Known Issues & Problems with Giant Products + Help, Solutions & Fixes

I have a Giant Explore E-2 with apparent electrical issues. I got caught out in fairly heavy rain one day and decided to climb a very steep hill so I pushed it up to max power - then it wouldn't come back down to lower power levels. When I got home, still in max power, the battery wouldn't turn off so I had to take the battery right out. Put it back in the next day and the lights wouldn't turn on. Later the front one came on but not the back one. Then the bike decided to adjust the power level automatically - jumping up and down between levels!

Took the bike to my lbs - they tested, rode etc and couldn't make it fault.

After a week in my sick bed I finally got out for another ride today, seven km in and the motor stops assisting but the power levels were still able to be adjusted. Decided to try the old Microsoft technique of turning off and on but it wouldn't turn back on. It was a very long, hard ride home without any power assist! Battery is currently on the charger but it wasn't showing as flat so I doubt it will help.

I guess it's back to the lbs on Monday but I am very frustrated as this is a new bike, not yet three months old. I paid a lot of money and have looked after it!
Update from my lbs is that Giant will replace the control unit due to "known" issues with moisture getting in. An updated control unit that addresses this problem is being sent out.
 
Anyone had the chain come off while going over bumps? The chain will jam in between the front chainring and motor cover, it's hard to pull out and will damage the plastic covers.
I had this happen and fortunately had some allen keys with me. I found the only viable way of getting the chain out without damaging stuff was to take the chainring off (unfortunately not before I had tried to pull it out and scratched up the plastic covers I fair bit).
 
This is my loose yamaha motor


Wow. Are the motor bolts tight when you do that ?

I changed my motor bolts and nuts to titanium ones with 2 washers and a lock washer and the motor is nice and snug. I found the original bolts got rusty and the Allen heads started to round off little when loosening the bolts.
 
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My Giant Quick E+ is in the shop getting two issues sorted

1) After a ride in the rain yesterday the bike no longer powers on (at least not when you push the button on the controller, it does however sometime turn on randomly while the bike is just sitting there, with no-one touching it). Taking the battery out and replacing it will cause the bike to power on (without pushing the power button) but as soon as you power it off you can't turn it on again (without removing and replacing the battery). Based on other comments I suspect moisture has got into the controller. The mechanic said he has had to replace a few controllers due to issues with them. Hopefully a new controller will fix the problem. My Evo display has also been fogging up, so clearly moisture is getting into that as well.

2) The chain keeps skipping on my smallest sprocket. I thought this would just be require a derailleur adjustment but a couple of shops have adjusted it for me and the problem still persists. The mechanic this morning said he things the sprocket is worn and needs replacing (I've only done 900km on it so was surprised at that). I ride almost exclusively in the smallest sprocket and usually use the higher assist levels to ride at a fair pace but even so I would have thought a cassette was good for more km than that.
 

PDoz

Well-Known Member
My Giant Quick E+ is in the shop getting two issues sorted

1) After a ride in the rain yesterday the bike no longer powers on (at least not when you push the button on the controller, it does however sometime turn on randomly while the bike is just sitting there, with no-one touching it). Taking the battery out and replacing it will cause the bike to power on (without pushing the power button) but as soon as you power it off you can't turn it on again (without removing and replacing the battery). Based on other comments I suspect moisture has got into the controller. The mechanic said he has had to replace a few controllers due to issues with them. Hopefully a new controller will fix the problem. My Evo display has also been fogging up, so clearly moisture is getting into that as well.

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My full e pro had the same symptoms following water in the evo screen , it started to behave after about 4/5 days in the dry only to return next time I got it wet. The screen was replaced under warranty and the problem seems to be solved now. The shop ordered a new controller but were only sent the bar bracket...thankfully it was just the screen.

Nb the differences between the old and new screen - silicon along all joints / cable points etc
 

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My Giant Quick E+ is in the shop getting two issues sorted

1) After a ride in the rain yesterday the bike no longer powers on (at least not when you push the button on the controller, it does however sometime turn on randomly while the bike is just sitting there, with no-one touching it). Taking the battery out and replacing it will cause the bike to power on (without pushing the power button) but as soon as you power it off you can't turn it on again (without removing and replacing the battery). Based on other comments I suspect moisture has got into the controller. The mechanic said he has had to replace a few controllers due to issues with them. Hopefully a new controller will fix the problem. My Evo display has also been fogging up, so clearly moisture is getting into that as well.

2) The chain keeps skipping on my smallest sprocket. I thought this would just be require a derailleur adjustment but a couple of shops have adjusted it for me and the problem still persists. The mechanic this morning said he things the sprocket is worn and needs replacing (I've only done 900km on it so was surprised at that). I ride almost exclusively in the smallest sprocket and usually use the higher assist levels to ride at a fair pace but even so I would have thought a cassette was good for more km than that.
On e bikes the torque increases the wear on cassettes and chains hugely. This has happened to me. Best thing is to keep the chain and cassette as clean as possible. Lube the chain often. Another problem I had was a worn freehub body caused side play in the cassette and caused premature wear in the smallest sprocket on the cassette. Invest in a chain wear tool as well. Also check that the cassette lock ring is secure as that can cause problems.
 
My Giant Quick E+ is in the shop getting two issues sorted

1) After a ride in the rain yesterday the bike no longer powers on (at least not when you push the button on the controller, it does however sometime turn on randomly while the bike is just sitting there, with no-one touching it). Taking the battery out and replacing it will cause the bike to power on (without pushing the power button) but as soon as you power it off you can't turn it on again (without removing and replacing the battery). Based on other comments I suspect moisture has got into the controller. The mechanic said he has had to replace a few controllers due to issues with them. Hopefully a new controller will fix the problem. My Evo display has also been fogging up, so clearly moisture is getting into that as well.

2) The chain keeps skipping on my smallest sprocket. I thought this would just be require a derailleur adjustment but a couple of shops have adjusted it for me and the problem still persists. The mechanic this morning said he things the sprocket is worn and needs replacing (I've only done 900km on it so was surprised at that). I ride almost exclusively in the smallest sprocket and usually use the higher assist levels to ride at a fair pace but even so I would have thought a cassette was good for more km than that.
Mine started slipping at 800 miles, I swapped the 2 smallest cogs with my road bike and got a further 900. The chain will be stretched by now so will slip. I've changed the whole drivetrain now, I have a 11-25 cassette and larger front ring to spread the wear, and I ease the effort when changing gear.
 
Wow. Are the motor bolts tight when you do that ?

I changed my motor bolts and nuts to titanium ones with 2 washers and a lock washer and the motor is nice and snug. I found the original bolts got rusty and the Allen heads started to round off little when loosening the bolts.
Yes bolts are tight, but I'll look at fitting washers or different bolts. It's still under warranty so I can Giant to do it, but if I repair it I would ream the holes and fit a bush to tighten everything up.
 
I commute 70km return 3x per week on a 2019 quick E limited to 45km/h (NZ version) which is a fantastic bike except for two issues:

1 - motor vibration through the pedals which leaves my feet buzzing after longer rides (45-60 mins). I didn’t get this on my old Shimano mid drive and it seems to be getting worse but the shop tell me there is nothing wrong. Anyone else had this issue?

2 - my first controller unit leaked on first contact with rain and stopped responding / kept turning on by itself. Thanks to this forum I knew what it was and got a free replacement with no issues since.
 
I commute 70km return 3x per week on a 2019 quick E limited to 45km/h (NZ version) which is a fantastic bike except for two issues:

1 - motor vibration through the pedals which leaves my feet buzzing after longer rides (45-60 mins). I didn’t get this on my old Shimano mid drive and it seems to be getting worse but the shop tell me there is nothing wrong. Anyone else had this issue?

2 - my first controller unit leaked on first contact with rain and stopped responding / kept turning on by itself. Thanks to this forum I knew what it was and got a free replacement with no issues since.
I'm also on an NZ version, loving the 45km/h speed! I haven't noticed any motor vibrations on my 25min commute though thankfully.
I may be experiencing controller issues as you have, my electric assist randomly cuts out (just for a second) at various speeds. I've noticed my speed indicator on the display flashes up 99km/h while it's cutting out. Yesterday I checked the top recorded speed on the trip computer and it has registered a top speed of 655km/h (which i'm sure I didn't get up to since I keep arriving late to work).
Were you (or anyone) experiencing any of these speed/cutout anomalies with your controller waterproofing issues?? p.s. i've Checked the positioning of my cadence magnet and it is correctly positioned.
 
I'm also on an NZ version, loving the 45km/h speed! ...
...Were you (or anyone) experiencing any of these speed/cutout anomalies with your controller waterproofing issues?? p.s. i've Checked the positioning of my cadence magnet and it is correctly positioned.
No sorry. That sounds like it needs to be sorted. Mine would turn on walk mode by itself and start ghost riding in to the wall or not responding to changes in assist level unless I pushed the walk button each time I wanted to change.
 
Mu bike wouldn't switch on one say, so under warranty I had my control switch replaced, probably because of water ingress, so far so good.
I get some vibration through the pedals as my cadance increases, I think there is a s
 
sensor for the motor that reduces the assistance to stop overspending. I change up until I run out of gears which on my bike is 29mph.