Larger sprocket (27t) for Nexus hub

[ElCani]

This post is mainly for information, no nobody makes the same mistake I did.

In my internet search for the largest possible sprocket for a Shimano Nexus 7sp IGH, I came across more than one forum post suggesting purchasing the C7000 27t (link below) and then grinding off three of the six mounting tabs. But nobody seemed to have actually done it. I did, and… the diameter of the mounting hole is much larger and it very much doesn’t work! Presumably the 5 speed E-bike hubs these are meant for have a larger mount than other Nexus IGHs.

https://hollandbikeshop.com/en-gb/bicyc ... ck-619648/

Cheers.

[mumbojumbo]

Careful if grinding.

[Mick F]

I'm fairly sure Sturmey Archer use the same system as Nexus.
Can you buy a SA sprocket in 27t?

[ElCani]

I'm fairly sure Sturmey Archer use the same system as Nexus.
Can you buy a SA sprocket in 27t?

I think that only fits on their 8 speed hub.

But I did just find this, which looks good.

https://hollandbikeshop.com/en-gb/bicyc ... ck-811699/

Edit: those actually go up to 30t!

[ikenbikeit]

I think the 26 tooth sprocket is for a sturmey 8 speed. It has 6 notched and nexus has 3. I don't think it will fit.

[Mick F]

Nexus indeed has three teeth like SA3sp do.
As for 7sp vs 8sp Nexus differences, I can't comment. All I know about is 8sp, so I expected they would be the same.

[ElCani]

Actually I think it’s for the Nexus e-bike 5sp hub. So the same as the sprocket in my OP, meaning I’m an idiot and didn’t notice that my solution to the problem was in fact just repeating my original mistake. Duh.

[Tigerbiten]

This page -> https://www.sjscycles.co.uk/hub-gear-sprockets-guide/ may help.

According to SJS, the C7000 has an internal diameter of 35mm, see -> https://www.sjscycles.co.uk/sprockets/s ... ocket-30t/
So it should fit with the extra tabs ground off.
I'd double check the internal diameter of the one you've got and does the Shimano part number of the one you've got/looking at match the ones on SJS.

Luck ...........

[crg]

This page -> https://www.sjscycles.co.uk/hub-gear-sprockets-guide/ may help.

According to SJS, the C7000 has an internal diameter of 35mm, see -> https://www.sjscycles.co.uk/sprockets/s ... ocket-30t/
So it should fit with the extra tabs ground off.
I'd double check the internal diameter of the one you've got and does the Shimano part number of the one you've got/looking at match the ones on SJS.

Luck ...........

Just checked with SJS. Apparently the spacing of the tabs is different and grinding excess tabs will not help.

[ElCani]

This page -> https://www.sjscycles.co.uk/hub-gear-sprockets-guide/ may help.

According to SJS, the C7000 has an internal diameter of 35mm, see -> https://www.sjscycles.co.uk/sprockets/s ... ocket-30t/
So it should fit with the extra tabs ground off.
I'd double check the internal diameter of the one you've got and does the Shimano part number of the one you've got/looking at match the ones on SJS.

Luck ...........

Just checked with SJS. Apparently the spacing of the tabs is different and grinding dxtrsvtabs will not help.

Yes. This fact is the point of my OP.

[crg]

This page -> https://www.sjscycles.co.uk/hub-gear-sprockets-guide/ may help.

According to SJS, the C7000 has an internal diameter of 35mm, see -> https://www.sjscycles.co.uk/sprockets/s ... ocket-30t/
So it should fit with the extra tabs ground off.
I'd double check the internal diameter of the one you've got and does the Shimano part number of the one you've got/looking at match the ones on SJS.

Luck ...........

Just checked with SJS. Apparently the spacing of the tabs is different and grinding dxtrsvtabs will not help.

Yes. This fact is the point of my OP.

Perhaps it is less expensive but more grinding to buy a cassette with required cogs and modify the cogs. 27t is part of expensive road cassettes. Have seen 24, 26, 28, 30 cogs in inexpensive cassettes.

[asinus]

The other thing to remember is that hub gears usually have a minimum ratio of chainwheel teeth to sprocket teeth, to reduce the risk of excess force stripping the teeth on the sun pinion, and my recollection is that for most Alfine hubs it's in excess of 2.0, and Nexus might well be the same - best check before you fit an oversize sprocket.