Stefan Mikes
Well-Known Member
- Region
- Europe
- City
- Mazovia, Poland
The Narrow Wide chainring teeth pattern was invented and patented as early as 1978 by a Wisconsin company Gehl. The idea was to create alternating narrow and wide tooth pattern to prevent chain dropping from the sprocket in agriculture machinery. Later, other tooth patterns such as SRAM X-SYNC or Praxis WAVE were invented. The special chainring tooth arrangement patterns became important since the introduction of 1x bicycle drivetrain by SRAM in 2012. The 1x drivetrain with a single chainring and no front derailleur has become the almost the only mid-drive e-bike drivetrain system used.
In the 1x drivetrain, especially with the growing number of gears and increasing cassette range (as huge as 10-52T cassettes), the chain line is very far from being straight. To prevent chain dropping incidents, the special pattern chainrings are used; additionally, premium derailleurs are equipped with a clutch that keeps the chain tensioned at all times.
Several Creo or Vado SL users have reported the chain dropping towards the e-bike frame, and attributed that to the Praxis WAVE tooth pattern of their chainring.
The background
I replaced the Shimano CS-HG500-10 cassette (10-speed, 11-42T) on my new Vado SL 4.0 in July 2021, after 1 month of riding the e-bike with the original drivetrain. My choice was the Deore XT CS-M771-10 cassette (10-speed, 11-36T) as it had it gears more evenly spaced. I have kept the original Praxis 44T chainring with chainguard. I was replacing chains as soon as each of them got stretched past the 0.5% mark. Doing so made the cassette still flawless after more than 10,000 km ridden!
Yes, I had a chain dropping towards the frame twice in quick succession. It turned out the derailleur/shifter indexing got misadjusted by one full position towards the largest sprocket, and the derailleur L limit screw was not set properly, either. After the necessary adjustment, my drivetrain has become perfect, silent, and totally reliable.
Moving away from the WAVE chainring
I have recently decided I needed a granny gear anyway (the Deore XT cassette has no granny gear!) so I reused the original 11-42T Deore one. Now, I wanted to use 116 link chains as these are easy to buy and not overly expensive. My calculation made me understand I needed a 42T chainring, so the derailleur would still work within its operational limit. Now, it has turned out buying a good 104 BCD, 4 hole, 42T chainring was almost impossible! Yes, no issue to buy a Garbaruk chainring, and Deckas chainrings could probably be bought (I have never tried a Deckas chainring before but I have a good experience with Garbaruk), To save me some money, I bought a French Stronglight chainring made of the 7075 superstrong aluminium alloy. Necessary to mention, the Stronglight has had a regular teeth pattern (and it was basically made for 2x drivetrains).
Note: The Praxis chainring showed the signs of being partly worn but it could probably be still used for the next several thousand of kilometres (a totally worn chainring has its teeth bent outside).
The Stronglight chainring installed on my Vado SL.
The little used 11-42T cassette reinstalled. I also used a brand new Shimano CN-HG95 chain (10-speed, 116L).
I paid a lot of attention to precisely adjust the derailleur/shifter and tested the setup on a 8 km ride. Then I set off for a 100 km gravel ride that involved a 9.2% grade climb and some descents.
The chain consistently dropping from the chainring in outer gears
While the drivetrain was working nicely in middle gears (2nd to 9th), the chain was consistently dropping from the chainring in these two exact situations:
A word on Garbaruk chainrings
Yes, I have no other choice (except perhaps a Deckas) to replace the chainring than using a Garbaruk one. I have used two different Garbaruk chainrings on my e-bikes but there is a heads-up: Garbaruk chainrings use extremely long chainring teeth to prevent the chain dropping. It indeed works but the ring emits a grating noise when you are in the lowest cassette sprockets. Nothing wrong with that because you probably use the lowest gears rarely but be warned anyway. (At least the chain does not drop from a Garbaruk chainring).
Repeating myself: The WAVE or Narrow Wide pattern of your chainring is not the reason for your chain dropping! Blame anything else but the advanced chainring! Note: A Narrow Wide 1x chainring would work very well too (tested on my Vado 6.0).
In the 1x drivetrain, especially with the growing number of gears and increasing cassette range (as huge as 10-52T cassettes), the chain line is very far from being straight. To prevent chain dropping incidents, the special pattern chainrings are used; additionally, premium derailleurs are equipped with a clutch that keeps the chain tensioned at all times.
Several Creo or Vado SL users have reported the chain dropping towards the e-bike frame, and attributed that to the Praxis WAVE tooth pattern of their chainring.
The background
I replaced the Shimano CS-HG500-10 cassette (10-speed, 11-42T) on my new Vado SL 4.0 in July 2021, after 1 month of riding the e-bike with the original drivetrain. My choice was the Deore XT CS-M771-10 cassette (10-speed, 11-36T) as it had it gears more evenly spaced. I have kept the original Praxis 44T chainring with chainguard. I was replacing chains as soon as each of them got stretched past the 0.5% mark. Doing so made the cassette still flawless after more than 10,000 km ridden!
Yes, I had a chain dropping towards the frame twice in quick succession. It turned out the derailleur/shifter indexing got misadjusted by one full position towards the largest sprocket, and the derailleur L limit screw was not set properly, either. After the necessary adjustment, my drivetrain has become perfect, silent, and totally reliable.
Moving away from the WAVE chainring
I have recently decided I needed a granny gear anyway (the Deore XT cassette has no granny gear!) so I reused the original 11-42T Deore one. Now, I wanted to use 116 link chains as these are easy to buy and not overly expensive. My calculation made me understand I needed a 42T chainring, so the derailleur would still work within its operational limit. Now, it has turned out buying a good 104 BCD, 4 hole, 42T chainring was almost impossible! Yes, no issue to buy a Garbaruk chainring, and Deckas chainrings could probably be bought (I have never tried a Deckas chainring before but I have a good experience with Garbaruk), To save me some money, I bought a French Stronglight chainring made of the 7075 superstrong aluminium alloy. Necessary to mention, the Stronglight has had a regular teeth pattern (and it was basically made for 2x drivetrains).
Note: The Praxis chainring showed the signs of being partly worn but it could probably be still used for the next several thousand of kilometres (a totally worn chainring has its teeth bent outside).
The Stronglight chainring installed on my Vado SL.
The little used 11-42T cassette reinstalled. I also used a brand new Shimano CN-HG95 chain (10-speed, 116L).
I paid a lot of attention to precisely adjust the derailleur/shifter and tested the setup on a 8 km ride. Then I set off for a 100 km gravel ride that involved a 9.2% grade climb and some descents.
The chain consistently dropping from the chainring in outer gears
While the drivetrain was working nicely in middle gears (2nd to 9th), the chain was consistently dropping from the chainring in these two exact situations:
- Towards the frame in the 1st gear
- Towards the crank in the top gear
A word on Garbaruk chainrings
Yes, I have no other choice (except perhaps a Deckas) to replace the chainring than using a Garbaruk one. I have used two different Garbaruk chainrings on my e-bikes but there is a heads-up: Garbaruk chainrings use extremely long chainring teeth to prevent the chain dropping. It indeed works but the ring emits a grating noise when you are in the lowest cassette sprockets. Nothing wrong with that because you probably use the lowest gears rarely but be warned anyway. (At least the chain does not drop from a Garbaruk chainring).
Repeating myself: The WAVE or Narrow Wide pattern of your chainring is not the reason for your chain dropping! Blame anything else but the advanced chainring! Note: A Narrow Wide 1x chainring would work very well too (tested on my Vado 6.0).
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