front chainrings

[jomo11]

The Aventon Level ebike comes with a 46 tooth front chainring. Would it be possible to change this to a 42 tooth chainring to make this ebike a better bike for climbing hills.

 

[theemartymac]

Yes (and no).

You can certainly change the front ring and make it easier for you to pedal up hills, BUT, the change can also cause you to "run out of gears" at higher speeds (i.e. ghost-pedaling) before the bike hits top speed. In that case, it becomes a throttle-only bicycle if you want to use that 28mph top speed. Also, a rear hub needs to turn at a minimum speed to produce reasonable power, and when it's speed drops too low the power delivery declines rapidly, and heat generation is increased. If you are crawling up hills at 5mph in low gear, you won't be getting as much assist from the rear hub as you might if you maintain say 8-10mph. Crawl around on hills at very low speed and high assist and you could shorten the life of the hub significantly.

Not trying to discourage you from the swap, as off-roaders often go down in tooth count to get better hill climbing ability, but just beware there are costs to every modification.

 

[theemartymac]

To determine a compatible chainring, measure the distance between each bolt holding the ring on the spider, and then refer to a chart like this one below to determine the Bolt Circle Diameter (BCD). Also, check for any offset (is it a flat chainring, or dished to one side like a dinner plate?) If it's offset, you need to match that as well when ordering one. And finally, make sure the chainring tooth width matches the chain you are using. If you are going to down in size, you might need to remove a link or two from the chain to maintain a minimum derailleur tension and geometry.

Wolf Tooth - How to measure Bolt Circle Diameter (BCD)

Bolt Circle Diameter (BCD) is the diameter of the circle that goes through the center of all of the bolts on your chainring. On bicycle chainrings this dimension is usually measured in millimeters. It is critical to know the BCD of your crankset when you are selecting a new chainring for your bike.

www.wolftoothcomponents.com

 

[jomo11]

Thanks for the replys. The BCD on my Level is 104mm with 4 hole pattern. I found several chainrings on the market that I am sure will work. Maybe a 44 tooth chainring might be better as it may not affect the top speed as much.

 

[theemartymac]

You'll barely even notice the difference with just 2 teeth, probably not quite a full gear shift. I went up from a 44 to a 49 on mine for better high speed performance, and that was a shift of maybe 1.5 gears. You might also be able to find a wide-range cassette for the back that has a larger low gear cog and/or smaller high gear, but you have to make sure your derailleur will work for that range.

 

[LimboJim]

ok so the stock one comes with 8 speed, 12T-32T cassette.

Here's an alternative:

8 speed, 11T-46T

13.65US $ 31% OFF|Sunshine Mtb Cassette 8/9/10/11/12 Speed 32/36/40/42/46/50/52t Mountain Bicycle Freewheel Bicycle Sprocket For Shimano/sram - Bicycle Freewheel - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

I believe that the Acera rear derailleur stocked on that bike has a low-sprocket range of 32-36T, at least according to the Shimano website:

SHIMANO ACERA Rear Derailleur 9-speed | SHIMANO BIKE-US

The SHIMANO ACERA M3000 rear derailleur lets you ride aggressively with fewer interruptions thanks to its SHIMANO SHADOW design.

bike.shimano.com

So if you go with a 46T-max 8-speed cassette, you'll also need a new long-cage derailleur, otherwise max the new cassette at 36T.

 

[LimboJim]

I believe that the Acera rear derailleur stocked on that bike has a low-sprocket range of 32-36T, at least according to the Shimano website:

SHIMANO ACERA Rear Derailleur 9-speed | SHIMANO BIKE-US

The SHIMANO ACERA M3000 rear derailleur lets you ride aggressively with fewer interruptions thanks to its SHIMANO SHADOW design.

bike.shimano.com

So if you go with a 46T-max 8-speed cassette, you'll also need a new long-cage derailleur, otherwise max the new cassette at 36T.

Unless it's the trekking version of the Acera derailleur, which seems more likely given the style of bike. That has a limit of 34T:

SHIMANO ACERA Rear Derailleur 9-speed for Trekking | SHIMANO BIKE-US

Designed for 9-speed trekking drivetrains, the SHIMANO ACERA T3000 derailleur shifts with accurate, dependable performance.

bike.shimano.com

 

[LimboJim]

That's why it comes with derailleur hanger extension.

Ha, learn something new. I've never bought a cassette that came with a hanger extension!