Quote:
Originally Posted by Andrew Lawrence
I love the 3-CIM shifter, but the ratio is terrible. 17 ft/s is a great high gear for 3 CIMs, and 5 ft/s is a great low gear for 3 CIMs, but speeds of 9-12 fps low or high gear don't benefit much from the extra CIM. In order to see a noticeable increase in power/acceleration with the extra CIM, your high gear needs to be pretty high (I'd say 17 ft/s is a good starting point), and your low gear needs to be pretty low (4-5 ft/s is what I'd personally do with 3 CIMs).
tl;dr - the extra CIM isn't going to help unless your high gear is really high, and your low gear is really low.
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You could go after a traction limited at 40 Amps per motor Low Gear in the range of 7-9 fps with 3 CIMs, whereas this range is around 4.5-6.5 fps with 2 CIMs per gearbox. However, then you're running the risk of popping the Main Breaker with a 240 Amp traction limit with just your drive train. I would tend to go with a 160 Amp traction limit in low gear on my drive train even with 6 CIMs, just to be sure I won't pop my main breaker in any reasonable sustained pushing match. At least until I would get more experience working with 6 CIMs in drive gearboxes. Because of this preference, the advantage of 6 CIMs in a shifting drive train would be better acceleration at higher speeds, not a faster low gear (even though reasonable arguments could be made for a faster low gear).
I do agree though, I already much dislike the gearing differential between low gear and high gear of the VP ball shifter for 2 CIM gearboxes, and it seems even less attractive for 3 CIM gearboxes.