Roam E+ Chain Popped Off

Stillhart

New Member
Region
USA
So, went on a ride today and the chain popped off the front sprocket. I was in the highest gear, I think, on a straight, flat, smooth road. Just came off out of nowhere.

I thought I read somewhere before that this was a problem, but I thought it was fixed? Anyone know what the deal is with that? Anything I can do to prevent it? This was like my second long ride on the bike and I consider that a Bad Sign in such an expensive bike.
 

conix67

Member
Region
Canada
Yes, I'm the one who had that experience. I suspect this is due to the bad derailleur. Here's my review I posted on Giant Canada website with the photos - https://www.giant-bicycles.com/ca/roam-eplus-gts

As you have noted, it only happens on tall gears, probably at speed 9. Avoid this speed, the chain may come off if you hit a bump or rear bounces for whatever reason. The weight of chain pulls the derailleur arm down (weak spring?) which causes it to misalign from the main sprocket while the chain slaps down toward the sprocket causing it to fall - which is my assessment. I've been careful not to hit bumps at speed 8 or 9, and was able to avoid this last couple of weeks.

So, I'd say this is a design defect, my main gripe with this model along with the tires. Of course, not acceptable for a bike at this price range and Giant won't do a thing about it. My dealer told me I push the bike outside of its design limit. lol. On the contrary, this never happens when riding on a trail since there's less chance I'd be at speed 8 or 9.
 

Stillhart

New Member
Region
USA
Well that's disappointing. I tend to spend a lot of time in the higher gears as I mainly use it on the road. I wonder if the Explore, with its slightly upgraded components, is better about it. I could get one if I were willing to wait ~5 weeks.

EDIT - Looks like they're both Alvio. :-/
 

conix67

Member
Region
Canada
Right. Explore E+ isn't much of upgrade from Roam E+. You will need to go all the way up to Explore Pro to get derailleur upgrade. Chain coming off is one thing but once it's off, it's ugly. The chain usually get wedge between the sprocket and the motor cover, requiring some force to free it. This puts scratches on the bike, potentially damaging the chain, and worst of all leaves your hand with sticky oily residue. For this reason I carry disposable glove but I've not had a use for it last couple of weeks.
Anyway, initially I thought it was just me and my bike. I think Giant should do something about this before more people run into the same issue.
 

Stillhart

New Member
Region
USA
Right. Explore E+ isn't much of upgrade from Roam E+. You will need to go all the way up to Explore Pro to get derailleur upgrade. Chain coming off is one thing but once it's off, it's ugly. The chain usually get wedge between the sprocket and the motor cover, requiring some force to free it. This puts scratches on the bike, potentially damaging the chain, and worst of all leaves your hand with sticky oily residue. For this reason I carry disposable glove but I've not had a use for it last couple of weeks.
Anyway, initially I thought it was just me and my bike. I think Giant should do something about this before more people run into the same issue.
Yes, that's totally what happened to mine. Wasn't happy about the mess or the amount of force needed to free it. Looks like there's something called a "chain catcher" that might help, I'm doing some research now to see if it might do the trick.
 

Stillhart

New Member
Region
USA
Alright well, I did some looking around town and some looking around the internet and decided to return my Roam E+. There were just too many little things I didn't like about it and for a $2500 bike (before tax), that's just not okay with me.

I did end up purchasing a 2021 Momentum Transend E+ to replace it. I rode one today and I just liked it better in all the areas I was disappointed with the Roam. I think I'll be pretty happy with it. Picking it up tomorrow!

Sorry Giant sub-forum, but it looks like I'll be moving over to the Momentum one... which is a weird demarcation since they're both Giant but whatever. :-D
 

conix67

Member
Region
Canada
Alright well, I did some looking around town and some looking around the internet and decided to return my Roam E+. There were just too many little things I didn't like about it and for a $2500 bike (before tax), that's just not okay with me.

I did end up purchasing a 2021 Momentum Transend E+ to replace it. I rode one today and I just liked it better in all the areas I was disappointed with the Roam. I think I'll be pretty happy with it. Picking it up tomorrow!

Sorry Giant sub-forum, but it looks like I'll be moving over to the Momentum one... which is a weird demarcation since they're both Giant but whatever. :-D
Well, I might have made similar choice if they accepted returns in Canada. Looks like there's very favorable policy in US vs Canada there. At least you won't be having the chain drop issue with Transcend :D
 

Stillhart

New Member
Region
USA
Well, I might have made similar choice if they accepted returns in Canada. Looks like there's very favorable policy in US vs Canada there. At least you won't be having the chain drop issue with Transcend :D
Yeah I don't know if it's a US thing or just because I bought direct from Giant (rather than through a private LBS) or what, but I feel lucky it worked out.

And yeah, definitely no chain drop with the internally geared hub on the Transend, looking forward to not having to downshift before I stop anymore. :-D
 

st0ut

Member
Region
USA
Well that's disappointing. I tend to spend a lot of time in the higher gears as I mainly use it on the road. I wonder if the Explore, with its slightly upgraded components, is better about it. I could get one if I were willing to wait ~5 weeks.

EDIT - Looks like they're both Alvio. :-/
I have Exploere +GTS 2021 US spec'd. I had this happen 1 time albeiet my bike is fairly new just over 400 miles so far. I was in top gear about 26mph when the chain came off front sporket.

Stopped put the chain back on the ring and continued on.

this isnt a design flaw. this is a bicycle. stuff happens
 

Gordon71

Well-Known Member
That happened to me once on a gravel bike trail going downhill last year on my Rad Rover. In my case it was a low gear (2nd I believe). I stopped put it back on no problem and it hasn't happened again although I almost never use 1st or 2nd gear.
 

conix67

Member
Region
Canada
I have Exploere +GTS 2021 US spec'd. I had this happen 1 time albeiet my bike is fairly new just over 400 miles so far. I was in top gear about 26mph when the chain came off front sporket.

Stopped put the chain back on the ring and continued on.

this isnt a design flaw. this is a bicycle. stuff happens

This *never* happened with my old bike which is a cheap MTB /w 21 speed. I say this is a design defect because it happened very easily. I can easily ride this bike on most surfaces because of the electric assistance, so I had the gear set to 8 or 9 most of the time. When this occurred for the first time, I told myself that it can happen. But the very next day it happened again, at around 10mph. This is when I contacted Giant Canada who asked me to contact local dealer for a look. After several days of failed attempt to get through my local dealer, I finally got through their service department and explained what happened. I was told that it is NOT normal, something is off with the bike and they will take care of it.

So I dropped off my bike happily expecting they would resolve the issue for me. Next day I got a call saying the bike is ready and the issue is taken care of. They did not explain what exactly they did but I did not care much as long as it's fixed. Upon picking up the bike, I was asked to check it out before I leave so I took it for a ride in the parking lot in front of the Giant dealer. The parking lot had speed bumps to force cars to slow down. I hit the speed bump at low speed (<20Km/h, any faster it would become dangerous). After hitting the speed bump 3-4 times the chain promptly came off. I had to take it right back to the dealer.

Later I got a call saying that I'm riding the bicycle at the manner it's NOT designed for. I should not be using the tall gears on this bike, which was the explanation. Riding the bicycle at low speed at tall gear is a wrong thing to do. At this point, I was convinced that the issue is real, and they want me to believe what they are saying. The fix they suggested is to downshift on bumps on flats. WTF.

Anyway, by this time I was completely exhausted. I just wanted my bike back. Since then I carry pair of gloves just so that I can get the chain back on without getting my hands covered with sticky oily residue when this happens.

Yes, stuff happens on bicycles. However, chain coming off 3 times on a 4 day span under normal riding condition is definitely NOT normal, and can only be explained by design defect/limitation. 9 speed cassette paired with single speed sprocket isn't a good match to begin with, in my opinion. The derailleur does not have a clutch and appears to have relatively weak return spring, which I believe is part of the issue.

Luckily, I've not had the chain come off lately and it is mainly because I consciously try to avoid the situation where this can occur, like forcing the assistance level down to ECO+ or normal at the highest. This way I'm forced to ride at lower gear below 8 and avoid the situation altogether. Roam E+ is one of the cheapest options available from Giant for an E-bike, but the overall features fit my needs and still fairly expensive for a bike. At this price, I feel like I have a right to ask for a robust design that will minimize issues like this.
 

Stillhart

New Member
Region
USA
Yeah I gotta agree. This isn't my first bicycle and I'm sorry but chains don't just pop off for no apparent reason. They pop off when your derailleur cable isn't tightened correctly or when you hit big bumps or do something dumb like not slow down when shifting or whatever. They don't happen on a brand new, perfectly tuned bike on a straight, flat road when you're just pedaling along.
 

conix67

Member
Region
Canada
So, the chain guard arrived. It's highly adjustable and fits my Roam E+.

PXL_20210704_222654831.jpg


I tried to adjust it to ensure there's even space on both sides of chainring but there's minor rub somewhere that I can hear. Not a big deal as long as it does the job without causing other issues.

Good news is that this does the trick! I've done few trips with this chain guard installed, including some crazy bumpy trails. The chain never dropped, not once. As you can see there's no place for the chain to slip out the chain guard.

While I'm happy the problem is solved now, this is something Giant should have installed from factory. I see their mountain E-bikes come with a similar chain guard, and I think this is essential for any single speed chainring setup.
 

Luto

Active Member
You could just pull a link or two and tighten up the chain. I would check the rear derailleur arm for tension, in the full range. They might have not put on the right length chain for the full range. Likewise, the derailleur chosen for the bike might be the wrong arm length. Also derailleurs with clutches help a lot with the wide range issue. It is a balancing act for bikes with a wide range of gear.

It does happen sometimes on my bike, IF, the rear derailleur sprockets are caked heavily with dust-mud. The chain will every so slightly stick a bit more, enough to create too much slack.
 

conix67

Member
Region
Canada
You could just pull a link or two and tighten up the chain. I would check the rear derailleur arm for tension, in the full range. They might have not put on the right length chain for the full range. Likewise, the derailleur chosen for the bike might be the wrong arm length. Also derailleurs with clutches help a lot with the wide range issue. It is a balancing act for bikes with a wide range of gear.

It does happen sometimes on my bike, IF, the rear derailleur sprockets are caked heavily with dust-mud. The chain will every so slightly stick a bit more, enough to create too much slack.
Thanks for suggestions. My dealer service looked into it and I was told everything is fine, I did mention possibility of wrong chain length and I was told it was correct for the bike. The advice I got was - just because initially it would happen on paved road - I got a wrong bike, I should have gotten a road bike instead if I were to ride it on the paved road.

I was completely dumbfounded when they told me this. It was clear they didn't want to accept any sort of design/quality issue with the bike.

Anyway, initially the issue was occurring at high gear, and I thought it was because of the spring tension being too loose but later it also occurred at low gear as well, so that threw off the theory of it being related to the tension/chain length. It was literally happening on a daily basis unless I make an effort to avoid it so I needed a permanent solution to it. This is on a brand new bike (now 2 months old) from day 1.
 

Luto

Active Member
Thanks for suggestions. My dealer service looked into it and I was told everything is fine, I did mention possibility of wrong chain length and I was told it was correct for the bike. The advice I got was - just because initially it would happen on paved road - I got a wrong bike, I should have gotten a road bike instead if I were to ride it on the paved road.

I was completely dumbfounded when they told me this. It was clear they didn't want to accept any sort of design/quality issue with the bike.

Anyway, initially the issue was occurring at high gear, and I thought it was because of the spring tension being too loose but later it also occurred at low gear as well, so that threw off the theory of it being related to the tension/chain length. It was literally happening on a daily basis unless I make an effort to avoid it so I needed a permanent solution to it. This is on a brand new bike (now 2 months old) from day 1.
On some bikes there is an offset of the chain ring teeth and the chain. I.e. they have to go on "in sync" and cannot be off by one link. Check to see if the teeth are all uniform on the chain ring. If not it may require you to reset the chain by one link forward or back.

I agree and call bunk of the dealer. You can build a bike and create a situation where the derailleur, cassette cog range and chain ring simple do NOT work. There is a range that is acceptable and a range that is optimal, and a range that is not workable, period. Also some chain ring teeth and some chains are not that great meshing.

You should just check your new bike, since it works. Go highest and lowest gears. Check the derailleur arm location. It should not be strained or slack. i.e. it should have tension. Lift and drop the bike like going over a curb. But it sounds like you got a non derailleur setup now.

Lastly a top of the line Shimano GRX 810 long arm derailleur, 11 speed, with a 10-42 range is only 100 bucks or so and is available to buy.

Best of luck with the new ride.
 
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conix67

Member
Region
Canada
Derailleur arm location/tension looks reasonable, although the return spring on derailleur appears to be on the weaker side - when I drop the bike from 2-3 inch height, you can see the weight of chain pulling the derailleur arm down which causes momentary slack.

The chainring is aligned to the center of the 9 speed cassette so I believe as you move away from the center (speed 9 or 8 for example), there's a greater chance of the chain drop. I feel that 1x9 setup is not an ideal match. At the highest speed setting (9), pedaling does not feel smooth - as if the chain is pulled in angle too far. 8 is substantially better, 7 feels like what it should be (smooth).

I had considered the derailleur replacement. Giant service told me that along with a new derailleur (/w clutch), I need a new cassette (no high end derailleurs with 9 speed support) and new shifter. So I decided to look for a simpler and cheaper solution for now, and this chain guard appears to fit my need.
 

Luto

Active Member
Every derailleur has a maximum-minimum range rating. So figure out:
Smallest rear cog's teeth
Largest rear cog's teeth

Then check the derailleur specifications.

Here is an excerpt:

The Calculation Process of the Drivetrain Capacity

Now that we know about rear derailleurs, let us dive ride into the calculations. The total drivetrain capacity of the rear derailleur is basically the highest quantity of slack chain that the derailleur cage can accommodate. And the higher the quantity of slack, the larger the derailleur cage needs to be. The overall gearing range of your bicycle is often referred to as the drivetrain capacity or also the tooth capacity. A lot of the time it is even called the drivetrain tooth capacity. Regardless of what you choose to call it, you can find it by first calculating the difference between the smallest and largest front & rear gears. After that, you can add these two values and get your results. Let’s take a look at an example so that you can understand it better. Let us go through this step by step to get the whole idea.

    • Firstly, you must calculate the maximum chainring difference. You can do this by deducting the number of teeth between the largest and smallest chainring. Let us say that the largest is 44 and the smallest is 22, then we get 22.
    • Secondly, you must calculate the maximum cassette cog difference. This can be done by deducting the number of teeth between the largest and smallest cassette cog. Let us assume that the largest is 32 and the smallest is 11 which gives us 21.
    • Now you can find out the total drivetrain capacity by simply adding the maximum chainring difference and the maximum cassette cog difference. And the final result is 43.
      You should also note the maximum cassette cog.
And specs from a Shimano 9 speed: