Chain slip??

[Yuma G]

RadCity 16 .. in any gear/ pas setting and while peddling and left foot at top of stroke and starting the push down I experience a short "slip" ?? where chain is not engaged for a split second and then is re-engaged ?? … does not seem to happen with right foot , only the left and not all the time... sort of a "clunk" as gear tooth re-engages chain ? Sorry don't know how to explain it better. Thanks for input, appreciate your help

 

[AZOldTech]

RadCity 16 .. in any gear/ pas setting and while peddling and left foot at top of stroke and starting the push down I experience a short "slip" ?? where chain is not engaged for a split second and then is re-engaged ?? … does not seem to happen with right foot , only the left and not all the time... sort of a "clunk" as gear tooth re-engages chain ? Sorry don't know how to explain it better. Thanks for input, appreciate your help

How many miles do you have on that chain and/or cassette? Do you have a chain checker?

 

[Yuma G]

Bike is brand new only 68 miles on it less than a month of use. and No I don't have a chain checker

 

[mrgold35]

Could the rear derailleur be slightly out of adjustment? Do you have the same slipage if you start in a higher gear or only in the lower gears? Do you hear a slight "ticking" sound when riding like the chain is ready to shift to another gear? My two 16 Radrovers seem to need rear derailleur adjustments every month or so. Most of the time just taking out the slack in the cable works. I sometimes have to click up twice and down once to upshift one single gear when it starts to get out of adjustment.

 

[Yuma G]

I'm not shifting at all , I'm in 6th or 7th gear and a low pas and I get this "slip" at the top of left foot as I push down on the pedal and again on the next down stroke of the left pedal only the left never the right...weird ???? but that's what's happening. It happens while I'm riding BUT not all the time, might happen for 4-5 successive down strokes of the left pedal and then all is good for a while UNTIL it happens again...????

 

[Rover1701]

RadCity 16 .. in any gear/ pas setting and while peddling and left foot at top of stroke and starting the push down I experience a short "slip" ?? where chain is not engaged for a split second and then is re-engaged ?? … does not seem to happen with right foot , only the left and not all the time... sort of a "clunk" as gear tooth re-engages chain ? Sorry don't know how to explain it better. Thanks for input, appreciate your help

Sounds like your left crank arm is loose. Tighten the crank arm bolts and see if it gets better! (A new bike should not have any chain or gear wear)

 

[mrgold35]

I had an issue with one of my Rovers with around 1500 miles that sound kinda the same. It felt like the chain was jumping or skipping when pedaling at random times. I mostly remember it happening during normal pedaling; not, when starting out or with the left pedal crank only. It took a while; but, it would only happen 2X-4X a month, then 2X-4X a week, and eventually it would happen 2X-4X a day. It failed completely 1/2 to work and the pedals would spin freely frontwards and backwards. The locking mechanical mechanism in the rear hub that allows you to backpedal freely and locks the gears in place to turn the rear wheel forward failed (2 month after one year warranty expired). So glad I had the throttle to get me the +3 miles the rest of the way to work.

Not a common failure; but, it can happen with the inexpensive parts used by Rad Power Bikes. My 2nd rover never had this issue and both ebikes have +3200 miles on each of them.

 

[Yuma G]

Thanks everyone for your input.

 

[AZOldTech]

Bike is brand new only 68 miles on it less than a month of use. and No I don't have a chain checker

With such low miles is not any of the chain/cassette. So you need to look at "alignment" (derailleur and chainring) and that every bolt is tight on the drive train. Let us know when you finally find out what fixed the problem. Thanks.

 

[Lysle]

With such low miles is not any of the chain/cassette. So you need to look at "alignment" (derailleur and chainring) and that every bolt is tight on the drive train. Let us know when you finally find out what fixed the problem. Thanks.

I have a 2019 Radcity with 200
Miles. What I notice is a “clunk” when starting to pedal after coasting. The factory response to my inquiry about this annoying noise is that this is common to all the 2019 Radpower bikes. They don’t offer any solution. I like everything else about this bike, but after owning several other Ebikes , I could not recommend Radpower.

 

[Dirkdaddy]

I bet the chain join link or one of them is stiff. Check each link for ease of movement 45 degrees each direction, you can easily do this with a rag and turning crank backwards. One link is probably not bending as much and its skipping. I have had that before.

When you find the stiff link, using rags grab chain on either side of the stiff one and give some pressure attempting to bend the chain in the side directions each way - like a V toward you then away from you just a bit to loosen up that link. It normally will loosen right up. a bit of chain lube also helps.

FYI later if you suspect chain stretch after 1000 miles or something measure 12 links pin to pin should be 12" between them. If its about 1/4" long chain needs replacing. Each link is 1". At least last time I checked...now I use a stretch tool.

 

[AHicks]

This has to be something related to the crank because of the unusual timing of the event. If it were a chain or anything in the rear, the timing would change after several revolutions of the crank. It would not stay at the top of the left pedal down stroke. So that's where my focus would be.

Pedal loose in the crank, something in a pedal bearing not allowing the pedal to turn smoothly (bad pedal), loose crank bolt, loose sprocket, bent tooth on the sprocket, etc. Something on the crank, whatever....

 

[AHicks]

I have a 2019 Radcity with 200
Miles. What I notice is a “clunk” when starting to pedal after coasting. The factory response to my inquiry about this annoying noise is that this is common to all the 2019 Radpower bikes. They don’t offer any solution. I like everything else about this bike, but after owning several other Ebikes , I could not recommend Radpower.

I think this is silly. You're abandoning an entire line of bikes because the manf can't diagnose your problem over the phone?

Have you considered taking it to a dealer?

As a reminder, these bikes are supposed to be assembled professionally. If you didn't have that done, then this issue is on you! Many riders are capable of doing this on their own, and many MANY have done so successfully. However, there is no guarantee, as mechanical abilities vary widely. I like the idea of giving it a good try on your own, but if something gets sideways on you, THEN take the bike to a dealer or have a mobile service come check the bike out. It's hardly fair though, to condemn an entire line of bikes for a problem that comes up at 200 miles.

Consider the "other" brands of e-bikes that don't even offer the option of saving money by assembling them yourself, OR offering phone service.

All that said, I have to say the whoever made the comment indicating "all RAD's do that" is pretty ignorant. They don't.......

 

[Pay Jota]

Yeah, neither of mine have that clunk. At 300 and 150 miles, respectively.

 

[Lysle]

Velofix assembled the bike and did the first service as well. $200. The tech said he thought this normal.
The factory sent me a video of a Radcity and a Rad mini both making the same clunk and the Senior Customer Service person is the one who said they all make the noise.

 

[AHicks]

It would be interesting to hear/see the reaction of a 3rd person regarding this "clunk", to get an arms length opinion on the matter? Though the word "clunk" might be a bit subjective for all of us, it doesn't sound normal to me. I can assure you my City has no clunks, but in all honesty, my City isn't very stock either.

Could this noise be coming from the seat, possibly the handlebar area, or basically someplace not in the drive train, or do you actually feel it in your feet when you start to pedal?

 

[Lysle]

It would be interesting to hear/see the reaction of a 3rd person regarding this "clunk", to get an arms length opinion on the matter? Though the word "clunk" might be a bit subjective for all of us, it doesn't sound normal to me. I can assure you my City has no clunks, but in all honesty, my City isn't very stock either.

Could this noise be coming from the seat, possibly the handlebar area, or basically someplace not in the drive train, or do you actually feel it in your feet when you start to pedal?

It’s definitely in the rear wheel because it can be duplicated with the wheel on the bench just by moving the sprocket back and forth. The noise is amplified by the large motor housing.

 

[Lysle]

 

[sl_duck]

View attachment 36817

The term for that part is "freehub body". They probably use an inexpensive one that requires more rotation until the prawls engage.
There are very nice freehub bodies that tout "immediate" engagement with six or more prawls, but they are usually matched to the hub so it's unlikely you could swap it out for an upgraded version.
If you rotate the pedals backwards slowly and listen to the click-click-click of the prawls, it should be a regular rhythm. If it's irregular, like click-click....click-click, then you might have a sticky prawl. There's a couple specialized tools you'd need to get in there, but a bike shop should be able to do it easily.

As for the original post, I'm guessing loose crank arm. Try standing on the pedals with your cranks horizontal, left foot forward. Then again with left foot back and see if it clunks. The square taper crank arms often need an extra tightening a few miles after initial assembly.

 

[AHicks]

Rad changed to a DNP 11:32 rear freewheel for '19 because the stock gear they used on the earlier bikes didn't allow an average person to peddle fast enough to even get to 20mph. A bunch of us made this move in '18. NOBODY complained about a "clunk" being part of normal operations. This move was so popular Rad put it into production for '19.

Since then, I've replaced my motor a 3rd time (another story) but to save time on that install, I installed another DNP 11:32 freewheel (just a couple of days ago). THAT freewheel operates clunk free as well.

Logic would tell us that if all the '19 RAD's operated with a "clunk", this would not be the first time I've heard or read anything about it.

My point is, there's an issue somewhere, or you're able to hear/feel something that nobody else is noticing.

I'd kinda like to see those attachments they sent if you could forward them?