2 New RAD City bikes- cresting over a hill.

[Stv_Szy]

We recently purchased 2 Rad City bikes which are quite fun to ride on flat terrain.
On hills we are having issues after climbing a hill. Once you reach the top and dial the PAS down to 2,1 or even zero the bikes seem to freeze and are very difficult to pedal. It seems you need to stop completely, turn the controller off and set out again. Are we missing something here?

 

[RangerDave]

Can you elaborate further on what freezes? You can’t move the pedals forward or backward? The motor doesn’t work with the throttle? What gear are you in? Does the bike roll easily? Etc. Pas-0 will be more difficult to pedal as you have turned off the motor assist and are pedaling a very heavy bike with your own effort. Also, the direct drive motor will add a bit of drag due to the motor magnets vs a geared hub motor.

RangerDave

 

[Stv_Szy]

I understand they are heavier bikes but when your are on flat ground prior to any slope you can pedal them quite easily with power off or power assist set to 0.

To elaborate you climb the hill in 1st or second gear PAS level 5. Get to the top of the hill still in the lower gear and turn put PAS to 0 or completely off and in 1st gear it feels like 7th gear. Near impossible to pedal. Turn everything off and wait 30 seconds or more and pedaling is easier again.

I can check if the bikes will roll after the rain stops here.

 

[RangerDave]

That does sound peculiar. When you set to a lower PAS level, do you continue pedaling as you do that or do you stop pedaling for 1-2 seconds, then resume pedaling? I’ve found with my 2019 City Step Thru you must stop pedaling for a brief period so the display reads zero watts when going to a lower PAS setting before it takes effect. I don’t understand why it would suddenly become difficult to pedal when doing that unless there is something wrong with the bike. It sounds like both of your bikes are doing this?

RangerDave

 

[Stv_Szy]

Yes both bikes are the same. If the rain stops tomorrow I will do some more tests with your information.
Thx.

 

[rich c]

Are you shifting at the crest too? I'm thinking it has to do with the cadence sensor, PAS setting, bike gear, and bike speed. Try getting a higher crank rpm for the cadence sensor.

 

[robbur]

I’m experiencing exactly the same condition on my Radcity 4. After lowering the PAS back to 1 or 2 and trying to increase the gear it feels like the brakes are on or there is a lot of resistance in the motor, noticeable even when trying to coast.

 

[Stv_Szy]

Tried this again yesterday. Cresting over the hill PAS set to 5 and 1st gear. Drop PAS to 1 and bike seems to freeze up. You cannot peddle at all.
Let wattage go to zero. No difference. Wait about 20-30 seconds and then it seems to wake up. Very frustrating.

 

[RangerDave]

Have you touched the motor housing to see how hot it may be? Same with the controller box? It sounds like quite a hill to pedal in 1st gear at PAS-5. How many minutes (or seconds) does it take to crest the hill? Over what distance? Can you continue pedaling in 1st gear and PAS-5 after you crest the hill without issues?

Definitely worth a call to Rad Support. Very strange problem, indeed.

I hope you can get the issue resolved. - RangerDave

 

[GrandPappyMike]

I have the 2018 and have the same issues. It doesn't lock but it is hard to pedal. I live in the Catskill mountains and every direction I ride is uphill. You can see in the picture, on yesterday's ride we climbed 1636 feet. Rad says to avoid steep hills or walk the bike on hills you can't peddle up in 3 PAS or lower, which is not possible for me. I figure when the motor goes I'll see the bike for parts and buy a different brand more suitable for my needs. This is from their website. https://radpowerbikes.zendesk.com/h...-Off-Road-in-Wet-Weather-and-on-Hilly-Terrain

Riding on Steep Hills

Always pedal when climbing hilly terrain to avoid straining the motor.

A rider should keep the bike moving at a reasonable and steady pace when using high levels of power assistance. Demanding high power output when the bike is moving at slow speeds may strain the motor. Pedaling in a low level of pedal assist (levels 1, 2, or 3) or riding with the twist throttle only partially applied can help keep the bike moving without high power demand, which will increase the longevity of the bike's motor. Plan your route to avoid very steep hills (over 15% grade) if possible.

Hills with a 15% or Greater Grade

Never ride up hills which exceed a 15% grade with the motor fully engaged.

If you need to ride up hills steeper than a 15% grade, it is important to set the bike to a lower level of pedal assist (levels 1, 2, or 3) and to maintain a reasonable speed above a walking pace. For hills that exceed your ability to climb as a cyclist, you can engage "walk mode."

 

[RangerDave]

With other people reporting similar symptoms after long hill climbs, it sounds to me like maybe the motor is overheating and causing friction due to thermal expansion, then things go back to normal after a brief cool down period.

From the information I’ve gleaned over the years, it seems direct drive motors perform best at higher speeds on level terrain, whereas geared hub motors shine at lower speeds due to their higher torque output. I’m sure both will overheat when run at max power for an extended period, but I suppose the geared motor may assist you to the top of the hill faster than a DD motor and thereby run less time and not overheat. Then again, the motor is spinning faster and the internal gears are causing friction spinning in the housing and generating heat also. Chose your poison, I guess.

I have found on very rare occasions with my non-ebike that is it sometimes easier to get off and push the bike rather than pedal. The leg movement and physical effort to move just 3 feet up a steep hill is significantly less to push then to pedal. The walk-mode on the ebike significantly reduces even this effort.

RangerDave

 

[AHicks]

Dave, for whatever it's worth, it sounds more like a software issue to me. It sounds like the the bike is going into regen mode - which would make it really draggy. Problem is, it shouldn't do that unless one of the brake switches is telling it a brake is on.

Absolutely no clue what's going on with this issue, but I can say the direct drives can dissipate heat quite a bit better than a geared hub or mid drive because the windings are in direct contact with a side cover - which acts as an air cooled heat sink. The geared bikes can't offer that. They run completely enclosed, with no air circulation. -Al

 

[RangerDave]

Regen kicking in never occurred to me! I’ve never tried to pedal while braking, but I assume the brake cutoff would override the pedal movement and not reactivate the motor.

I’m thankful this isn’t happening with my bike, but it would sure be nice to have access to one to help debug the issue.

 

[AHicks]

That's the kicker here. There should be no power to the motor available if one of the brakes is on. The brake activates the regen circuit AND cuts off power to the motor!

 

[GrandPappyMike]

We recently purchased 2 Rad City bikes which are quite fun to ride on flat terrain.
On hills we are having issues after climbing a hill. Once you reach the top and dial the PAS down to 2,1 or even zero the bikes seem to freeze and are very difficult to pedal. It seems you need to stop completely, turn the controller off and set out again. Are we missing something here?

Just as a side note regarding riding up and down hills on a regular basis. I replaced the brake calipers with the JUIN TECH R1 Hydraulic Hybrid calipers. I'v gone over a 1000 miles before feeling the need to change the pads. And I have never had to adjust them in that time which is just wonderful.

 

[goldconch]

Just as a side note regarding riding up and down hills on a regular basis. I replaced the brake calipers with the JUIN TECH R1 Hydraulic Hybrid calipers. I'v gone over a 1000 miles before feeling the need to change the pads. And I have never had to adjust them in that time which is just wonderful.

@GrandPappyMike Anecdotally, from your experience, how noticeable is the improvement in stopping power with the Juin Tech R1? Was it a worthwhile upgrade? I'm considering those...

 

[GrandPappyMike]

@GrandPappyMike Anecdotally, from your experience, how noticeable is the improvement in stopping power with the Juin Tech R1? Was it a worthwhile upgrade? I'm considering those...

If I remember correctly they were about the same, maybe some improvement. The biggest benefit for me was not having to adjust them a couple of times a week like I did with the stock ones. I feel they are worth the money. I would say overall they are better at stopping, because if your going down a steep hill and then realize your breaks need adjusting again it's not a good thing.

 

[BKing]

We recently purchased 2 Rad City bikes which are quite fun to ride on flat terrain.
On hills we are having issues after climbing a hill. Once you reach the top and dial the PAS down to 2,1 or even zero the bikes seem to freeze and are very difficult to pedal. It seems you need to stop completely, turn the controller off and set out again. Are we missing something here?

Did you find out anything more?
We have two Radcity 2019 and ours don’t do this. It’s flat around here but we take them to the mountains. I’m 245 lbs and have heated up the motor pretty good several times. I will walk it unless I can climb with 500 watts and stay above 10 mph.