OK - so I purchased a Radmission knowing that some things could use improvement based on the price point. Among what I feel are shortcomings is the single speed chain line. Where simplicity is king, and some folks get into this, the single speed is where to go. However, your torque input to the pedals is fairly low given the 3.125:1 stock gearing, so the result is poor battery life. In hilly SW Wisconsin I was getting around 25-30 miles per charge down to empty. Once you get below about 50% battery the driveline starts to struggle.
I have successfully converted the front drive using a pair (48/38) of 130BCD chainrings, proper spacers and bolts and a vintage derailleur - all from my unloved toy collection. The derailleur was a trick, as there are limited positioning options and this one worked with only a repositioning of the controller up the tube. An old Sun friction shifter on the left bar below the controller interface (I actually used a right one on the left mounted upside down as I like the way that shifts - backward, but easy to use) and routed the cable down the down tube along with everything else. I added a nicer chain guard, as the stock unit is pretty drab. The only last thing necessary was to increase the tension on the chain tensioner by 1 spring point (look at install instructions for that item and you will know what I mean) and I now have a 2 speed front end. FYI, I doubt the stock tensioner can take up more than 10 teeth - and I might change the 38 out for a 40 as it is near it's limits with this configuration.
With the low range gear (2.375:1) I can keep the boost at a 1 or 2 and ride comfortably at 14+mph for the 1st 3 bars of the battery b4 it drops off. Due to gearing and simply the cadence that is comfortable with the stock gearing, I used to ride at 16-17mph at boost 2-3. Due to the improved ability to get leg torque to the wheel in low range, battery life has increased to 30-35 miles/full charge, or about 20%. Also, generally climbing hills or pedaling with no boost (read as dead battery or broken electronics) is easier to manage (obvious).
On high range, a 4% reduction from stock to 3:1, I can tool along all day at 18mph without feeling like my legs are flailing. (if you look at the math here, about the same cadence at 14mph low range as 18mph high range.
All changes are completely reversible.
Posting this so other Radmission owners can contemplate the benefits. Total conversion cost, even if I had to find a new derailleur which would do the job, should be around $125-$175 depending on brand of components used. Of the tweaks I have done thus far, this is the one that has had the most positive impact on rideability. Keep in mind this is from a 62 year old trail rider who is putting down 18-22 miles a day on this machine every day - at least until the snow flies.
Feel free to contact me with any questions, I will try to help.
Show pictures!
I would like to do that too.
BTW - one tech error, these are 110BCD chainrings - still easy to get hold of - I used a set of vintage Shimano Biopace rings, you can grab a complete crankset with chainrings in decent shape on Ebay for around 40-50 bucks if you shop a bit. I've put about 50 miles on this in 2 test rides and it works well - I shift back and forth as I feel fit base on how fast I want to go and how much pedal I want to use versus motor.
Really cool. Really interesting. Makes me wonder how gearing affects the cadence measurement.
so, if cadence is an estimate of rider effort, then having a larger front cog would cause the rad system to under estimate your effort, being on a smaller front cog would cause the rad system to over estimate your effort. is that true?
speed measurement comes from the drive wheel? It would be interesting to understand how the assist level is calculated...assist amps = alpha*(cadences/speed).
The system does not really estimate "effort" like a torque system does - but that is a separate discussion.
Using 2 sprockets, the larger of which is a 48 (vs the stock 50) and the smaller being 38 gives you two fallbacks. First, if you live near any kind of hills the 500w hub can be a bit underwhelming, so dropping back to the 38 tooth front gives you more leg power to the wheel in the form of torque. The 48T sprocket compares very closely to the stock 50, just what I had on hand since the type of stock sprocket used is rather plain and does not behave with the shifter.
Anyway, just sharing an idea that I consider an improvement.
Quote from: mtatkow on November 06, 2021, 09:46:05 AM
The system does not really estimate "effort" like a torque system does - but that is a separate discussion.
yeah, it was all hypothesis on my part. Sometimes it seems like the mission assist is just on /off. Or like you said, not really estimating effort/torque.
Quote from: mtatkow on November 06, 2021, 09:46:05 AM
First, if you live near any kind of hills the 500w hub can be a bit underwhelming, so dropping back to the 38 tooth front gives you more leg power to the wheel in the form of torque.
yeah, whenever I hit a hill, I'm slowly losing speed, even with the throttle all the way on.
Quote from: mtatkow on November 06, 2021, 09:46:05 AM
Anyway, just sharing an idea that I consider an improvement.
I do think this is really interesting. I was just trying to raise question for an overall discussion, not be critical. Thanks for sharing.
BTW - I recently completed the gearing change. I installed a 3 speed freewheel - yes, Chinese replacements are still available out there in ether-land, right off Amazon - and a vintage Suntour VGT Luxe derailleur I had on hand along with the matching friction shifter from what I showed above on the left. Just what the Dr. called for - rear cogs of 16/19/22 in combination with the front 48/38 lets me ride this much of the time like a bicycle and hit the boost when I have a bad headwind or a hill. It also got rid of the proprietary chain tensioner used by RAD. I can now climb most light grade hills in level 1 or 2 without too much effort - all up to the rider and their desire to get a workout vs using the throttle. If anyone wants pictures and some guidance on how to do this, please contact me offline. If you have sources for some parts, or have a parts bin from your bicycle hobby, this is an inexpensive and a major upgrade to the bike. The hardest part was finding a derailleur hanger - I used one from a TREK 7100 that I was able to modify in about 20 minutes with hand tools for the job.
PS - I had to add a spacer on the hub to assure that the derailleur did not touch spokes. My measurements say I could have installed a 5 speed freewheel (barely! - but without a spacer), but it would have been so close, with minimal added benefit, that I did not go there - even though I have several 5 speed cogs in the parts pins. The driveline alignment with the spacer and 3 speed freewheel is about perfect - another reason I did not bother with the 5 speed rear hub..
thought I would add a photo
Nice job mtatkow!
I really want to upgrade from the RAD stock tensioner on my Mission1. My original tensioner failed after 500 miles, the part is not good quality. I brought my bike to my LBS and they found a good tensioner (SURLY SINGLEATOR) that they would mount to the rear hub but they could not find a hanger plate that would fit the Mission. You mentioned using one from a TREK 7100. Any ideas of where I could source a tensioner that would fit without modification? The opening needs to be 12mm?
Quote from: mtatkow on February 27, 2022, 08:53:56 AM
thought I would add a photo
If you put 3 or 5 gears in the rear wheel and not change the front at all, do you think that would work?
It would be so great to have this bike be somewhat useful with no battery.
This post and a couple others I have read have got me thinking, while I had originally wanted an e-bike with multiple gears I just couldn't pass up the current sale, so I bought 2 (one for the wife) So my thinking now is instead of going through the hassle of trying to mount derailleurs amd maybe finding a front suspension fork that works and installing a handlebar riser why not just start with either a 27.5 complete mountain bike or just frame and needed components and strip the e-bike components from the radmission and install on it so I could have any where from a 7 speed to a 21 speed (since the price of the RadMission on sale was less then a conversion kit and battery would be) Though this is just a thought at this time I haven't even received my RadMissions yet so don't know how I will feel after riding it.
Quote from: mtatkow on November 06, 2021, 09:46:05 AM
The system does not really estimate "effort" like a torque system does - but that is a separate discussion.
I agree. If you juggle the pedal up and down without rotating, it will also trigger pedal assist. This is just for fun - there is no real world use for this.
I just swapped the rear 16 tooth freewheel with an 18 tooth. Didn?t lose much top end, better torque starting out and on hills. Easy swap to do.
Quote from: Spoonbender on October 15, 2022, 12:17:06 AM
I just swapped the rear 16 tooth freewheel with an 18 tooth. Didn?t lose much top end, better torque starting out and on hills. Easy swap to do.
Is it easier to start out pedaling with no battery?
I put a 20 tooth rear sprocket on today, epic.. easy starts, cranks hills easy.. starts are way better. Still cruising at 20 mph on the flats, love it!!
Quote from: J3rry on October 15, 2022, 05:04:14 PM
Quote from: Spoonbender on October 15, 2022, 12:17:06 AM
I just swapped the rear 16 tooth freewheel with an 18 tooth. Didn?t lose much top end, better torque starting out and on hills. Easy swap to do.
Is it easier to start out pedaling with no battery?
The 20 tooth I don?t even need battery power :)
@Spoonbender would you please post the part number or link for the 20 tooth that you put on? Thanks!
Quote from: crorris on October 17, 2022, 05:11:45 AM
@Spoonbender would you please post the part number or link for the 20 tooth that you put on? Thanks!
Amazon (https://amzn.to/3sa9Wuo) has lots, standard size. It?s very hilly where I live, this was a game changer!
Thanks!
Quote from: Spoonbender on October 16, 2022, 06:32:34 PM
Quote from: J3rry on October 15, 2022, 05:04:14 PM
Quote from: Spoonbender on October 15, 2022, 12:17:06 AM
I just swapped the rear 16 tooth freewheel with an 18 tooth. Didn?t lose much top end, better torque starting out and on hills. Easy swap to do.
Is it easier to start out pedaling with no battery?
The 20 tooth I don?t even need battery power :)
I know, 20 tooth rules
Quote from: mtatkow on October 27, 2021, 06:12:57 PM
Feel free to contact me with any questions, I will try to help.
Hey mtatkow! I purchased a Radmission during the recent sale in the hopes of being able to do an upgrade like what you've done here. Your post here is the only one I can find of someone adding a rear derailleur! I was sure this would be a more common conversion as there seems to be plenty of room (as you've demonstrated).
I'm much more familiar with rear cassettes than freewheels and I'm having trouble figuring out what freewheel to purchase. My parts horde is embarrassingly large but only includes one freewheel and it's much too wide (a vintage Suntour Perfect 6 speed). I measure ~22mm to 25mm of space between the motor and the chainstay to squeeze in some gears. You mentioned that you thought you'd could potentially get a 5-speed in there but I haven't found any under 30mm (when I can even find measurements listed). Would you mind pointing me in the direction of which ones you think might work?
since Mtatkow has not been active since March 10, 2022 I doubt he will answer but I would love to know more on adding a derailleur and gears too
Hi There,
I'm new to the RadMission (I used to have a RadRover) community but also have interest in a simple 2 (Front) or 3 speed+(rear) solution.
Love to hear if anyone else has accomplished this that's active.
Expensive as hell but one way to get a 3 speed front gearing is the Efneo Gtro gearbox which mounts in place of the crank but at 499$ its the same price I paid for my mission
Quote from: mtatkow on October 27, 2021, 06:12:57 PM
However, your torque input to the pedals is fairly low given the 3.125:1 stock gearing, so the result is poor battery life.
The old way to express gearing is in gear inches, where you multiply the sprocket ratio by the tire diameter. I believe the Radmission has 86 gear inches. My Radrunner has 76 gear inches, but my pedaling would have been pathetic even with a lower gear. The seat was so far forward that I couldn't put much power into the crank.
When Raleigh introduced the three-speed gearshift in 1902, second was 53 gear inches because that was standard for a one-speed. They soon changed sprockets for 50-67-89 gear inches. In other words, their gear for steepest climbing was almost the same as the cruising gear on other bikes. Their 60 degree frame allowed tall, widely spaced gearing. For every inch the saddle was raised to accommodate longer legs, it moved aft half an inch to accommodate longer femurs and give somebody with a taller spine half an inch longer to the bars.
To test seat position fore and aft, you raise it for full leg extension, then put the ball of your foot on a pedal that's forward and level ( 9 o'clock for the left pedal ). As a rule of thumb, the seat is right if the forward end of the knee is plumb with the spindle. My straddle is 35", which according to one survey, is average for adult male cyclists. With the OEM post, my knee was 7" ahead of the spindle, as if the bike were designed for second-graders.
With a layback seatpost, the end of my knee was over the spindle at 9 o'clock, and my knee wasn't doubled over at top dead center. This increased torque in two ways. I could start my power stroke sooner, and my quads had a better mechanical advantage. I could steam up 4% grades like a locomotive, and pedaling felt good. I added the plywood support after I discovered that my cantilevered weight was gradually bending the post farther aft.
The stock Radmission isn't so bad. I can get the rule of thumb knee position by sliding the seat all the way back on the rails and letting my butt hang off the back. I chose the Radmission partly because of the strong rack, in case I needed a layback. I've ordered one. A plywood support requires only a hole for the post and notches for the rack. Locking the post down holds the support.
Still, I am interested in the possibility of gears...
I Would like to know too. Hopefully some one make a YouTube video
Have wrenched quite a few bikes and built a few, too. Thinking some combination of gearing for the Radmission would be possible. Feedback on putting a 3-speed freewheel with a derailleur with integral hangar bracket in the rear and a triple up front with an up pulling derailleur. Still working through my analysis. Parts considered attached. Asking for feedback.
Quote from: boilerjad on December 16, 2022, 07:28:04 PM
Have wrenched quite a few bikes and built a few, too. Thinking some combination of gearing for the Radmission would be possible. Feedback on putting a 3-speed freewheel with a derailleur with integral hangar bracket in the rear and a triple up front with an up pulling derailleur. Still working through my analysis. Parts considered attached. Asking for feedback.
Reviving this old thread because this is a very small community. Boilerjad, did you end up trying this out? What was the outcome. I just picked up a used, like new Mission and I?m exploring my options. I?d like to be able to climb hills easier and be able to keep cranking on the downhills at higher speeds.
I?m thinking swapping the rear cog to a 15 and putting a 40/45/50 triple up front would be pretty slick if I could make it work.