Swapping out a Shimano Nexus 3-Speed Hub for an 8-Speed Hub

[SwissJetPilot]

My FSM Saxonette eBike came with the Shimano Nexus 3-speed (SG-3C41) geared hub and I have really come to dislike the functionality and performance of this hub.

I find the shifting is imprecise and even when adjusted correctly (which is more difficult than it should be IMHO) the gear shifting still isn't that great and tends to miss a gear or fails to engage correctly. Given the few number of gears to start with, I find 2nd really doesn't seem to be of any real benefit and what I really need is a much lower gear for moderate inclines. Since this 3-speed hub is not free-wheeling it makes my rear V-brake redundant, not to mention it's a PITA when trying to set up the pedals after a stop since you can't spin the pedals backwards.

I was wondering if anyone has any experience with replacing this 3-speed hub with a Shimano 8-speed (SG-C6061-8V) hub. Or if anyone has experience with the 8-speed hub and would care to comment.

 

[rarobo]

My priority current has a 5 speed shimano and I seldom use first gear, maybe two or three times since I’ve had it ( July 21)

 

[SwissJetPilot]

@ rarobo - Do you find the 5-speed gives you enough gears for gradual hills and such? It might be an option too.

 

[rarobo]

Yes it does for me, I’ve had it in the mountains of North Carolina, usually stay in 3-4-5, the Current motor has good torque, might make a difference

 

[SwissJetPilot]

Great, thanks for your recommendation.

 

[rarobo]

Great, thanks for your recommendation.

I looked at your previous post, my bike would have a lot more torque than yours, don’t know if 1st gear ratio changes much between a 3-5-8 speed, I’m not a expert on this, maybe someone will comment on this, changing a IGH is a big deal

 

[SwissJetPilot]

Fair enough. My bike is far to the left on the power and torque scale. ;-)
Back in the day (okay, many many days back) I used to mountain bike the California Sierras with a 21-speed, fully suspended titanium bike with a granny gear for serious cranking on uphill climbs.
So fast forward 20-years to today, with a low-end eBike with a "kiddy" 3-speed is a bit of a eye opener. I guess it will just take some getting used to.

 

[indianajo]

The shimano 8 speed has a good reputation on mtbforum. More expensive rohloff leaks.
I

 

[BobR]

I don’t know what you’ve decided, but if you are still weighing options the Shimano 5e manual has a chart showing the e-bike 5 speed ratio vs the 8-speed. The 8-speed adds lower gears for hills, with it’s 1:1 ratio at 4th gear. The 5-speed IHG starts 1:1 in first gear and ends up with a 5th gear that is taller. Usually 3-speeds have 1:1 in second gear. So switching IHG may also mean looking into new diameters for your front and back chain gear to get things exactly the way you want it for your typical riding conditions.

By the way, I too have a Priority Current, and I really like the Shimano 5-speed e-bike version IHG it came with. Once I got the alignment mark set up it clicks up through the gears easily even when pedaling. I do have to pause when downshifting. It is supposed to take higher torque than the 8-speed.

 

[Kayakguy]

My Ariel Rider C class has the Shimano Nexus 7 speed. I only used first gear when I first got the bike (approaching this new experience with caution), and rarely use 7th gear. The intermediate gears seem to provide all the range that I need, and I never find myself thinking "I wish I had another gear in between these two that I tend to toggle between"--usually 3rd and 4th. Of course, I am old and weak and feel no need to go faster than 20 mph. I find that shifting is very quick and easy, and I love being able to shift at an intersection while at a standstill. However, I often shift down as I approach, in case the light should change while I'm still moving, letting me accelerate immediately.

This is my first bike with an IGH, and I would be reluctant to give it up to go back to a derailleur.

 

[SwissJetPilot]

Great information guys, thanks!

 

[Whyzee]

Know that if you choose the Shimano Nexus 5sp IGH designed for Ebikes, you can get three different cogs. 30T (as delivered), 27T and 24T.
My Townie Go (2022 model year) was equipped with the 30T which put me into the 4-5 gear mostly. I ordered a 27T (from Japan), easily installed/adjusted it myself, and now find 2-3-4-5 gears much more versatile. I have small inclines in my city riding and the Bosch active line plus pulls them easily. I suppose if you/I had steeper climbs, 1st would still provide a granny gear.
Enjoy the Ride!

 

[SwissJetPilot]

Thanks Whyzee! Good to know.

 

[PedalUma]

I have been using IGH's for years. I like my 3 speed Shimano and am building a second one today because I like it so much. Only shift when coasting or you will eat your IGH. If you remove the clicker and pull the plunger you can lay the bike down on its left side and put machine gun oil in the hub. They love that stuff. It could be that you have a kink or rough spot in your shift cable housing. Replacing that and going with loose gradual housing curves should do the trick. I have also owned and used 7 speeds and 8 speeds. If there is no photo then it didn't happen, so I will include some builds. Sturmey Archer has a heavy duty 5 speed with coaster brake. https://www.sturmey-archer.com/en/products/detail/rx-rc5. On my three speed Shimano I have dropped the cog to 16 teeth. In your case you might want to lower the gearing by using a larger cog on the hub. I have a CVT hub that I have yet to install. It is kind of heavy. It might land on a Giant Liv that I will give 90Nm on the torque sensing mid-drive.