Ball Shifter High Gear Issues

[Mike Marandola]

Originally Posted by asid61

12.6fps free speed for high gear is nowhere near the max speed for a 4 cim setup. We ran 15fps on 4 cims easily last year, and bumped it up to 17fps later with no problems (at least not on the gearbox side).
Are your c-c distances correct on the gears? The situations you describe are high-torque situations, and the ratcheting sound might be gears slipping. Get out some calipers and measure the c-c distance. Also, try running it without load and see if the issue persists.

That's what I figured. It would really be nice to have a solid 14ish fps high option. I have not measured it but it is a COTS gearbox so unless something is seriously wrong I don't think it would be the c-c. With no load there is no noise. Thank you for the suggestions.

[jeremylee]

We had ratcheting noise on our 14U last season, found some pulleys were cracked. Doesn't explain all your symptoms though.

[Bryce2471]

I can almost guarantee that you are experiencing a worn out shifting shaft/plunger.

When you were geared so low all season, I assume that you usually used high gear, which means that the shaft was consistently exposed to large compressing forces that deformed it. You probably didn't notice the damage because not a lot of input torque was required to drive around with such a slow gear ratio. After all, you had low gear for the heavy stuff.
When you switched to the taller ratio, there was an increase in load that made the ratcheting start. The part I am referring to is made out of aluminum, and vex may be changing it to steel for future years.

There is a possibility that i got this wrong though. You can confirm my theory by disassembling the gearbox, but that's a pain...

[Mike Marandola]

Originally Posted by Bryce2471

I can almost guarantee that you are experiencing a worn out shifting shaft/plunger.

When you were geared so low all season, I assume that you usually used high gear, which means that the shaft was consistently exposed to large compressing forces that deformed it. You probably didn't notice the damage because not a lot of input torque was required to drive around with such a slow gear ratio. After all, you had low gear for the heavy stuff.
When you switched to the taller ratio, there was an increase in load that made the ratcheting start. The part I am referring to is made out of aluminum, and vex may be changing it to steel for future years.

There is a possibility that i got this wrong though. You can confirm my theory by disassembling the gearbox, but that's a pain...

Thanks for the suggestion. We recently disassembled them since we suspected the issue to be wear on the plunger or gears but that was not the case. Also, I believe the majority of the force is put on the ball carrier, which is why it's steel.

[audietron]

Originally Posted by Mike Marandola

Thanks for the suggestion. We recently disassembled them since we suspected the issue to be wear on the plunger or gears but that was not the case. Also, I believe the majority of the force is put on the ball carrier, which is why it's steel.

I would suggest checking the distance that the shifter is pulled toward the cylinder to get to the correct part of the plunger. If it is on the edge if the hump in it it is prying the cylinder out of gear. We had this issue several times from the coupler coming loss through the season.

[Ether]

Originally Posted by Mike Marandola

We recently disassembled them since we suspected the issue to be wear on the plunger or gears but that was not the case.

Are you saying that you found the problem but it was not where expected?

Or are you saying that you found no evidence of damage or wear on any of the parts? Did you inspect them with strong light and adequate magnification?