I recently discovered ultra-compact oval chainrings (46-30) unfortunately they only work with Shimano cranksets...
Shame because 30:46 is the same gear inches as my current 26:40 setup and I can get home with that ratio.
I have been riding 2 to 3 times a week again - I take the trike to GF's place in the boot of her Yaris and set out from there. The hill just opposite here is a killer, unreasonable heart rate attained when I get to the top
I have often thought "to hell with it, put the Mxus wheel in" but the fear of broken spokes brings me back to reason. Work starts in a couple of weeks so mucking about with motors isn't too far off.
I have had the time to set down a final plan (as well as getting seriously strong again):
- smallest double compatible internal chainwheel I can fit on the GSM is 32
- get me home with an empty battery gear inches equivalent to what I have now would be 32:50
- thus chainwheels 46-32 (never use 48:11 so a 46 will do, maybe even a 44) and cassette 11 speed 11-50 Sunrace
11 speed chain is horribly expensive compared to 10 speed but thinking about the drive train, a whole lot of it is enclosed in tubes and it is very clean despite the serious km I have been putting on recently - at least 100 km a week, over a thousand since the beginning of January.
I have (finally) decided to stay with a 15 Amp controller so will get a KT 36/48v sine wave controller with Jullet plugs from C & D. A small controller holder for the boom has been designed so the water resistant plugs are required. I want it out in the airflow and a heat sink will be stuck on top. Battery will be home made from 21700 cells and 2 x 6P6S bricks without BMS (balance charged) will be connected in series for 44.4v nominative. That combination gives 747 W peak down to 657 W at LVC in assistance level 5. Battery capacity will be between 24 Ah and 30 Ah depending on choice of cells so 1.06 kWh approx. Battery will go in custom box fixed to the lowrider rack, the battery box will also house a buck converter for 12v required for accessories.
I need a new rear wheel with a disk brake hub - a separate rear parking brake to replace the two on the front. A wider rim and Schwalbe Allmotion tubeless tyre on the rear. Two new front wheels with Gingko ventilated brakes and 40 mm wide rims in either 24" or 20" size (to be decided). Though I would love to learn how to build my own wheels I think the cost of having them made by Gingko is a more economical sollution.
The new supernova tail light with brake light has caught my fancy and a b+m 150 lux headlight and b+m electric horn will go on the front. HW brake sensors on both front brakes. Combined 2x11 shifter/brake levers will free up some handle bar space for buttons. An LCD-8 vertical version with cadence indicator means I will keep the external PAS disk. Shorter Miranda cranks will make for more comfortable spinning and happier knees. A rear Wingee fender will replace the SKS and add a couple of panier racks for the big Ortleib bags. I will most probably fit a nose of some sort to keep my feet dry, there are several options being considered. Last but not least a Hinterher Hmax trailer with aluminium box - fishing, camping and shopping require a boot!
If you have been following and add all that up it is a fair whack of cash to lay out but this trike is a car replacement. Running the math the rig will pay for itself in about 18 months. When I get really old I'll raise the seat, put in a bigger battery and add a throttle...