# How much tension can I expect to get out of a lego chain before it starts to give away?

Assuming I am using the technic chain links to make a chain, how much force can I expect to be able to get out of the chain before it breaks?

Suppose I am using a 16t gear to directly drive a 24t gear and have it at the optimal tension for a short distance

And when it does reach its limit, will it break or will the links just snap undone?

P.S. - I don't currently own any of these pieces, and would like to get a rough idea first before I buy any and start playing with them - I am hoping to get a considerably larger amount of force from then than a rubber band before it starts to slip, say the full stall power of a PF M motor.

edit: theoretical test methodology: Starting from Philo's motor comp, I would pick a motor that I had (say a PF M motor), and gear it up (so that it spins fast), say by 1:3 with a 24t driving an 8t - after that, I would put another 24t on the same axle as the 8t, and place the chain on it - then put another 24 such that the chain lands on it, and lock the last 24t gear's axle such that it does not move (perhaps the last 24t gear can be a clutch gear). Then turn on the motor and see if it holds - assuming it does, I would know that the chain can handle at least 1/3 (gearing) 11 N.cm (PF M stall torque from Philo) - from then I would change the gearing, perhaps with a 20t and 12t, or even 1:1 depending on how it seems to fare, and repeat the test until it does break. If the clutch gear starts to spin, I would briefly lock it in place with my hands to get an accurate measure.

• If you can accommodate them, the Technic wide track links are significantly stronger – Móż Dec 14 '15 at 2:48
• I don't have a number for you, but I did discover fairly quickly that they're much stronger if you turn the clips outward instead of the prettier inward. Done that way, it'll easily stall a 71427 motor with a 14t gear, which is the smallest I've seen that works. (I use two of these face-to-face: alpha.bricklink.com/pages/clone/catalogitem.page?P=4143) The 8t just doesn't have enough tooth depth to grab it very well: alpha.bricklink.com/pages/clone/catalogitem.page?P=3647 I've never actually broken a link, but I've had them unclip a lot when they were turned inward. – AaronD Dec 17 '15 at 3:04
• @AaronD thanks, that's definitely useful to know – user2813274 Dec 17 '15 at 19:59
• I have had a lot of bad luck with these standard technic chain links, everything from slipping to coming unlinked to even breaking under enough stress (which isn't a lot in my experience). My current go-to for chain/belt driven devices is the old Technic, Link Chain Large, which is driven with the Expert Builder gears (parts g9, g15, and g21). – PGmath Jul 4 '16 at 16:40

## 1 Answer

Simply test it, then divide the force by 2 in order to stay the safe side.

• See the PS part of the question - I would test it if I had the parts – user2813274 Dec 7 '15 at 4:14
• To improve your answer - could you detail the testing methodology you would use, as well as the measuring setup ? – Phil B. Dec 7 '15 at 19:31
• @PhilB. addedᅠᅠ – user2813274 Dec 8 '15 at 2:44
• @user2813274 - Thanks, but I was suggesting this as an addition to Niels' answer, as his answer is a little too concise and needs some elaborating. – Phil B. Dec 8 '15 at 3:37