As I stated in the link I posted previously, my Step-through Radcity 5's wobbles were cured by replacing the OEM tires. I have ridden it at 40mph downhill since then without issue. It is quite stable at speed as long as you don't mind the coefficient of drag close to 1... it feels like I have a parachute on compared to my road bikes. I don't think it's possible to exceed 40mph unless you throw it off a cliff.

Seems this may be a safety issue:

https://www.bicycleretailer.com/industry-news/2022/08/02/rad-power-bikes-giro-face-wrongful-death-suit#.YusCdXbMJhE

I have to wonder whether it was actually the quick release or the tires?

The Radcity 5+ is not very aerodynamic with it's upright rider position, and it is also a very heavy ebike. I agree that that combination essentially makes pedaling efforts at 20mph and over pretty ineffective. With the hack 25mph is a very useful and reasonable top speed, but it does mean that it essentially is an electric scooter at those speeds. I use my RadCity 5+ for commuting and shopping with panniers exclusively and use it only at level 5 or throttle control in that capacity for that reason. The only time I really pedal with effort is on really steep inclines where the motor struggles at slower speeds and the pedal effort adds significantly to the bike's speed. I will say that the motor has very respectable torque that allows me to ride up double digit inclines where other electric bikes would struggle. I do however worry about how much that stresses the battery and if this will change as the battery degrades over time.

Totally agree about the mirror. Especially if you're wearing a jacket/hood in cold weather, you can't really turn your head so easily.

I ride non-electric bikes for exercise, so my RadCity is used only for commuting and shopping (with panniers) and in that capacity I use only assist level 5. Given current gas prices I figure I've saved $50 so far over 200 miles...

I don't see how anyone over 5'10" could ride the step through version without purchasing a longer seat post. I'm 5'7" and it is maxed out.

Quote from: david.platt@mac.com on May 05, 2022, 04:44:29 PM
Did you try locking out the front shock.
O I think you can adjust the firmness too.

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwjL8OjrxMn3AhXSWM0KHd2GBNEQFnoECBUQAw&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DtGl3I0Ez974&usg=AOvVaw3YearcbuHiGl_eXU94MBBp

The lockout didn't change anything. The first thing I did when I noticed the wobble was lockout the fork. The fork quality is pretty terrible but I wasn't expecting much given the bike's price. It works well enough.

I can tell you that the stock tires are garbage, they aren't round. The rims are pretty crappy too but they should be sturdy enough to last a while. There is nothing specific about these wheel or tires (except for the motor mounted on the rear rim), they are standard 27.5 inch, which is half way between a 26 inch MTB tire and a 29 inch tire. Although it's probably the least common "standard" tire size they aren't hard to find. Just look for a 2 inch wide 27.5 inch (also called ISO 584) size.

Please see my post here:

https://www.radowners.com/index.php?topic=1733.0

Short version of this post - the problem was the "Rad City" tires

Long version:

I tried again riding the bike with the panniers over the axles and with even weight distribution. I tried different tire pressures. No improvement. At this point I double checked for tightness on the bar, stem, headset, fork, and axles. No issues. I spun the wheels and noticed that the tires seemed to be out of true both laterally and radially, with significant "humping" on at least 2 spots. I proceeded to remove both wheels (rear is pretty easy actually which was surprising). I put the wheels on my truing stand and checked spoke tension and lateral trueness. The front wheel was off a few mm and the spoke tension was fairly uneven but given the spoke count I didn't think that was the issue and I expected some of this as the rims aren't really high end quality. I unmounted both tires and put the wheels back on the truing stand, no radial issues at all. I retrued and tensioned the wheels, but mounting the tires I could see the issue was still there, so it had to be the "Rad City" OEM tires causing the problem. They are anything but round and seem very unbalanced. I had to order replacement tires since I only stock 700c tires, The ones I ordered aren't "pro" tires or anything (Vittoria Randonneur), they are the same size (2 inch) and very similar tread. The stock tires weigh over 1400 grams each (wow!) while the replacements weighed over 900, which isn't light either but that's an improvement of 2.2 pounds just in tires! After re-installation the problem is gone, I can ride fully loaded without any issues. There is a noticeable improvement in ride comfort as well as the bike rolls much more smoothly. Before if I let go of the handlebars the bike would vibrate back and forth uncontrollably even at 5 mph, now I can ride no handed at 25mph (not recommended!) 

I have a Rad City 5 Plus step through, I'm 5'7" with a pretty average leg length and the seat post is almost at it's maximum setting in order for me to get the proper leg extension. I'd have to agree that anyone over 5'10" will need a longer seat post, which is pretty easy to do as the seat post is standard diameter 27.2mm.

I looked into this some more on other forums, and apparently there are two things I hadn't considered that I will try:

1) Make sure the weight distribution in both panniers is fairly equal and
2) Make sure the pannier bags are centered over the rear axle, not behind.

My panniers were neither of those, so I will try to correct and report back.

I have a RadCity 5 Plus step-thru, and I was returning from my grocery run from (banally bourgeois) Trader Joes with fully loaded rear Ortlieb Panniers when I started to notice a resonant wobble throughout the bike frame when turning the front wheel even mildly rapidly. It feels quite unsafe. This occurs even when almost stopped so it isn't a speed wobble. I checked the wheels, headset and stem and everything is tight. The wobble pretty much goes away if the panniers aren't loaded, so I'm wondering if this due to the geometry of the bike and long steerer (moving too much weight off the front wheel maybe?), an insufficiently rigid fork (it feels better with the fork locked), or perhaps just a side effect of the step-through design? Has anyone else experienced this?