Hi pepndon, I have looked and looked for a rack that had a load capacity high enough for two heavily modified Radrunners and the only ones I could find did not have roll on ramps. My sweetie and I don't want to lift 100 lb. bikes on and off a rack. The only racks that had the load rating were ones built for motorcycles and not really suited for e-bikes. A while back I stumbled on a single rack and called the manufacturer Vershaul inquiring about a 2-bike version. They emailed me a link to a two-bike version that is made for a company that makes the UBCO 2-wheel drive electric motorcycles that weigh 150 lbs each. I purchased the rack and assembled it but have not used it yet. It is a very nice and well built rack, It does not fold, but can be easily converted to a one or two bike rack. Be prepared for sticker shock, I bought it because it is the ONLY RACK tailored for the weight capacity I required and has a nice loading ramp and really nice tie down points.

https://ubco.com/collections/shop-ubco-products/products/2x2-double-carrier-with-ramp

hope this helps, Cygnan

Hello Kese, this is cygnan, the original poster for the efneo gearbox.The issue was that when I received my gearbox it was supplied with a replacement bottom bracket adjusted in width to accommodate the extra width of the gearbox. The problem was that the replacement bottom bracket measured 0.660" shaft diameter and the stock Radrunner bottom bracket measured 0.623".  In one of my last communications with Wiktor I inquired about a fix for the cadence sensor fit issue for future Radrunner gearboxes. He said that he would be able to source a bottom bracket that would have a compatible shaft diameter for the Radrunner's cadence sensor. I would recommend contact Wictor directly about this, he is the best customer service representative I have ever worked with.  I sent a PowerPoint document to him describing the assembly process because this was a first installation on a Radrunner, ask him to reference this if he needs a memory jog. That said If you do not have a fair amount of machining skills I would not recommend attempting any modifications to your cadence unit. The cadence unit has an inner bore with spiral cuts radiating outward that functions as a spring to grip onto the bottom bracket. If it didn't have these spiral cuts but a smooth bore, modifying this would be simpler. If Wiktor doesn't have an compatible bottom bracket and you decide to purchase a gearbox I would recommend taking the new bottom bracket along with the inner portion of the cadence sensor to a machine shop and have them fit these together to provide a relatively firm slip fit. A good machinist should have the tools, skills and knowledge to make this a quick and simple task. If you end up purchasing an efneo gearbox I doubt you will have any regrets, my gearbox has proven to be a lot more useful than I expected it to be. The Radrunner1 is a great little e-bike and very usable as originally sold, but changing it from a single speed to a three speed has made it so much more enjoyable and versatile. Oh another neat thing about the efneo is it's ability to be shifted while peddling or not. 

That information is detailed in my original post.

That is the choice of you want your middle 2nd gear close to what you have for a single speed now with the addition of a lower gear as well as an overdrive or higher gear. This needs to be your decision based on what you need or want from your Radrunner1. Efneo is absolutely wonderful for answering questions such as the, I recommend emailing them.

wkindred, as noted in my post I'm using a grip shift. There is no way to install a belt on the Radrunner1 so I'm using a chain.

Here are two photos one of the gearbox on the bike and one showing the gearbox cable and torque reaction arm.

I do not like to write on forums or do reviews BUT this needs to be shared with Radrunner1 owners that would like to make their ebikes way more fun and usable.

I quite by chance discovered this gearbox while searching for something else and emailed some questions to efneo with some questions. They asked for specific pictures of my Radrunner1 and answered a lot of questions in a lot of emails. Great support for potential customers! I ordered a unit for my ebike, it shipped from Poland on Monday, went through Customs and domestic shipping and I received it the following Wednesday (Prime 2-Day and shipping should seek advice from efneo).

I was really hoping that this would help solve my little Radrunner1 gearing with it's single speed gearing that was a little too high for most of my typical rides, or a little too low when traveling longer distances or going downhill. This gearbox made a world of difference. If you ride a Radrunner1 then you know about the high spinning rate when traveling 17-20 mph. Now I simply shift to 3rd for a nice and pleasant cadence rate. Now I can travel a lot longer and farther with much less effort. With 400 pounds total weight (yea I know 300# max) in 1st gear I can climb steep hills as easy as I could with the stock single gearing with 215 pounds total weight. The efneo 2nd gear (middle) is exactly the same as the stock 53t but now you have an additional 1st gear that is 37t and 3rd gear that is equivalent to 66t. A real surprise is how much I use 1st gear cruising around with or without my sweetie on board. If you like to do trails or simply cruise around town you will really make good use of the lower than stock 1st gear.

Installation is a breeze (if you don't route the cable internally like I did). The shifter, cable and gearbox / crank arrive pre-assembled so not much to do there. There is a torque reaction arm that needs to be positioned correctly that is held on by small cross head screws, This torque arm is a bit tall to fit between the motor controller box and the chainstay so this can be hack sawed shorter or the motor controller box spaced ¼" farther away (downward on one end) which is what I did. There were some issues because of having the first ever Radrunner1 installation but these have been remedied by efneo. If you decide to upgrade to this 3 speed gearbox you will need to change your left grip to a shorter grip shift type. If you choose the twist shifter version route the cable above the brake lever to allow everything to fit and work together.

I wanted to put a couple hundred miles on this prior to my post and I am happy to report no problems other than the chainring needing some break-in miles that eliminated the chain falling off. My Radrunner1 is so much more useful and fun to ride now and It is really neat to be able to shift anytime riding or stopped, peddling or not. An added bonus is that the crank is unlike the stock one in that it is an easy-on-the-eyes, nice looking unit.

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 neighborhoods. 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.

Efneo sells the gearbox for $500 and there was an online coupon for $100 when I purchased mine. Shipping from Poland to SLC was only $9. If you would like to make your Radrunner1 a lot more versatile, fun and easier to ride I highly recommend this upgrade.

Gary