What is Ready-To-Run?

The unit comes completely assembled, wired and configured. Installation is straightforward and involves removing your existing crankset and bottom bracket and installing ours. The Cycle Analyst is usually mounted on the handlebars and only one wire is run between the CA and Castle Creations ESC (mounted on the left side plate).

How does it ride?

Great. The Ascent makes very controllable torque from 0 - 150 pedal RPM (PAS setup) and the Castle Creations ESC has no problem with starting from a stop, or in the middle of a switchback, or a steep ungroomed mountain run. Using the full range of gears will minimize driveline stress and reduce current draw, extending your range. The Ascent is capable of turning the crankset with as much force as your full body weight, making gear selection straight forward and the Cycle Analyst provides easy control over power delivery. Throttle based kits use a lower reduction ratio to generate 250 pedal RPM, giving the rider a longer pull in each gear and use the larger rear cogs at higher RPM than the PAS gear ratio. A throttle is easily added to the PAS kits.

Is it silent?

No, it sounds awesome. Besides, it's only fair to give other people a heads up when you're coming in hot. Some big manufacturers use plastic gearing to reduce noise, vibration, efficiency and the power handling. Tangent doesn't cheat; we use Chromoly steel for the highest efficiency and power. Our custom reduction gear will become very quiet after 50 miles of use. 

The sound of the unit is a secondary concern; pedestrians and trail goers are more interested in how quickly you're overtaking them.

Is the unit sealed? Maintenance?

Yes and all bearings are also sealed. The grease interval is 100 miles when 1cc is injected through the fill port. There is zero internal maintenance required however the reduction unit can be removed and disassembled with a flat blade screwdriver. Only use Vigogrease RE0. A 2 year supply of grease is about $10 and will be available through our webstore.

How can I ensure the mounting hardware will fit my frame?

Print out one (or all) of the PDF's on the top of the Installation page, make sure 'fit to frame' is unchecked and you should have a 1-to-1 print of the mounting hardware to hold up to your frame. For now, the frame needs to have a threaded bottom bracket.

The Ascent's housing is configured for 68/73mm bottom bracket widths. We use a spacer plate to adapt the 73mm wide Ascent to 83mm and 100mm BB's for increased flexibility- move one drive between all of your rides.

Can I use regenerative braking?

No, the unit is not designed to be back-driveable. The amount of energy reclaimed by bicycle regenerative braking does not warrant the complexity or overall efficiency losses caused by never disengaging the motor from the driveline. You will experience a rough feel when rolling your bike backwards due to the drive. You won't harm the unit, just minimize how often you ride your bike backwards.

Whats the range?

A road bike with 28" wheels and a 42 tooth front chainring with stock rear cassette can achieve 30 real-world miles using a 10Ah pack. This is maintaining an average speed of 25mph+ with the drive doing all of the hill climbing. You should see 6-12Wh/mi consumption using the PAS ratio on road. Off-road uses 30-40Wh/mi under racing conditions. 

What batteries should I use?

We recommend a high power 52V battery pack from LunaCycle.com that utilizes Samsung 25R cells. These packs include a Battery Monitoring System and charger to give you charge-and-ride simplicity. We've tested these packs to 100A burst, 80A continuous and love the crisp motor response of their 52V packs. The 25R cells are capable of several times the current demanded by the Tangent kit ensuring max performance and long life. 

Cycle Analyst settings?

Don't forget to do your homework: Cycle Analyst V3 User Guide


  • batt->chemistryRC LIPO
  • batt-string# 12 or 14 (12 for LiPo, 14 for any 52V LunaCycle pack)
  • batt-->capacity XXXX (only affects the battery charge meter)
  • Batt-vlt cutoff (3 x batt-string#)
  • Batt->LoVGain 800


  • ThrI->Cntrl Mode Current (A) 
  • Min Input-> 0.01V (for Domino throttle)
  • Max Input-> 4.94V (for Domino throttle)
  • Fault Volt-> 4.99V (for Domino throttle)
  • Min Input-> 0.90V (for hall thumb throttle)
  • Max Input-> 4.24V (for hall thumb throttle)
  • Fault Volt-> 4.35V (for hall thumb throttle)


  • Thr0->Outpt Mode R/C Pulse
  • Thr0->Min Out 0.99msec
  • Tr0->Max Out 2.00msec
  • Th0->Up Rate 4mS/sec (sharpness of throttle up response)
  • PAS Up Rate-> 0.5msec/sec (CA firmware rev 3.1beta required)
  • Th0->Down Rate 14mS/sec (want high to stop motor quickly)
  • Th0->Fast Rate 0.05mS/sec (speed of spinup prior to freewheel engagement)
  • Th0->Fast Thrs 2amps (indication of freewheel catching to allow full power)


  • Max Curent->  60A (3kW)
  • Max Current-> 95A (6kW)
  • Again-> 45 (soft throttle response)
  • Again-> 75 (immediate throttle response)
  • Max Power -> 9900W (we use current limits, not wattage limits)


  • Pas Poles-> 8 (THUN)
  • Sensor Type-> 2-wire
  • Strt Thrsh-> 24 (should be set to a multiple of 8)
  • Stop Thrsh-> 45 (~2x start threshold, higher will cut power quicker, too high may erroneously cut power)


  • Sensor Type -> THUN
  • Asst Factr-> 3 (factory setting, user adjustable)
  • Asst Start-> 25W (pedal effort needed before motor energized)
  • Asst Avg-> 16 (multiple of 8, higher provides smoother but slower response)


  • Sensor-> Linear Type
  • 0deg-> 0.45V
  • T Scale-> 262.1V/degC
  • Thrsh Temp-> 150 degC
  • Max Temp-> 160 deg C


  • Function-> Limits
  • Scale Lim-> PAS level


Wiring diagrams?

Yep, right here.