drag in dash rear wheel

blackflag

New Member
I'm new to this site, but believe this will be a good place to seek some information. I've been commuting on an izip dash for approx 6 weeks now. Over time, I noticed a very slight intermittent vibration that I determined to be coming from the rear end. I've never had a bike with disc brakes and figured that was the likely source of the vibration and what feels like some drag in the back wheel. I have since had the rear brake adjusted twice, the last of which the mechanic showed me that the brake was properly adjusted, and completely loosened the brake cable so I could see the disc move between the pads, without rubbing, and the back wheel still made the intermittent vibration, and definitely has drag compared to the front wheel. I suppose I might expect a bit of slowing as the rear wheel spins, but the wheel might make 2 rotations before coming to a complete stop, when forcefully spun. Is there anyone on here that has had a similar experience, either with the sensation of drag, or of the rear wheel hub rubbing. . . .something? Any input is appreciated.
 

Brian(J)

Active Member
Have not experienced that with my Dash, but have experienced only the best customer support from Currie/iZip on every issue raised with them, so suggest contacting them. They will probably post to this topic pretty soon anyway with their thoughts.
 

Bud

Member
Just picked up a Dash and posted my purchase story today. I concluded by noting my sole concern which is an intermittent cyclical vibration that I feel through the pedals. A vrum.. vrum.. vrum.. as I pedal. Usually under high load and over 15 MPH. If that sounds like what you were/are experiencing I would be interested to know if you figured it out. Thanks.
 

Shea N Encinitas

Active Member
My 2014 Dash seemed to have a slight clearance issue inside the motor, an odd noise that I most noticed when coasting with a warm motor. Fortunately it went away after a few hundred more miles,... I'd love to have a look inside there. Good luck! -S
 

wwjd

Member
I too have the same effect on my 2014 Dash model when spinning it on the rack, even with the new and improved rear hub motor. At first I thought it was the disc brake rubbing, but when I checked that it was fine. Doesn’t seem to pose a problem for me though. But I am wondering if the slight drag could effect overall proficiency and performance. As for now, though, I really can’t complain.
 

Bud

Member
Same thing here! Had mine in the shop last night. They confirmed the presence of the vibration so I know I'm not nuts. They assured me it was not the motor or the bottom bracket, but they could not offer an explanation. Like you, it does not seem to affect the performance, it's just a little unnerving. It's got to be coming from somewhere and mean something! I just hope it doesn't mean much!
 

wwjd

Member
I am wondering if it could still be due to some magnetism in the motor going on when spinning freely while the power is turned off, kind of like the cogging effect that we experience while freewheeling with the power on? But we definitely do not feel this "cogging" effect while riding the bike and freewheeling when the power is turned off, so I am not too troubled by all of this. But, again, it could maybe put a little bit of a damper on the performance of this bike. If so, it is negligible and unnoticeable.
 

Shea N Encinitas

Active Member
kind of like the cogging effect that we experience while freewheeling with the power on?
Just because the bike is powered does not mean the stator coils are energized, especially if you just hit the brakes or are free-coasting. Just so we are on the same page; freewheeling means spinning at a cadence that is comfortable, VS requiring much effort. If you ride around in diagnostic mode, level 3 specifically, you can keep an eye on what power settings are going to the motor. I'm guessing true cogging is a matter of a 1 or 2 newton meters, barely noticeable with the leverage of the cranks and our legs, but enough to prevent the wheel spinning free for more than a few revolutions. A strong resistance in the pedals (usually from a stand still) is No Power, and the Dash is known for a lag in PAS response. If this happens while you are riding along at 20 mph then you may have a short in the brake sensor or some other strain or dust issue with the electronics. Diag Lvl 3 will reveal any brake sensor issues, I've seen mine (Normally closed) (000) and open circuit (001) whilst manually strain relieving the harness near the display. -S
 

Derek Kerton

New Member
I'm on my 5th ebike (I still have all of them for family use) so I'm pretty sure the drag you experience when trying to spin the rear wheel in the air is normal. It is cogging, or a magnetic resistance inside the hub. Geared rear hub bikes, or center-motor ebikes do not have this, and freewheel normally, so it is the low price we pay for having much simpler robust gearless hub motors.

As for the vibrations in the E3 Dash, I have a 2015 version, which I love - except the vibration that comes from the motor EVERY time I ride anywhere between 14 and 17 mph with power engaged. It doesn't happen outside this speed range, and always happens within it.

I know the 2014 model had some quality control issues in the rear hub motor, which Currie fixed for you guys. But my motor is 2015.

I, too, would love answers as to what's going on.
 

Ann M.

Well-Known Member
The Dash has some pretty good diagnostic tools built into that console. Have you tried using them? Currie Tech has a cool set of tools as part of the Electric Bike Competency Center (EBCC) on their website which is available for all ebike folks to use. Each model and year has a specific set of diagnostics that you can work through (these are for the 2015 Dash) and will help the IZip guys help you. Chawn at Currie Tech technical support, (800) 377 - 4532, is a specialist on these bikes and a great resource but do the diag first!
 

Derek Kerton

New Member
Thanks. Good advice. I called Shawn. A very pleasant call, short IVR system, and short wait for Shawn. Then he seemed glad to help. Said the vibes were not normal, and if I'd like to take it into my dealer, they would arrange a rear-wheel swap-out and take the vibrating motor back.

So far, good customer service from Currie/iZip.