is possible ,to have enought space out of road. On the other side, motor sprocket should be so big as is possible to avoid “polygon effect”. See fallowing link. Sprocket Design Tutorial - CAD - Chief Delphi
Therefore in case that You would like to have fast board (slighly more than 50km/h) and still usefull torque , my recomandation is to choose motor with low kv and gear ratio aroun 1:3. For efample 140kv and 10:36 (or 9:35)with 06B chain.
In industry , to have long chain life, motor sprocket should have odd number of tooths and wheel sprocket even number of tooths. Reason is to have equal abrasion for complet setup. I do not want to put all rules here, You can check Your gear ratio here: ⚡Chain and Sprocket Calculator | RPM and Chain Speeds

Iam already made few of calculation. I would like to use motor Flipsky 6374 140kv 3,5kW. This motor have max. torque 8N/m. My targer was to use ASA25H chain becouse of small pitch, unfortenatly with this motor Iam slighly cross safety border line. So I must choose B06 or ASA35. Iam from Europe so B06 is for me most avalible. If You are not able calculate it, You can use following pictures. It looks for me also usefull.


and

Next point is the maintenance. Chain shoul be time to time greased and in case of any mechanical damage should be replaced. Based on Czech or Slovak standard should be replaced after 2% of extension ,according EU standard it is after 3% extension. I mean this is very important unfortenatly I never saw this on any Youtube builds where guis are using chain from Alixpres without any strength tension value introduced by seller. I would say ,it can be little risky.
Idea of closed chain gear it looks nice, maybe I will design it, but definitly with 06B chain. I do not want to see ,what can happen inside gearbox in case that chain will be broken and block wheel:(

Thank You All for reading this comment and please let us to know if this theory was tested by You.

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