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coln72
10 W
Looks like a Greenspeed chain ring. Have an 80 tooth version on my pedal battery charger 
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Takemehome
1 kW
I hope you don't have a lot of stop and go on your commute.nutsandvolts said:
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dogman dan
1 PW
Depends on the number of teeth on the back sprocket, the dummies. Dunno what speed you are looking at cruising at, but with my lame 36v setup, I ride about 25-27 mph, while the motor only is good for about 23-24 mph. So I'm pedaling in 58-14 gear 98% of the time. I do tend to downshift for an uphill start to 16 rear, or 18 rear sprocket, and then back up to the 14 cog once moving.
My controller is sensorless, but only needs a tiny push to roll forward. Half throttle keeps the motor stalling down starting up, and I start to pedal and push full throttle once going about 6 mph. I have the range, so I don't worry about blowing a few watts on starts. 72-14 might be a bit harder to get going . So you just motor till 15 mph, no big deal. It might tend to jump teeth on the rear 14 tooth though, mine does if I push too hard on a startup. It doesn't do this on the 16 tooth gear. It will be like a longer lever pulling on the chain. Fixie will help with that though, since you won't have slack in the chain, or just a stronger tensioner than a normal deriailur. I bet 72 front and about 20 to 24 rear will feel sweet. Aim for about 3 mph faster than the motors top cruising speed. It's just too hard to pedal a motor much more fast than it's top speed. Too much, and you'll leave the sweet spot and may as well just turn off the motor and pedal.
My controller is sensorless, but only needs a tiny push to roll forward. Half throttle keeps the motor stalling down starting up, and I start to pedal and push full throttle once going about 6 mph. I have the range, so I don't worry about blowing a few watts on starts. 72-14 might be a bit harder to get going . So you just motor till 15 mph, no big deal. It might tend to jump teeth on the rear 14 tooth though, mine does if I push too hard on a startup. It doesn't do this on the 16 tooth gear. It will be like a longer lever pulling on the chain. Fixie will help with that though, since you won't have slack in the chain, or just a stronger tensioner than a normal deriailur. I bet 72 front and about 20 to 24 rear will feel sweet. Aim for about 3 mph faster than the motors top cruising speed. It's just too hard to pedal a motor much more fast than it's top speed. Too much, and you'll leave the sweet spot and may as well just turn off the motor and pedal.
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It's not for a bike, but I just ran across this on an image search for something unrelated:
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Biggest Chainring
LOLZ
LOLZ
coln72
10 W
pfft - I'll grab a pic if my 80 tooth gear tomorrow
Random pic from the web...
HAL9000v2.0
10 kW
Schlumpf with 52 teeth is equal to 132 teeth sprocket...
... but it is 800€.
... but it is 800€.
Forgot I had this, but this is the biggest chainring I actually have here:
It's a 144 tooth ring off of an exercycle's pedals, for the smaller 3/8" chain, I think it is. Same chain the ScootnGo electric scooter used, but I think that was a 72-tooth on it's rear wheel.
The bottom pic also has the back of my St Bernard, Nana, who is herself almost big enough to ride.
It's a 144 tooth ring off of an exercycle's pedals, for the smaller 3/8" chain, I think it is. Same chain the ScootnGo electric scooter used, but I think that was a 72-tooth on it's rear wheel.
The bottom pic also has the back of my St Bernard, Nana, who is herself almost big enough to ride.
random pic from the web...
207-MPH, 334 k/h, Bruce Burford
By our very own Thud. An experiment with polycarbonate:
http://endless-sphere.com/forums/viewtopic.php?f=28&t=46704&start=30#p690885
http://endless-sphere.com/forums/viewtopic.php?f=28&t=46704&start=30#p690885
104T from Royce (http://www.royceuk.co.uk/Royce-Uk.html).
Pic taken from the 5:11 mark in the video. http://www.royceuk.co.uk/Royce-Uk.html
Pic taken from the 5:11 mark in the video. http://www.royceuk.co.uk/Royce-Uk.html
bobc
10 kW
Your local laser cutters are your friends.... from memory this beast was £20
From Jamil.Siddiqi, 100T
https://endless-sphere.com/forums/viewtopic.php?f=28&t=57720&start=5175#p1725834
https://endless-sphere.com/forums/viewtopic.php?f=28&t=57720&start=5175#p1725834
harrisonpatm
10 kW
- Joined
- Aug 8, 2022
- Messages
- 824
coln72 said:Looks like a Greenspeed chain ring. Have an 80 tooth version on my pedal battery charger
Can I see a pic of the charger as a whole? I love human powered generators
lnanek
1 kW
- Joined
- Sep 26, 2022
- Messages
- 450
I've been using this 75t and can still feel resistance pedaling at 25mph with a 11-34t freewheel:
https://www.amazon.com/dp/B07D6JHN5J
I admit to drooling over a 120t I see on AliExpress, though. Might let me assist my bike even when it is going 30mph.
https://www.amazon.com/dp/B07D6JHN5J
I admit to drooling over a 120t I see on AliExpress, though. Might let me assist my bike even when it is going 30mph.
Chalo
100 TW
Y'all need to keep in mind that above 30 mph, aero drag from pedaling begins to eat up more energy than most people make with the pedals. The faster you go above that speed, the more range and performance it costs when you pedal. So these giant chainrings are just so much stupid theater. If you want to pedal effectively, go at pedal bike speeds.
Note that the only two established applications for such huge chainrings are stationary cycling and motorpaced cycling, both of which skirt around the aero drag issue (but aren't relevant to what we do with our bikes).
Note that the only two established applications for such huge chainrings are stationary cycling and motorpaced cycling, both of which skirt around the aero drag issue (but aren't relevant to what we do with our bikes).
