Help, availability and advice on 40 tooth chainring

[Xman]

Hi guys
Need some help on chainring availability.
My bike and proposed setup
Cube khatmandu with bosch gen 4 cx motor fitted with a 104 bcd spider.
The bike will fitted with the new shimano cues 11 speed gear set.
Currently finding it very difficult to get a 40 tooth chainring.
Any help or advice would be much appreciated
Thx Geoff

 

[Xman]

Sorry, I should add the chainring needs to be the narrow/wide design

 

[Jackware]

If you're not too concerned about the brand there's various 40T chainrings on Amazon and eBay.

 

[Plummet]

Why 40t? That's big. I'm running a 34 and easily hit motor cut out before spinning out the 34t. Practically you can't go much faster than motor cut on an ebike unless you have gravity on your side. Then you can easily hit 50 to 60kph, so why bother with a 40t?

 

[steve_sordy]

Have you checked that the 40t will not chew into your chain stay?

 

[Xman]

Hi
And thx for your replies, all very valid points which I will respond too.
The bike as new comes with a 40 toothed ring but it's not the N/W type, the best my supplier could do is 38 t on a 104 bcd. The bike runs ok with this but I find myself constantly in the top 4 gears and not making much use of the remaining 6 unless tackling a difficult hill.
I am currently trialing one steel ring from ebay but find the chain can come off sometimes when engaging the lowest gear. It's clearly an alignment issue. Now trialing one from amazon which is al aloy, its seems to work better in so much the chain does not come off but I'm not convinced about durability.
Hence would prefer one from a known brand.
40 t ring does not interfere with the chain guard as this is what the bike is designed for.
When I move to the 11 speed gear set there is a rational to try a 42 t ring, what this does in combo with the 11 speed gear set is give me a bit more at the top and bottom of the range compared to the current 38 t 10 speed combo, if you get my drift.

 

[Xman]

Another benefit of the 42 t 11 speed combo is it pushes my general riding further up the gear range giving even better durability because I'm using the top 4 gears less, if you get my drift

 

[mustclime]

Seem to be a bunch of 40t 104bcd narrow wide rings on Amazon…..your bike is a hybrid, I hope you are not riding it on “ real” Mtb trails.

 

[Xman]

Hi
Thx for your reply. Road and gravel paths for me. As I said in a previous reply I'm currently trialing an amazon offering but would prefer one from a known brand

 

[irie]

Hi
Thx for your reply. Road and gravel paths for me. As I said in a previous reply I'm currently trialing an amazon offering but would prefer one from a known brand

How is/will the Cube khatmandu be de-restricted so as to be able to benefit from a 40t chain ring?

 

[Xman]

It won't be de-ristricted as its never been tampered with, it will be put back to it original spec, as supplied with a 40 t ring but this time of the N/W tooth design, that's all I'm after. And it will make the bike perform as originally intended

 

[stratosa]

Hi guys
Need some help on chainring availability.
My bike and proposed setup
Cube khatmandu with bosch gen 4 cx motor fitted with a 104 bcd spider.
The bike will fitted with the new shimano cues 11 speed gear set.
Currently finding it very difficult to get a 40 tooth chainring.
Any help or advice would be much appreciated
Thx Geoff

I use 44t DECKAS chainring on my emtb for the same reasons you describe plus that i run de-restricted. Chainring is narrow/wide and i use it without any chainguard without any problem. Change every 5000 Km.

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[franciscoasismm]

For my ebike 38T it's enough,
40T these are steel and work quite well
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