Giant Dirt E+1 2017 Chain ring

cncservsys

Finding my (electric) wheels
Feb 18, 2017
9
2
61
South East UK
Hi All,

I am thinking of changing the Chain ring(s) on my E-Bike as it is quite low geared & I do more road than offroad. The front gearset is 38/28T & made by FSA. They mount to a 4 spoke drive with allen bolt/nuts. I can see various 4 spoke FSA Chain rings on the Web but will they fit the drive hub? How can I tell if compatible? On the outer chain ring I can see M11/D10.
Are there any specific E=Bike considerations i.e due to the extra torque. It also appears the outer chain ring is quite badly worn, or are they supposed to look like that? Bike has less than 200 miles on the clock! See attached photos. Expect I will need a new (Longer) chain or need to add links to make up for the extra teeth. All advice gratefully received.20170427_090800.jpg 20170427_090829.jpg 20170427_090945.jpg
 

Don

Just Joined
Jul 31, 2017
1
0
45
canada
Hi CNCSERVSYS did you manage to make the change? I want to do the same MOD and have the same questions.
 

cncservsys

Finding my (electric) wheels
Feb 18, 2017
9
2
61
South East UK
Hi CNCSERVSYS did you manage to make the change? I want to do the same MOD and have the same questions.
Hi Don,

I did change my front chainring from 38 to 44 teeth, and it's a definite improvement. If you have a tuning module you can easily reach 30 mph ( off road only of course!).

I purchased this item from best bike parts on eBay.
FSA, Haibike Yamaha Sduro Sprocket 44 Teeth Aluminium - 2x10s and it's an easy fit when you have the correct tools i.e. Crank puller, 36mm thin wall socket, chainring nut tool, chain splitter.
You will need a longer chain I bought KMC X10e Ebike chain 118 links and shortened it to get rear derailleur adjusted correctly for all gears.
I had to move the front derailleur up to the next mounting hole position.
The front derailleur works ok with this setup.
The wear I reported was not wear at all it appears to be designed that way for the front gear shift.
Apart from the cost of the parts and tools I would recommend this modification for road use, and you can still use the bike off-road just as before.
As a matter of interest, do you get a creaking noise from the bottom bracket when pushing the pedals hard? Not sure if this is a fault or the torque sensor making a noise.
 

cncservsys

Finding my (electric) wheels
Feb 18, 2017
9
2
61
South East UK
Hi Don,

I did change my front chainring from 38 to 44 teeth, and it's a definite improvement. If you have a tuning module you can easily reach 30 mph ( off road only of course!).

I purchased this item from best bike parts on eBay.
FSA, Haibike Yamaha Sduro Sprocket 44 Teeth Aluminium - 2x10s and it's an easy fit when you have the correct tools i.e. Crank puller, 36mm thin wall socket, chainring nut tool, chain splitter.
You will need a longer chain I bought KMC X10e Ebike chain 118 links and shortened it to get rear derailleur adjusted correctly for all gears.
I had to move the front derailleur up to the next mounting hole position.
The front derailleur works ok with this setup.
The wear I reported was not wear at all it appears to be designed that way for the front gear shift.
Apart from the cost of the parts and tools I would recommend this modification for road use, and you can still use the bike off-road just as before.
As a matter of interest, do you get a creaking noise from the bottom bracket when pushing the pedals hard? Not sure if this is a fault or the torque sensor making a noise.
Correction The chain was 136 links and I shortened it by 20 links to make it 116 links long which works fine.
 

preciseposter

Finding my (electric) wheels
Jul 24, 2017
11
6
72
Northampton
I have the Road E +1

My chainset is 50/34T. The rear cassette is Ultegra 11 so I rarely need the larger chain wheel. Since Giant offer all kinds of combinations across mountain, hybrid, city and road - an option would be to go to a Giant dealer if there is one within reach, and getting the exact size you require. That way you can be sure it is manufactured to e-bike spec.
 
Last edited:

chris_n

Esteemed Pedelecer
Apr 29, 2016
579
364
58
Austria , Niederau or NE England
I have the Road E +1

The larger chain ring has 51 teeth. Not sure about the inner chain ring. Since Giant offer all kinds of combinations across mountain, hybrid, city and road - I would advice going to a Giant dealer and getting the exact size you require. That way you can be sure it is manufactured to e-bike spec.
None of it is e bike spec, they are all standard mtb or road chainrings depending on the application.
 

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