MicroShift super short derailleurs for 20 inch wheels
 

MicroShift have new super short derailleurs for 20 inch wheels.

https://www.microshift.com/news/intr...g-super-short/

Has anyone tried these with trikes? I have a Stein Mungo with a 20 inch rear wheel and always worry about tearing off my Deore rear derailleur. The MicroShift might be a good option. I have a Schlumf mountain drive in considering fitting to the trike, so could get truly epic gear ranges.

Do you ride off-road? I've owned two 20 inch drive wheel trikes and one 700C drive wheel trike since 2003 and never destroyed a rear derailleur with the exception of the time a rear light came loose and fell into the chain on my Catrike. My Greenspeed GTO uses a Shimano 105 8 speed short cage RD. I replaced it just once in about 30K miles when metal fatigue finally did it in. By that time the idler wheels were worn smooth. It shifted perfectly even as worn as that. When I compared the ground clearance on the GTO with that on my Catrike 700 which has wide range (11-36 cassette) and long cage RD, the distance is nearly identical. None of my three trikes were designed for off-road so that wasn't a factor.


Be sure this RD is compatible with your drive system. It is 9 speed and suitable for 11-34 or 11-36 cassettes. You will need to use the shifter designed for the RD. Adding the Schlumpf Mountain Drive may or may not be helpful. Do you need more low end gearing? My GS GTO has the SMD but it was coupled with using a single 65 tooth chainring and 3X8 in the rear including SRAM Dual-Drive. It turned out to have a wider gear range than I really needed. First trike was 19-98 gear inches. OK at first but limited at top end once I got used to riding the trike. GTO is something like 14-132 GI and the Catrike 700 is is 21.9 -124.2 GI. I don't really miss the low end gears on the Catrike. It works OK on even the steepest hills I encounter.

Like VT said, I've owned three rear 20" trikes and never came close to damaging a rear derailleur under normal usage.

I don't know about 'epic', but it is likely with a Schlumpf drive and the 'Super Short' drivetrain you could have a decent (i.e. conventional) span of gears vs the very much limited one you will have if you use the 'Super Short' drivetrain as a 1X package like MicroShift expects. But, to the point other posters have made, I have had 'normal' rear derailleurs on 20" folding bikes over all manner of road surface and have never experienced the RD coming in contact with road debris.

I have busted a couple of Deore long cage derailleurs, on tree stumps and roots, since they only have about an inch clearance from the ground. I have a SRAM Dual Drive on this trike, and use the lowest gear on that rather than on my cassette, to keep the derailleur away from the ground. Combined with a 30, 40, 52 crank set, and 12-36 cassette, it gives me a lot of gears and a broad range. Running a Dual Drive, with an 11-38 cassette and a Schlumpf Mountain Drive (1-2.5x) and a 50 tooth front chain ring gives me a range ov 7.2 to 115.6 gear inches, or 1600% range! AS it is, i can climb a wall with my trike. I had to put a 20kg cast iron weight on the rear rack to maintain grip on the steepest sections of my old driveway, which was about 25% gradient. With these types of numbers I reckon I could drag a piano up a wall, and could certainty drag the heaviest touring load up the steepest road I am ever likely to encounter.

Sheldon Brown's calculator gives some rough estimates.

https://cimg1.ibsrv.net/gimg/bikefor...ea72ab45b7.jpg

Even losing the dual drive gives 866% range. More than enough for most people, and simplifies the drive train.

The derailleur will be furthest from the ground when you're in the combination that takes the most chain. That usually means the largest cog on the cassette.