Another DIY rear derailleur cage.

After testing different combinations, I'm happy with the one in the video to producing final version. Maybe not the optimal, but shifts well and the cage does not look too large, that is something I'm trying to avoid just for aesthetics.

There are many factors to consider other than the position of the pulleys in my prototype, like lenght of the chain, and basically distance between pulleys, as with more distance (larger cage), more lever to get down the upper pulley, but this combination works well also with the big chainring (that's the last secs at the end of the video)

As the stem arrived I was able to try on the road but did not work very well honestly as the chain felt off the pulleys but I believe this is because the chain normal wiggle so inner cage definitely needed and also proper thikness (4mm ) to avoid cage bending.

 
I'm starting to thing this is useless.... I've drafted potential outer cage designs and the first one guess what is pretty similar to the Rally one ;) I've realized that the cage for the 1st gen Rally was following the design of the later super record v2 outer cage already (better said, the later super record v2 followed the design of 1st gen Rally outer cage). Please any one with more knowledge feel free to correct me / extend on this.

Anyhow, here below you can see 3 sketches of potential outer cages. It is not worth to replicate the one similar to the Rally, as I could buy one already or get the nice new mod already available (sure bets) But if the goal was to do something to look pretty close to the original NR/SR 1st gen, maybe the one I like the most is the one on the right, closer to the original. What do you thing ????

I've already ordered a 4 mm aluminium plate but starting to thing I'd better put a rear mech extender I have somewhere and go with the original cages ;(


RD mymod.jpg
 
I have both 1st and 2nd generation, the 2nd gen's had a bit of a harder life, both share the same cage. Looking a the wear on the back of the cages you may need to extend above the jockey wheel as per the original, looks like this aided shifting and chain retention 👍

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I'm starting to thing this is useless.... I've drafted potential outer cage designs and the first one guess what is pretty similar to the Rally one ;) I've realized that the cage for the 1st gen Rally was following the design of the later super record v2 outer cage already (better said, the later super record v2 followed the design of 1st gen Rally outer cage). Please any one with more knowledge feel free to correct me / extend on this.

Anyhow, here below you can see 3 sketches of potential outer cages. It is not worth to replicate the one similar to the Rally, as I could buy one already or get the nice new mod already available (sure bets) But if the goal was to do something to look pretty close to the original NR/SR 1st gen, maybe the one I like the most is the one on the right, closer to the original. What do you thing ????

I've already ordered a 4 mm aluminium plate but starting to thing I'd better put a rear mech extender I have somewhere and go with the original cages ;(


View attachment 799863

good tip! thanks for the advice
Just checked the lower cage and more wear so maybe the cage was extended again for aiding the upshifts. The jockey wheels and pivot form a 90⁰ 75mm x 30mm L shape if that makes sense 👍

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Perhaps a loony idea, and perhaps I should be condemned to the asylum good and proper....

If you take the existing short cage, but strive for it to be more horizontal in the largest sprocket it may work. It should then revolve and be more vertical or even swept back in the smaller sprocket. You would need to get the chain length spot on and potentially drill another hole in the cage for the spring to engage. You would essentially be making something like a Simplex Juy 59. It's a bit whacky so you will need wine too, but in faireness to Simplex, all the derailleur functions of doing chain wrap and taking up chain length are there but another way of going about it.

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