Giant Fathom E+ 3 chain dropping

[Ayolin]

Hi all,

I already quickly mentioned I have an issue with my new bike in my introduction. As the topic states I have a Giant Fathom E+ 3. It is brand new, I only took it on three rides. As I am getting more confident on the bike, the riding gets rougher. The issue I have is on my last ride the chain dropped off the front sprocket three times. This usually occurs on descents. I live in the Netherlands, so no extreme descending since it's basically flat and only some very small drops. I don't paddle along either, keeping my feet horizontal.

I think the derailler (is that a good translation) is bouncing around so hard it drops the chain. The bike is fitted with a deore 1x9 gear system. Now, I also inquired on a Dutch forum and their response is there shouldn't be a factory spec 1x9. It could drop the chain since this specific version does not have a clutch.

What are your thought on this? Has anyone else encountered this? And if so, how did you remedy it? I am thinking I need to update to an (1x11) XT with new shifters, chain, etc. or perhaps look into a chain guide. I also haven't contacted the shop or Giant itself yet. I will today since I think selling an mtb that drops the chain on a light descent shouldn't happen.

 

[Zimmerframe]

I had a similar problem last year with a 10 speed hardtail shimano bike.

Once you got to a certain speed on the bumpy stuff .. bye bye chain ..

I ended up buying the RD-M786 as it had a clutch. I did also install a chain guide afterwards as I'd already ordered it - but the clutch derailleur fixed the problem.

For robustness and reliability and cost, you're probably aswell moving to a 10 speed setup. It's cheaper and more than does the job on an e-bike.

I don't think there are any 9 speed's with a clutch .. @Gary ?

 

[Ayolin]

Just called the dealer. They advised to bring the bike in to increase the tension on the derailleur. Does that make sense? I'll go ahead and try that first anyway.

 

[Gary]

I don't think there are any 9 speed's with a clutch .. @Gary

No not 9 spd with 9 spd sprocket spacing... But...
It's fairly easy to modify a 10 spd shimano mech to index with a SRAM 9spd shifter.
Finding a decent quality sram 9 speed shifter is the difficult part. (if you don't have access to my spares bunker)

 

[Gary]

How does this bike have 9 speed Deore when Deore has been 10speed for years now?

 

[Zimmerframe]

Maybe they have GIANT stocks of them : all "Deore 9 speed" .. Maybe they grind a speed off ...


2019
FR

Fathom E+ 3 (2019) | Hommes Trail Vélo | Giant Bicycles France

UK

Fathom E+ 3 Electric Bike (2020) | Giant Bicycles UK

2020

FR

Fathom E+ 3 (2020) | Hommes Trail Vélo | Giant Bicycles France

International ..

Fathom E+ 3 29er (2019) | Men Trail bike | Giant Bicycles International

Even the Americal .. bigger is better .... 9 speed Deore ..

Fathom E+ 3 POWER (2019) | Men Trail bike | Giant Bicycles United States

 

[Ayolin]

Why would a manufacturer sell a mountainbike, that is advertised as a good trail bike, with such a configuration. It seems a bit negligent to me. Anyway, I'll go to the dealer tomorrow to get this sorted out. I wonder if increasing the tension will be sufficient.

As a follow up, does anyone know what chain guide will fit on my bike?

 

[Zimmerframe]

I suppose ultimately a derailleur with a clutch, thought of in it's most simplified way, is a derailleur with considerably more tension and a way to release that tension so you can work on the drivetrain.... so maybe

Giant seem to sell a number of own brand chain guides for less than €20, so they should be able to fit the appropriate one of those :

for example :

Keep in mind though that if it's coming off at the bottom of the chainring first, it still might pop off, but it should pop back on when you pedal and at least not be sucked down behind the chainring.

As to WHY ... My first two EMTB's were hardtails. They didn't have clutched derailleurs. I think 99% of people who buy them will plod along fire roads and maybe, but only maybe, ride down a curb once in a lifetime .. so most people wouldn't notice.

 

[04fuxake]

What are your thought on this? Has anyone else encountered this? And if so, how did you remedy it? I am thinking I need to update to an (1x11) XT with new shifters, chain, etc. or perhaps look into a chain guide. I also haven't contacted the shop or Giant itself yet. I will today since I think selling an mtb that drops the chain on a light descent shouldn't happen.

My 2019 Fathom E+ 3 came with a chain guide. I wonder why some variants didn't come with them. I can say that would certainly help. I haven't dropped a chain yet.

 

[04fuxake]

As to WHY ... My first two EMTB's were hardtails. They didn't have clutched derailleurs. I think 99% of people who buy them will plod along fire roads and maybe, but only maybe, ride down a curb once in a lifetime .. so most people wouldn't notice.

Or maybe, just maybe, they bought what they could afford and make do.

 

[rik672001]

My Fathom is 6 weeks old and the chain had several cracks in it. Replaced with a Shimano chain under warranty by the dealer

 

[Nonphixionx]

I'm have the same issue on my 2020 its fallen off 20 times in 2 months.

 

[funnel]

Happens to me too. Usually if I have on the 7,8,9 gear. I think the derailler needs some more tension. Also when I clean the chain and lube seems like it doesn't drop for a few rides.