Freewheel replacement for Rad City

Geosp8l

New Member
Region
USA
I think my question got lost in the discussion, so I am posting it plain and simple...

I have a 2021 Rad City with the Shengyi DD motor and the 6-7 sp Screw freewheel, 11-34 7sp. I would like to upgrade to a 10 speed, 11-40, or even 11-42. Is it even possible?

This is not about more power, or more speed; simply a smoother shifting experience.
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
I don't think I've ever seen anyone talking about something like that. I would not just be about swapping out the freewheel. Additional would be 10s derailleur, shifter, and chain.

If I were going to attempt this project, I would start with the freewheel sprocket. Install that on the motor and see if it will even fit back on the bike. If so, and the chain line looks like it will clear on both sides (when in 1st and 10th), then go ahead and make your purchase of the other parts.

As far as smooth shifting, I couldn't expect anything better than what I'm getting with my 'city. If you're talking about additional gear ratios being preferable for your purposes, I can see that maybe.

Just one other thought. Personally, I find getting the 'City's derailleur set "just right" WAY easier than a supposedly higher quality 9 speed derailleur on a different bike. The 9 speed is nice when set right, but much pickier about "being set right".

If you decide to go for it, hope you'll keep us posted on your experience. -Al
 

Geosp8l

New Member
Region
USA
Unfortunately, I already bought all the parts, only to find out about this 'Screw(y)' freewheel thingy. I had never heard of such a thing until visiting this forum! The notion of a Screw Freewheel seems antiquated and less versatile. Why they used a Screw on this bike is beyond me, to save a few (hundred) bucks? It is a minor annoyance, I don't find it that intolerable, I just thought the fix was going to be easy, like any bike. Having a Cassette seems like a maintenance advantage down the road, as I am hearing that cogs wear out somewhat faster on an eBike. Anyway...

When I first went to the Shengyi website, they only had one DD motor listed that looked the same as what is on the bike. It spec'd as 500/750W and said 8-10sp Cassette, so I thought it would work. Now they have added what I believe is the actual motor, with a nice schematic at the bottom, here http://www.syimotor.com/productDe_5.html. It looks like it comes in a 8-10sp Cassette and 6-7 sp Screw, basically a different motor cover it appears. The overall axle length is the same for both, ergo, the drop-out should be wide enough for the 8-10sp Cassette. I saw another thread where they replaced the motor cover to achieve the same outcome as I am seeking. So that is my next plan of action - to see if I can obtain said motor cover.

I sent Shengyi a email inquiry and have not heard back. I am tempted to call them and see if I can find someone who speaks English. The other avenue is to try Rad, again, and see if they are will to give me any info on this. So now my question has changed a bit - Where can I find this motor cover? I will keep the forum posted on my experience.
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
If you want to discuss anything that doesn't come on the bike new from RAD, you're very likely wasting your time approaching them with an idea like this. They talk about the bikes as sold by them like it's written in stone and sent by God himself. To speak of ANY mod, is heresy.....

Clearly, they do watch popular opinion. Previous to the '18 model year for instance, they used a 14 tooth freewheel. It was impossible for most to pedal over 14-15mph. Then somebody shared the idea of the 11 tooth available from DNP. Despite the fact DNP didn't have the greatest reputation, they became a VERY popular mod, dispelling the bad rep they had earlier, and RAD started using them as standard OEM for the '18 model year (with nothing mentioned about the popularity of the mod on their earlier bikes of course....).

The guy that switched his motor cover, if it's the same guy I'm thinking of, has a Bafang geared hub, and though coming up with the right part was likely difficult, it is possible there - one of the reasons I like Bafang personally.

I get your confusion regarding the 2 types of gears. Early on when I was asking a LOT of questions, I ask about the difference in a bike shop (one of the very few I trust to this day). They relayed what I beleive MOST people I think, referring to the screw on type as a freewheel, where the other type is refered to as a cartridge type. That's not so true in some of the ad copy unfortunately... -Al
 

Geosp8l

New Member
Region
USA
re: RAD customer service - in the one correspondence I've had with them they couched their reply in company policy, ...tested for safety and functionality... Their business model seems geared (pun intended?) towards novice or people that would otherwise not be out riding? It's a good market, obviously, since they seem to be doing quite well financially. Can't say it's a bad thing, getting more people out exercising that normally wouldn't be. I sold my Rad Rover to a Woman who had never owned a bike before...!

Interesting about the popular opinion. Maybe I will send them mine, regarding the cassette issue... I really can't see how the 8-10sp cassette motor setup could be that much more expensive for a big company like Rad. It's the same stock motor, they should be able to absorb an inexpensive 8sp setup and still hit their price point. So much easier to replace a worn out cog set down the road.

Yes, that must be the same post. It was a geared Bafang motor. Thanks for all the input, I have learned a lot in the short time I have been on this site. Martin
 

Geosp8l

New Member
Region
USA
For what it's worth... It looks like this cannot be achieved with this motor, adding credence to Rad CS's '...good luck with your upgrade...' They used a motor that can't be switched to a Cassette freewheel, the axel is being part of the problem. The only recourse would be to switch out the entire motor, which, considering this is not a huge problem, seems a bit drastic.

When this cogset wears out, what recourse do I even have? The options for this Screw freewheel is limited to 6-7 speeds and no way to really change the gear ratios at all!?! Shame on Rad for not thinking this through. Shengyi has the same motor in a Cassette version that wouldn't have impacted their price point. Not sure it's worth wasting my breath on them for this issue. Thanks again for all the assistance...
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
What kind of options are you thinking of? Seems like there are several different gear ratios available among the different 7sp freewheels that would work.
 

Geosp8l

New Member
Region
USA
I haven't started looking... I am a little deflated atm. My mechanic mentioned off-hand that there are not a lot of options. If I want to increase the gear range, i.e. a little lower, then that just increases the gap between gears. The derailleur cage might not handle any larger cogs. Change the front sprocket...? I don't know, I guess I will wait until they wear and tackle it then.

I will ride happily for now, it is still a really fun bike, especially after adding the new suspension fork. ...maybe the ultimate solution is to get another bike for my off-road adventures.
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
A front sprocket change would change things for sure. You would use that AND available freewheel ratios together to get the overall ratio you're looking for. I'm 99% sure you'll be able to find something suitable to whatever you want to do when you get around to it.
 

ExPatBrit

Active Member
I notice the NCM bikes have multiple front chainrings (3) . Wonder if it possible to do something like that.

NCM Prague.JPG


Leave rear hub intact but add a 42T inner second ring. You could actually manually move the chain for different modes if you don't want to add the extra lever. There is not much room on a city step-thru to attach the front derailleur
 
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