Pedal? , crank? problem

[sparky]

Strange... I have this problem with my folding bike, also. I figured the problem would be within the bottom bracket, but that doesn't make any sense.

When I pedal standing up, it just slips (no resistance whatsoever) for like 10% of a revolution, and then it catches again.

I know the dual freewheel in the back clicks once every revolution, and it could very well be what's causing me to slip. I've just never experienced slipping like this when pedaling, and I cannot understand it.

 

[duivendyk]

What kind of rear hub do you have, did you mean "click" while pedaling or while freewheeling ?

 

[sparky]

Just talking about the dual freewheel hub on the folding bike from www.fiveflagsmotorbikes.com ...

All of my problems have to do with the pedal freewheel, I believe. It slips while standing up to pedal... a very small portion, but still noticeable... almost like the chain broke for a second. And I actually just noticed the clicking frequency while pedaling depends on where on the freewheel I catch it at (start pedaling)... sometimes it's just one click per revolution, sometimes it's none, sometimes it could be 5 or 6 clicks.

It's strange because I haven't noticed the "slipping" problem too much recently, but if I feel it again, I'm prolly gonna break down and open the thing up to make sure it's lubed properly. The dual freewheel hub is the main reason I bought that bike in the first place, and if it breaks... I'm gonna be very, very PO'ed.

 

[duivendyk]

Let me get this straight, you have a freewheel on the left for the engine sprocket,that one would be free wheeling (clicking) when you are pedaling with the engine off,that's not a regular steady clicking?.When you are doing this and stand on the pedals for more power, you sometimes skip forward,right?.If you are pedaling normally this does not happen?.Do you have a coasterbrake like hub ?.If all this is true, I think that the freewheel one way clutch is malfunctioning,usually involves steel rollers ride up a ramp and getting jammed between the ramp and the inside of the hub to lock the pedal drive to the hub.Quite uncommon for this to happen though.

 

[sparky]

Actually, both freewheels are on the right side of the hub -- the inner freewheel is the larger of the two (44t) for the engine chain, the outer freewheel is the smaller of the two (16t) for the pedal chain.

As for the rest, I think you mostly understand that I have two problems, all of which happen regardless of the engine being on or off. (1) When pedaling while standing, I have had the crank just "slip" forward with no resistance for a tiny bit... then it catches and I can pedal standing up with normal resistance again. I don't remember the last time this actually happened, tho... it seems to have been a while, or perhaps I've just been pedaling a lot less these days?? (2) When pedaling while sitting, the hub clicks quite a few times per revolution, and sometimes it won't click at all, and sometimes it'll click just once per revolution. I think this has to do with which part of the ratchet mechanism of the freewheel catches first when I start pedaling.

As far as I know, the entire bike was made in China, and I'm fairly sure the hub/wheel came from there also. Lack of grease? Prolly all over this bike.

 

[duivendyk]

The first phenomenon is nothing special I think, the rear sprocket ratchet or roller does not necessarily engage the hub right away upon rotation, so there can be some slack at the pedals.The clicking of the hub or the lack of it when you are pedaling must have to do with the inside freewheel,could it be that the 44 turn sprocket is turning at times so that its freewheel isn't actually freewheeling (seems unlikely).It would take another freewheel in the drive train or a centrifugal clutch on the engine to allow this to happen.Possibly the ratchets are gunky and stay retracted.Anyway you don't seem to have any real troubles with the drive setup as far as I can see.

 

[sparky]

The first phenomenon is nothing special I think, the rear sprocket ratchet or roller does not necessarily engage the hub right away upon rotation, so there can be some slack at the pedals.

It's not just when I've first engaged the hub, tho... It happens after I've been constantly pedaling for quite a while and then stand up for a few pedals. Once I get to a certain speed or something, that's when it slips... not just when I first start pedaling.

As for the clicking, I can live with it. But the slipping is unheard of for me & quite annoying.

 

[duivendyk]

Must be annoying& unnerving.something's amiss with the drive clutch.Chinese products are not noted for quality I'm afraid.Their quality control is lacking.These are fairly standard designs but if the surface hardening is not up to snuff they'll wear.Are there any lube nipples on this hub?

 

[sparky]

No lube nipple. Does the NuVinci have one?

Oh well, I guess I'll have to wait for it to break before I know for sure if the slipping is caused by the freewheel or the crank. It's gotta be the freewheel, tho.

 

[duivendyk]

I very much doubt that the crank is in the picture.No nipple,the NV is sealed,it uses a unique fluid or oil that "solidifies" under pressure,that's why it can handle substantial torque.