2017-06-11, 09:44
(Modification du message : 2017-06-24, 07:21 par Oran.
Raison de la modification: Changed graph
)
At the moment I’m delaying uploading any updated code as I’m now aware of how worn out my hub really is and how I’ve adapted the code to compensate. I’m unable to continue perfecting the code with the shifting from underdrive being so unpredictable.
I’ve been struggling to rid of a big lag in upshifting during acceleration and sometimes a ratio that is too low on slow hill climbs. There’s a very noticeable period just as the ratio suddenly increases when the hub feels very squishy during this transition. Like it’s trying to get to a higher ratio but doesn’t quite manage it and oscillates under the load until the servo shifts up enough. There have been times when I’ve felt like I’m getting stuck at about 10 – 12 mph. My cadence goes so high I can’t get the power to make the bike speed up enough to get the servo shift up for the hub to engage in a proper up shift.
![[Image: Zk9WKe.jpg]](http://imageshack.com/a/img924/233/Zk9WKe.jpg)
(Changed the graph as I logged some more data without a delay on the servo position this time. Also recorded speed to 2 decimal places instead of an integer.)
As I’m data logging the servos real position via its internal potentiometer and the hubs ratio, calculatable from speed and cadence, I analyzed some of the data to see what’s going on. The graph proved exactly what I’m experiencing, an inability of the hub to shift into a higher ratio despite the servo being in the correct position. From what I can tell it seems that the problem occurs when the hub is under load and upshifting.
When I think about it the problem has occurred after changing the plastic bushings on the eccentric gears. Worn bushings increased the amount of travel on the shifter to got the full range. The worn stator has the opposite affect all the shifting is occurring in two thirds of the available range. In a way I’d be better off with the worn bushings as the two types of wear cancel each other out. Maybe its time to ask for another hub.
I’ve been struggling to rid of a big lag in upshifting during acceleration and sometimes a ratio that is too low on slow hill climbs. There’s a very noticeable period just as the ratio suddenly increases when the hub feels very squishy during this transition. Like it’s trying to get to a higher ratio but doesn’t quite manage it and oscillates under the load until the servo shifts up enough. There have been times when I’ve felt like I’m getting stuck at about 10 – 12 mph. My cadence goes so high I can’t get the power to make the bike speed up enough to get the servo shift up for the hub to engage in a proper up shift.
(Changed the graph as I logged some more data without a delay on the servo position this time. Also recorded speed to 2 decimal places instead of an integer.)
As I’m data logging the servos real position via its internal potentiometer and the hubs ratio, calculatable from speed and cadence, I analyzed some of the data to see what’s going on. The graph proved exactly what I’m experiencing, an inability of the hub to shift into a higher ratio despite the servo being in the correct position. From what I can tell it seems that the problem occurs when the hub is under load and upshifting.
When I think about it the problem has occurred after changing the plastic bushings on the eccentric gears. Worn bushings increased the amount of travel on the shifter to got the full range. The worn stator has the opposite affect all the shifting is occurring in two thirds of the available range. In a way I’d be better off with the worn bushings as the two types of wear cancel each other out. Maybe its time to ask for another hub.
- Oran