9-Speed Freewheel

[Deleted member 4366]

I ordered one just to see what they're like. The stack height is 41mm compared with 38mm for a DNP 8 speed and 37mm for a 7 speed. That'll be too wide for most ebike applications.

595g too compared to 490g for the 7 speed, which is already pretty heavy.

https://www.aliexpress.com/item/6-7-8-9-10-11-Speed-Gear-Freewheel-Flywheel-Sproket-And-Cassette-18-21-24/32840759206.html?spm=a2g0s.9042311.0.0.1a894c4duNluy9

 

[Planemo]

I'm a bit grey over the whole freewheel vs cassette thing, having only had experience with cassettes when it comes to anything over 5 or 6 speed (as found on bargain basement mtbs for example). Can you explain why someone would buy a 9sp freewheel over a 9sp cassette? There must be a reason for it, but I cant work it out. Are some motor hubs only suitable for freewheels? I assumed it was just old tech (quill stems vs aheadsets for example) but if they have just released a 9sp freewheel then it must be a current requirement? Cheers

 

[anotherkiwi]

The tiny Xiongda rear hub motor for example is freewheel only.

 

[anotherkiwi]

I ordered one just to see what they're like. The stack height is 41mm compared with 38mm for a DNP 8 speed and 37mm for a 7 speed. That'll be too wide for most ebike applications.

595g too compared to 490g for the 7 speed, which is already pretty heavy.

https://www.aliexpress.com/item/6-7-8-9-10-11-Speed-Gear-Freewheel-Flywheel-Sproket-And-Cassette-18-21-24/32840759206.html?spm=a2g0s.9042311.0.0.1a894c4duNluy9

My idea is to disassemble a 7 speed and mount 8 speed cogs on the 7 speed body to have a wider range (up to 34 tooth granny). There is the Aussie guy on ES who has cut a 7 speed down to make a 5 speed which is also an interesting read.

 

[Deleted member 4366]

I'm a bit grey over the whole freewheel vs cassette thing, having only had experience with cassettes when it comes to anything over 5 or 6 speed (as found on bargain basement mtbs for example). Can you explain why someone would buy a 9sp freewheel over a 9sp cassette? There must be a reason for it, but I cant work it out. Are some motor hubs only suitable for freewheels? I assumed it was just old tech (quill stems vs aheadsets for example) but if they have just released a 9sp freewheel then it must be a current requirement? Cheers

Some rear motors (most of them in fact) have the freewheel thread rather than the cassette spline.

 

[Woosh]

for 9-speed cassette compatibility, go for a Sunrace 9--speed freewheel

http://www.sunrace.com/en/products/detail/mfez1

 

[Planemo]

Thanks I didnt know that most motor hubs were threaded! I havent seen the thread of a rear hub since my BMX days over 30 years ago. I assumed that everything other than single speed would be splined nowadays.

 

[Planemo]

Ps thats a 10sp Whoosh!

 

[Woosh]

thanks Planemo. I wasn't fully awake when I posted the picture!
From the customer support's point of view, replacing a cassette mount on the motor is a messy business, I would have to retrieve the motor wheel, whereas replacing an 8/9/10-speed freewheel is quick, cheap and much less stressful.

 

[Deleted member 4366]

for 9-speed cassette compatibility, go for a Sunrace 9--speed freewheel

http://www.sunrace.com/en/products/detail/mfez1

That Sunrace one is exactly the same weight as the one I have, which is probably a clone. The most important characteristic, as far as ebikes are concerned, is the stack-height. Can you confirm whether it's the same as mine at 41mm?

 

[Woosh]

I fitted the one I had some weeks back, only keep 8-speed DNP as stock item. The DNP has the same stack height as a Shimano cassette so no problem there.
I try to check the stack height next time when I get one 9-speed freewheel.

 

[anotherkiwi]

Unfortunately Sunrace don't publish stack heights. They also don't reply to end user e-mail... They are much more OEM orientated than DNP who are lovely people.

 

[anotherkiwi]

Here is a couple of the DNP 9 speeds:


Stack height = 40.5mm

This would make a perfect 8 speed 13-34 just by removing the 14 tooth and a spacer and diminishing the height of the freewheel body to about 37mm. Of course you would use a 9 speed shifter and limit shifting to 8 gears on the derailleur.

Imagine that on a 201 rpm Q128H 36v overvolted and oil cooled <diabolical cackle> with a Patterson Metropolis 36-57 up front giving a spin-out speed of around 65 km/h...