Thanks. Electrical engineer, but engineer after allThat's really quite ingenious as a means for determining a workable design. Me like. Are you an engineer by profession?
Right, Spencer Wofl mods (there are several ones) was a source of inspiration, like the campagnolo rally cage, the Suntour GT and the XC with 3 pulleys. Also the old Shimano MTB XT rd's. But at the end , I want to create something that looks similar to the original, and the constrain I have is not to make it too long because then it looks ugly in my opinion.... I still have room for another hole and lower the upper pulley a little bit. We'll see the end.
That is a good question. I still need to investigate and learn further but what I've observed is that both magnitudes are related, as the cage really pivots over the frame bolt. And the amount of rotation depends on the size of the cage and the size of the cogg. What in a 13 cogg you see a hole from the right in a lower positon for example, when the chain is on the 34, that hole is really up, because the rd has pivoted. At the end, the most favourable position for the upper wheel I see is as as lower as possible, back to the main bold. Like modern RD in fact. I'll give another try to my prototye with another hole even lower at the left of the main bolt but then probably I have to lower as well the bottom pulley making a larger RD that is what I don't like asthetically.....Looks great. I'm wondering how much of a difference changing the position of the pulley wheel makes. I can understand it obviously does vertically, but horizontally? What did you notice?
That is the goal! thanksLooks like it works very well indeed.
With aluminium of the same thickness as the original cage and copy the profiling, of the old cage, and your cage will look oem.
Agreed! that's my next step, thanks for the hint.The top jockey I think needs to be closer to the cage pivot point (making it lower) to help with large sprocket clearance, and to the right (front of the bicycle) to help with chain wrap for the small sprocket when the entire cage swings back to take chain slack.
He has explained that it's a prototype and it he's pimped it with some Drillium so it ought to tick your boxes. I judge it as a hack. It does the job without costing a sh**load of dosh.. Chapeau i'd say.Hack or bodge