Radcity and cadence sensor

[adreamer]

I was planning to buy RadCity as my first ebike. I couldn't "test ride" that bike near by area. However, I was able to rent a pedego electric bike for an hour.

The behavior of that bike is a bit different than what I was "expecting" it to do. For ex: in pedego, when I was in pedal assist level 3, it's top speed was around 14 miles. However, what I found is, speed of the bike is not too related to the speed at which I was pedaling. For ex: when I start from complete stop, even with a slow pedal speed, I found that bike is going quickly up to 14 miles limit(pedal assist 3 limit).

In other words, after a minimal threshold(Ex: like pedaling 10 times per minute), my pedaling speed doesn't seem to be directly related to motor power output.

Is that how RadCity also behaves?

 

[WattsUpDude]

This is normal for a cadence sensor’d bike, yes. Not all controllers are programmed the same but this is basically what you get from a cadence sensor PAS. Generally speaking, you can think of a cadence sensor as an on/off switch that goes to the preset speed or wattage and a torque sensor is like a volume knob that you can power in a very granular way via your own pedal pressure. It’s very easy and natural to pedal as slow as you want even in the highest assist level.

 

[adreamer]

Thanks for the replies.

Today I was able to rent a torque sensor bike(gazelle model with bosch performance motor) and it felt more like what I was expecting. In general it feels a lot like a normal bike with 2-3 gears down shifted, depending on assist level.

However, there a couple of things I missed here

1. There was no throttle, which I really liked in pedego model (and i think radcity also has it)
2. Gazelle bike required "lot more" from the user. I had to put in lot more effort to get the bike up to similar speed. It could be because of low powered motor or that is how these torque sensor are. I'm not sure.

Since getting a non bosch based torque sensor bikes seems a bit hard(very few models to choose from and can't test ride much), I've decided to buy RadCity itself. Hopefully, I'll be able to get used to the bike.

 

[AHicks]

Thanks for the replies.

Today I was able to rent a torque sensor bike(gazelle model with bosch performance motor) and it felt more like what I was expecting. In general it feels a lot like a normal bike with 2-3 gears down shifted, depending on assist level.

However, there a couple of things I missed here

1. There was no throttle, which I really liked in pedego model (and i think radcity also has it)
2. Gazelle bike required "lot more" from the user. I had to put in lot more effort to get the bike up to similar speed. It could be because of low powered motor or that is how these torque sensor are. I'm not sure.

Since getting a non bosch based torque sensor bikes seems a bit hard(very few models to choose from and can't test ride much), I've decided to buy RadCity itself. Hopefully, I'll be able to get used to the bike.

After a lot of time on both geared hub and mid drive bikes, I think there is little question that the geared hub bikes are easier to ride. That said, all else being equal, the mid drive bikes will generally have more hill climbing power.

Throttle or no is a personal call. There's been raging yes/no debates that are just endless. I don't care which way you decide, but personally, I wouldn't be without one. Mine is used mostly to get the bike moving from a stop, if only for 3 feet while I'm getting my balance. It was also used once to get me home after the bike dumped me (after a little loss of balance argument with the bike, the bike won). It was damned nice to have it that day too....

 

[Widgets]

There are a couple factors that impact the "feel" of a cadence based bike. The number of magnets in the disc will impact the responsiveness, as will any manufacturer programmed startup or shutdown delays. There can also be a power ramp up/down to keep from having a surge of power. Additionally, the PAS levels may be specified as speeds or assist power levels. The number of PAS levels is another variable. Then, some manufacturers let you change the assist levels to customize your bike. You can also change to an aftermarket controller if you want more control than the manufacturer provides.

I have had my RadCity ST for a few months and 850 miles. I almost always keep it on PAS 1, and at this low power level I dot really feel any surge (or i have gotten used to it).

Like @AHicks, I want my bike to have a throttle for when my knees or back decide to act up. I don't normally use it except for an enexpected stop where I forgot to downshift. It is more a safety net to limp home.

I was lucky to have an outfit nearby that rents Rad bikes, so I was able to test drive the models I was considering before I purchased.

 

[GenXrider]

I went with Ride1Up because its cadence sensor based PAS is "power" based rather than "speed" based like a cruise control, plus the power level is user configurable for every assist level, and you can select among several different ranges as well. I actually adjusted PAS 1 so low that the bike would go only about 6 mph on level ground if I was to just spin the pedals lightly - the bike doesn't get ahead of me because I'm actually pedaling with force , so I get a good workout. Other than when assist initially kicks in, it feels very natural as I continue pedaling continuously until my next stop.

 

[adreamer]

I was looking at Ride1up also, but found that top speed is 28mph. I think it is a bit too fast for me. Is it possible to limit the maximum speed to 20mph?

Reg. direct hub and geared motors, I don't have much preference. Routes I plan to use doesn't have lot of hills. Based on the youtube videos I saw (not much useful I agree), I felt that RadCity is much quieter than geared motor models. That is one the main reasons I thought of getting that.

Once again, thanks for all the pointers.

 

[GenXrider]

Yes, you can lower it down to 25km/h (15mph) which is a common speed limit for Japan and Europe.
Check out Page 9 on Ride1Up display manual.

Regarding Ride1Up 700, you wouldn't know it from the manual, but that speed limit setting on the KD218 manual for current generation 700's only affects the max speed of throttle only, which has a range setting of 11 to 28 mph, so pedal assist will still assist to 28 mph regardless of that speed limit setting. But, it's still not an issue if someone is worried about a 28 mph limit being too fast. The power is configurable for each PAS level, plus even the lowest PAS levels are low enough with the default settings that the bike isn't going to just take off to 28 mph when the rider doesn't want to go that fast. I'm usually riding under 20 mph with constant pedal effort and low PAS power, and the only time I've gone 28 mph was testing higher PAS & throttle or going down a big hill (which was due to gravity, plus it has good brakes so that I could have kept it under 20 then also).

 

[AHicks]

2 things. As far as operating noise, after a ton of time on both direct drive (up to 1500 watts) and geared hubs (500w-1500w) I can safely say neither has much of an advantage. The noise and high maintenance issues you hear about regarding the geared hubs are pure sales hype used by salespeople pushing direct drives. Neither are true. Not any more anyway. Sure there is a low quiet whine due to the gears in a geared hub, but creating just as much noise is the power hum coming from the electronic polarity switching going on inside the direct drive - especially when accelerating! They don't mention that very often.....

And as as the number of magnets in a PAS sensor controlling the sensitivity to crank movement, that is true, but only to a certain extent. Many times, the controller is sitting there waiting to turn on the power to the motor, while counting the number of magnets/pulses coming from the PAS sensor. How the controller has been set up is generally going to have more say when it comes to PAS sensitivity. The controller may be counting/waiting for 3-4 or more magnets to pass prior to turning on.... -Al