I used to really like my little ebike now I really LOVE it. This gearbox has made a significant difference in useability and performance. The single-speed gear ratio Rad Power chose was a good compromise and was a blast to ride but adding a couple of gears turned my Radrunner1 into a useful little vehicle for most of my around-town errands and for fun little jaunts cruising around parks and neighbourhoods. I live on the East Bench in Salt Lake City, where there are very steep but short hills that I used to avoid and now enjoy climbing. I still need to work while climbing, but with the lower 1st gear, there is not a hill on the North or East Benches that I haven’t been able to pedal all the way up, and there are some really steep hills.
Installation is a breeze (if you don’t route the cable internally as I did). The shifter, cable and gearbox/crank arrive pre-assembled, so not much to do there.
RadMini owner
GO TO:
COMPATIBILITY & USABILITY
GTRO is compatible with most rear hub motor ebikes and front hub motor ebikes. It is not compatible with mid-drive (aka central) motors.
If, after watching our Installation video, you have any doubts if GTRO is compatible with your ebike, please email us at service@efneo.com with a brand and model name.
There are at least five reasons why GTRO is a superior gear shifting system for an ebike in comparison to a rear derailleur:
1. you can downshift to the first gear after stopping, which makes starting easy
2. starting always from the first gear saves your battery
3. you can upshift under a full load when accelerating – that is a wonderful feeling; GTRO upshifts as quickly as if it was a sports car!
4. it’s compatible with belt systems (e.g. Carbon Gates)
5. it’s a zero-maintenance system
DIFFERENCES BETWEEN GTRO AND GTRO FOR EBIKE
GTRO FOR EBIKE is the same product as a standard GTRO in terms of how it looks and works.
However, some ebikes are specific regarding how their frame (and particularly their BB shell area) is constructed. Therefore, if you choose your ebike brand from a drop-down menu in our web store, you will get your GTRO customized for your frame (e.g. we will add some spacers if necessary, or a reaction lever will be positioned for your bike).
If your ebike brand is not on the list, don’t worry. Just choose “GTRO for ebike” and tell us your bike’s brand name in a Comment field on a checkout site. We will assist you in the installation, if necessary (in 90%, it is not necessary, but we are always here to help, and we reply within a couple of hours at worst).
SHIFTER TYPES
Efneo offers two types of shifters for ebikes.
Grip shifter
Trigger shifter
Compatibility with an original Shimano triple shifter.
GTRO is compatible with Shimano Deore triple crankset shifter standard in term of the cable pulls.
If you want to use your current shifter, follow our manual “Shifter replacement” from Manuals & Tutorials website.
Tip: if you plan to use your current shifter, choose GTRO with our shifter of the type you currently have, e.g. if you currently hava a grip shifter for a front derailleur, choose GTRO with a grip shifter.
SHIFTING CABLE ROUTING
On most ebikes, a shifting cable is routed the same way as on human-powered full-size bikes.
Our default shifting cable length for ebikes is 107 cm (42 1/8 inches). It works for the majority of the frames.
If it is too long, you can easily trim it following one of our manuals on a Manual & Tutorials website.
The cable is usually routed alongside a down tube.
On some bikes, it is routed internally. Please check our manual “Shifting cable exchange” to find out how to detach a cable for internal routing and how to fix it afterwards.
CADENCE AND TORQUE SENSORS
CADENCE SENSOR (aka PAS)
Most of the ebikes on which GTRO is installed have a cadence sensor. On some bikes, it is installed on a right BB axle, on other bikes, it is installed on a left BB axle.
With GTRO, it needs to be on a left axle. If necessary, you can relocate it from the right side to the left side. Usually, it is an easy operation.
Here is how a PAS looks like on a left side axle on a Sondors fat tyre ebike.
TORQUE SENSOR
If your bike has a torque sensor installed in a bottom bracket, contact us before your purchase. We must check if your sensor is compatible with GTRO to avoid confusion.
For bike builders: email us at fm@efneo.com. We will send you a list of BB torque sensors compatible with GTRO. We can also check the compatibility of the sensor you use currently.
CHAIN / BELT OPTIONS
GTRO is available with two versions of a chainring size – 28T or 38T.
GTRO is also available with a 130BCD adapter which is compatible with belt sprockets (e.g. Carbon Gates 46T CDX)
28T chainring
Equivalent to a 28/40/50T triple crankset.
Recommended for most of the ebikes.
If you are not sure which chainring to choose, choose 28T.
90% of ebike owners choose 28T.
Our 28T chainring is made of high-quality steel – Chromoly, of 30 Rockwell C Scale hardness. It is irreplaceable.
We grant a lifetime guarantee for this chainring. You will never need to replace it because of wear.
38T chainring
Equivalent to a 38/54/68T triple crankset.
Recommended for speed pedelecs (e.g. 45km/h or 28mph ebikes).
38T chainring is replaceable in case of wear.
If you like numbers, you can find a fantastic tool to analyze gear ratios here: https://www.sheldonbrown.com/gear-calc.html
Sheldon Brown’s calculator is probably the best tool you can find online to analyze bicycle gear ratios and find out what could work best for you!
Is it possible to mount something between 28T and 38T?
The short answer is – no.
Is it possible to mount something larger than 38T?
The short answer is – yes.
If you choose a 38T chainring as your option, you will get a GTRO with a 130BCD adapter and a 38T chainring installed on it. If you wish, you can take it off and put any larger chainring compatible with a 130BCD standard. However, as far as we know, even speed pedelecs owners rarely use GTRO with anything larger than 38T. On a third gear, it is equivalent to a 68T chainring!
Beltring
If you want to put a beltring on your GTRO, choose “Adapter 130BCD” as an option in a chain/belt drop-down menu.
Any belt sprocket in a 130BCD adapter can be fitted on it. Most of our customers use a 46T sprocket from Carbon Gates, but other standards are also available.
If you choose GTRO for a belt sprocket, you must know that it is essential to align a front sprocket with a rear sprocket (e.g. keep the same beltline for both). You can adjust GTRO’s beltline with spacers.
BUY GTRO FOR EBIKE
Check, if your bike fits one of our “Ebike” options from the list.
30-day money-back guarantee.
In a package you get:
1. GTRO gearbox (right crank)
2. left crank
3. dedicated bottom bracket
4. shifter with a shifting cable
5. axle bolts and cable ties
Pedals not included.
If your ebike’s brand is not on the list, please email us and we’ll advise if we can deliver a GTRO for your ebike – service@efneo.com
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| Weight | 12 kg |
|---|---|
| Ebike | Rear-wheel engine, Sondors fat-bike, Bike with a Zehus engine, Superpedestrian / Copenhagen Wheel, RadPowerbikes, FLX Babymaker, Sondors Thin |
| Color | Black, Silver |
| Shifter | Rapid-fire, Twist-grip |
| Chain/belt | Chainring 28T, Chainring 38T, Adapter (130BCD, 5 bolts) for chainring or beltring |
