Gear Changes

[Geoffrad]

I recently purchased a lightly used RADRover 5 (105 km).  It came with one manual that doesn't explain anything about riding the bike or how it works.  My gear cluster on the rear wheel chatters sometimes after changing gears and other times when i change pedal assistance the gears will sometimes change without me operating the controls.  With regard to the chatter i assume i can adjust it out of the derailleur.  But is the bike supposed to automatically change gears when i increase or decrease the power assistance?  It's a bit disconcerting going up a hill to have the gears change on their own and interrupt my rhythm.  I live at sea level in a very hilly area and everywhere is up from here.

[SQFRad]

I don't know much about that model, but I doubt it's intended to be changing gears in it's own. It seems likely to be related to the derailleur needing an adjustment. I'd probably start by reading Rads documentation on shifting, https://radpowerbikes.zendesk.com/hc/en-us/articles/360042472994-Gear-shifting-information then looking at their guide to derailleur adjustment

[Naranja_CT5+]

First of all, I am glad you asked this question.

Just like a regular bicycle if you are having difficulty pedalling you shift to the next gear. With e-bike it gave you a motor and a pedal assist (PA) to control how much assistance you need. It all depends on the rider to select the amount of assistance. But it is not like an automobile, there are no automatic transmission.

I am no stranger to gear shifting as I am very familiar with manual transmission. But I am also very new to electric bikes. I rode around using PA 1&2 for a while and I thought I had the gists of how PA works but I had a misfortune of crashing big time when I tried climbing a big hill. I am in my 60's and my balance is not as good as it used to be. The combination of heavy bike, wrong gears, physical strength to pedal caused me to roll back and dropped the bike. The fall was hard enough that it broke my mirror. First time I am glad of wearing a helmet.

What I found was that it is not instantaneous, you cannot jump from 1 to 5 you have to ease up to it. You need to let the PA have time to sense the amount of torque. My incident happened on a curve therefore I have room to build my momentum. I have learned that I have to "feel" my pedaling to be confident enough to tackle a certain hill.

So now I use PA1 and go through gear 1 to 7 before I will use PA2. I am sure skipping gears and just using the pedal assist are what people are doing. And most importantly I look ahead and be ready if a big hill is in my path.

It also probably worth knowing that the throttle gives you boost if you need assistance to get over a small hill without changing your PA.

I am still learning and I do not mind being corrected if I am wrong.

[inoxa]

the derailer might be bent from a fall.  adjusting the derailer might help but it might need to be pulled/pushed into alignment.

[Geoffrad]

Thanks for those responses. I have another 100 km experience with my RAD Rover 5 and have learned more about the gear shifts.  I understand there is no "automatic transmission" but i was curious if the gears were set up to sense tension and shift on their own because under stress my gears would sometimes change. I have adjusted the derailleur in and out to fine tune it and now it doesn't happen as often.  It sometime will jump 2 gears when I change but that is easier to deal with then unexpectedly shifting to a higher gear when hill climbing.  ANd everything is hill-climbing around here. Leaving my house i have a 1.6 km climb to get to the trail.

Now i have a rubbing noise that is coming from somewhere between the pedal hub and the rear wheel. It doesn't sound like the derailleur.

[Geoffrad]

Naranja CT5+ - i am also over 60 and find the size and weight of my Rad Rover 5 a bit intimidating.  I have not yet had a fall but i have prepared myself (and my wife) for the day i come home with gravel in my knees and palms. I am getting used to it and tried a little rough trail lately.  The bike was surprisingly good on the narrow grassy trail covered with roots. At the very end of the trail i met a melon-sized rock that refused to move.  The fat tires absorbed the shock well and glanced off. My slow speed allowed me to recover without a fall. I rode an 18 speed road bike for years but not for 10 years now; I am enjoying getting back into riding. My typical ride is 15 kilometers on pavement and gravel. Even with the hilly terrain and my 190 pounds it takes 2 or 3 rides to deplete the battery 1 bar.  I am doing a lot of the work!  G

[inoxa]

Thanks for those responses. I have another 100 km experience with my RAD Rover 5 and have learned more about the gear shifts.  I understand there is no "automatic transmission" but i was curious if the gears were set up to sense tension and shift on their own because under stress my gears would sometimes change. I have adjusted the derailleur in and out to fine tune it and now it doesn't happen as often.  It sometime will jump 2 gears when I change but that is easier to deal with then unexpectedly shifting to a higher gear when hill climbing.  ANd everything is hill-climbing around here. Leaving my house i have a 1.6 km climb to get to the trail.

Now i have a rubbing noise that is coming from somewhere between the pedal hub and the rear wheel. It doesn't sound like the derailleur.

These bikes are strictly manually shifted when tuned correctly.  You might need to take it to a bike shop for fine tuning if you can't figure it out.  YouTube has tutorials on the subject.
Another possibility the chain might be dirty and need cleaning.  That can cause noise.  Sounds like you don't have many miles on the bike but the chain will stretch over time and can cause some issues.

[John Rose]

I wonder if the spring for the idler pulley was weak, would it result in random single-step gear changes?

... You need to let the PA have time to sense the amount of torque. ...

🤔 Does that model have a torque sensor or a cadence sensor? If a cadence sensor, it only needs to detect *any* rotation of the pedals at all, with no regard for torque. It probably requires a minimum RPM within, say, half a turn, before it kicks in though.

Even if it was a torque sensor (and/or had a mid drive motor), I don't think it would be able to select which gear is needed.

[complete side-topic, feel free to ignore it: I wonder if there are any ebikes that use a self-adjusting belt drive transmission like the driven pulley on a snowmobile?]

[Naranja_CT5+]

If a cadence sensor, it only needs to detect *any* rotation of the pedals at all, with no regard for torque. It probably requires a minimum RPM within, say, half a turn, before it kicks in though.

thanks for the correction.

[Bobk]

I have done 8.000 km on my Read City 5 plus. When I was younger I covered thousand of km per year on my 10 speed. I could not get a clean derailleur adjustment on my Rad  until I replaced the chain and freewheel at $6,000 km. It turns out the the freewheel was defective from the factory. Check the freewheel for side to side movement. There should be none. If there is replace the freewheel and chain.

The other thing that could cause this is a bent derailleur hanger. The bike may have fallen on its side.

[Geoffrad]

I have adjusted the derailleur by carefully changing gears one at a time, waiting for the noise and mis-change. I sorted that out and i am now satisfied with the gearchange performance. I think this discussion topic is exhausted. Thanks for your contributions. I am going to start another one about rubbing noises.
Geoff