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The 15% discount on GRIN products for people who didn't go out shopping on Black Friday is still going until the end of this weekend, right up until we get to the shop on Monday morning.

Those after torque proportional pedal assist systems now have a new plug-and-play option available. The bottom bracket sensor from TDCM uses novel geometry to measure the backwards chain force on the cranks rather than the spindle torque in order to sense your pedaling force.

This enables it to sense both the left and right pedal effort, giving a more immediately responsive PAS system at a much lower cost than magnetostrictive torque sensors. On the other hand, it is not as accurate at measuring human watts as the THUN sensor, and the installation is a bit more complicated as well.

We have the TDCM units custom made to run directly off the 5-pin V3 Cycle Analyst plug just like the THUN sensors, and have these new pedal sensor options available in the CA Parts page in 114, 120, and 128mm spindle lengths. The TDCM is a better option if the main goal is proportional pedalec assist, while the THUN unit is best if accurate human power output is needed, or if the chainline is not perpendicular to the legs (e.g. recumbent bikes)

We have been working for some time with AllCell to produce a custom frame-bag mounted battery pack using their unique PCM material both as a structural support for the cells, and as a means to keep the pack temperature under check. This is still progressing, surely, but in the meantime we're happy to offer their standard rectangular 36V 20Ah and 48V 20Ah batteries as an option for all of our kits. With a full 20Ah in the tank, these offer a nice high capacity choice for cases where the 10 and 14Ah eZee packs won't go the distance.

While these packs don't have a rigid enclosure or mounting hardware, they can fit inside regular trunk bags OK and offer a great long range battery choice with USA warranty and support.

And while we were skeptical of the claimed benefits of the PCM material, there is no doubt in our testing that it does effectively keep the pack temperature rise clamped at about 40 degrees Celcius. The graphs below show a direct comparison of the eZee flat pack and an Allcell pack we had assembled in the same geometry, under a steady high current (28A) discharge test.

To everyone who didn't go bargain hunting and online shopping this Black Friday / Cyber Monday, and honoured buy nothing day instead, we respect that. We're offering you a 15% discount on all locally Grin manufactured items, which includes Torque Arms, ebike Lights, Cycle Analysts, Stokemonkey kits, Battery Rails, and DC-DC converters. Just indicate during the checkout that for whatever reason don't indulge in any consumer shopping over the long weekend, and we'll apply the appropriate discount. This will be valid until Dec 15th.

The FTDI USB->TTL cables we'd been offering for programming the Cycle Analyst have been superbly reliable, but also a bit pricey. So we designed our own USB communication circuit based on the same chip family, and made them with an extra long (3m) cable so that it's easier to reach from your computer/laptop to the CA on your bike for reflashing. And as a plus, they now come included as standard with each V3 Cycle Analyst device.